监听弹幕时获取用户头像

[sunft1996]

Clear and concise description of the problem

如题

Suggested solution

如题

Alternative

No response

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[ddiu8081]

目前原始弹幕消息中不包含头像数据，获取头像需要手动通过接口取，给框架添加此功能可能带来一些问题：

1. 可能会引入额外依赖，目前仅读取 Websocket / TCP 流，如果读取 HTTP 接口可能还需要增加依赖库
2. 弹幕密集时可能会被频控限制
3. 浏览器环境存在跨域问题，无法获取

因此添加头像可能比较困难，目前建议是自行维护头像获取和频控逻辑。之后调研如果方便的话 会内置进来

[micooz]

也许能用隔壁的方案：xfgryujk/blivedm@2b04284

具体做法是在 DANMU_MSG.parser 中添加解析 dm_v2 字段的代码。

blive-message-listener/src/parser/DANMU_MSG.ts

Lines 31 to 33 in 9976d78

	const parser = (data: DataType, roomId: number): DanmuMsg => {
	const rawData = data.info
	const content = rawData[1]

dm_v2 是一个经过 base64 编码的 protobuf 报文，里面包含用户头像字段，协议格式在上面的 blivedm/pb_models.py 中有实现。

echo -n "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" | base64 -d | hexdump -C

可能还需要引入一个类似 pure-protobuf 的 decoder 来方便解析。

[Tsuk1ko]

可以使用 protobufjs，分享一个我自己测试可行的方案

import { length as b64len, decode as b64dec } from '@protobufjs/base64';
import { Type, Field } from 'protobufjs';

const decodeB64 = str => {
  const length = b64len(str);
  const buffer = new Uint8Array(length);
  b64dec(str, buffer, 0);
  return buffer;
};

const UserInfo = new Type('UserInfo').add(new Field('face', 4, 'string'));
const DanmakuMessageV2 = new Type('DanmakuMessageV2').add(UserInfo).add(new Field('user', 20, 'UserInfo'));

/**
 * @param {string} str
 * @returns {{ user: { face: string } }}
 */
export const decodeDmV2 = str => {
  const buffer = decodeB64(str);
  return DanmakuMessageV2.decode(buffer);
};