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- # stream-http [![Build Status](https://travis-ci.org/jhiesey/stream-http.svg?branch=master)](https://travis-ci.org/jhiesey/stream-http)
-
- [![Sauce Test Status](https://saucelabs.com/browser-matrix/stream-http.svg)](https://saucelabs.com/u/stream-http)
-
- This module is an implementation of Node's native `http` module for the browser.
- It tries to match Node's API and behavior as closely as possible, but some features
- aren't available, since browsers don't give nearly as much control over requests.
-
- This is heavily inspired by, and intended to replace, [http-browserify](https://github.com/substack/http-browserify).
-
- ## What does it do?
-
- In accordance with its name, `stream-http` tries to provide data to its caller before
- the request has completed whenever possible.
-
- Backpressure, allowing the browser to only pull data from the server as fast as it is
- consumed, is supported in:
- * Chrome >= 58 (using `fetch` and `WritableStream`)
-
- The following browsers support true streaming, where only a small amount of the request
- has to be held in memory at once:
- * Chrome >= 43 (using the `fetch` API)
- * Firefox >= 9 (using `moz-chunked-arraybuffer` responseType with xhr)
-
- The following browsers support pseudo-streaming, where the data is available before the
- request finishes, but the entire response must be held in memory:
- * Chrome
- * Safari >= 5, and maybe older
- * IE >= 10
- * Most other Webkit-based browsers, including the default Android browser
-
- All browsers newer than IE8 support binary responses. All of the above browsers that
- support true streaming or pseudo-streaming support that for binary data as well
- except for IE10. Old (presto-based) Opera also does not support binary streaming either.
-
- ### IE8 note:
- As of version 2.0.0, IE8 support requires the user to supply polyfills for
- `Object.keys`, `Array.prototype.forEach`, and `Array.prototype.indexOf`. Example
- implementations are provided in [ie8-polyfill.js](ie8-polyfill.js); alternately,
- you may want to consider using [es5-shim](https://github.com/es-shims/es5-shim).
- All browsers with full ES5 support shouldn't require any polyfills.
-
- ## How do you use it?
-
- The intent is to have the same API as the client part of the
- [Node HTTP module](https://nodejs.org/api/http.html). The interfaces are the same wherever
- practical, although limitations in browsers make an exact clone of the Node API impossible.
-
- This module implements `http.request`, `http.get`, and most of `http.ClientRequest`
- and `http.IncomingMessage` in addition to `http.METHODS` and `http.STATUS_CODES`. See the
- Node docs for how these work.
-
- ### Extra features compared to Node
-
- * The `message.url` property provides access to the final URL after all redirects. This
- is useful since the browser follows all redirects silently, unlike Node. It is available
- in Chrome 37 and newer, Firefox 32 and newer, and Safari 9 and newer.
-
- * The `options.withCredentials` boolean flag, used to indicate if the browser should send
- cookies or authentication information with a CORS request. Default false.
-
- This module has to make some tradeoffs to support binary data and/or streaming. Generally,
- the module can make a fairly good decision about which underlying browser features to use,
- but sometimes it helps to get a little input from the developer.
-
- * The `options.mode` field passed into `http.request` or `http.get` can take on one of the
- following values:
- * 'default' (or any falsy value, including `undefined`): Try to provide partial data before
- the request completes, but not at the cost of correctness for binary data or correctness of
- the 'content-type' response header. This mode will also avoid slower code paths whenever
- possible, which is particularly useful when making large requests in a browser like Safari
- that has a weaker JavaScript engine.
- * 'allow-wrong-content-type': Provides partial data in more cases than 'default', but
- at the expense of causing the 'content-type' response header to be incorrectly reported
- (as 'text/plain; charset=x-user-defined') in some browsers, notably Safari and Chrome 42
- and older. Preserves binary data whenever possible. In some cases the implementation may
- also be a bit slow. This was the default in versions of this module before 1.5.
- * 'prefer-stream': Provide data before the request completes even if binary data (anything
- that isn't a single-byte ASCII or UTF8 character) will be corrupted. Of course, this option
- is only safe for text data. May also cause the 'content-type' response header to be
- incorrectly reported (as 'text/plain; charset=x-user-defined').
- * 'disable-fetch': Force the use of plain XHR regardless of the browser declaring a fetch
- capability. Preserves the correctness of binary data and the 'content-type' response header.
- * 'prefer-fast': Deprecated; now a synonym for 'default', which has the same performance
- characteristics as this mode did in versions before 1.5.
-
- * `options.requestTimeout` allows setting a timeout in millisecionds for XHR and fetch (if
- supported by the browser). This is a limit on how long the entire process takes from
- beginning to end. Note that this is not the same as the node `setTimeout` functions,
- which apply to pauses in data transfer over the underlying socket, or the node `timeout`
- option, which applies to opening the connection.
-
- ### Features missing compared to Node
-
- * `http.Agent` is only a stub
- * The 'socket', 'connect', 'upgrade', and 'continue' events on `http.ClientRequest`.
- * Any operations, including `request.setTimeout`, that operate directly on the underlying
- socket.
- * Any options that are disallowed for security reasons. This includes setting or getting
- certain headers.
- * `message.httpVersion`
- * `message.rawHeaders` is modified by the browser, and may not quite match what is sent by
- the server.
- * `message.trailers` and `message.rawTrailers` will remain empty.
- * Redirects are followed silently by the browser, so it isn't possible to access the 301/302
- redirect pages.
- * The `timeout` event/option and `setTimeout` functions, which operate on the underlying
- socket, are not available. However, see `options.requestTimeout` above.
-
- ## Example
-
- ``` js
- http.get('/bundle.js', function (res) {
- var div = document.getElementById('result');
- div.innerHTML += 'GET /beep<br>';
-
- res.on('data', function (buf) {
- div.innerHTML += buf;
- });
-
- res.on('end', function () {
- div.innerHTML += '<br>__END__';
- });
- })
- ```
-
- ## Running tests
-
- There are two sets of tests: the tests that run in Node (found in `test/node`) and the tests
- that run in the browser (found in `test/browser`). Normally the browser tests run on
- [Sauce Labs](http://saucelabs.com/).
-
- Running `npm test` will run both sets of tests, but in order for the Sauce Labs tests to run
- you will need to sign up for an account (free for open source projects) and put the
- credentials in a [`.zuulrc` file](https://github.com/defunctzombie/zuul/wiki/zuulrc).
-
- To run just the Node tests, run `npm run test-node`.
-
- To run the browser tests locally, run `npm run test-browser-local` and point your browser to
- `http://localhost:8080/__zuul`
-
- ## License
-
- MIT. Copyright (C) John Hiesey and other contributors.
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