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HTTP, Please

There are a lot of JS libraries for making HTTP requests in JavaScript. Why use this one? Because it's awesome, that's why. And this is why it's awesome:

  • Designed for "isomorphic" JavaScript (supporting both client and server with the same codebase)
  • …but with a browser-driven focus that keeps in mind the limitations of that environment (filesize, old IE)
  • Extensible via a simple but powerful plugin system (which it dogfoods)

browserify and webpack users can simply npm install httpplease.

Bower users can bower install httpplease.

<script> tag fans can grab the standalone build from the "browser-builds" directory.

Minified and gzipped, the standalone browser build is <2K.

API

Making a request

httpplease.get('http://example.com', function (err, res) {
    // Do something with the result.
});

Alternatively, you can pass a request options object as the first parameter:

httpplease.get({url: 'http://example.com'}, function (err, res) {
    // Do something with the result.
});

If you'd rather include the method in the object, that's okay too:

httpplease({method: 'GET', url: 'http://example.com'}, function (err, res) {
    // Do something with the result.
});

You can create a new http function with default request object values:

var http = httpplease.defaults({method: 'GET', errorOn404: false});
http('http://example.com', function (err, res) {
    // This request was made using the defaults specified above.
});

The request object

When you call one of the http functions (http, http.get, etc.), the result is a Request object. This object can also be processed by plugins. It has the same properties as the request options object you pass to the http function (though properties that you didn't pass will be filled by defaults). Those properties are:

Name Description
url The URL to request.
method The HTTP method to use for the request.
body The body to send with the request.
headers An object containing HTTP headers to send, for example: {Accept: '*/*'}.
timeout The number of milliseconds to wait before canceling the request. If the request takes longer than this, your callback will be invoked with an error whose name is "Timeout".
errorOn404 A boolean specifying whether a 404 response should be treated as an error or not. Defaults to true.
header A method for getting and setting individual headers. This is simply a convenience method for reading and manipulating the headers dictionary that accounts for the case-insensitivity of headers. For example: req.header('Content-Type', 'text/html') sets a header and req.header('Content-Type') returns its value.
abort A method for aborting the request. This will will result in your callback being invoked. If an error was caused by an abort() call, its name will be "Abort".

The error object

In the event of an error, an error object will be passed as the first argument to your callback. If the error is an HTTP error, it will have all of the properties that a response object has (listed below), but will be a JS Error object (which can be useful if relying on instanceof checks). It also has one additional property—message—which contains a description of the error.

The response object

The response object passed to your callback in the event of a successful request has the following properties:

status The numeric status code.
text The raw response text.
body The processed response body. Depending on the content type of the response and the plugins being used, this may be the same as `response.text` (a string) or some other object (like a parsed JSON object).
contentType The content type of the response.
headers An object containing the parsed response headers.
header A method for looking up the value of a specific header. This takes into account the case-insensitivity of headers. For example, res.header('content-type') will return the correct value regardless of the actual capitalization.
isHttpError A boolean that specifies whether this object represents a server-reported HTTP error. This may be false—even on error objects—in the case of non-HTTP errors like XDomain failures or plugin errors.
request An object representing the request.
xhr The XHR or XDomain object used to make the request.

Plugins

httpplease supports plugins for changing how requests are made. Some plugins are built in:

Name Enabled by Default? Description
jsonresponse No Converts JSON responses into JS objects on response.body.
jsonrequest No Serializes regular JavaScript objects stored on request.body and sets the Content-Type header to "application/json".
json No Combines the "jsonrequest" and "jsonresponse" plugins.
cleanurl Yes Encodes unencoded characters in the request URL. Required by some browsers if you're using non-ASCII characters.
oldiexdomain No Enables cross domain requests in IE9 by (transparently) using the XDomainRequest object when necessary.
oldieactivex No For super old versions of IE that didn't define XMLHttpRequest, use an ActiveX object.
setprotocol No Automatically set the protocol for protocol-relative URLs, allowing them to be used in Node. Protocol-relative URLs are important and should be preferred since some browsers don't allow cross-protocol requests. This plugin can also optionally force an override of protocols even when they're present in the URL so that you can be sure you won't have cross-protocol request issues in browsers.

Plugins are enabled with the use method:

var json = require('httpplease/plugins/json');
httpplease = httpplease.use(json);

Or, if you're using the standalone build:

<script src="httpplease.js" type="text/javascript"></script>
<script src="httppleaseplugins.js" type="text/javascript"></script>
var json = httppleaseplugins.json;
httpplease = httpplease.use(json);

Notice that use returns a new httpplease instance. This is so that you can create multiple instances, each with their own plugins:

var http = httpplease.use(json);

http
  .use(oldiexdomain)
  .get('http://example.com', function (err, res) { ... }); // Uses "json" plugin and "oldiexdomain".
http.get('http://example.com', function (err, res) { ... }); // Only uses "json" plugin.
httpplease.get('http://example.com', function (err, res) { ... }); // No extra plugins are used.

You can use as many plugins as you want—either by passing multiple plugins to use or chaining calls:

var http = httpplease
  .use(json, oldiexdomain, myPlugin)
  .use(anotherPlugin);

In order to keep your builds as small as possible, most plugins aren't enabled by default. (See the table above.) However, some small plugins are. If you want to disable all plugins, use the bare() method:

var http = httpplease.bare();

Like use(), this method also returns a new httpplease instance so you can continue to use the old object with the original plugins intact.

Custom Plugins

In addition to the bundled plugins, you can create your own. Plugins are simply objects that implement one or more of the following methods:

Method Description
createXHR(req) Creates an XHR object. The first plugin that return a non-null value from this method will be used.
processRequest(req) This method gives the plugin a chance to manipulate the request object before the request is made. For example, it can change the body or add headers.
processResponse(res) This method gives the plugin a chance to manipulate the response object before the callback is invoked.

Similar Projects

Thanks

This project is mostly just a small wrapper around XMLHttpRequest and an (I hope) sensible structure for extending functionality. The reason it works on the server is because of driverdan's awesome node-XMLHttpRequest library—it's the secret sauce that makes the browser-focused design of httpplease possible!

Changelog

I try to write good commit messages so the commit log should be very readable, but here's a summary of some notable changes.

  • v0.16.0
    • Use onload on onerror where available since onreadystatechange can't differentiate between 0 status code errors and successes (gilbarbara/react-inlinesvg#10)
  • v0.15.0
    • Rename "jsonparser" to "jsonresponse"
    • Set Accept header in "jsonresponse" instead of "jsonrequest"
    • Add "json" plugin that combines "jsonrequest" and "jsonresponse"
  • v0.14.0
    • Move plugins from httpplease/lib/plugins to httpplease/plugins
  • v0.13.1
    • Don't add Content-Type header if request has no body in jsonrequest plugin. (This avoids an unneeded preflight request.)
  • v0.13.0
    • Add support for timeouts
  • v0.12.0
    • Add abort to request object
  • v0.11.0
    • Add setprotocol plugin
  • v0.9.0
    • Ignore request headers when using oldiexdomain
    • Change when plugin methods are called
  • v0.8.1
    • Add Accept header if not present for jsonrequest
  • v0.8.0
    • Add onload and onerror
  • v0.7.0
    • Goodbye CoffeeScript
  • v0.6.0
    • Add jsonrequest plugin
    • Add header() to Request and Response objects
    • More tests
  • v0.5.3
    • Improve content-type matching
  • v0.5.1
    • Fix bug with non-404s being suppressed by errorOn404
  • v0.5.0
    • Return request object from http methods
  • v0.4.0
    • Added errorOn404 option
    • Make defaults a method
    • Make plugins a method
  • v0.3.0
    • Response-like errors
    • More tests
  • v0.2.0
    • Initial release as "httpplease"