http-proxy-stream

a proxy tool which damn convenient with stream pipe. also with 90+% test coverage. inspired by request

features

pipe http proxy
modify response before pipe to destination stream
cache request data and response data for later usage

Install

npm i --save http-proxy-stream

API

proxy(request, [options, response])

request: http.IncomingMessage instance or other instance of request.
options: Object, all options of http.request.
options.url: String, the target url with protocal and search part. like http://www.google.com?search=foo
options.modifyResponse: Function(response), Optional, modify response before pipe to destination stream. accept one argument which is the body of response. the this keyword is reference of request.Request instance. the return value will be the new content of response.
options.skipModifyResponse: Function(response), return true will skip modifyResponse.
options.onResponse: Function(response), call once when http.ClientRequest emit 'response' event.
options.cache: Boolean|Function(response), default false, if true will cache resopnse data for later usage. if function will call with response as first argument, return true will cache response.
response: Optional, writable stream, like http.ServerResponse instance.
Return: Promise

proxy.mime

proxy.mime.isText(mimeType)

the miem type mean the http body is text which need deconding with charset

proxy.mime.isJSON(mimeType)

true the content can been json stringified, false otherwise.

proxyReturn.contentType

a object parsed from http header 'content-type' field which like {type: 'text/plain', charset: 'utf-8', parameters: {}}

proxyReturn.contentEncoding

then value of 'Content-Encoding' header

Usage

Normal Proxy

const proxy = require('http-proxy-stream');
const http = require('http');

// http useage
http.createServer((req, res) => {
  proxy(req, {
    url: `http://www.google.com${req.url}`,
    onResponse() {
      // A chance to rewrite response headers before pipe
      response.headers.test = 'test';
    }
  }, res);
}).listen(8000);

http.createServer((req, res) => {
  proxy(req, {
    url: `http://www.google.com${req.url}`,
    onResponse() {
      // A chance to rewrite response headers before pipe
      response.headers.test = 'test';
    }
  })
    .then(resp => resp.pipe(res))
    .catch(err => {
      res.writeHead(500);
      res.end(err)
    });
}).listen(8000);

// koa middleware
function* koaProxy(next) {
  this.body = yield proxy(this.req, {
    url: `http://www.google.com${this.req.url}`,
    onResponse(response) {
      response.headers.test = 'test';
    }
  });
}

Modify Reponse Before Pipe

Some times we want modify the response of the backend services. you can define a function as options.modifyResponse.

const proxy = require('http-proxy-stream');
const http = require('http');

// http useage
http.createServer((req, res) => {
  proxy(req, {
    url: `http://www.google.com${req.url}`,
    onResponse(response) {
      response.headers.test = 'test';
    },
    modifyResponse(response) {
      // change headers
      response.headers['content-type'] = 'application/json; charset: utf8';
      // use new content, can be string, buffer, null, undefined or object;
      response.body = {content: body};
    }
  }, res);
}).listen(8000);

Skip Modify Reponse

modify response will cause unzip and charset decode, some response like downloading big file is bad performance. we can use options.skipModifyResponse to skip it;

const proxy = require('http-proxy-stream');
const http = require('http');

// http useage
http.createServer((req, res) => {
  proxy(req, {
    url: `http://www.google.com${req.url}`,
    onResponse(response) {
      response.headers.test = 'test';
    },
    skipModifyResponse(response) {
      return proxy.mime.isText(response.contentType.type);
    },
    modifyResponse(response) {
      // change headers
      response.headers['content-type'] = 'application/json; charset: utf8';
      // use new content, can be string, buffer, null, undefined or object;
      response.body = {content: body};
    }
  }, res);
}).listen(8000);

Get Data After Pipe

for debug reason, you may want log the response status or monitor the content. but if we read content everytime that may be negative to performance. so we can use options.cache for a chance to read data after http reponse finished. options.cache can be a function or boolean, default is false. let's see a example.

http.createServer((req, res) => {
  proxy(req, {
    url: `http://www.google.com${req.url}`,
    cache(response) {
      // only when the content is text type, cache the data
      return proxy.isText(response.contentType.type);
    }
  }, res)
    .then(resp => {
      res.on('finish', () => {
        resp.resetReadable();
        let responseChunks = [];
        resp.on('data', (chunk) => {
          responseChunks.push(chunk);
        });
        resp.on('end', (chunk) => {
          chunk && responseChunks.push(chunk);
        });

        resp.reqCacheStream.resetReadable();
        let requestChunks = [];
        resp.reqCacheStream.on('data', (chunk) => {
          requestChunks.push(chunk);
        });
        resp.reqCacheStream.on('end', (chunk) => {
          chunk && requestChunks.push(chunk);
        });
      });
    });
}).listen(8000);

Auto Redirect

autoSameOriginRedirect

Develop

$> npm i
$> npm test
$> npm publish

Release Note

v1.0.3 2017-02-16 * catch inner error

v1.0.2 2017-02-07 * refactor readBody method of read-content.js

v1.0.1 2017-02-07

* CacheStream add clearCahce method
* tiny fix
* README update

v1.0.0 2017-02-06

* new api and new lib name

v0.1.3 2016-09-22

* catch some errors and reject them

v0.1.2 2016-09-17

* modifyResponse can set response.body to object, null and undefined.

v0.1.1 2016-09-17

* fix some bugs in koa flow.

v0.1.0 2016-09-12

* first version

QubitProducts/http-proxy-stream