onProxyRes相關代碼:
option.onProxyRes = function (proxyRes: any, req: any, res: any) {
// 參考:https://www.jianshu.com/p/f8ac6e813b96
const oriWriteHead = res.writeHead;
const oriWrite = res.write;
const oriEnd = res.end;
let chunks: any = [];
let size = 0;
Object.assign(res, {
writeHead: () => {},
write: (chunk: any) => {
chunks.push(chunk);
size += chunk.length;
},
end: () => {
let oriBuffer = Buffer.concat(chunks, size);
console.log('buffer:', oriBuffer);
console.log('************');
console.log(oriBuffer.toString());
console.log('************');
const buffer = Buffer.concat(chunks, size); // 一定要轉成buffer,buffer長度和string長度不一樣
const headers = Object.keys(proxyRes.headers)
.reduce((prev, key) => {
const value = key === 'content-length' ? buffer.length : proxyRes.headers[key];
return Object.assign({}, prev, {[key]: value});
}, {});
oriWriteHead.apply(res, [200, headers]);
oriWrite.call(res, buffer);
oriEnd.call(res);
}
});
};
當接口返回數據不包含中文時,可以正常打印數據
當接口數據包含中文時,發現亂碼了:
查詢過很多解決方案都沒辦法解決這個問題,嘗試過的解決方法:
- 利用Buffer.concat
- 利用iconv-lite decode
解決方案
觀察接口響應header,發現了這樣一個字段:
content-encoding: gzip
瞬間就聯想到是不是代理的數據是被壓縮過的,於是查看node如何解壓縮gzip數據,發現了zlib這個包,對接收到的chunk數據進行gunzip之後發現能夠正常解析數據了。
還是前文的代碼,在end函數中對oriBuffer進行處理:
let oriBuffer = Buffer.concat(chunks);
const compressBuffer = handleBuffer(oriBuffer,proxyRes.headers['content-encoding'], handleJsonResFunc);
handleBuffer方法如下:
const zlib = require('zlib');
/**
* 根據Content-Encoding消息頭確定解碼方式,處理完數據之後再編碼回去
* @param oriBuffer
* @param encoding 消息頭中的編碼格式
* @param handleJsonResFunc
*/
function handleBuffer(oriBuffer: Buffer, encoding: string, handleJsonResFunc: Function) {
let decodeMethod: string = '';
let encodeMethod: string = '';
// 編碼格式介紹:https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Headers/Content-Encoding
switch (encoding) {
case 'gzip':
decodeMethod = 'gunzipSync';
encodeMethod = 'gzipSync';
break;
case 'deflate':
decodeMethod = 'inflateSync';
encodeMethod = 'deflateSync';
break;
case 'br':
decodeMethod = 'brotliDecompressSync';
encodeMethod = 'brotliCompressSync';
break;
default:
break;
}
let decodeBuffer: Buffer = oriBuffer;
if (decodeMethod && encodeMethod) {
decodeBuffer = zlib[decodeMethod](oriBuffer);
}
// 當JSON數據轉換錯的時候提示前端報錯
let oriJSONRes: any;
try {
oriJSONRes = JSON.parse(decodeBuffer.toString());
}
catch (e) {
console.error('[error]: JSON parse error! origin string: ', decodeBuffer.toString());
// ErrorMessage爲自定義的消息格式,可以忽略ErrorMessage相關代碼
oriJSONRes = new ErrorMessage({server: 'from node'}, 'Server Proxy data error');
}
const handledJSONRes = oriJSONRes instanceof ErrorMessage ? oriJSONRes : handleJsonResFunc(oriJSONRes);
// 一定要轉成buffer,buffer長度和string長度不一樣
const buffer = new Buffer(JSON.stringify(handledJSONRes));
return decodeMethod && encodeMethod ? zlib[encodeMethod](buffer) : buffer;
}