Google Mail Component

Since Camel 2.15

Both producer and consumer is supported

The Google Mail component provides access to Gmail via the Google Mail Web APIs.

Google Mail uses the OAuth 2.0 protocol for authenticating a Google account and authorizing access to user data. Before you can use this component, you will need to create an account and generate OAuth credentials. Credentials comprise of a clientId, clientSecret, and a refreshToken. A handy resource for generating a long-lived refreshToken is the OAuth playground.

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

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

URI Format

The GoogleMail Component uses the following URI format:

        google-mail://endpoint-prefix/endpoint?[options]

Endpoint prefix can be one of:

  • attachments

  • drafts

  • history

  • labels

  • messages

  • threads

  • users

GoogleMailComponent

The Google Mail component supports 5 options, which are listed below.

Name Description Default Type

configuration (common)

To use the shared configuration

GoogleMailConfiguration

clientFactory (advanced)

To use the GoogleCalendarClientFactory as factory for creating the client. Will by default use BatchGoogleMailClientFactory

GoogleMailClientFactory

basicPropertyBinding (advanced)

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

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

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.

false

boolean

The Google Mail endpoint is configured using URI syntax:

google-mail:apiName/methodName

with the following path and query parameters:

Path Parameters (2 parameters):

Name Description Default Type

apiName

Required What kind of operation to perform

GoogleMailApiName

methodName

Required What sub operation to use for the selected operation

String

Query Parameters (28 parameters):

Name Description Default Type

accessToken (common)

OAuth 2 access token. This typically expires after an hour so refreshToken is recommended for long term usage.

String

applicationName (common)

Google mail application name. Example would be camel-google-mail/1.0

String

clientId (common)

Client ID of the mail application

String

clientSecret (common)

Client secret of the mail application

String

inBody (common)

Sets the name of a parameter to be passed in the exchange In Body

String

refreshToken (common)

OAuth 2 refresh token. Using this, the Google Calendar component can obtain a new accessToken whenever the current one expires - a necessity if the application is long-lived.

String

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.

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

exceptionHandler (consumer)

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)

Sets the exchange pattern when the consumer creates an exchange.

ExchangePattern

pollStrategy (consumer)

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

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

basicPropertyBinding (advanced)

Whether the endpoint should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

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. You can also specify time values using units, such as 60s (60 seconds), 5m30s (5 minutes and 30 seconds), and 1h (1 hour).

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. You can also specify time values using units, such as 60s (60 seconds), 5m30s (5 minutes and 30 seconds), and 1h (1 hour).

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.

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

none

String

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.

MILLISECONDS

TimeUnit

useFixedDelay (scheduler)

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

true

boolean

Spring Boot Auto-Configuration

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

The component supports 12 options, which are listed below.

Name Description Default Type

camel.component.google-mail.basic-property-binding

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

Boolean

camel.component.google-mail.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.google-mail.client-factory

To use the GoogleCalendarClientFactory as factory for creating the client. Will by default use BatchGoogleMailClientFactory. The option is a org.apache.camel.component.google.mail.GoogleMailClientFactory type.

String

camel.component.google-mail.configuration.access-token

OAuth 2 access token. This typically expires after an hour so refreshToken is recommended for long term usage.

String

camel.component.google-mail.configuration.api-name

What kind of operation to perform

GoogleMailApiName

camel.component.google-mail.configuration.application-name

Google mail application name. Example would be "camel-google-mail/1.0"

String

camel.component.google-mail.configuration.client-id

Client ID of the mail application

String

camel.component.google-mail.configuration.client-secret

Client secret of the mail application

String

camel.component.google-mail.configuration.method-name

What sub operation to use for the selected operation

String

camel.component.google-mail.configuration.refresh-token

OAuth 2 refresh token. Using this, the Google Calendar component can obtain a new accessToken whenever the current one expires - a necessity if the application is long-lived.

String

camel.component.google-mail.enabled

Enable google-mail component

true

Boolean

camel.component.google-mail.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

Producer Endpoints

Producer endpoints can use endpoint prefixes followed by endpoint names and associated options described next. A shorthand alias can be used for some endpoints. The endpoint URI MUST contain a prefix.

Endpoint options that are not mandatory are denoted by []. When there are no mandatory options for an endpoint, one of the set of [] options MUST be provided. Producer endpoints can also use a special option inBody that in turn should contain the name of the endpoint option whose value will be contained in the Camel Exchange In message.

Any of the endpoint options can be provided in either the endpoint URI, or dynamically in a message header. The message header name must be of the format CamelGoogleMail.<option>. Note that the inBody option overrides message header, i.e. the endpoint option inBody=option would override a CamelGoogleMail.option header.

For more information on the endpoints and options see API documentation at: https://developers.google.com/gmail/api/v1/reference/

Consumer Endpoints

Any of the producer endpoints can be used as a consumer endpoint. Consumer endpoints can use Scheduled Poll Consumer Options with a consumer. prefix to schedule endpoint invocation. Consumer endpoints that return an array or collection will generate one exchange per element, and their routes will be executed once for each exchange.

Message Headers

Any URI option can be provided in a message header for producer endpoints with a CamelGoogleMail. prefix.

Message Body

All result message bodies utilize objects provided by the underlying APIs used by the GoogleMailComponent. Producer endpoints can specify the option name for incoming message body in the inBody endpoint URI parameter. For endpoints that return an array or collection, a consumer endpoint will map every element to distinct messages.