3 To use the HTTP server and client one must `require('http')`.
5 The HTTP interfaces in Node are designed to support many features
6 of the protocol which have been traditionally difficult to use.
7 In particular, large, possibly chunk-encoded, messages. The interface is
8 careful to never buffer entire requests or responses--the
9 user is able to stream data.
11 HTTP message headers are represented by an object like this:
13 { 'content-length': '123',
14 'content-type': 'text/plain',
15 'connection': 'keep-alive',
18 Keys are lowercased. Values are not modified.
20 In order to support the full spectrum of possible HTTP applications, Node's
21 HTTP API is very low-level. It deals with stream handling and message
22 parsing only. It parses a message into headers and body but it does not
23 parse the actual headers or the body.
25 HTTPS is supported if OpenSSL is available on the underlying platform.
29 This is an `EventEmitter` with the following events:
33 `function (request, response) { }`
35 `request` is an instance of `http.ServerRequest` and `response` is
36 an instance of `http.ServerResponse`
38 ### Event: 'connection'
40 `function (stream) { }`
42 When a new TCP stream is established. `stream` is an object of type
43 `net.Stream`. Usually users will not want to access this event. The
44 `stream` can also be accessed at `request.connection`.
48 `function (errno) { }`
50 Emitted when the server closes.
54 `function (request, response) {}`
56 Emitted each time there is request. Note that there may be multiple requests
57 per connection (in the case of keep-alive connections).
59 ### Event: 'checkContinue'
61 `function (request, response) {}`
63 Emitted each time a request with an http Expect: 100-continue is received.
64 If this event isn't listened for, the server will automatically respond
65 with a 100 Continue as appropriate.
67 Handling this event involves calling `response.writeContinue` if the client
68 should continue to send the request body, or generating an appropriate HTTP
69 response (e.g., 400 Bad Request) if the client should not continue to send the
72 Note that when this event is emitted and handled, the `request` event will
77 `function (request, socket, head)`
79 Emitted each time a client requests a http upgrade. If this event isn't
80 listened for, then clients requesting an upgrade will have their connections
83 * `request` is the arguments for the http request, as it is in the request event.
84 * `socket` is the network socket between the server and client.
85 * `head` is an instance of Buffer, the first packet of the upgraded stream, this may be empty.
87 After this event is emitted, the request's socket will not have a `data`
88 event listener, meaning you will need to bind to it in order to handle data
89 sent to the server on that socket.
91 ### Event: 'clientError'
93 `function (exception) {}`
95 If a client connection emits an 'error' event - it will forwarded here.
97 ### http.createServer(requestListener)
99 Returns a new web server object.
101 The `requestListener` is a function which is automatically
102 added to the `'request'` event.
104 ### server.listen(port, [hostname], [callback])
106 Begin accepting connections on the specified port and hostname. If the
107 hostname is omitted, the server will accept connections directed to any
108 IPv4 address (`INADDR_ANY`).
110 To listen to a unix socket, supply a filename instead of port and hostname.
112 This function is asynchronous. The last parameter `callback` will be called
113 when the server has been bound to the port.
116 ### server.listen(path, [callback])
118 Start a UNIX socket server listening for connections on the given `path`.
120 This function is asynchronous. The last parameter `callback` will be called
121 when the server has been bound.
124 ### server.setSecure(credentials)
126 Enables HTTPS support for the server, with the crypto module credentials specifying the private key and certificate of the server, and optionally the CA certificates for use in client authentication.
128 If the credentials hold one or more CA certificates, then the server will request for the client to submit a client certificate as part of the HTTPS connection handshake. The validity and content of this can be accessed via verifyPeer() and getPeerCertificate() from the server's request.connection.
132 Stops the server from accepting new connections.
135 ## http.ServerRequest
137 This object is created internally by a HTTP server--not by
138 the user--and passed as the first argument to a `'request'` listener.
140 This is an `EventEmitter` with the following events:
144 `function (chunk) { }`
146 Emitted when a piece of the message body is received.
148 Example: A chunk of the body is given as the single
149 argument. The transfer-encoding has been decoded. The
150 body chunk is a string. The body encoding is set with
151 `request.setBodyEncoding()`.
157 Emitted exactly once for each message. No arguments. After
158 emitted no other events will be emitted on the request.
163 The request method as a string. Read only. Example:
169 Request URL string. This contains only the URL that is
170 present in the actual HTTP request. If the request is:
172 GET /status?name=ryan HTTP/1.1\r\n
173 Accept: text/plain\r\n
176 Then `request.url` will be:
180 If you would like to parse the URL into its parts, you can use
181 `require('url').parse(request.url)`. Example:
183 node> require('url').parse('/status?name=ryan')
184 { href: '/status?name=ryan',
185 search: '?name=ryan',
187 pathname: '/status' }
189 If you would like to extract the params from the query string,
190 you can use the `require('querystring').parse` function, or pass
191 `true` as the second argument to `require('url').parse`. Example:
193 node> require('url').parse('/status?name=ryan', true)
194 { href: '/status?name=ryan',
195 search: '?name=ryan',
196 query: { name: 'ryan' },
197 pathname: '/status' }
207 Read only; HTTP trailers (if present). Only populated after the 'end' event.
209 ### request.httpVersion
211 The HTTP protocol version as a string. Read only. Examples:
213 Also `request.httpVersionMajor` is the first integer and
214 `request.httpVersionMinor` is the second.
217 ### request.setEncoding(encoding=null)
219 Set the encoding for the request body. Either `'utf8'` or `'binary'`. Defaults
220 to `null`, which means that the `'data'` event will emit a `Buffer` object..
225 Pauses request from emitting events. Useful to throttle back an upload.
230 Resumes a paused request.
232 ### request.connection
234 The `net.Stream` object associated with the connection.
237 With HTTPS support, use request.connection.verifyPeer() and
238 request.connection.getPeerCertificate() to obtain the client's
239 authentication details.
243 ## http.ServerResponse
245 This object is created internally by a HTTP server--not by the user. It is
246 passed as the second parameter to the `'request'` event. It is a `Writable Stream`.
248 ### response.writeContinue()
250 Sends a HTTP/1.1 100 Continue message to the client, indicating that
251 the request body should be sent. See the the `checkContinue` event on
254 ### response.writeHead(statusCode, [reasonPhrase], [headers])
256 Sends a response header to the request. The status code is a 3-digit HTTP
257 status code, like `404`. The last argument, `headers`, are the response headers.
258 Optionally one can give a human-readable `reasonPhrase` as the second
263 var body = 'hello world';
264 response.writeHead(200, {
265 'Content-Length': body.length,
266 'Content-Type': 'text/plain' });
268 This method must only be called once on a message and it must
269 be called before `response.end()` is called.
271 ### response.write(chunk, encoding='utf8')
273 This method must be called after `writeHead` was
274 called. It sends a chunk of the response body. This method may
275 be called multiple times to provide successive parts of the body.
277 `chunk` can be a string or a buffer. If `chunk` is a string,
278 the second parameter specifies how to encode it into a byte stream.
279 By default the `encoding` is `'utf8'`.
281 **Note**: This is the raw HTTP body and has nothing to do with
282 higher-level multi-part body encodings that may be used.
284 The first time `response.write()` is called, it will send the buffered
285 header information and the first body to the client. The second time
286 `response.write()` is called, Node assumes you're going to be streaming
287 data, and sends that separately. That is, the response is buffered up to the
290 ### response.addTrailers(headers)
292 This method adds HTTP trailing headers (a header but at the end of the
293 message) to the response.
295 Trailers will **only** be emitted if chunked encoding is used for the
296 response; if it is not (e.g., if the request was HTTP/1.0), they will
297 be silently discarded.
299 Note that HTTP requires the `Trailer` header to be sent if you intend to
300 emit trailers, with a list of the header fields in its value. E.g.,
302 response.writeHead(200, { 'Content-Type': 'text/plain',
303 'Trailer': 'TraceInfo' });
304 response.write(fileData);
305 response.addTrailers({'Content-MD5': "7895bf4b8828b55ceaf47747b4bca667"});
309 ### response.end([data], [encoding])
311 This method signals to the server that all of the response headers and body
312 has been sent; that server should consider this message complete.
313 The method, `response.end()`, MUST be called on each
316 If `data` is specified, it is equivalent to calling `response.write(data, encoding)`
317 followed by `response.end()`.
322 An HTTP client is constructed with a server address as its
323 argument, the returned handle is then used to issue one or more
324 requests. Depending on the server connected to, the client might
325 pipeline the requests or reestablish the stream after each
326 stream. _Currently the implementation does not pipeline requests._
328 Example of connecting to `google.com`:
330 var http = require('http');
331 var google = http.createClient(80, 'www.google.com');
332 var request = google.request('GET', '/',
333 {'host': 'www.google.com'});
335 request.on('response', function (response) {
336 console.log('STATUS: ' + response.statusCode);
337 console.log('HEADERS: ' + JSON.stringify(response.headers));
338 response.setEncoding('utf8');
339 response.on('data', function (chunk) {
340 console.log('BODY: ' + chunk);
344 There are a few special headers that should be noted.
346 * The 'Host' header is not added by Node, and is usually required by
349 * Sending a 'Connection: keep-alive' will notify Node that the connection to
350 the server should be persisted until the next request.
352 * Sending a 'Content-length' header will disable the default chunked encoding.
354 * Sending an 'Expect' header will immediately send the request headers.
355 Usually, when sending 'Expect: 100-continue', you should both set a timeout
356 and listen for the `continue` event. See RFC2616 Section 8.2.3 for more
362 `function (request, socket, head)`
364 Emitted each time a server responds to a request with an upgrade. If this event
365 isn't being listened for, clients receiving an upgrade header will have their
368 See the description of the `upgrade` event for `http.Server` for further details.
370 ### Event: 'continue'
374 Emitted when the server sends a '100 Continue' HTTP response, usually because
375 the request contained 'Expect: 100-continue'. This is an instruction that
376 the client should send the request body.
379 ### http.createClient(port, host='localhost', secure=false, [credentials])
381 Constructs a new HTTP client. `port` and
382 `host` refer to the server to be connected to. A
383 stream is not established until a request is issued.
385 `secure` is an optional boolean flag to enable https support and `credentials` is an optional credentials object from the crypto module, which may hold the client's private key, certificate, and a list of trusted CA certificates.
387 If the connection is secure, but no explicit CA certificates are passed in the credentials, then node.js will default to the publicly trusted list of CA certificates, as given in http://mxr.mozilla.org/mozilla/source/security/nss/lib/ckfw/builtins/certdata.txt
389 ### client.request(method='GET', path, [request_headers])
391 Issues a request; if necessary establishes stream. Returns a `http.ClientRequest` instance.
393 `method` is optional and defaults to 'GET' if omitted.
395 `request_headers` is optional.
396 Additional request headers might be added internally
397 by Node. Returns a `ClientRequest` object.
399 Do remember to include the `Content-Length` header if you
400 plan on sending a body. If you plan on streaming the body, perhaps
401 set `Transfer-Encoding: chunked`.
403 *NOTE*: the request is not complete. This method only sends the header of
404 the request. One needs to call `request.end()` to finalize the request and
405 retrieve the response. (This sounds convoluted but it provides a chance for
406 the user to stream a body to the server with `request.write()`.)
408 ### client.verifyPeer()
410 Returns true or false depending on the validity of the server's certificate in the context of the defined or default list of trusted CA certificates.
412 ### client.getPeerCertificate()
414 Returns a JSON structure detailing the server's certificate, containing a dictionary with keys for the certificate 'subject', 'issuer', 'valid\_from' and 'valid\_to'
417 ## http.ClientRequest
419 This object is created internally and returned from the `request()` method
420 of a `http.Client`. It represents an _in-progress_ request whose header has
423 To get the response, add a listener for `'response'` to the request object.
424 `'response'` will be emitted from the request object when the response
425 headers have been received. The `'response'` event is executed with one
426 argument which is an instance of `http.ClientResponse`.
428 During the `'response'` event, one can add listeners to the
429 response object; particularly to listen for the `'data'` event. Note that
430 the `'response'` event is called before any part of the response body is received,
431 so there is no need to worry about racing to catch the first part of the
432 body. As long as a listener for `'data'` is added during the `'response'`
433 event, the entire body will be caught.
437 request.on('response', function (response) {
438 response.on('data', function (chunk) {
439 console.log('BODY: ' + chunk);
443 // Bad - misses all or part of the body
444 request.on('response', function (response) {
445 setTimeout(function () {
446 response.on('data', function (chunk) {
447 console.log('BODY: ' + chunk);
452 This is a `Writable Stream`.
454 This is an `EventEmitter` with the following events:
458 `function (response) { }`
460 Emitted when a response is received to this request. This event is emitted only once. The
461 `response` argument will be an instance of `http.ClientResponse`.
464 ### request.write(chunk, encoding='utf8')
466 Sends a chunk of the body. By calling this method
467 many times, the user can stream a request body to a
468 server--in that case it is suggested to use the
469 `['Transfer-Encoding', 'chunked']` header line when
470 creating the request.
472 The `chunk` argument should be an array of integers
475 The `encoding` argument is optional and only
476 applies when `chunk` is a string.
479 ### request.end([data], [encoding])
481 Finishes sending the request. If any parts of the body are
482 unsent, it will flush them to the stream. If the request is
483 chunked, this will send the terminating `'0\r\n\r\n'`.
485 If `data` is specified, it is equivalent to calling `request.write(data, encoding)`
486 followed by `request.end()`.
489 ## http.ClientResponse
491 This object is created when making a request with `http.Client`. It is
492 passed to the `'response'` event of the request object.
494 The response implements the `Readable Stream` interface.
498 `function (chunk) {}`
500 Emitted when a piece of the message body is received.
502 Example: A chunk of the body is given as the single
503 argument. The transfer-encoding has been decoded. The
504 body chunk a String. The body encoding is set with
505 `response.setBodyEncoding()`.
511 Emitted exactly once for each message. No arguments. After
512 emitted no other events will be emitted on the response.
514 ### response.statusCode
516 The 3-digit HTTP response status code. E.G. `404`.
518 ### response.httpVersion
520 The HTTP version of the connected-to server. Probably either
522 Also `response.httpVersionMajor` is the first integer and
523 `response.httpVersionMinor` is the second.
527 The response headers object.
529 ### response.trailers
531 The response trailers object. Only populated after the 'end' event.
533 ### response.setEncoding(encoding=null)
535 Set the encoding for the response body. Either `'utf8'`, `'ascii'`, or `'base64'`.
536 Defaults to `null`, which means that the `'data'` event will emit a `Buffer` object..
540 Pauses response from emitting events. Useful to throttle back a download.
542 ### response.resume()
544 Resumes a paused response.
548 A reference to the `http.Client` that this response belongs to.