教程

B站直播开发平台弹幕获取教程01

代码

1、引入相关库

dependencies:crypto: ^3.0.3uuid: ^4.1.0dio: ^5.3.3archive: ^3.3.7

2、创建bili_project.dart

import 'dart:convert';
import 'package:bili_websocket.dart';
import 'package:crypto/crypto.dart';
import 'package:uuid/uuid.dart';
import 'package:dio/dio.dart';class BiliOpenApi{static const Uuid myUuid = Uuid();static Dio dio = Dio();static const String host = "https://live-open.biliapi.com";late int _appId;late String _accesskey;late String _accessSecret;BiliOpenApi(this._appId, this._accesskey, this._accessSecret);///开始项目Future<Response> start(String code) async {Map data = {'code': code,'app_id': _appId};return _post("/v2/app/start", data);}///项目心跳Future<Response> heartbeat(String gameId) async {Map data = {'game_id': gameId};return _post("/v2/app/heartbeat", data);}///批量发送心跳Future<Response> batchHeartbeat(List<String> gameId) async {Map data = {'game_ids': gameId};return _post("/v2/app/batchHeartbeat", data);}///结束项目Future<Response> end(String gameId) async {Map data = {'app_id': _appId,'game_id': gameId};return _post("/v2/app/end", data);}//自定义POST请求Future<Response> _post(String url ,Map data) async {String body =  json.encode(data);Options options = Options();///请求header的配置options.contentType="application/json";options.headers = _headers(body);return await dio.post('$host$url',options:options, data: body);}/// 添加B站请求头Map<String,String> _headers(String body){int timestamp = DateTime.now().millisecondsSinceEpoch ~/ 1000;print(timestamp);Map<String,String> headers = {'Accept':	'application/json','Content-Type':	'application/json','x-bili-content-md5':	md5.convert(utf8.encode(body)).toString(),'x-bili-timestamp':	timestamp.toString(),'x-bili-signature-method':	'HMAC-SHA256','x-bili-signature-nonce':	myUuid.v4(),'x-bili-accesskeyid':	_accesskey,'x-bili-signature-version':	'1.0','Authorization':	''};headers['Authorization'] = _generateSignature(headers);return headers;}/// B站请求头签名String _generateSignature(Map<String,String> headers){String? contentMd5 = headers['x-bili-content-md5'];String? nonce = headers['x-bili-signature-nonce'];String? timestamp = headers['x-bili-timestamp'];String sginText = "x-bili-accesskeyid:$_accesskey\nx-bili-content-md5:$contentMd5\nx-bili-signature-method:HMAC-SHA256\nx-bili-signature-nonce:$nonce\nx-bili-signature-version:1.0\nx-bili-timestamp:$timestamp";List<int> key = utf8.encode(_accessSecret);List<int> message = utf8.encode(sginText);return Hmac(sha256, key).convert(message).toString();}
}

3、新建 bili_websocket.dart

注意：解压zip数据部分，我没办法测试，比较没这么大量，请自行测试

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';
import 'package:dio/dio.dart';
import 'package:archive/archive.dart';///根据start的响应 打开websocket
Future<void> openApiWsByStartResp(Response response) async {var data = response.data['data'];var anchorInfo = data['anchor_info'];//个人信息var gameInfo = data['game_info'];//项目游戏场次var websocketInfo = data['websocket_info'];var authBody = websocketInfo['auth_body'];//鉴权数据var wssLink = websocketInfo['wss_link'];//弹幕服务地址//打开websocketopenApiWs(wssLink[0], authBody);
}
///打开websocket
Future<void> openApiWs(String url,String authBody) async {print("连接websocket地址:$url");var socket = await WebSocket.connect(url);if(socket.readyState == WebSocket.open){print("发送鉴权包");socket.add(_authPack(authBody));// 发送心跳包sendHeartbeatPack(socket);//监听socket.listen((data) {//解包unpack(convertUint8ArrayViewToUint8List(data));}, onDone: () {print('WebSocket断开');},onError: (e){print("服务异常:$e");});}
}
///将Websocket响应转为Uint8List
Uint8List convertUint8ArrayViewToUint8List(dynamic view) {final list = Uint8List(view.length);for (var i = 0; i < view.length; i++) {list[i] = view[i];}return list;
}///Operation：消息的类型： int32:四个字节
const int optCodeHeartbeat = 2; //客户端发送的心跳包(30秒发送一次)
const int optCodeHeartbeatReply = 3; //服务器收到心跳包的回复
const int optCodeSendSmsReply = 5; //服务器推送的弹幕消息包
const int optCodeAuth = 7; //客户端发送的鉴权包(客户端发送的第一个包)
const int optCodeAuthReply = 8; //服务器收到鉴权包后的回复///生成鉴权包
List<int> _authPack(String authBody){return _pack(authBody, optCodeAuth);
}
///生成心跳包
List<int> _HeartbeatPack(){return _pack("", optCodeHeartbeat);
}/// 定时每30秒发送心跳包
sendHeartbeatPack(WebSocket webSocket){Timer.periodic(Duration(seconds: 30), (Timer t){if (webSocket.readyState == WebSocket.open) {webSocket.add(_HeartbeatPack());print("发送心跳");}});
}///封包
List<int> _pack(String body,int optCode){List<int> result = [];List<int> bodyBytes = [];if(body != ""){print("鉴权body:$body");bodyBytes = utf8.encode(body);}ByteData bd = ByteData(16);//Packet Length：整个Packet的长度，包含Header int32:四个字节bd.setInt32(0, 16+bodyBytes.length);// Header Length：Header的长度，固定为16。int16:两个个字节bd.setInt16(4, 16);//Version：int16:两个个字节//如果Version=0，Body中就是实际发送的数据。//如果Version=2，Body中是经过压缩后的数据，请使用zlib解压，然后按照Proto协议去解析。bd.setInt16(6, 0);bd.setInt32(8, optCode);//Sequence ID：保留字段，可以忽略。int32:四个字节bd.setInt32(12, 1);for (int i = 0; i < bd.lengthInBytes; i++) {result.add(bd.getUint8(i));}result.addAll(bodyBytes);return result;
}///解包
void unpack(Uint8List uint8list){ByteData byteData = ByteData.sublistView(uint8list);int packLength = byteData.getInt32(0);//包大小//int headerLength = byteData.getInt16(4);//头部长度int version = byteData.getInt16(6);//版本：判断是否压缩包. 2为压缩包int optCode = byteData.getInt32(8);//操作码//int sequence = byteData.getInt32(12);//Sequence ID：保留字段，可以忽略。int32:四个字节print("包大小:$packLength,版本：$version，操作码：$optCode");Uint8List bodyList = uint8list.sublist(16, packLength);//如果是压缩包，就再解包if(version == 2){//Deflate解压没测试过，我直播间没有这么大的量bodyList = Uint8List.fromList(Deflate(bodyList).getBytes());unpack(bodyList);return;}if(optCode == optCodeHeartbeatReply){print('收到服务器心跳');return;}String bodyStr = utf8.decode(bodyList);Map<String, dynamic> BodyMap = json.decode(bodyStr);if(optCode == optCodeAuthReply && BodyMap["code"] == 0){print("鉴权成功");}//弹幕消息if(optCode == optCodeSendSmsReply){//获得真正的消息String cmdCode = BodyMap["cmd"];switch(cmdCode){case "NOTICE_MSG":{//print('通知消息:$bodyStr');}case "STOP_LIVE_ROOM_LIST":{//print('离开房间ID列表:$bodyStr');}default:{print('弹幕数据类型:$cmdCode');Map<String, dynamic> dataMap = BodyMap["data"];print('弹幕数据:$dataMap');//todo//你自定义处理数据方法}}}//只有压缩包，存在这种情况if(packLength < uint8list.lengthInBytes){unpack(uint8list.sublist(packLength));}
}

4、使用

void main(){BiliOpenApi bp = BiliOpenApi(你的应用ID,你的Access_key,你的Access_Secret);//调用项目start方法，获取弹幕服务信息Future<Response> start = bp.start(你的身份码);start.then((response) => {//根据弹幕服务信息 打开WebsocketopenApiWsByStartResp(response)});
}

参数获取
Access_key 和 Access_Secret	去B站直播开放平台注册申请个人开发者
应用ID	成为个人开发者后，在直播开放平台创建应用后，就能获得应用ID
身份码	登录B站直播间找到幻星-互动玩法，在里面就能找到身份码

注意：
项目没有上架前，调用BiliOpenApi的start方法不能获得场次ID，所以调用BiliOpenApi的heartbeat和end方法都会报错。
但这没有关系，start方法能正常获得弹幕服务信息，就可以获得个人直播间弹幕了。