MongoDB GridFS

Since Camel 2.18

Both producer and consumer are supported

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-mongodb-gridfs</artifactId>
    <version>x.y.z</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI format

mongodb-gridfs:connectionBean?database=databaseName&bucket=bucketName[&moreOptions...]

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. 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.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

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

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

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

Component Options

The MongoDB GridFS component supports 3 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 occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. 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.

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.

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.

boolean

Endpoint Options

The MongoDB GridFS endpoint is configured using URI syntax:

mongodb-gridfs:connectionBean

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

connectionBean (common)

Required Name of com.mongodb.client.MongoClient to use.

String

Query Parameters (16 parameters)

Name Description Default Type

bucket (common)

Sets the name of the GridFS bucket within the database. Default is fs.

String

database (common)

Required Sets the name of the MongoDB database to target.

String

readPreference (common)

Sets a MongoDB ReadPreference on the Mongo connection. Read preferences set directly on the connection will be overridden by this setting. The com.mongodb.ReadPreference#valueOf(String) utility method is used to resolve the passed readPreference value. Some examples for the possible values are nearest, primary or secondary etc.

ReadPreference

writeConcern (common)

Set the WriteConcern for write operations on MongoDB using the standard ones. Resolved from the fields of the WriteConcern class by calling the WriteConcern#valueOf(String) method.

Enum values:

  • ACKNOWLEDGED

  • W1

  • W2

  • W3

  • UNACKNOWLEDGED

  • JOURNALED

  • MAJORITY

WriteConcern

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. 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.

boolean

delay (consumer)

Sets the delay between polls within the Consumer. Default is 500ms.

long

fileAttributeName (consumer)

If the QueryType uses a FileAttribute, this sets the name of the attribute that is used. Default is camel-processed.

String

initialDelay (consumer)

Sets the initialDelay before the consumer will start polling. Default is 1000ms.

long

persistentTSCollection (consumer)

If the QueryType uses a persistent timestamp, this sets the name of the collection within the DB to store the timestamp.

String

persistentTSObject (consumer)

If the QueryType uses a persistent timestamp, this is the ID of the object in the collection to store the timestamp.

String

query (consumer)

Additional query parameters (in JSON) that are used to configure the query used for finding files in the GridFsConsumer.

String

queryStrategy (consumer)

Sets the QueryStrategy that is used for polling for new files. Default is Timestamp.

Enum values:

  • TimeStamp

  • PersistentTimestamp

  • FileAttribute

  • TimeStampAndFileAttribute

  • PersistentTimestampAndFileAttribute

QueryStrategy

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

  • InOptionalOut

ExchangePattern

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.

boolean

operation (producer)

Sets the operation this endpoint will execute against GridFs.

String

Configuration of database in Spring XML

The following Spring XML creates a bean defining the connection to a MongoDB instance.

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="mongoBean" class="com.mongodb.Mongo">
        <constructor-arg name="host" value="${mongodb.host}" />
        <constructor-arg name="port" value="${mongodb.port}" />
    </bean>
</beans>

Sample route

The following route defined in Spring XML executes the operation findOne on a collection.

Get a file from GridFS

<route>
  <from uri="direct:start" />
  <!-- using bean 'mongoBean' defined above -->
  <to uri="mongodb-gridfs:mongoBean?database=${mongodb.database}&amp;operation=findOne" />
  <to uri="direct:result" />
</route>

GridFS operations - producer endpoint

count

Returns the total number of file in the collection, returning an Integer as the OUT message body.

// from("direct:count").to("mongodb-gridfs?database=tickets&operation=count");
Integer result = template.requestBodyAndHeader("direct:count", "irrelevantBody");
assertTrue("Result is not of type Long", result instanceof Integer);

You can provide a filename header to provide a count of files matching that filename.

Map<String, Object> headers = new HashMap<String, Object>();
headers.put(Exchange.FILE_NAME, "filename.txt");
Integer count = template.requestBodyAndHeaders("direct:count", query, headers);

listAll

Returns an Reader that lists all the filenames and their IDs in a tab separated stream.

// from("direct:listAll").to("mongodb-gridfs?database=tickets&operation=listAll");
Reader result = template.requestBodyAndHeader("direct:listAll", "irrelevantBody");

filename1.txt   1252314321
filename2.txt   2897651254

findOne

Finds a file in the GridFS system and sets the body to an InputStream of the content. Also provides the metadata has headers. It uses Exchange.FILE_NAME from the incoming headers to determine the file to find.

// from("direct:findOne").to("mongodb-gridfs?database=tickets&operation=findOne");
Map<String, Object> headers = new HashMap<String, Object>();
headers.put(Exchange.FILE_NAME, "filename.txt");
InputStream result = template.requestBodyAndHeaders("direct:findOne", "irrelevantBody", headers);

create

Creates a new file in the GridFs database. It uses the Exchange.FILE_NAME from the incoming headers for the name and the body contents (as an InputStream) as the content.

// from("direct:create").to("mongodb-gridfs?database=tickets&operation=create");
Map<String, Object> headers = new HashMap<String, Object>();
headers.put(Exchange.FILE_NAME, "filename.txt");
InputStream stream = ... the data for the file ...
template.requestBodyAndHeaders("direct:create", stream, headers);

remove

Removes a file from the GridFS database.

// from("direct:remove").to("mongodb-gridfs?database=tickets&operation=remove");
Map<String, Object> headers = new HashMap<String, Object>();
headers.put(Exchange.FILE_NAME, "filename.txt");
template.requestBodyAndHeaders("direct:remove", "", headers);

Spring Boot Auto-Configuration

When using mongodb-gridfs 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-mongodb-gridfs-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 4 options, which are listed below.

Name Description Default Type

camel.component.mongodb-gridfs.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.mongodb-gridfs.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. 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.mongodb-gridfs.enabled

Whether to enable auto configuration of the mongodb-gridfs component. This is enabled by default.

Boolean

camel.component.mongodb-gridfs.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