LINE Messaging API SDK for Java

Introduction

The LINE Messaging API SDK for Java makes it easy to develop bots using LINE Messaging API, and you can create a sample bot within minutes.

Documentation

See the official API documentation for more information.

• English: https://developers.line.biz/en/docs/messaging-api/overview/
• Japanese: https://developers.line.biz/ja/docs/messaging-api/overview/

Requirements

This library requires Java 17 or later.

Installation

We've uploaded this library to the Maven Central Repository. You can install the modules using Maven or Gradle.

https://central.sonatype.com/search?smo=true&q=com.linecorp.bot

Gradle (Kotlin) example

implementation("com.linecorp.bot:line-bot-messaging-api-client:<VERSION>")
implementation("com.linecorp.bot:line-bot-insight-client:<VERSION>")
implementation("com.linecorp.bot:line-bot-manage-audience-client:<VERSION>")
implementation("com.linecorp.bot:line-bot-module-attach-client:<VERSION>")
implementation("com.linecorp.bot:line-bot-module-client:<VERSION>")
implementation("com.linecorp.bot:line-bot-shop-client:<VERSION>")
implementation("com.linecorp.bot:line-channel-access-token-client:<VERSION>")
implementation("com.linecorp.bot:line-liff-client:<VERSION>")

implementation("com.linecorp.bot:line-bot-webhook:<VERSION>")
implementation("com.linecorp.bot:line-bot-parser:<VERSION>") // You don't need to depend on this explicitly.

implementation("com.linecorp.bot:line-bot-spring-boot-webmvc:<VERSION>")
implementation("com.linecorp.bot:line-bot-spring-boot-client:<VERSION>") // If you want to write spring-boot API client
implementation("com.linecorp.bot:line-bot-spring-boot-handler:<VERSION>") // You don't need to depend on this explicitly.
implementation("com.linecorp.bot:line-bot-spring-boot-web:<VERSION>") // You don't need to depend on this explicitly.

Sample code

This project contains the following sample projects:

• sample-spring-boot-echo: A simple echo server.
• sample-spring-boot-kitchensink: Full featured sample code.
• sample-spring-boot-echo-kotlin: A simple echo server written in Kotlin.
• sample-manage-audience: A sample code for Manage Audience API.

Spring Boot integration

The line-bot-spring-boot module lets you build a bot application as a Spring Boot application.

package com.example.bot.spring.echo;

import java.util.List;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import com.linecorp.bot.messaging.client.MessagingApiClient;
import com.linecorp.bot.messaging.model.ReplyMessageRequest;
import com.linecorp.bot.messaging.model.TextMessage;
import com.linecorp.bot.spring.boot.handler.annotation.EventMapping;
import com.linecorp.bot.spring.boot.handler.annotation.LineMessageHandler;
import com.linecorp.bot.webhook.model.Event;
import com.linecorp.bot.webhook.model.MessageEvent;
import com.linecorp.bot.webhook.model.TextMessageContent;

@SpringBootApplication
@LineMessageHandler
public class EchoApplication {
    private final MessagingApiClient messagingApiClient;

    public static void main(String[] args) {
        SpringApplication.run(EchoApplication.class, args);
    }

    public EchoApplication(MessagingApiClient messagingApiClient) {
        this.messagingApiClient = messagingApiClient;
    }

    @EventMapping
    public void handleTextMessageEvent(MessageEvent<TextMessageContent> event) {
        System.out.println("event: " + event);
        final String originalMessageText = ((TextMessageContent) event.message()).text();
        messagingApiClient.replyMessage(
            new ReplyMessageRequest.Builder(event.replyToken(), List.of(new TextMessage(originalMessageText)))
                .build()
        );
    }

    @EventMapping
    public void handleDefaultMessageEvent(Event event) {
        System.out.println("event: " + event);
    }
}

How do I use a proxy server?

You can use a proxy with this module.

api = MessagingApiClient.builder("MY_OWN_TOKEN")
        .apiEndPoint(URI.create("https://api.line.me/"))
        .proxy(new Proxy(Proxy.Type.HTTP,
                new InetSocketAddress("proxy.example.com", 8080)
        ))
        .build();

Note: You don't need to use an add-on like Fixie to have static IP addresses for proxy servers. You can make API calls without entering IP addresses on the server IP whitelist.

How to get x-line-request-id header and error message

You may need to store the x-line-request-id header obtained as a response from several APIs. In this case, you can get it from Result<T>.

Result<Object> apiResponse = messagingApiClient
    .narrowcast(retryKey, new NarrowcastRequest.Builder(messages).build())
    .get();
System.out.println("x-line-request-id: " + apiResponse.requestId());

You can get error messages from MessagingApiClientException when you use MessagingApiClient. Each client defines its own exception class.

try {
    messagingApiClient.replyMessage(new ReplyMessage(replyToken, messages));
} catch (ExecutionException e) {
    if (e.getCause() instanceof MessagingApiClientException){
        MessagingApiClientException exception=(MessagingApiClientException)e.getCause();
        System.out.println("Error http status code: " + exception.getCode());
        System.out.println("Error response: " + exception.getDetails());
        System.out.println("Error message: " + exception.getMessage());
    }
}

When you need to get x-line-accepted-request-id header from error response, you can get it: exception.getHeader("x-line-accepted-request-id").

Help and media

FAQ: https://developers.line.biz/en/faq/

News: https://developers.line.biz/en/news/

Versioning

This project respects semantic versioning.

See http://semver.org/.

From version 7.x

LINE's SDK developer team decides to generate SDK code based on OpenAPI spec. As a result, LINE bot sdk 7.x is not compatible with 6.x. But it can follow the future API changes very quickly.

• line-bot-model and line-bot-api-client are splitted to line-bot-webhook and clients/ modules
• line-bot-servlet is no longer supported.
• line-bot-cli is no longer supported.
• line-bot-spring-boot was splitted.
  • Splitted to following modules.
    • line-bot-spring-boot-client is a client bean configuration module.
      • If you want to write spring-boot API client,
    • line-bot-spring-boot-handler is a handler configuration.
      • You don't need to depend this explicitly.
    • line-bot-spring-boot-web is a spring-web binding.
      • You don't need to depend this explicitly.
    • line-bot-spring-boot-webmvc is a spring-webmvc binding.
      • usually, you want to depend on this module.

Contributing

Please check CONTRIBUTING before making a contribution.

License

Copyright (C) 2016 LINE Corp.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.