Chapter 141. Telegram 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. Note 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. 141.1. Dependencies When using telegram with Red Hat build of Camel 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> </dependency> 141.2. URI format 141.3. Configuring Options Camel components are configured on two separate levels: component level endpoint level 141.3.1. 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. 141.3.2. 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. 141.4. Component Options The Telegram component supports 7 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. String client (advanced) To use a custom AsyncHttpClient. AsyncHttpClient clientConfig (advanced) To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance. AsyncHttpClientConfig authorizationToken (security) The default Telegram authorization token to be used when the information is not provided in the endpoints. String 141.5. Endpoint Options The Telegram endpoint is configured using URI syntax: with the following path and query parameters: 141.5.1. 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 141.5.2. Query Parameters (30 parameters) 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 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 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 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) 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. 4096 int clientConfig (advanced) To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance. AsyncHttpClientConfig 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 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 poll. 500 long greedy (scheduler) If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the 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 141.5.3. Message Headers Name Description CamelTelegramChatId 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. CamelTelegramMediaType 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. CamelTelegramMediaTitleCaption This header is used to provide a caption or title for outgoing binary messages. CamelTelegramParseMode This header is used to format text messages using HTML or Markdown (see org.apache.camel.component.telegram.TelegramParseMode ). 141.6. 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). 141.7. 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 141.8. 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 141.9. 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). 141.10. 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 . 141.11. 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 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"); 141.12. 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>{CamelSBVersion}</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. 141.13. Spring Boot Auto-Configuration The component supports 8 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. 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 AsyncHttpClient. The option is a org.asynchttpclient.AsyncHttpClient type. AsyncHttpClient camel.component.telegram.client-config To configure the AsyncHttpClient to use a custom com.ning.http.client.AsyncHttpClientConfig instance. The option is a org.asynchttpclient.AsyncHttpClientConfig type. AsyncHttpClientConfig camel.component.telegram.enabled Whether to enable auto configuration of the telegram component. This is enabled by default. 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

Commands:
<dependency> <groupId>org.apache.camel.springboot</groupId> <artifactId>camel-telegram-starter</artifactId> </dependency>
telegram:type[?options]
telegram:type
from("direct:start").to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere");
<route> <from uri="direct:start"/> <to uri="telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere"/> <route>
from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere") .bean(ProcessorBean.class)
<route> <from uri="telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere"/> <bean ref="myBean" /> <route> <bean id="myBean" class="com.example.MyBean"/>
public class MyBean { public void process(String message) { // or Exchange, or org.apache.camel.component.telegram.model.IncomingMessage (or both) // do process } }
from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere") .bean(ChatBotLogic.class) .to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere");
<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"/>
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 } }
from("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere") .to("log:INFO?showHeaders=true");
from("timer:tick") .setBody().constant("Hello") to("telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere&chatId=123456")
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");
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");
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-netty-http</artifactId> <version>{CamelSBVersion}</version> <!-- use the same version as your Camel core version --> </dependency>
from("webhook:telegram:bots?authorizationToken=123456789:insertYourAuthorizationTokenHere").to("log:info");