README.md
1agent-base
2==========
3### Turn a function into an [`http.Agent`][http.Agent] instance
4[](https://travis-ci.org/TooTallNate/node-agent-base)
5
6This module provides an `http.Agent` generator. That is, you pass it an async
7callback function, and it returns a new `http.Agent` instance that will invoke the
8given callback function when sending outbound HTTP requests.
9
10#### Some subclasses:
11
12Here's some more interesting uses of `agent-base`.
13Send a pull request to list yours!
14
15 * [`http-proxy-agent`][http-proxy-agent]: An HTTP(s) proxy `http.Agent` implementation for HTTP endpoints
16 * [`https-proxy-agent`][https-proxy-agent]: An HTTP(s) proxy `http.Agent` implementation for HTTPS endpoints
17 * [`pac-proxy-agent`][pac-proxy-agent]: A PAC file proxy `http.Agent` implementation for HTTP and HTTPS
18 * [`socks-proxy-agent`][socks-proxy-agent]: A SOCKS (v4a) proxy `http.Agent` implementation for HTTP and HTTPS
19
20
21Installation
22------------
23
24Install with `npm`:
25
26``` bash
27$ npm install agent-base
28```
29
30
31Example
32-------
33
34Here's a minimal example that creates a new `net.Socket` connection to the server
35for every HTTP request (i.e. the equivalent of `agent: false` option):
36
37```js
38var net = require('net');
39var tls = require('tls');
40var url = require('url');
41var http = require('http');
42var agent = require('agent-base');
43
44var endpoint = 'http://nodejs.org/api/';
45var parsed = url.parse(endpoint);
46
47// This is the important part!
48parsed.agent = agent(function (req, opts) {
49 var socket;
50 // `secureEndpoint` is true when using the https module
51 if (opts.secureEndpoint) {
52 socket = tls.connect(opts);
53 } else {
54 socket = net.connect(opts);
55 }
56 return socket;
57});
58
59// Everything else works just like normal...
60http.get(parsed, function (res) {
61 console.log('"response" event!', res.headers);
62 res.pipe(process.stdout);
63});
64```
65
66Returning a Promise or using an `async` function is also supported:
67
68```js
69agent(async function (req, opts) {
70 await sleep(1000);
71 // etc…
72});
73```
74
75Return another `http.Agent` instance to "pass through" the responsibility
76for that HTTP request to that agent:
77
78```js
79agent(function (req, opts) {
80 return opts.secureEndpoint ? https.globalAgent : http.globalAgent;
81});
82```
83
84
85API
86---
87
88## Agent(Function callback[, Object options]) → [http.Agent][]
89
90Creates a base `http.Agent` that will execute the callback function `callback`
91for every HTTP request that it is used as the `agent` for. The callback function
92is responsible for creating a `stream.Duplex` instance of some kind that will be
93used as the underlying socket in the HTTP request.
94
95The `options` object accepts the following properties:
96
97 * `timeout` - Number - Timeout for the `callback()` function in milliseconds. Defaults to Infinity (optional).
98
99The callback function should have the following signature:
100
101### callback(http.ClientRequest req, Object options, Function cb) → undefined
102
103The ClientRequest `req` can be accessed to read request headers and
104and the path, etc. The `options` object contains the options passed
105to the `http.request()`/`https.request()` function call, and is formatted
106to be directly passed to `net.connect()`/`tls.connect()`, or however
107else you want a Socket to be created. Pass the created socket to
108the callback function `cb` once created, and the HTTP request will
109continue to proceed.
110
111If the `https` module is used to invoke the HTTP request, then the
112`secureEndpoint` property on `options` _will be set to `true`_.
113
114
115License
116-------
117
118(The MIT License)
119
120Copyright (c) 2013 Nathan Rajlich <nathan@tootallnate.net>
121
122Permission is hereby granted, free of charge, to any person obtaining
123a copy of this software and associated documentation files (the
124'Software'), to deal in the Software without restriction, including
125without limitation the rights to use, copy, modify, merge, publish,
126distribute, sublicense, and/or sell copies of the Software, and to
127permit persons to whom the Software is furnished to do so, subject to
128the following conditions:
129
130The above copyright notice and this permission notice shall be
131included in all copies or substantial portions of the Software.
132
133THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
134EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
135MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
136IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
137CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
138TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
139SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
140
141[http-proxy-agent]: https://github.com/TooTallNate/node-http-proxy-agent
142[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
143[pac-proxy-agent]: https://github.com/TooTallNate/node-pac-proxy-agent
144[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
145[http.Agent]: https://nodejs.org/api/http.html#http_class_http_agent
146
){kind=link}