Telegram

Since Camel 2.18

Both producer and consumer are supported

The Telegram component provides access to the Telegram Bot API. It allows a Camel-based application to send and receive messages by acting as a Bot, participating in direct conversations with normal users, private and public groups or channels.

A Telegram Bot must be created before using this component, following the instructions at the Telegram Bot developers home. When a new Bot is created, the BotFather provides an authorization token corresponding to the Bot. The authorization token is a mandatory parameter for the camel-telegram endpoint.

In order to allow the Bot to receive all messages exchanged within a group or channel (not just the ones starting with a '/' character), ask the BotFather to disable the privacy mode, using the /setprivacy command.

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

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

URI format

telegram:type[?options]

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 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, 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 Telegram component supports 8 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.

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

baseUri (advanced)

Can be used to set an alternative base URI, e.g. when you want to test the component against a mock Telegram API.

https://api.telegram.org

String

client (advanced)

To use a custom java.net.http.HttpClient.

HttpClient

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

authorizationToken (security)

The default Telegram authorization token to be used when the information is not provided in the endpoints.

String

Endpoint Options

The Telegram endpoint is configured using URI syntax:

telegram:type

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

type (common)

Required The endpoint type. Currently, only the 'bots' type is supported.

Enum values:

  • bots

String

Query Parameters (30 parameters)

Name Description Default Type

limit (consumer)

Limit on the number of updates that can be received in a single polling request.

100

Integer

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

timeout (consumer)

Timeout in seconds for long polling. Put 0 for short polling or a bigger number for long polling. Long polling produces shorter response time.

30

Integer

bridgeErrorHandler (consumer (advanced))

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

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

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

chatId (producer)

The identifier of the chat that will receive the produced messages. Chat ids can be first obtained from incoming messages (eg. when a telegram user starts a conversation with a bot, its client sends automatically a '/start' message containing the chat id). It is an optional parameter, as the chat id can be set dynamically for each outgoing message (using body or headers).

String

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

baseUri (advanced)

Can be used to set an alternative base URI, e.g. when you want to test the component against a mock Telegram API.

String

bufferSize (advanced)

The initial in-memory buffer size used when transferring data between Camel and AHC Client.

1048576

int

client (advanced)

To use a custom HttpClient.

HttpClient

proxyHost (proxy)

HTTP proxy host which could be used when sending out the message.

String

proxyPort (proxy)

HTTP proxy port which could be used when sending out the message.

Integer

proxyType (proxy)

HTTP proxy type which could be used when sending out the message.

Enum values:

  • HTTP

  • SOCKS4

  • SOCKS5

HTTP

TelegramProxyType

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

authorizationToken (security)

Required The authorization token for using the bot (ask the BotFather).

String

Message Headers

The Telegram component supports 6 message header(s), which is/are listed below:

Name Description Default Type

CamelTelegramChatId (producer)

Constant: TELEGRAM_CHAT_ID

This header is used by the producer endpoint in order to resolve the chat id that will receive the message. The recipient chat id can be placed (in order of priority) in message body, in the CamelTelegramChatId header or in the endpoint configuration (chatId option). This header is also present in all incoming messages.

Object

CamelTelegramMediaType (common)

Constant: TELEGRAM_MEDIA_TYPE

This header is used to identify the media type when the outgoing message is composed of pure binary data. Possible values are strings or enum values belonging to the org.apache.camel.component.telegram.TelegramMediaType enumeration.

TelegramMediaType or String

CamelTelegramMediaTitleCaption (common)

Constant: TELEGRAM_MEDIA_TITLE_CAPTION

This header is used to provide a caption or title for outgoing binary messages.

String

CamelTelegramMediaMarkup (common)

Constant: TELEGRAM_MEDIA_MARKUP

The reply markup.

ReplyMarkup

CamelTelegramParseMode (common)

Constant: TELEGRAM_PARSE_MODE

This header is used to format text messages using HTML or Markdown.

Enum values:

  • HTML

  • MARKDOWN

TelegramParseMode

CamelMessageTimestamp (common)

Constant: MESSAGE_TIMESTAMP

The message timestamp.

long

Usage

The Telegram component supports both consumer and producer endpoints. It can also be used in reactive chat-bot mode (to consume, then produce messages).

Producer Example

The following is a basic example of how to send a message to a Telegram chat through the Telegram Bot API.

in Java DSL

from("direct:start").to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere");

or in Spring XML

<route>
    <from uri="direct:start"/>
    <to uri="telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere"/>
<route>

The code 123456789:insertYourAuthorizationTokenHere is the authorization token corresponding to the Bot.

When using the producer endpoint without specifying the chat id option, the target chat will be identified using information contained in the body or headers of the message. The following message bodies are allowed for a producer endpoint (messages of type OutgoingXXXMessage belong to the package org.apache.camel.component.telegram.model)

Java Type Description

OutgoingTextMessage

To send a text message to a chat

OutgoingPhotoMessage

To send a photo (JPG, PNG) to a chat

OutgoingAudioMessage

To send a mp3 audio to a chat

OutgoingVideoMessage

To send a mp4 video to a chat

OutgoingDocumentMessage

To send a file to a chat (any media type)

OutgoingStickerMessage

To send a sticker to a chat (WEBP)

OutgoingAnswerInlineQuery

To send answers to an inline query

EditMessageTextMessage

To edit text and game messages (editMessageText)

EditMessageCaptionMessage

To edit captions of messages (editMessageCaption)

EditMessageMediaMessage

To edit animation, audio, document, photo, or video messages. (editMessageMedia)

EditMessageReplyMarkupMessage

To edit only the reply markup of message. (editMessageReplyMarkup)

EditMessageDelete

To delete a message, including service messages. (deleteMessage)

SendLocationMessage

To send a location (setSendLocation)

EditMessageLiveLocationMessage

To send changes to a live location (editMessageLiveLocation)

StopMessageLiveLocationMessage

To stop updating a live location message sent by the bot or via the bot (for inline bots) before live_period expires (stopMessageLiveLocation)

SendVenueMessage

To send information about a venue (sendVenue)

byte[]

To send any media type supported. It requires the CamelTelegramMediaType header to be set to the appropriate media type

String

To send a text message to a chat. It gets converted automatically into a OutgoingTextMessage

Consumer Example

The following is a basic example of how to receive all messages that telegram users are sending to the configured Bot. In Java DSL

from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere")
.bean(ProcessorBean.class)

or in Spring XML

<route>
    <from uri="telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere"/>
    <bean ref="myBean" />
<route>

<bean id="myBean" class="com.example.MyBean"/>

The MyBean is a simple bean that will receive the messages

public class MyBean {

    public void process(String message) {
        // or Exchange, or org.apache.camel.component.telegram.model.IncomingMessage (or both)

        // do process
    }

}

Supported types for incoming messages are

Java Type Description

IncomingMessage

The full object representation of an incoming message

String

The content of the message, for text messages only

Reactive Chat-Bot Example

The reactive chat-bot mode is a simple way of using the Camel component to build a simple chat bot that replies directly to chat messages received from the Telegram users.

The following is a basic configuration of the chat-bot in Java DSL

from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere")
.bean(ChatBotLogic.class)
.to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere");

or in Spring XML

<route>
    <from uri="telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere"/>
    <bean ref="chatBotLogic" />
    <to uri="telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere"/>
<route>

<bean id="chatBotLogic" class="com.example.ChatBotLogic"/>

The ChatBotLogic is a simple bean that implements a generic String-to-String method.

public class ChatBotLogic {

    public String chatBotProcess(String message) {
        if( "do-not-reply".equals(message) ) {
            return null; // no response in the chat
        }

        return "echo from the bot: " + message; // echoes the message
    }

}

Every non-null string returned by the chatBotProcess method is automatically routed to the chat that originated the request (as the CamelTelegramChatId header is used to route the message).

Getting the Chat ID

If you want to push messages to a specific Telegram chat when an event occurs, you need to retrieve the corresponding chat ID. The chat ID is not currently shown in the telegram client, but you can obtain it using a simple route.

First, add the bot to the chat where you want to push messages, then run a route like the following one.

from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere")
.to("log:INFO?showHeaders=true");

Any message received by the bot will be dumped to your log together with information about the chat (CamelTelegramChatId header).

Once you get the chat ID, you can use the following sample route to push message to it.

from("timer:tick")
.setBody().constant("Hello")
to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere&chatId=123456")

Note that the corresponding URI parameter is simply chatId.

Customizing keyboard

You can customize the user keyboard instead of asking him to write an option. OutgoingTextMessage has the property ReplyMarkup which can be used for such thing.

from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere")
    .process(exchange -> {

        OutgoingTextMessage msg = new OutgoingTextMessage();
        msg.setText("Choose one option!");

        InlineKeyboardButton buttonOptionOneI = InlineKeyboardButton.builder()
                .text("Option One - I").build();

        InlineKeyboardButton buttonOptionOneII = InlineKeyboardButton.builder()
                .text("Option One - II").build();

        InlineKeyboardButton buttonOptionTwoI = InlineKeyboardButton.builder()
                .text("Option Two - I").build();

        ReplyKeyboardMarkup replyMarkup = ReplyKeyboardMarkup.builder()
                .keyboard()
                    .addRow(Arrays.asList(buttonOptionOneI, buttonOptionOneII))
                    .addRow(Arrays.asList(buttonOptionTwoI))
                    .close()
                .oneTimeKeyboard(true)
                .build();

        msg.setReplyMarkup(replyMarkup);

        exchange.getIn().setBody(msg);
    })
    .to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere");

If you want to disable it the next message must have the property removeKeyboard set on ReplyKeyboardMarkup object.

from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere")
    .process(exchange -> {

        OutgoingTextMessage msg = new OutgoingTextMessage();
        msg.setText("Your answer was accepted!");

        ReplyKeyboardMarkup replyMarkup = ReplyKeyboardMarkup.builder()
                .removeKeyboard(true)
                .build();

        msg.setReplyKeyboardMarkup(replyMarkup);

        exchange.getIn().setBody(msg);
    })
    .to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere");

Webhook Mode

The Telegram component supports usage in the webhook mode using the camel-webhook component.

In order to enable webhook mode, users need first to add a REST implementation to their application. Maven users, for example, can add netty-http to their pom.xml file:

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

Once done, you need to prepend the webhook URI to the telegram URI you want to use.

In Java DSL:

from("webhook:telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere").to("log:info");

Some endpoints will be exposed by your application and Telegram will be configured to send messages to them. You need to ensure that your server is exposed to the internet and to pass the right value of the camel.component.webhook.configuration.webhook-external-url property.

Refer to the camel-webhook component documentation for instructions on how to set it.

Spring Boot Auto-Configuration

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

The component supports 9 options, which are listed below.

Name Description Default Type

camel.component.telegram.authorization-token

The default Telegram authorization token to be used when the information is not provided in the endpoints.

String

camel.component.telegram.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.telegram.base-uri

Can be used to set an alternative base URI, e.g. when you want to test the component against a mock Telegram API.

https://api.telegram.org

String

camel.component.telegram.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.telegram.client

To use a custom java.net.http.HttpClient. The option is a java.net.http.HttpClient type.

HttpClient

camel.component.telegram.enabled

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

Boolean

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

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

true

Boolean

camel.component.telegram.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.telegram.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
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