File

Since Camel 1.0

Both producer and consumer are supported

The File component provides access to file systems, allowing files to be processed by any other Camel Components or messages from other components to be saved to disk.

URI format

file:directoryName[?options]

Where directoryName represents the underlying file directory.

Only directories

Camel supports only endpoints configured with a starting directory. So the directoryName must be a directory. If you want to consume a single file only, you can use the fileName option, e.g., by setting fileName=thefilename. Also, the starting directory must not contain dynamic expressions with ${ } placeholders. Again use the fileName option to specify the dynamic part of the filename.

Avoid reading files currently being written by another application

Beware the JDK File IO API is a bit limited in detecting whether another application is currently writing/copying a file. And the implementation can be different depending on the OS platform as well. This could lead to that Camel thinks the file is not locked by another process and start consuming it. Therefore, you have to do your own investigation what suites your environment. To help with this Camel provides different readLock options and doneFileName option that you can use. See also Consuming files from folders where others drop files directly.

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

At the component level, you set general and shared configurations that are, then, inherited by the endpoints. It is the highest configuration level.

For example, a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre-configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

You can configure components using:

  • the Component DSL.

  • in a configuration file (application.properties, *.yaml files, etc).

  • directly in the Java code.

Configuring Endpoint Options

You usually spend more time setting up endpoints because they have many options. These options help you customize what you want the endpoint to do. The options are also categorized into whether the endpoint is used as a consumer (from), as a producer (to), or both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL and DataFormat DSL as a type safe way of configuring endpoints and data formats in Java.

A good practice when configuring options is to use Property Placeholders.

Property placeholders provide a few benefits:

  • They help prevent using hardcoded urls, port numbers, sensitive information, and other settings.

  • They allow externalizing the configuration from the code.

  • They help the code to become more flexible and reusable.

The following two sections list all the options, firstly for the component followed by the endpoint.

Component Options

The File component supports 5 options, which are listed below.

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

boolean

healthCheckConsumerEnabled (health)

Used for enabling or disabling all consumer based health checks from this component.

true

boolean

healthCheckProducerEnabled (health)

Used for enabling or disabling all producer based health checks from this component. Notice: Camel has by default disabled all producer based health-checks. You can turn on producer checks globally by setting camel.health.producersEnabled=true.

true

boolean

Endpoint Options

The File endpoint is configured using URI syntax:

file:directoryName

With the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

directoryName (common)

Required The starting directory.

File

Query Parameters (96 parameters)

Name Description Default Type

charset (common)

This option is used to specify the encoding of the file. You can use this on the consumer, to specify the encodings of the files, which allow Camel to know the charset it should load the file content in case the file content is being accessed. Likewise when writing a file, you can use this option to specify which charset to write the file as well. Do mind that when writing the file Camel may have to read the message content into memory to be able to convert the data into the configured charset, so do not use this if you have big messages.

String

doneFileName (common)

Producer: If provided, then Camel will write a 2nd done file when the original file has been written. The done file will be empty. This option configures what file name to use. Either you can specify a fixed name. Or you can use dynamic placeholders. The done file will always be written in the same folder as the original file. Consumer: If provided, Camel will only consume files if a done file exists. This option configures what file name to use. Either you can specify a fixed name. Or you can use dynamic placeholders.The done file is always expected in the same folder as the original file. Only $\{file.name} and $\{file.name.next} is supported as dynamic placeholders.

String

fileName (common)

Use Expression such as File Language to dynamically set the filename. For consumers, it’s used as a filename filter. For producers, it’s used to evaluate the filename to write. If an expression is set, it take precedence over the CamelFileName header. (Note: The header itself can also be an Expression). The expression options support both String and Expression types. If the expression is a String type, it is always evaluated using the File Language. If the expression is an Expression type, the specified Expression type is used - this allows you, for instance, to use OGNL expressions. For the consumer, you can use it to filter filenames, so you can for instance consume today’s file using the File Language syntax: mydata-$\{date:now:yyyyMMdd}.txt. The producers support the CamelOverruleFileName header which takes precedence over any existing CamelFileName header; the CamelOverruleFileName is a header that is used only once, and makes it easier as this avoids to temporary store CamelFileName and have to restore it afterwards.

String

delete (consumer)

If true, the file will be deleted after it is processed successfully.

false

boolean

moveFailed (consumer)

Sets the move failure expression based on Simple language. For example, to move files into a .error subdirectory use: .error. Note: When moving the files to the fail location Camel will handle the error and will not pick up the file again.

String

noop (consumer)

If true, the file is not moved or deleted in any way. This option is good for readonly data, or for ETL type requirements. If noop=true, Camel will set idempotent=true as well, to avoid consuming the same files over and over again.

false

boolean

preMove (consumer)

Expression (such as File Language) used to dynamically set the filename when moving it before processing. For example to move in-progress files into the order directory set this value to order.

String

preSort (consumer)

When pre-sort is enabled then the consumer will sort the file and directory names during polling, that was retrieved from the file system. You may want to do this in case you need to operate on the files in a sorted order. The pre-sort is executed before the consumer starts to filter, and accept files to process by Camel. This option is default=false meaning disabled.

false

boolean

recursive (consumer)

If a directory, will look for files in all the sub-directories as well.

false

boolean

sendEmptyMessageWhenIdle (consumer)

If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.

false

boolean

bridgeErrorHandler (consumer (advanced))

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

directoryMustExist (consumer (advanced))

Similar to the startingDirectoryMustExist option but this applies during polling (after starting the consumer).

false

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

ExchangePattern

extendedAttributes (consumer (advanced))

To define which file attributes of interest. Like posix:permissions,posix:owner,basic:lastAccessTime, it supports basic wildcard like posix:, basic:lastAccessTime.

String

includeHiddenDirs (consumer (advanced))

Whether to accept hidden directories. Directories which names starts with dot is regarded as a hidden directory, and by default not included. Set this option to true to include hidden directories in the file consumer.

false

boolean

includeHiddenFiles (consumer (advanced))

Whether to accept hidden files. Files which names starts with dot is regarded as a hidden file, and by default not included. Set this option to true to include hidden files in the file consumer.

false

boolean

inProgressRepository (consumer (advanced))

A pluggable in-progress repository org.apache.camel.spi.IdempotentRepository. The in-progress repository is used to account the current in progress files being consumed. By default a memory based repository is used.

IdempotentRepository

localWorkDirectory (consumer (advanced))

When consuming, a local work directory can be used to store the remote file content directly in local files, to avoid loading the content into memory. This is beneficial, if you consume a very big remote file and thus can conserve memory.

String

onCompletionExceptionHandler (consumer (advanced))

To use a custom org.apache.camel.spi.ExceptionHandler to handle any thrown exceptions that happens during the file on completion process where the consumer does either a commit or rollback. The default implementation will log any exception at WARN level and ignore.

ExceptionHandler

pollStrategy (consumer (advanced))

A pluggable org.apache.camel.PollingConsumerPollingStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel.

PollingConsumerPollStrategy

probeContentType (consumer (advanced))

Whether to enable probing of the content type. If enable then the consumer uses Files#probeContentType(java.nio.file.Path) to determine the content-type of the file, and store that as a header with key Exchange#FILE_CONTENT_TYPE on the Message.

false

boolean

processStrategy (consumer (advanced))

A pluggable org.apache.camel.component.file.GenericFileProcessStrategy allowing you to implement your own readLock option or similar. Can also be used when special conditions must be met before a file can be consumed, such as a special ready file exists. If this option is set then the readLock option does not apply.

GenericFileProcessStrategy

startingDirectoryMustExist (consumer (advanced))

Whether the starting directory must exist. Mind that the autoCreate option is default enabled, which means the starting directory is normally auto created if it doesn’t exist. You can disable autoCreate and enable this to ensure the starting directory must exist. Will throw an exception if the directory doesn’t exist.

false

boolean

startingDirectoryMustHaveAccess (consumer (advanced))

Whether the starting directory has access permissions. Mind that the startingDirectoryMustExist parameter must be set to true in order to verify that the directory exists. Will thrown an exception if the directory doesn’t have read and write permissions.

false

boolean

appendChars (producer)

Used to append characters (text) after writing files. This can for example be used to add new lines or other separators when writing and appending new files or existing files. To specify new-line (slash-n or slash-r) or tab (slash-t) characters then escape with an extra slash, eg slash-slash-n.

String

checksumFileAlgorithm (producer)

If provided, then Camel will write a checksum file when the original file has been written. The checksum file will contain the checksum created with the provided algorithm for the original file. The checksum file will always be written in the same folder as the original file.

Enum values:

  • MD2

  • MD5

  • SHA_1

  • SHA_224

  • SHA_256

  • SHA_384

  • SHA_512

  • SHA_512_224

  • SHA_512_256

  • SHA3_224

  • SHA3_256

  • SHA3_384

  • SHA3_512

String

fileExist (producer)

What to do if a file already exists with the same name. Override, which is the default, replaces the existing file. - Append - adds content to the existing file. - Fail - throws a GenericFileOperationException, indicating that there is already an existing file. - Ignore - silently ignores the problem and does not override the existing file, but assumes everything is okay. - Move - option requires to use the moveExisting option to be configured as well. The option eagerDeleteTargetFile can be used to control what to do if an moving the file, and there exists already an existing file, otherwise causing the move operation to fail. The Move option will move any existing files, before writing the target file. - TryRename is only applicable if tempFileName option is in use. This allows to try renaming the file from the temporary name to the actual name, without doing any exists check. This check may be faster on some file systems and especially FTP servers.

Enum values:

  • Override

  • Append

  • Fail

  • Ignore

  • Move

  • TryRename

Override

GenericFileExist

flatten (producer)

Flatten is used to flatten the file name path to strip any leading paths, so it’s just the file name. This allows you to consume recursively into sub-directories, but when you eg write the files to another directory they will be written in a single directory. Setting this to true on the producer enforces that any file name in CamelFileName header will be stripped for any leading paths.

false

boolean

jailStartingDirectory (producer)

Used for jailing (restricting) writing files to the starting directory (and sub) only. This is enabled by default to not allow Camel to write files to outside directories (to be more secured out of the box). You can turn this off to allow writing files to directories outside the starting directory, such as parent or root folders.

true

boolean

moveExisting (producer)

Expression (such as File Language) used to compute file name to use when fileExist=Move is configured. To move files into a backup subdirectory just enter backup. This option only supports the following File Language tokens: file:name, file:name.ext, file:name.noext, file:onlyname, file:onlyname.noext, file:ext, and file:parent. Notice the file:parent is not supported by the FTP component, as the FTP component can only move any existing files to a relative directory based on current dir as base.

String

tempFileName (producer)

The same as tempPrefix option but offering a more fine grained control on the naming of the temporary filename as it uses the File Language. The location for tempFilename is relative to the final file location in the option 'fileName', not the target directory in the base uri. For example if option fileName includes a directory prefix: dir/finalFilename then tempFileName is relative to that subdirectory dir.

String

tempPrefix (producer)

This option is used to write the file using a temporary name and then, after the write is complete, rename it to the real name. Can be used to identify files being written and also avoid consumers (not using exclusive read locks) reading in progress files. Is often used by FTP when uploading big files.

String

allowNullBody (producer (advanced))

Used to specify if a null body is allowed during file writing. If set to true then an empty file will be created, when set to false, and attempting to send a null body to the file component, a GenericFileWriteException of 'Cannot write null body to file.' will be thrown. If the fileExist option is set to 'Override', then the file will be truncated, and if set to append the file will remain unchanged.

false

boolean

chmod (producer (advanced))

Specify the file permissions which is sent by the producer, the chmod value must be between 000 and 777; If there is a leading digit like in 0755 we will ignore it.

String

chmodDirectory (producer (advanced))

Specify the directory permissions used when the producer creates missing directories, the chmod value must be between 000 and 777; If there is a leading digit like in 0755 we will ignore it.

String

eagerDeleteTargetFile (producer (advanced))

Whether or not to eagerly delete any existing target file. This option only applies when you use fileExists=Override and the tempFileName option as well. You can use this to disable (set it to false) deleting the target file before the temp file is written. For example you may write big files and want the target file to exists during the temp file is being written. This ensure the target file is only deleted until the very last moment, just before the temp file is being renamed to the target filename. This option is also used to control whether to delete any existing files when fileExist=Move is enabled, and an existing file exists. If this option copyAndDeleteOnRenameFails false, then an exception will be thrown if an existing file existed, if its true, then the existing file is deleted before the move operation.

true

boolean

forceWrites (producer (advanced))

Whether to force syncing writes to the file system. You can turn this off if you do not want this level of guarantee, for example if writing to logs / audit logs etc; this would yield better performance.

true

boolean

keepLastModified (producer (advanced))

Will keep the last modified timestamp from the source file (if any). Will use the FileConstants.FILE_LAST_MODIFIED header to located the timestamp. This header can contain either a java.util.Date or long with the timestamp. If the timestamp exists and the option is enabled it will set this timestamp on the written file. Note: This option only applies to the file producer. You cannot use this option with any of the ftp producers.

false

boolean

lazyStartProducer (producer (advanced))

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

moveExistingFileStrategy (producer (advanced))

Strategy (Custom Strategy) used to move file with special naming token to use when fileExist=Move is configured. By default, there is an implementation used if no custom strategy is provided.

FileMoveExistingStrategy

autoCreate (advanced)

Automatically create missing directories in the file’s pathname. For the file consumer, that means creating the starting directory. For the file producer, it means the directory the files should be written to.

true

boolean

bufferSize (advanced)

Buffer size in bytes used for writing files (or in case of FTP for downloading and uploading files).

131072

int

copyAndDeleteOnRenameFail (advanced)

Whether to fallback and do a copy and delete file, in case the file could not be renamed directly. This option is not available for the FTP component.

true

boolean

renameUsingCopy (advanced)

Perform rename operations using a copy and delete strategy. This is primarily used in environments where the regular rename operation is unreliable (e.g. across different file systems or networks). This option takes precedence over the copyAndDeleteOnRenameFail parameter that will automatically fall back to the copy and delete strategy, but only after additional delays.

false

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used.

false

boolean

antExclude (filter)

Ant style filter exclusion. If both antInclude and antExclude are used, antExclude takes precedence over antInclude. Multiple exclusions may be specified in comma-delimited format.

String

antFilterCaseSensitive (filter)

Sets case sensitive flag on ant filter.

true

boolean

antInclude (filter)

Ant style filter inclusion. Multiple inclusions may be specified in comma-delimited format.

String

eagerMaxMessagesPerPoll (filter)

Allows for controlling whether the limit from maxMessagesPerPoll is eager or not. If eager then the limit is during the scanning of files. Where as false would scan all files, and then perform sorting. Setting this option to false allows for sorting all files first, and then limit the poll. Mind that this requires a higher memory usage as all file details are in memory to perform the sorting.

true

boolean

exclude (filter)

Is used to exclude files, if filename matches the regex pattern (matching is case in-sensitive). Notice if you use symbols such as plus sign and others you would need to configure this using the RAW() syntax if configuring this as an endpoint uri. See more details at configuring endpoint uris.

String

excludeExt (filter)

Is used to exclude files matching file extension name (case insensitive). For example to exclude bak files, then use excludeExt=bak. Multiple extensions can be separated by comma, for example to exclude bak and dat files, use excludeExt=bak,dat. Note that the file extension includes all parts, for example having a file named mydata.tar.gz will have extension as tar.gz. For more flexibility then use the include/exclude options.

String

filter (filter)

Pluggable filter as a org.apache.camel.component.file.GenericFileFilter class. Will skip files if filter returns false in its accept() method.

GenericFileFilter

filterDirectory (filter)

Filters the directory based on Simple language. For example to filter on current date, you can use a simple date pattern such as $\{date:now:yyyMMdd}.

String

filterFile (filter)

Filters the file based on Simple language. For example to filter on file size, you can use $\{file:size} 5000.

String

idempotent (filter)

Option to use the Idempotent Consumer EIP pattern to let Camel skip already processed files. Will by default use a memory based LRUCache that holds 1000 entries. If noop=true then idempotent will be enabled as well to avoid consuming the same files over and over again.

false

Boolean

idempotentKey (filter)

To use a custom idempotent key. By default the absolute path of the file is used. You can use the File Language, for example to use the file name and file size, you can do: idempotentKey=$\{file:name}-$\{file:size}.

String

idempotentRepository (filter)

A pluggable repository org.apache.camel.spi.IdempotentRepository which by default use MemoryIdempotentRepository if none is specified and idempotent is true.

IdempotentRepository

include (filter)

Is used to include files, if filename matches the regex pattern (matching is case in-sensitive). Notice if you use symbols such as plus sign and others you would need to configure this using the RAW() syntax if configuring this as an endpoint uri. See more details at configuring endpoint uris.

String

includeExt (filter)

Is used to include files matching file extension name (case insensitive). For example to include txt files, then use includeExt=txt. Multiple extensions can be separated by comma, for example to include txt and xml files, use includeExt=txt,xml. Note that the file extension includes all parts, for example having a file named mydata.tar.gz will have extension as tar.gz. For more flexibility then use the include/exclude options.

String

maxDepth (filter)

The maximum depth to traverse when recursively processing a directory.

2147483647

int

maxMessagesPerPoll (filter)

To define a maximum messages to gather per poll. By default no maximum is set. Can be used to set a limit of e.g. 1000 to avoid when starting up the server that there are thousands of files. Set a value of 0 or negative to disabled it. Notice: If this option is in use then the File and FTP components will limit before any sorting. For example if you have 100000 files and use maxMessagesPerPoll=500, then only the first 500 files will be picked up, and then sorted. You can use the eagerMaxMessagesPerPoll option and set this to false to allow to scan all files first and then sort afterwards.

int

minDepth (filter)

The minimum depth to start processing when recursively processing a directory. Using minDepth=1 means the base directory. Using minDepth=2 means the first sub directory.

int

move (filter)

Expression (such as Simple Language) used to dynamically set the filename when moving it after processing. To move files into a .done subdirectory just enter .done.

String

exclusiveReadLockStrategy (lock)

Pluggable read-lock as a org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy implementation.

GenericFileExclusiveReadLockStrategy

readLock (lock)

Used by consumer, to only poll the files if it has exclusive read-lock on the file (i.e. the file is not in-progress or being written). Camel will wait until the file lock is granted. This option provides the build in strategies: - none - No read lock is in use - markerFile - Camel creates a marker file (fileName.camelLock) and then holds a lock on it. This option is not available for the FTP component - changed - Changed is using file length/modification timestamp to detect whether the file is currently being copied or not. Will at least use 1 sec to determine this, so this option cannot consume files as fast as the others, but can be more reliable as the JDK IO API cannot always determine whether a file is currently being used by another process. The option readLockCheckInterval can be used to set the check frequency. - fileLock - is for using java.nio.channels.FileLock. This option is not avail for Windows OS and the FTP component. This approach should be avoided when accessing a remote file system via a mount/share unless that file system supports distributed file locks. - rename - rename is for using a try to rename the file as a test if we can get exclusive read-lock. - idempotent - (only for file component) idempotent is for using a idempotentRepository as the read-lock. This allows to use read locks that supports clustering if the idempotent repository implementation supports that. - idempotent-changed - (only for file component) idempotent-changed is for using a idempotentRepository and changed as the combined read-lock. This allows to use read locks that supports clustering if the idempotent repository implementation supports that. - idempotent-rename - (only for file component) idempotent-rename is for using a idempotentRepository and rename as the combined read-lock. This allows to use read locks that supports clustering if the idempotent repository implementation supports that.Notice: The various read locks is not all suited to work in clustered mode, where concurrent consumers on different nodes is competing for the same files on a shared file system. The markerFile using a close to atomic operation to create the empty marker file, but its not guaranteed to work in a cluster. The fileLock may work better but then the file system need to support distributed file locks, and so on. Using the idempotent read lock can support clustering if the idempotent repository supports clustering, such as Hazelcast Component or Infinispan.

Enum values:

  • none

  • markerFile

  • fileLock

  • rename

  • changed

  • idempotent

  • idempotent-changed

  • idempotent-rename

none

String

readLockCheckInterval (lock)

Interval in millis for the read-lock, if supported by the read lock. This interval is used for sleeping between attempts to acquire the read lock. For example when using the changed read lock, you can set a higher interval period to cater for slow writes. The default of 1 sec. may be too fast if the producer is very slow writing the file. Notice: For FTP the default readLockCheckInterval is 5000. The readLockTimeout value must be higher than readLockCheckInterval, but a rule of thumb is to have a timeout that is at least 2 or more times higher than the readLockCheckInterval. This is needed to ensure that ample time is allowed for the read lock process to try to grab the lock before the timeout was hit.

1000

long

readLockDeleteOrphanLockFiles (lock)

Whether or not read lock with marker files should upon startup delete any orphan read lock files, which may have been left on the file system, if Camel was not properly shutdown (such as a JVM crash). If turning this option to false then any orphaned lock file will cause Camel to not attempt to pickup that file, this could also be due another node is concurrently reading files from the same shared directory.

true

boolean

readLockIdempotentReleaseAsync (lock)

Whether the delayed release task should be synchronous or asynchronous. See more details at the readLockIdempotentReleaseDelay option.

false

boolean

readLockIdempotentReleaseAsyncPoolSize (lock)

The number of threads in the scheduled thread pool when using asynchronous release tasks. Using a default of 1 core threads should be sufficient in almost all use-cases, only set this to a higher value if either updating the idempotent repository is slow, or there are a lot of files to process. This option is not in-use if you use a shared thread pool by configuring the readLockIdempotentReleaseExecutorService option. See more details at the readLockIdempotentReleaseDelay option.

int

readLockIdempotentReleaseDelay (lock)

Whether to delay the release task for a period of millis. This can be used to delay the release tasks to expand the window when a file is regarded as read-locked, in an active/active cluster scenario with a shared idempotent repository, to ensure other nodes cannot potentially scan and acquire the same file, due to race-conditions. By expanding the time-window of the release tasks helps prevents these situations. Note delaying is only needed if you have configured readLockRemoveOnCommit to true.

int

readLockIdempotentReleaseExecutorService (lock)

To use a custom and shared thread pool for asynchronous release tasks. See more details at the readLockIdempotentReleaseDelay option.

ScheduledExecutorService

readLockLoggingLevel (lock)

Logging level used when a read lock could not be acquired. By default a DEBUG is logged. You can change this level, for example to OFF to not have any logging. This option is only applicable for readLock of types: changed, fileLock, idempotent, idempotent-changed, idempotent-rename, rename.

Enum values:

  • TRACE

  • DEBUG

  • INFO

  • WARN

  • ERROR

  • OFF

DEBUG

LoggingLevel

readLockMarkerFile (lock)

Whether to use marker file with the changed, rename, or exclusive read lock types. By default a marker file is used as well to guard against other processes picking up the same files. This behavior can be turned off by setting this option to false. For example if you do not want to write marker files to the file systems by the Camel application.

true

boolean

readLockMinAge (lock)

This option is applied only for readLock=changed. It allows to specify a minimum age the file must be before attempting to acquire the read lock. For example use readLockMinAge=300s to require the file is at last 5 minutes old. This can speedup the changed read lock as it will only attempt to acquire files which are at least that given age.

0

long

readLockMinLength (lock)

This option is applied only for readLock=changed. It allows you to configure a minimum file length. By default Camel expects the file to contain data, and thus the default value is 1. You can set this option to zero, to allow consuming zero-length files.

1

long

readLockRemoveOnCommit (lock)

This option is applied only for readLock=idempotent. It allows to specify whether to remove the file name entry from the idempotent repository when processing the file is succeeded and a commit happens. By default the file is not removed which ensures that any race-condition do not occur so another active node may attempt to grab the file. Instead the idempotent repository may support eviction strategies that you can configure to evict the file name entry after X minutes - this ensures no problems with race conditions. See more details at the readLockIdempotentReleaseDelay option.

false

boolean

readLockRemoveOnRollback (lock)

This option is applied only for readLock=idempotent. It allows to specify whether to remove the file name entry from the idempotent repository when processing the file failed and a rollback happens. If this option is false, then the file name entry is confirmed (as if the file did a commit).

true

boolean

readLockTimeout (lock)

Optional timeout in millis for the read-lock, if supported by the read-lock. If the read-lock could not be granted and the timeout triggered, then Camel will skip the file. At next poll Camel, will try the file again, and this time maybe the read-lock could be granted. Use a value of 0 or lower to indicate forever. Currently fileLock, changed and rename support the timeout. Notice: For FTP the default readLockTimeout value is 20000 instead of 10000. The readLockTimeout value must be higher than readLockCheckInterval, but a rule of thumb is to have a timeout that is at least 2 or more times higher than the readLockCheckInterval. This is needed to ensure that ample time is allowed for the read lock process to try to grab the lock before the timeout was hit.

10000

long

backoffErrorThreshold (scheduler)

The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.

int

backoffIdleThreshold (scheduler)

The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.

int

backoffMultiplier (scheduler)

To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured.

int

delay (scheduler)

Milliseconds before the next poll.

500

long

greedy (scheduler)

If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.

false

boolean

initialDelay (scheduler)

Milliseconds before the first poll starts.

1000

long

repeatCount (scheduler)

Specifies a maximum limit of number of fires. So if you set it to 1, the scheduler will only fire once. If you set it to 5, it will only fire five times. A value of zero or negative means fire forever.

0

long

runLoggingLevel (scheduler)

The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.

Enum values:

  • TRACE

  • DEBUG

  • INFO

  • WARN

  • ERROR

  • OFF

TRACE

LoggingLevel

scheduledExecutorService (scheduler)

Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool.

ScheduledExecutorService

scheduler (scheduler)

To use a cron scheduler from either camel-spring or camel-quartz component. Use value spring or quartz for built in scheduler.

none

Object

schedulerProperties (scheduler)

To configure additional properties when using a custom scheduler or any of the Quartz, Spring based scheduler.

Map

startScheduler (scheduler)

Whether the scheduler should be auto started.

true

boolean

timeUnit (scheduler)

Time unit for initialDelay and delay options.

Enum values:

  • NANOSECONDS

  • MICROSECONDS

  • MILLISECONDS

  • SECONDS

  • MINUTES

  • HOURS

  • DAYS

MILLISECONDS

TimeUnit

useFixedDelay (scheduler)

Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details.

true

boolean

shuffle (sort)

To shuffle the list of files (sort in random order).

false

boolean

sortBy (sort)

Built-in sort by using the File Language. Supports nested sorts, so you can have a sort by file name and as a 2nd group sort by modified date.

String

sorter (sort)

Pluggable sorter as a java.util.Comparator class.

Comparator

Message Headers

The File component supports 16 message header(s), which is/are listed below:

Name Description Default Type

CamelFileLength (consumer)

Constant: FILE_LENGTH

A long value containing the file size.

long

CamelFileLastModified (consumer)

Constant: FILE_LAST_MODIFIED

A Long value containing the last modified timestamp of the file.

long

CamelFileLocalWorkPath (producer)

Constant: FILE_LOCAL_WORK_PATH

The local work path.

File

CamelFileNameOnly (common)

Constant: FILE_NAME_ONLY

Only the file name (the name with no leading paths).

String

CamelFileName (common)

Constant: FILE_NAME

(producer) Specifies the name of the file to write (relative to the endpoint directory). This name can be a String; a String with a xref:languages:file-language.adocFile Language or xref:languages:simple-language.adocSimple expression; or an Expression object. If it’s null then Camel will auto-generate a filename based on the message unique ID. (consumer) Name of the consumed file as a relative file path with offset from the starting directory configured on the endpoint.

String

CamelFileNameConsumed (consumer)

Constant: FILE_NAME_CONSUMED

The name of the file that has been consumed.

String

CamelFileAbsolute (consumer)

Constant: FILE_ABSOLUTE

A boolean option specifying whether the consumed file denotes an absolute path or not. Should normally be false for relative paths. Absolute paths should normally not be used but we added to the move option to allow moving files to absolute paths. But can be used elsewhere as well.

Boolean

CamelFileAbsolutePath (consumer)

Constant: FILE_ABSOLUTE_PATH

The absolute path to the file. For relative files this path holds the relative path instead.

String

CamelFileExtendedAttributes (consumer)

Constant: FILE_EXTENDED_ATTRIBUTES

The extended attributes of the file.

Map

CamelFileContentType (consumer)

Constant: FILE_CONTENT_TYPE

The content type of the file.

String

CamelFilePath (consumer)

Constant: FILE_PATH

The file path. For relative files this is the starting directory the relative filename. For absolute files this is the absolute path.

String

CamelFileRelativePath (consumer)

Constant: FILE_RELATIVE_PATH

The relative path.

String

CamelFileParent (common)

Constant: FILE_PARENT

The parent path.

String

CamelFileNameProduced (producer)

Constant: FILE_NAME_PRODUCED

The actual absolute filepath (path name) for the output file that was written. This header is set by Camel and its purpose is providing end-users with the name of the file that was written.

String

CamelOverruleFileName (producer)

Constant: OVERRULE_FILE_NAME

Is used for overruling CamelFileName header and use the value instead (but only once, as the producer will remove this header after writing the file). The value can be only be a String. Notice that if the option fileName has been configured, then this is still being evaluated.

Object

CamelFileInitialOffset (consumer)

Constant: INITIAL_OFFSET

A long value containing the initial offset.

long

Default behavior for file producer

By default, it will override any existing file if one exists with the same name.

Move, Pre Move and Delete operations

By default, Camel will move consumed files to the .camel subfolder relative to the directory where the file was consumed.

If you want to delete the file after processing, the route should be:

from("file://inbox?delete=true").to("bean:handleOrder");

Move, Delete and the Routing process

Any move or delete operations are executed after the routing has completed. So, during processing of the Exchange the file is still located in the inbox folder.

Let’s illustrate this with an example:

from("file://inbox?move=.done").to("bean:handleOrder");

When a file is dropped in the inbox folder, the file consumer notices this and creates a new FileExchange that is routed to the handleOrder bean. The bean then processes the File object. At this point in time the file is still located in the inbox folder. After the bean completes, and thus the route is completed, the file consumer will perform the move operation and move the file to the .done sub-folder.

The move and the preMove options are considered as a directory name. Though, if you use an expression such as File Language, or Simple, then the result of the expression evaluation is the file name to be used. E.g., if you set:

move=../backup/copy-of-${file:name}

Then that’s using the File Language which we use to return the file name to be used. This can be either relative or absolute. If relative, the directory is created as a subfolder from within the folder where the file was consumed.

Move and Pre Move operations

We have introduced a preMove operation to move files before they are processed. This allows you to mark which files have been scanned as they are moved to this subfolder before being processed.

from("file://inbox?preMove=inprogress").to("bean:handleOrder");

You can combine the preMove and the regular move:

from("file://inbox?preMove=inprogress&move=.done").to("bean:handleOrder");

So in this situation, the file is in the inprogress folder when being processed, and after it’s processed, it’s moved to the .done folder.

Fine-grained control over Move and PreMove option

The move and preMove options are Expression-based, so we have the full power of the File Language to do advanced configuration of the directory and name pattern. Camel will, in fact, internally convert the directory name you enter into a File Language expression. So, when we use move=.done Camel will convert this into: ${file:parent}/.done/${file:onlyname}.

This is only done if Camel detects that you have not provided a ${ } in the option value yourself. So when you enter a ${ } Camel will not convert it, and thus you have the full power.

So if we want to move the file into a backup folder with today’s date, as the pattern, we can do:

move=backup/${date:now:yyyyMMdd}/${file:name}

About moveFailed

The moveFailed option allows you to move files that could not be processed successfully to another location such as an error folder of your choice. For example, to move the files in an error folder with a timestamp you can use moveFailed=/error/${file:name.noext}-${date:now:yyyyMMddHHmmssSSS}.${``file:ext}.

See more examples at File Language

Exchange Properties, file consumer only

As the file consumer implements the BatchConsumer it supports batching the files it polls. By batching, we mean that Camel will add the following additional properties to the Exchange:

Property Description

CamelBatchSize

The total number of files that was polled in this batch.

CamelBatchIndex

The current index of the batch. Starts from 0.

CamelBatchComplete

A boolean value indicating the last Exchange in the batch. Is only true for the last entry.

This allows you, for instance, to know how many files exist in this batch and for instance, let the Aggregator2 aggregate this number of files.

Using charset

The charset option allows configuring the encoding of the files on both the consumer and producer endpoints. For example, if you read utf-8 files and want to convert the files to iso-8859-1, you can do:

from("file:inbox?charset=utf-8")
  .to("file:outbox?charset=iso-8859-1")

You can also use the convertBodyTo in the route. In the example below, we have still input files in utf-8 format, but we want to convert the file content to a byte array in iso-8859-1 format. And then let a bean process the data. Before writing the content to the outbox folder using the current charset.

from("file:inbox?charset=utf-8")
  .convertBodyTo(byte[].class, "iso-8859-1")
  .to("bean:myBean")
  .to("file:outbox");

If you omit the charset on the consumer endpoint, then Camel does not know the charset of the file, and would by default use UTF-8. However, you can configure a JVM system property to override and use a different default encoding with the key org.apache.camel.default.charset.

In the example below, this could be a problem if the files are not in UTF-8 encoding, which would be the default encoding for read the files. In this example when writing the files, the content has already been converted to a byte array, and thus would write the content directly as is (without any further encodings).

from("file:inbox")
  .convertBodyTo(byte[].class, "iso-8859-1")
  .to("bean:myBean")
  .to("file:outbox");

You can also override and control the encoding dynamic when writing files, by setting a property on the exchange with the key Exchange.CHARSET_NAME. For example, in the route below, we set the property with a value from a message header.

from("file:inbox")
  .convertBodyTo(byte[].class, "iso-8859-1")
  .to("bean:myBean")
  .setProperty(Exchange.CHARSET_NAME, header("someCharsetHeader"))
  .to("file:outbox");

We suggest keeping things simpler, so if you pick up files with the same encoding, and want to write the files in a specific encoding, then favor to use the charset option on the endpoints.

Notice that if you have explicitly configured a charset option on the endpoint, then that configuration is used, regardless of the Exchange.CHARSET_NAME property.

If you have some issues then you can enable DEBUG logging on org.apache.camel.component.file, and Camel logs when it reads/write a file using a specific charset. For example, the route below will log the following:

from("file:inbox?charset=utf-8")
  .to("file:outbox?charset=iso-8859-1")

And the logs:

DEBUG GenericFileConverter           - Read file /Users/davsclaus/workspace/camel/camel-core/target/charset/input/input.txt with charset utf-8
DEBUG FileOperations                 - Using Reader to write file: target/charset/output.txt with charset: iso-8859-1

Common gotchas with folder and filenames

When Camel is producing files (writing files), there are a few gotchas affecting how to set a filename of your choice. By default, Camel will use the message ID as the filename, and since the message ID is normally a unique generated ID, you will end up with filenames such as: ID-MACHINENAME-2443-1211718892437-1-0. If such a filename is not desired, then you must provide a filename in the CamelFileName message header. The constant, Exchange.FILE_NAME, can also be used.

The sample code below produces files using the message ID as the filename:

from("direct:report").to("file:target/reports");

To use report.txt as the filename you have to do:

from("direct:report").setHeader(Exchange.FILE_NAME, constant("report.txt")).to( "file:target/reports");
  1. the same as above, but with CamelFileName:

from("direct:report").setHeader("CamelFileName", constant("report.txt")).to( "file:target/reports");

And a syntax where we set the filename on the endpoint with the fileName URI option.

from("direct:report").to("file:target/reports/?fileName=report.txt");

Filename Expression

Filename can be set either using the expression option or as a string-based File Language expression in the CamelFileName header. See the File Language for syntax and samples.

Consuming files from folders where others drop files directly

Beware if you consume files from a folder where other applications write files too. Take a look at the different readLock options to see what suits your use cases. The best approach is, however, to write to another folder and, after writing, move the file in the drop folder. However, if you write files directly to the drop folder, then the option changed could better detect whether a file is currently being written/copied as it uses a file changed algorithm to see whether the file size / modification changes over a period of time. The other readLock options rely on Java File API that, sadly, is not always very good at detecting this. You may also want to look at the doneFileName option, which uses a marker file (done file) to signal when a file is done and ready to be consumed.

Done files

Using done files

See also section writing done files below.

If you want only to consume files when a done file exists, then you can use the doneFileName option on the endpoint.

from("file:bar?doneFileName=done");

It will only consume files from the bar folder if a done file exists in the same directory as the target files. Camel will automatically delete the done file when it’s done consuming the files.

Camel does not delete automatically the done file if noop=true is configured.

However, it is more common to have one done file per target file. This means there is a 1:1 correlation. To do this, you must use dynamic placeholders in the doneFileName option. Currently, Camel supports the following two dynamic tokens: file:name and file:name.noext which must be enclosed in ${ }. The consumer only supports the static part of the done file name as either prefix or suffix (not both).

  • Suffix

  • Prefix

from("file:bar?doneFileName=${file:name}.done");

In this example, the files will only be polled if there exists a done file with the name file name.done. For example:

  • hello.txt: is the file to be consumed

  • hello.txt.done: is the associated done file

from("file:bar?doneFileName=ready-${file:name}");

You can also use a prefix for the done file, such as:

  • hello.txt: is the file to be consumed

  • ready-hello.txt: is the associated done file

Writing done files

After you have written a file, you may want to write an additional done file as a kind of marker, to indicate to others that the file is finished and has been written. To do that, you can use the doneFileName option on the file producer endpoint.

.to("file:bar?doneFileName=done");

This will create a file named done in the same directory as the target file.

However, it is more common to have one done file per target file. This means there is a 1:1 correlation. To do this, you must use dynamic placeholders in the doneFileName option. Currently, Camel supports the following two dynamic tokens: file:name and file:name.noext. They must be enclosed in ${ }:

  • Prefix and file name

  • Suffix and file name

  • File name without the extension

.to("file:bar?doneFileName=done-${file:name}");

This will, for example, create a file named done-foo.txt if the target file was foo.txt in the same directory as the target file.

.to("file:bar?doneFileName=${file:name}.done");

This will, for example, create a file named foo.txt.done if the target file was foo.txt in the same directory as the target file.

.to("file:bar?doneFileName=${file:name.noext}.done");

Will, for example, create a file named foo.done if the target file was foo.txt in the same directory as the target file.

Using flatten

If you want to store the files in the outputdir directory in the same directory, disregarding the source directory layout (e.g., to flatten out the path), you add the flatten=true option on the file producer side:

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir?flatten=true")

It will result in the following output layout:

outputdir/foo.txt
outputdir/bar.txt

Writing to files

Camel is also able to write files, i.e., produce files. In the sample below, we receive some reports on the SEDA queue that we process before they are being written to a directory.

Write to subdirectory using Exchange.FILE_NAME

Using a single route, it is possible to write a file to any number of subdirectories. If you have a route setup as such:

<route>
  <from uri="bean:myBean"/>
  <to uri="file:/rootDirectory"/>
</route>

You can have myBean set the header Exchange.FILE_NAME to values such as:

Exchange.FILE_NAME = hello.txt => /rootDirectory/hello.txt
Exchange.FILE_NAME = foo/bye.txt => /rootDirectory/foo/bye.txt

This allows you to have a single route to write files to multiple destinations.

Writing file through the temporary directory relative to the final destination

Sometimes you need to temporarily write the files to some directory relative to the destination directory. Such a situation usually happens when some external process with limited filtering capabilities is reading from the directory you are writing to. In the example below files will be written to the /var/myapp/filesInProgress directory and after data transfer is done, they will be atomically moved to the` /var/myapp/finalDirectory `directory.

from("direct:start").
  to("file:///var/myapp/finalDirectory?tempPrefix=/../filesInProgress/");

Avoiding reading the same file more than once (idempotent consumer)

Camel supports Idempotent Consumer directly within the component, so it will skip already processed files. This feature can be enabled by setting the idempotent=true option.

from("file://inbox?idempotent=true").to("...");

Camel uses the absolute file name as the idempotent key, to detect duplicate files. You can customize this key by using an expression in the idempotentKey option. For example, to use both the name and the file size as the key

<route>
  <from uri="file://inbox?idempotent=true&amp;idempotentKey=${file:name}-${file:size}"/>
  <to uri="bean:processInbox"/>
</route>

By default, Camel uses an in-memory store for keeping track of consumed files. It uses the least recently used cache holding up to 1000 entries. You can plug in your own implementation of this store by using the idempotentRepository option using the # sign in the value to indicate it’s a referring to a bean in the Registry with the specified id.

 <!-- define our store as a plain spring bean -->
 <bean id="myStore" class="com.mycompany.MyIdempotentStore"/>

<route>
  <from uri="file://inbox?idempotent=true&amp;idempotentRepository=#myStore"/>
  <to uri="bean:processInbox"/>
</route>

Camel will log at DEBUG level if it skips a file because it has been consumed before:

DEBUG FileConsumer is idempotent and the file has been consumed before. Will skip this file: target\idempotent\report.txt

Idempotent Repository

Using a file-based idempotent repository

In this section we will use the file-based idempotent repository org.apache.camel.processor.idempotent.FileIdempotentRepository instead of the in-memory one that is used as default. This repository uses a first level cache to avoid reading the file repository. It will only use the file repository to store the content of the first level cache. Thereby, the repository can survive server restarts. It will load the content of the file into the first level cache upon startup. The file structure is basic as it stores the key in separate lines in the file. By default, the file store has a size limit of 1mb. When the file grows larger, Camel will truncate the file store, rebuilding the content by flushing the first level cache into a fresh empty file.

We configure our repository using Spring XML creating our file idempotent repository and define our file consumer to use our repository with the idempotentRepository using # sign to indicate Registry lookup:

Using a JPA based idempotent repository

In this section, we will use the JPA based idempotent repository instead of the in-memory based that is used as default.

First we need a persistence-unit in META-INF/persistence.xml where we need to use the class org.apache.camel.processor.idempotent.jpa.MessageProcessed as the model.

<persistence-unit name="idempotentDb" transaction-type="RESOURCE_LOCAL">
  <class>org.apache.camel.processor.idempotent.jpa.MessageProcessed</class>

  <properties>
    <property name="openjpa.ConnectionURL" value="jdbc:derby:target/idempotentTest;create=true"/>
    <property name="openjpa.ConnectionDriverName" value="org.apache.derby.jdbc.EmbeddedDriver"/>
    <property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema"/>
    <property name="openjpa.Log" value="DefaultLevel=WARN, Tool=INFO"/>
    <property name="openjpa.Multithreaded" value="true"/>
  </properties>
</persistence-unit>

Next, we can create our JPA idempotent repository in the spring XML file as well:

<!-- we define our jpa based idempotent repository we want to use in the file consumer -->
<bean id="jpaStore" class="org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository">
    <!-- Here we refer to the entityManagerFactory -->
    <constructor-arg index="0" ref="entityManagerFactory"/>
    <!-- This 2nd parameter is the name (= a category name).
         You can have different repositories with different names -->
    <constructor-arg index="1" value="FileConsumer"/>
</bean>

And yes then we just need to refer to the jpaStore bean in the file consumer endpoint using the idempotentRepository using the # syntax option:

<route>
  <from uri="file://inbox?idempotent=true&amp;idempotentRepository=#jpaStore"/>
  <to uri="bean:processInbox"/>
</route>

Filtering Strategies

Camel supports pluggable filtering strategies. They are described below.

Filter using the GenericFilter

The filter option allows you to implement a custom filter in Java code by implementing the org.apache.camel.component.file.GenericFileFilter interface.

Implementing a GenericFilter

The interface has an accept method that returns a boolean. The meaning of the return values are:

  • true to include the file

  • false to skip the file.

There is also a isDirectory method on GenericFile to inform whether the file is a directory. This allows you to filter unwanted directories, to avoid traversing down unwanted directories.

Using the GenericFilter

You can then configure the endpoint with such a filter to skip certain files being processed.

In the sample we have built our own filter that skips files starting with skip in the filename:

And then we can configure our route using the filter attribute to reference our filter (using # notation) that we have defined in the spring XML file:

<!-- define our filter as a plain spring bean -->
<bean id="myFilter" class="com.mycompany.MyFileFilter"/>

<route>
  <from uri="file://inbox?filter=#myFilter"/>
  <to uri="bean:processInbox"/>
</route>

Filtering using ANT path matcher

The ANT path matcher is based on AntPathMatcher.

The file paths are matched with the following rules:

  • ? matches one character

  • * matches zero or more characters

  • ** matches zero or more directories in a path

The antInclude and antExclude options make it easy to specify ANT style include/exclude without having to define the filter. See the URI options above for more information.

The sample below demonstrates how to use it:

from("file://inbox?antInclude=**/*.txt").to("...");

Sorting Strategies

Camel supports pluggable sorting strategies. They are described below.

Sorting using Comparator

This strategy it to use the build in java.util.Comparator in Java. You can then configure the endpoint with such a comparator and have Camel sort the files before being processed.

In the sample, we have built our own comparator that just sorts by file name:

And then we can configure our route using the sorter option to reference to our sorter (mySorter) we have defined in the spring XML file:

 <!-- define our sorter as a plain spring bean -->
 <bean id="mySorter" class="com.mycompany.MyFileSorter"/>

<route>
  <from uri="file://inbox?sorter=#mySorter"/>
  <to uri="bean:processInbox"/>
</route>

URI options can reference beans using the # syntax

In the Spring DSL route above notice that we can refer to beans in the Registry by prefixing the id with #. So writing sorter=#mySorter, will instruct Camel to go look in the Registry for a bean with the ID, mySorter.

Sorting using sortBy

Camel supports pluggable sorting strategies. This strategy uses the File Language to configure the sorting. The sortBy option is configured as follows:

sortBy=group 1;group 2;group 3;...

Where each group is separated with semicolon. In the simple situations you just use one group, so a simple example could be:

sortBy=file:name

This will sort by file name, you can reverse the order by prefixing reverse: to the group, so the sorting is now Z to A:

sortBy=reverse:file:name

As we have the full power of File Language, we can use some of the other parameters, so if we want to sort by file size, we do:

sortBy=file:length

You can configure to ignore the case, using ignoreCase: for string comparison, so if you want to use file name sorting but to ignore the case, then we do:

sortBy=ignoreCase:file:name

You can combine ignore case and reverse. However, reverse must be specified first:

sortBy=reverse:ignoreCase:file:name

In the sample below we want to sort by the last modified file, so we do:

sortBy=file:modified

And then we want to group by name as a second option, so files with the same modification time are sorted by name:

sortBy=file:modified;file:name

Now there is an issue here, can you spot it? Well, the modified timestamp of the file is too fine as it will be in milliseconds, but what if we want to sort by date only and then subgroup by name? Well, as we have the true power of File Language, we can use its date command that supports patterns. So this can be solved as:

sortBy=date:file:yyyyMMdd;file:name

Yeah, that is pretty powerful, oh by the way, you can also use reverse per group, so we could reverse the file names:

sortBy=date:file:yyyyMMdd;reverse:file:name

Using GenericFileProcessStrategy

The option processStrategy can be used to use a custom GenericFileProcessStrategy that allows you to implement your own begin, commit and rollback logic. For instance, let’s assume a system writes a file in a folder you should consume. But you should not start consuming the file before another ready file has been written as well.

So by implementing our own GenericFileProcessStrategy we can implement this as:

  • In the begin() method we can test whether the special ready file exists. The begin method returns a boolean to indicate if we can consume the file or not.

  • In the abort() method special logic can be executed in case the begin operation returned false, for example, to clean up resources etc.

  • in the commit() method we can move the actual file and also delete the ready file.

Using bridgeErrorHandler

If you want to use the Camel Error Handler to deal with any exception occurring in the file consumer, then you can enable the bridgeErrorHandler option as shown below:

// to handle any IOException being thrown
onException(IOException.class)
    .handled(true)
    .log("IOException occurred due: ${exception.message}")
    .transform().simple("Error ${exception.message}")
    .to("mock:error");

// this is the file route that pickup files. Notice how we bridge the consumer to use the Camel routing error handler
// the exclusiveReadLockStrategy is only configured because this is from a unit test, so we use that to simulate exceptions
from("file:target/nospace?bridgeErrorHandler=true")
    .convertBodyTo(String.class)
    .to("mock:result");

So all you have to do is to enable this option, and the error handler in the route will take it from there.

When using bridgeErrorHandler, then interceptors, OnCompletions do not apply. The Exchange is processed directly by the Camel Error Handler, and does not allow prior actions such as interceptors, onCompletion to take action.

Debug logging

This component has log level TRACE that can be helpful if you have problems.

Samples

Reading from a directory and the default move operation

By default, Camel will move any processed file into a .camel subdirectory in the directory the file was consumed from.

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")

Affects the layout as follows:
before

inputdir/foo.txt
inputdir/sub/bar.txt

after

inputdir/.camel/foo.txt
inputdir/sub/.camel/bar.txt
outputdir/foo.txt
outputdir/sub/bar.txt

Read from a directory and write to another directory

from("file://inputdir/?delete=true").to("file://outputdir")

Read from a directory and write to another directory using a dynamic name

from("file://inputdir/?delete=true").to("file://outputdir?fileName=copy-of-${file:name}")

Listen to a directory and create a message for each file dropped there. Copy the contents to the outputdir and delete the file in the inputdir.

Reading recursively from a directory and writing to another

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")

Listen to a directory and create a message for each file dropped there. Copy the contents to the outputdir and delete the file in the inputdir. Will scan recursively into subdirectories. Will lay out the files in the same directory structure in the outputdir as the inputdir, including any subdirectories.

inputdir/foo.txt
inputdir/sub/bar.txt

It will result in the following output layout:

outputdir/foo.txt
outputdir/sub/bar.txt

Read from a directory and process the message in java

from("file://inputdir/").process(new Processor() {
  public void process(Exchange exchange) throws Exception {
    Object body = exchange.getIn().getBody();
    // do some business logic with the input body
  }
});

The body will be a File object that points to the file that was just dropped into the inputdir directory.

Using expression for filenames

In this sample, we want to move consumed files to a backup folder using today’s date as a subfolder name:

from("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}").to("...");

See File Language for more samples.

Spring Boot Auto-Configuration

When using file with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-file-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 13 options, which are listed below.

Name Description Default Type

camel.cluster.file.acquire-lock-delay

The time to wait before starting to try to acquire lock.

String

camel.cluster.file.acquire-lock-interval

The time to wait between attempts to try to acquire lock.

String

camel.cluster.file.attributes

Custom service attributes.

Map

camel.cluster.file.enabled

Sets if the file cluster service should be enabled or not, default is false.

false

Boolean

camel.cluster.file.id

Cluster Service ID.

String

camel.cluster.file.order

Service lookup order/priority.

Integer

camel.cluster.file.root

The root path.

String

camel.component.file.autowired-enabled

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

Boolean

camel.component.file.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.file.enabled

Whether to enable auto configuration of the file component. This is enabled by default.

Boolean

camel.component.file.health-check-consumer-enabled

Used for enabling or disabling all consumer based health checks from this component.

true

Boolean

camel.component.file.health-check-producer-enabled

Used for enabling or disabling all producer based health checks from this component. Notice: Camel has by default disabled all producer based health-checks. You can turn on producer checks globally by setting camel.health.producersEnabled=true.

true

Boolean

camel.component.file.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean