onProxyRes相关代码:
option.onProxyRes = function (proxyRes: any, req: any, res: any) {
// 参考: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); // 一定要转成buffer,buffer长度和string长度不一样
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);
}
});
};
当接口返回数据不包含中文时,可以正常打印数据
当接口数据包含中文时,发现乱码了:
查询过很多解决方案都没办法解决这个问题,尝试过的解决方法:
观察接口响应header,发现了这样一个字段:
content-encoding: gzip
瞬间就联想到是不是代理的数据是被压缩过的,于是查看node如何解压缩gzip数据,发现了zlib这个包,对接收到的chunk数据进行gunzip之后发现能够正常解析数据了。
还是前文的代码,在end函数中对oriBuffer进行处理:
let oriBuffer = Buffer.concat(chunks);
const compressBuffer = handleBuffer(oriBuffer,proxyRes.headers['content-encoding'], handleJsonResFunc);
handleBuffer方法如下:
const zlib = require('zlib');
/**
* 根据Content-Encoding消息头确定解码方式,处理完数据之后再编码回去
* @param oriBuffer
* @param encoding 消息头中的编码格式
* @param handleJsonResFunc
*/
function handleBuffer(oriBuffer: Buffer, encoding: string, handleJsonResFunc: Function) {
let decodeMethod: string = '';
let encodeMethod: string = '';
// 编码格式介绍: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);
}
// 当JSON数据转换错的时候提示前端报错
let oriJSONRes: any;
try {
oriJSONRes = JSON.parse(decodeBuffer.toString());
}
catch (e) {
console.error('[error]: JSON parse error! origin string: ', decodeBuffer.toString());
// ErrorMessage为自定义的消息格式,可以忽略ErrorMessage相关代码
oriJSONRes = new ErrorMessage({server: 'from node'}, 'Server Proxy data error');
}
const handledJSONRes = oriJSONRes instanceof ErrorMessage ? oriJSONRes : handleJsonResFunc(oriJSONRes);
// 一定要转成buffer,buffer长度和string长度不一样
const buffer = new Buffer(JSON.stringify(handledJSONRes));
return decodeMethod && encodeMethod ? zlib[encodeMethod](buffer) : buffer;
}