- Assertion Testing
- Async Hooks
- Buffer
- C++ Addons
- C/C++ Addons - N-API
- Child Processes
- Cluster
- Command Line Options
- Console
- Crypto
- Debugger
- Deprecated APIs
- DNS
- Domain
- ECMAScript Modules
- Errors
- Events
- File System
- Globals
- HTTP
- HTTP/2
- HTTPS
- Inspector
- Internationalization
- Modules
- Net
- OS
- Path
- Performance Hooks
- Process
- Punycode
- Query Strings
- Readline
- REPL
- Stream
- String Decoder
- Timers
- TLS/SSL
- Tracing
- TTY
- UDP/Datagram
- URL
- Utilities
- V8
- VM
- ZLIB
Node.js v9.9.0 Documentation
Table of Contents
- HTTP
- Class: http.Agent
- Class: http.ClientRequest
- Event: 'abort'
- Event: 'connect'
- Event: 'continue'
- Event: 'response'
- Event: 'socket'
- Event: 'timeout'
- Event: 'upgrade'
- request.abort()
- request.aborted
- request.connection
- request.end([data[, encoding]][, callback])
- request.flushHeaders()
- request.getHeader(name)
- request.removeHeader(name)
- request.setHeader(name, value)
- request.setNoDelay([noDelay])
- request.setSocketKeepAlive([enable][, initialDelay])
- request.setTimeout(timeout[, callback])
- request.socket
- request.write(chunk[, encoding][, callback])
- Class: http.Server
- Event: 'checkContinue'
- Event: 'checkExpectation'
- Event: 'clientError'
- Event: 'close'
- Event: 'connect'
- Event: 'connection'
- Event: 'request'
- Event: 'upgrade'
- server.close([callback])
- server.listen()
- server.listening
- server.maxHeadersCount
- server.setTimeout([msecs][, callback])
- server.timeout
- server.keepAliveTimeout
- Class: http.ServerResponse
- Event: 'close'
- Event: 'finish'
- response.addTrailers(headers)
- response.connection
- response.end([data][, encoding][, callback])
- response.finished
- response.getHeader(name)
- response.getHeaderNames()
- response.getHeaders()
- response.hasHeader(name)
- response.headersSent
- response.removeHeader(name)
- response.sendDate
- response.setHeader(name, value)
- response.setTimeout(msecs[, callback])
- response.socket
- response.statusCode
- response.statusMessage
- response.write(chunk[, encoding][, callback])
- response.writeContinue()
- response.writeHead(statusCode[, statusMessage][, headers])
- Class: http.IncomingMessage
- http.METHODS
- http.STATUS_CODES
- http.createServer([options][, requestListener])
- http.get(options[, callback])
- http.globalAgent
- http.request(options[, callback])
HTTP#
To use the HTTP server and client one must require('http')
.
The HTTP interfaces in Node.js are designed to support many features of the protocol which have been traditionally difficult to use. In particular, large, possibly chunk-encoded, messages. The interface is careful to never buffer entire requests or responses--the user is able to stream data.
HTTP message headers are represented by an object like this:
{ 'content-length': '123',
'content-type': 'text/plain',
'connection': 'keep-alive',
'host': 'mysite.com',
'accept': '*/*' }
Keys are lowercased. Values are not modified.
In order to support the full spectrum of possible HTTP applications, Node.js's HTTP API is very low-level. It deals with stream handling and message parsing only. It parses a message into headers and body but it does not parse the actual headers or the body.
See message.headers
for details on how duplicate headers are handled.
The raw headers as they were received are retained in the rawHeaders
property, which is an array of [key, value, key2, value2, ...]
. For
example, the previous message header object might have a rawHeaders
list like the following:
[ 'ConTent-Length', '123456',
'content-LENGTH', '123',
'content-type', 'text/plain',
'CONNECTION', 'keep-alive',
'Host', 'mysite.com',
'accepT', '*/*' ]
Class: http.Agent#
An Agent
is responsible for managing connection persistence
and reuse for HTTP clients. It maintains a queue of pending requests
for a given host and port, reusing a single socket connection for each
until the queue is empty, at which time the socket is either destroyed
or put into a pool where it is kept to be used again for requests to the
same host and port. Whether it is destroyed or pooled depends on the
keepAlive
option.
Pooled connections have TCP Keep-Alive enabled for them, but servers may
still close idle connections, in which case they will be removed from the
pool and a new connection will be made when a new HTTP request is made for
that host and port. Servers may also refuse to allow multiple requests
over the same connection, in which case the connection will have to be
remade for every request and cannot be pooled. The Agent
will still make
the requests to that server, but each one will occur over a new connection.
When a connection is closed by the client or the server, it is removed from the pool. Any unused sockets in the pool will be unrefed so as not to keep the Node.js process running when there are no outstanding requests. (see socket.unref()).
It is good practice, to destroy()
an Agent
instance when it is no
longer in use, because unused sockets consume OS resources.
Sockets are removed from an agent when the socket emits either
a 'close'
event or an 'agentRemove'
event. When intending to keep one
HTTP request open for a long time without keeping it in the agent, something
like the following may be done:
http.get(options, (res) => {
// Do stuff
}).on('socket', (socket) => {
socket.emit('agentRemove');
});
An agent may also be used for an individual request. By providing
{agent: false}
as an option to the http.get()
or http.request()
functions, a one-time use Agent
with default options will be used
for the client connection.
agent:false
:
http.get({
hostname: 'localhost',
port: 80,
path: '/',
agent: false // create a new agent just for this one request
}, (res) => {
// Do stuff with response
});
new Agent([options])#
options
<Object> Set of configurable options to set on the agent. Can have the following fields:keepAlive
<boolean> Keep sockets around even when there are no outstanding requests, so they can be used for future requests without having to reestablish a TCP connection. Defaults tofalse
keepAliveMsecs
<number> When using thekeepAlive
option, specifies the initial delay for TCP Keep-Alive packets. Ignored when thekeepAlive
option isfalse
orundefined
. Defaults to1000
.maxSockets
<number> Maximum number of sockets to allow per host. Defaults toInfinity
.maxFreeSockets
<number> Maximum number of sockets to leave open in a free state. Only relevant ifkeepAlive
is set totrue
. Defaults to256
.
The default http.globalAgent
that is used by http.request()
has all
of these values set to their respective defaults.
To configure any of them, a custom http.Agent
instance must be created.
const http = require('http');
const keepAliveAgent = new http.Agent({ keepAlive: true });
options.agent = keepAliveAgent;
http.request(options, onResponseCallback);
agent.createConnection(options[, callback])#
options
<Object> Options containing connection details. Checknet.createConnection()
for the format of the optionscallback
<Function> Callback function that receives the created socket- Returns: <net.Socket>
Produces a socket/stream to be used for HTTP requests.
By default, this function is the same as net.createConnection()
. However,
custom agents may override this method in case greater flexibility is desired.
A socket/stream can be supplied in one of two ways: by returning the
socket/stream from this function, or by passing the socket/stream to callback
.
callback
has a signature of (err, stream)
.
agent.keepSocketAlive(socket)#
socket
<net.Socket>
Called when socket
is detached from a request and could be persisted by the
Agent. Default behavior is to:
socket.setKeepAlive(true, this.keepAliveMsecs);
socket.unref();
return true;
This method can be overridden by a particular Agent
subclass. If this
method returns a falsy value, the socket will be destroyed instead of persisting
it for use with the next request.
agent.reuseSocket(socket, request)#
socket
<net.Socket>request
<http.ClientRequest>
Called when socket
is attached to request
after being persisted because of
the keep-alive options. Default behavior is to:
socket.ref();
This method can be overridden by a particular Agent
subclass.
agent.destroy()#
Destroy any sockets that are currently in use by the agent.
It is usually not necessary to do this. However, if using an
agent with keepAlive
enabled, then it is best to explicitly shut down
the agent when it will no longer be used. Otherwise,
sockets may hang open for quite a long time before the server
terminates them.
agent.freeSockets#
An object which contains arrays of sockets currently awaiting use by
the agent when keepAlive
is enabled. Do not modify.
agent.getName(options)#
Get a unique name for a set of request options, to determine whether a
connection can be reused. For an HTTP agent, this returns
host:port:localAddress
or host:port:localAddress:family
. For an HTTPS agent,
the name includes the CA, cert, ciphers, and other HTTPS/TLS-specific options
that determine socket reusability.
agent.maxFreeSockets#
By default set to 256. For agents with keepAlive
enabled, this
sets the maximum number of sockets that will be left open in the free
state.
agent.maxSockets#
By default set to Infinity. Determines how many concurrent sockets the agent
can have open per origin. Origin is the returned value of agent.getName()
.
agent.requests#
An object which contains queues of requests that have not yet been assigned to sockets. Do not modify.
agent.sockets#
An object which contains arrays of sockets currently in use by the agent. Do not modify.
Class: http.ClientRequest#
This object is created internally and returned from http.request()
. It
represents an in-progress request whose header has already been queued. The
header is still mutable using the setHeader(name, value)
,
getHeader(name)
, removeHeader(name)
API. The actual header will
be sent along with the first data chunk or when calling request.end()
.
To get the response, add a listener for 'response'
to the request object.
'response'
will be emitted from the request object when the response
headers have been received. The 'response'
event is executed with one
argument which is an instance of http.IncomingMessage
.
During the 'response'
event, one can add listeners to the
response object; particularly to listen for the 'data'
event.
If no 'response'
handler is added, then the response will be
entirely discarded. However, if a 'response'
event handler is added,
then the data from the response object must be consumed, either by
calling response.read()
whenever there is a 'readable'
event, or
by adding a 'data'
handler, or by calling the .resume()
method.
Until the data is consumed, the 'end'
event will not fire. Also, until
the data is read it will consume memory that can eventually lead to a
'process out of memory' error.
Note: Node.js does not check whether Content-Length and the length of the body which has been transmitted are equal or not.
The request implements the Writable Stream interface. This is an
EventEmitter
with the following events:
Event: 'abort'#
Emitted when the request has been aborted by the client. This event is only
emitted on the first call to abort()
.
Event: 'connect'#
response
<http.IncomingMessage>socket
<net.Socket>head
<Buffer>
Emitted each time a server responds to a request with a CONNECT
method. If this
event is not being listened for, clients receiving a CONNECT
method will have
their connections closed.
A client and server pair demonstrating how to listen for the 'connect'
event:
const http = require('http');
const net = require('net');
const url = require('url');
// Create an HTTP tunneling proxy
const proxy = http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('okay');
});
proxy.on('connect', (req, cltSocket, head) => {
// connect to an origin server
const srvUrl = url.parse(`http://${req.url}`);
const srvSocket = net.connect(srvUrl.port, srvUrl.hostname, () => {
cltSocket.write('HTTP/1.1 200 Connection Established\r\n' +
'Proxy-agent: Node.js-Proxy\r\n' +
'\r\n');
srvSocket.write(head);
srvSocket.pipe(cltSocket);
cltSocket.pipe(srvSocket);
});
});
// now that proxy is running
proxy.listen(1337, '127.0.0.1', () => {
// make a request to a tunneling proxy
const options = {
port: 1337,
hostname: '127.0.0.1',
method: 'CONNECT',
path: 'www.google.com:80'
};
const req = http.request(options);
req.end();
req.on('connect', (res, socket, head) => {
console.log('got connected!');
// make a request over an HTTP tunnel
socket.write('GET / HTTP/1.1\r\n' +
'Host: www.google.com:80\r\n' +
'Connection: close\r\n' +
'\r\n');
socket.on('data', (chunk) => {
console.log(chunk.toString());
});
socket.on('end', () => {
proxy.close();
});
});
});
Event: 'continue'#
Emitted when the server sends a '100 Continue' HTTP response, usually because the request contained 'Expect: 100-continue'. This is an instruction that the client should send the request body.
Event: 'response'#
response
<http.IncomingMessage>
Emitted when a response is received to this request. This event is emitted only once.
Event: 'socket'#
socket
<net.Socket>
Emitted after a socket is assigned to this request.
Event: 'timeout'#
Emitted when the underlying socket times out from inactivity. This only notifies that the socket has been idle. The request must be aborted manually.
See also: request.setTimeout()
Event: 'upgrade'#
response
<http.IncomingMessage>socket
<net.Socket>head
<Buffer>
Emitted each time a server responds to a request with an upgrade. If this event is not being listened for, clients receiving an upgrade header will have their connections closed.
A client server pair demonstrating how to listen for the 'upgrade'
event.
const http = require('http');
// Create an HTTP server
const srv = http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('okay');
});
srv.on('upgrade', (req, socket, head) => {
socket.write('HTTP/1.1 101 Web Socket Protocol Handshake\r\n' +
'Upgrade: WebSocket\r\n' +
'Connection: Upgrade\r\n' +
'\r\n');
socket.pipe(socket); // echo back
});
// now that server is running
srv.listen(1337, '127.0.0.1', () => {
// make a request
const options = {
port: 1337,
hostname: '127.0.0.1',
headers: {
'Connection': 'Upgrade',
'Upgrade': 'websocket'
}
};
const req = http.request(options);
req.end();
req.on('upgrade', (res, socket, upgradeHead) => {
console.log('got upgraded!');
socket.end();
process.exit(0);
});
});
request.abort()#
Marks the request as aborting. Calling this will cause remaining data in the response to be dropped and the socket to be destroyed.
request.aborted#
If a request has been aborted, this value is the time when the request was aborted, in milliseconds since 1 January 1970 00:00:00 UTC.
request.connection#
See request.socket
request.end([data[, encoding]][, callback])#
data
<string> | <Buffer>encoding
<string>callback
<Function>
Finishes sending the request. If any parts of the body are
unsent, it will flush them to the stream. If the request is
chunked, this will send the terminating '0\r\n\r\n'
.
If data
is specified, it is equivalent to calling
request.write(data, encoding)
followed by request.end(callback)
.
If callback
is specified, it will be called when the request stream
is finished.
request.flushHeaders()#
Flush the request headers.
For efficiency reasons, Node.js normally buffers the request headers until
request.end()
is called or the first chunk of request data is written. It
then tries to pack the request headers and data into a single TCP packet.
That's usually desired (it saves a TCP round-trip), but not when the first
data is not sent until possibly much later. request.flushHeaders()
bypasses
the optimization and kickstarts the request.
request.getHeader(name)#
Reads out a header on the request. Note that the name is case insensitive.
Example:
const contentType = request.getHeader('Content-Type');
request.removeHeader(name)#
name
<string>
Removes a header that's already defined into headers object.
Example:
request.removeHeader('Content-Type');
request.setHeader(name, value)#
Sets a single header value for headers object. If this header already exists in the to-be-sent headers, its value will be replaced. Use an array of strings here to send multiple headers with the same name.
Example:
request.setHeader('Content-Type', 'application/json');
or
request.setHeader('Set-Cookie', ['type=ninja', 'language=javascript']);
request.setNoDelay([noDelay])#
noDelay
<boolean>
Once a socket is assigned to this request and is connected
socket.setNoDelay()
will be called.
request.setSocketKeepAlive([enable][, initialDelay])#
Once a socket is assigned to this request and is connected
socket.setKeepAlive()
will be called.
request.setTimeout(timeout[, callback])#
timeout
<number> Milliseconds before a request times out.callback
<Function> Optional function to be called when a timeout occurs. Same as binding to thetimeout
event.
Once a socket is assigned to this request and is connected
socket.setTimeout()
will be called.
Returns request
.
request.socket#
Reference to the underlying socket. Usually users will not want to access
this property. In particular, the socket will not emit 'readable'
events
because of how the protocol parser attaches to the socket. After
response.end()
, the property is nulled. The socket
may also be accessed
via request.connection
.
Example:
const http = require('http');
const options = {
host: 'www.google.com',
};
const req = http.get(options);
req.end();
req.once('response', (res) => {
const ip = req.socket.localAddress;
const port = req.socket.localPort;
console.log(`Your IP address is ${ip} and your source port is ${port}.`);
// consume response object
});
request.write(chunk[, encoding][, callback])#
chunk
<string> | <Buffer>encoding
<string>callback
<Function>
Sends a chunk of the body. By calling this method
many times, a request body can be sent to a
server--in that case it is suggested to use the
['Transfer-Encoding', 'chunked']
header line when
creating the request.
The encoding
argument is optional and only applies when chunk
is a string.
Defaults to 'utf8'
.
The callback
argument is optional and will be called when this chunk of data
is flushed.
Returns true
if the entire data was flushed successfully to the kernel
buffer. Returns false
if all or part of the data was queued in user memory.
'drain'
will be emitted when the buffer is free again.
Class: http.Server#
This class inherits from net.Server
and has the following additional events:
Event: 'checkContinue'#
request
<http.IncomingMessage>response
<http.ServerResponse>
Emitted each time a request with an HTTP Expect: 100-continue
is received.
If this event is not listened for, the server will automatically respond
with a 100 Continue
as appropriate.
Handling this event involves calling response.writeContinue()
if the client
should continue to send the request body, or generating an appropriate HTTP
response (e.g. 400 Bad Request) if the client should not continue to send the
request body.
Note that when this event is emitted and handled, the 'request'
event will
not be emitted.
Event: 'checkExpectation'#
request
<http.IncomingMessage>response
<http.ServerResponse>
Emitted each time a request with an HTTP Expect
header is received, where the
value is not 100-continue
. If this event is not listened for, the server will
automatically respond with a 417 Expectation Failed
as appropriate.
Note that when this event is emitted and handled, the 'request'
event will
not be emitted.
Event: 'clientError'#
exception
<Error>socket
<net.Socket>
If a client connection emits an 'error'
event, it will be forwarded here.
Listener of this event is responsible for closing/destroying the underlying
socket. For example, one may wish to more gracefully close the socket with a
custom HTTP response instead of abruptly severing the connection.
Default behavior is to close the socket with an HTTP '400 Bad Request' response if possible, otherwise the socket is immediately destroyed.
socket
is the net.Socket
object that the error originated from.
const http = require('http');
const server = http.createServer((req, res) => {
res.end();
});
server.on('clientError', (err, socket) => {
socket.end('HTTP/1.1 400 Bad Request\r\n\r\n');
});
server.listen(8000);
When the 'clientError'
event occurs, there is no request
or response
object, so any HTTP response sent, including response headers and payload,
must be written directly to the socket
object. Care must be taken to
ensure the response is a properly formatted HTTP response message.
err
is an instance of Error
with two extra columns:
bytesParsed
: the bytes count of request packet that Node.js may have parsed correctly;rawPacket
: the raw packet of current request.
Event: 'close'#
Emitted when the server closes.
Event: 'connect'#
request
<http.IncomingMessage> Arguments for the HTTP request, as it is in the'request'
eventsocket
<net.Socket> Network socket between the server and clienthead
<Buffer> The first packet of the tunneling stream (may be empty)
Emitted each time a client requests an HTTP CONNECT
method. If this event is
not listened for, then clients requesting a CONNECT
method will have their
connections closed.
After this event is emitted, the request's socket will not have a 'data'
event listener, meaning it will need to be bound in order to handle data
sent to the server on that socket.
Event: 'connection'#
socket
<net.Socket>
This event is emitted when a new TCP stream is established. socket
is
typically an object of type net.Socket
. Usually users will not want to
access this event. In particular, the socket will not emit 'readable'
events
because of how the protocol parser attaches to the socket. The socket
can
also be accessed at request.connection
.
Note: This event can also be explicitly emitted by users to inject connections
into the HTTP server. In that case, any Duplex
stream can be passed.
Event: 'request'#
request
<http.IncomingMessage>response
<http.ServerResponse>
Emitted each time there is a request. Note that there may be multiple requests per connection (in the case of HTTP Keep-Alive connections).
Event: 'upgrade'#
request
<http.IncomingMessage> Arguments for the HTTP request, as it is in the'request'
eventsocket
<net.Socket> Network socket between the server and clienthead
<Buffer> The first packet of the upgraded stream (may be empty)
Emitted each time a client requests an HTTP upgrade. If this event is not listened for, then clients requesting an upgrade will have their connections closed.
After this event is emitted, the request's socket will not have a 'data'
event listener, meaning it will need to be bound in order to handle data
sent to the server on that socket.
server.close([callback])#
callback
<Function>
Stops the server from accepting new connections. See net.Server.close()
.
server.listen()#
Starts the HTTP server listening for connections.
This method is identical to server.listen()
from net.Server
.
server.listening#
A Boolean indicating whether or not the server is listening for connections.
server.maxHeadersCount#
- <number> Defaults to 2000.
Limits maximum incoming headers count, equal to 2000 by default. If set to 0 - no limit will be applied.
server.setTimeout([msecs][, callback])#
msecs
<number> Defaults to 120000 (2 minutes).callback
<Function>
Sets the timeout value for sockets, and emits a 'timeout'
event on
the Server object, passing the socket as an argument, if a timeout
occurs.
If there is a 'timeout'
event listener on the Server object, then it
will be called with the timed-out socket as an argument.
By default, the Server's timeout value is 2 minutes, and sockets are
destroyed automatically if they time out. However, if a callback is assigned
to the Server's 'timeout'
event, timeouts must be handled explicitly.
Returns server
.
server.timeout#
- <number> Timeout in milliseconds. Defaults to 120000 (2 minutes).
The number of milliseconds of inactivity before a socket is presumed to have timed out.
A value of 0
will disable the timeout behavior on incoming connections.
Note: The socket timeout logic is set up on connection, so changing this value only affects new connections to the server, not any existing connections.
server.keepAliveTimeout#
- <number> Timeout in milliseconds. Defaults to 5000 (5 seconds).
The number of milliseconds of inactivity a server needs to wait for additional
incoming data, after it has finished writing the last response, before a socket
will be destroyed. If the server receives new data before the keep-alive
timeout has fired, it will reset the regular inactivity timeout, i.e.,
server.timeout
.
A value of 0
will disable the keep-alive timeout behavior on incoming connections.
A value of 0
makes the http server behave similarly to Node.js versions prior to 8.0.0,
which did not have a keep-alive timeout.
Note: The socket timeout logic is set up on connection, so changing this value only affects new connections to the server, not any existing connections.
Class: http.ServerResponse#
This object is created internally by an HTTP server--not by the user. It is
passed as the second parameter to the 'request'
event.
The response implements, but does not inherit from, the Writable Stream
interface. This is an EventEmitter
with the following events:
Event: 'close'#
Indicates that the underlying connection was terminated before
response.end()
was called or able to flush.
Event: 'finish'#
Emitted when the response has been sent. More specifically, this event is emitted when the last segment of the response headers and body have been handed off to the operating system for transmission over the network. It does not imply that the client has received anything yet.
After this event, no more events will be emitted on the response object.
response.addTrailers(headers)#
headers
<Object>
This method adds HTTP trailing headers (a header but at the end of the message) to the response.
Trailers will only be emitted if chunked encoding is used for the response; if it is not (e.g. if the request was HTTP/1.0), they will be silently discarded.
Note that HTTP requires the Trailer
header to be sent in order to
emit trailers, with a list of the header fields in its value. E.g.,
response.writeHead(200, { 'Content-Type': 'text/plain',
'Trailer': 'Content-MD5' });
response.write(fileData);
response.addTrailers({ 'Content-MD5': '7895bf4b8828b55ceaf47747b4bca667' });
response.end();
Attempting to set a header field name or value that contains invalid characters
will result in a TypeError
being thrown.
response.connection#
See response.socket
.
response.end([data][, encoding][, callback])#
data
<string> | <Buffer>encoding
<string>callback
<Function>
This method signals to the server that all of the response headers and body
have been sent; that server should consider this message complete.
The method, response.end()
, MUST be called on each response.
If data
is specified, it is equivalent to calling
response.write(data, encoding)
followed by response.end(callback)
.
If callback
is specified, it will be called when the response stream
is finished.
response.finished#
Boolean value that indicates whether the response has completed. Starts
as false
. After response.end()
executes, the value will be true
.
response.getHeader(name)#
Reads out a header that's already been queued but not sent to the client. Note that the name is case insensitive.
Example:
const contentType = response.getHeader('content-type');
response.getHeaderNames()#
- Returns: <Array>
Returns an array containing the unique names of the current outgoing headers. All header names are lowercase.
Example:
response.setHeader('Foo', 'bar');
response.setHeader('Set-Cookie', ['foo=bar', 'bar=baz']);
const headerNames = response.getHeaderNames();
// headerNames === ['foo', 'set-cookie']
response.getHeaders()#
- Returns: <Object>
Returns a shallow copy of the current outgoing headers. Since a shallow copy is used, array values may be mutated without additional calls to various header-related http module methods. The keys of the returned object are the header names and the values are the respective header values. All header names are lowercase.
Note: The object returned by the response.getHeaders()
method does not
prototypically inherit from the JavaScript Object
. This means that typical
Object
methods such as obj.toString()
, obj.hasOwnProperty()
, and others
are not defined and will not work.
Example:
response.setHeader('Foo', 'bar');
response.setHeader('Set-Cookie', ['foo=bar', 'bar=baz']);
const headers = response.getHeaders();
// headers === { foo: 'bar', 'set-cookie': ['foo=bar', 'bar=baz'] }
response.hasHeader(name)#
Returns true
if the header identified by name
is currently set in the
outgoing headers. Note that the header name matching is case-insensitive.
Example:
const hasContentType = response.hasHeader('content-type');
response.headersSent#
Boolean (read-only). True if headers were sent, false otherwise.
response.removeHeader(name)#
name
<string>
Removes a header that's queued for implicit sending.
Example:
response.removeHeader('Content-Encoding');
response.sendDate#
When true, the Date header will be automatically generated and sent in the response if it is not already present in the headers. Defaults to true.
This should only be disabled for testing; HTTP requires the Date header in responses.
response.setHeader(name, value)#
name
<string>value
<string> | <string[]>
Sets a single header value for implicit headers. If this header already exists in the to-be-sent headers, its value will be replaced. Use an array of strings here to send multiple headers with the same name.
Example:
response.setHeader('Content-Type', 'text/html');
or
response.setHeader('Set-Cookie', ['type=ninja', 'language=javascript']);
Attempting to set a header field name or value that contains invalid characters
will result in a TypeError
being thrown.
When headers have been set with response.setHeader()
, they will be merged with
any headers passed to response.writeHead()
, with the headers passed to
response.writeHead()
given precedence.
// returns content-type = text/plain
const server = http.createServer((req, res) => {
res.setHeader('Content-Type', 'text/html');
res.setHeader('X-Foo', 'bar');
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('ok');
});
response.setTimeout(msecs[, callback])#
msecs
<number>callback
<Function>
Sets the Socket's timeout value to msecs
. If a callback is
provided, then it is added as a listener on the 'timeout'
event on
the response object.
If no 'timeout'
listener is added to the request, the response, or
the server, then sockets are destroyed when they time out. If a handler is
assigned to the request, the response, or the server's 'timeout'
events,
timed out sockets must be handled explicitly.
Returns response
.
response.socket#
Reference to the underlying socket. Usually users will not want to access
this property. In particular, the socket will not emit 'readable'
events
because of how the protocol parser attaches to the socket. After
response.end()
, the property is nulled. The socket
may also be accessed
via response.connection
.
Example:
const http = require('http');
const server = http.createServer((req, res) => {
const ip = res.socket.remoteAddress;
const port = res.socket.remotePort;
res.end(`Your IP address is ${ip} and your source port is ${port}.`);
}).listen(3000);
response.statusCode#
When using implicit headers (not calling response.writeHead()
explicitly),
this property controls the status code that will be sent to the client when
the headers get flushed.
Example:
response.statusCode = 404;
After response header was sent to the client, this property indicates the status code which was sent out.
response.statusMessage#
When using implicit headers (not calling response.writeHead()
explicitly), this property
controls the status message that will be sent to the client when the headers get
flushed. If this is left as undefined
then the standard message for the status
code will be used.
Example:
response.statusMessage = 'Not found';
After response header was sent to the client, this property indicates the status message which was sent out.
response.write(chunk[, encoding][, callback])#
chunk
<string> | <Buffer>encoding
<string>callback
<Function>- Returns: <boolean>
If this method is called and response.writeHead()
has not been called,
it will switch to implicit header mode and flush the implicit headers.
This sends a chunk of the response body. This method may be called multiple times to provide successive parts of the body.
Note that in the http
module, the response body is omitted when the
request is a HEAD request. Similarly, the 204
and 304
responses
must not include a message body.
chunk
can be a string or a buffer. If chunk
is a string,
the second parameter specifies how to encode it into a byte stream.
By default the encoding
is 'utf8'
. callback
will be called when this chunk
of data is flushed.
Note: This is the raw HTTP body and has nothing to do with higher-level multi-part body encodings that may be used.
The first time response.write()
is called, it will send the buffered
header information and the first chunk of the body to the client. The second
time response.write()
is called, Node.js assumes data will be streamed,
and sends the new data separately. That is, the response is buffered up to the
first chunk of the body.
Returns true
if the entire data was flushed successfully to the kernel
buffer. Returns false
if all or part of the data was queued in user memory.
'drain'
will be emitted when the buffer is free again.
response.writeContinue()#
Sends a HTTP/1.1 100 Continue message to the client, indicating that
the request body should be sent. See the 'checkContinue'
event on Server
.
response.writeHead(statusCode[, statusMessage][, headers])#
Sends a response header to the request. The status code is a 3-digit HTTP
status code, like 404
. The last argument, headers
, are the response headers.
Optionally one can give a human-readable statusMessage
as the second
argument.
Example:
const body = 'hello world';
response.writeHead(200, {
'Content-Length': Buffer.byteLength(body),
'Content-Type': 'text/plain' });
This method must only be called once on a message and it must
be called before response.end()
is called.
If response.write()
or response.end()
are called before calling
this, the implicit/mutable headers will be calculated and call this function.
When headers have been set with response.setHeader()
, they will be merged with
any headers passed to response.writeHead()
, with the headers passed to
response.writeHead()
given precedence.
// returns content-type = text/plain
const server = http.createServer((req, res) => {
res.setHeader('Content-Type', 'text/html');
res.setHeader('X-Foo', 'bar');
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('ok');
});
Note that Content-Length is given in bytes not characters. The above example
works because the string 'hello world'
contains only single byte characters.
If the body contains higher coded characters then Buffer.byteLength()
should be used to determine the number of bytes in a given encoding.
And Node.js does not check whether Content-Length and the length of the body
which has been transmitted are equal or not.
Attempting to set a header field name or value that contains invalid characters
will result in a TypeError
being thrown.
Class: http.IncomingMessage#
An IncomingMessage
object is created by http.Server
or
http.ClientRequest
and passed as the first argument to the 'request'
and 'response'
event respectively. It may be used to access response status,
headers and data.
It implements the Readable Stream interface, as well as the following additional events, methods, and properties.
Event: 'aborted'#
Emitted when the request has been aborted and the network socket has closed.
Event: 'close'#
Indicates that the underlying connection was closed.
Just like 'end'
, this event occurs only once per response.
message.destroy([error])#
error
<Error>
Calls destroy()
on the socket that received the IncomingMessage
. If error
is provided, an 'error'
event is emitted and error
is passed as an argument
to any listeners on the event.
message.headers#
The request/response headers object.
Key-value pairs of header names and values. Header names are lower-cased. Example:
// Prints something like:
//
// { 'user-agent': 'curl/7.22.0',
// host: '127.0.0.1:8000',
// accept: '*/*' }
console.log(request.headers);
Duplicates in raw headers are handled in the following ways, depending on the header name:
- Duplicates of
age
,authorization
,content-length
,content-type
,etag
,expires
,from
,host
,if-modified-since
,if-unmodified-since
,last-modified
,location
,max-forwards
,proxy-authorization
,referer
,retry-after
, oruser-agent
are discarded. set-cookie
is always an array. Duplicates are added to the array.- For all other headers, the values are joined together with ', '.
message.httpVersion#
In case of server request, the HTTP version sent by the client. In the case of
client response, the HTTP version of the connected-to server.
Probably either '1.1'
or '1.0'
.
Also message.httpVersionMajor
is the first integer and
message.httpVersionMinor
is the second.
message.method#
Only valid for request obtained from http.Server
.
The request method as a string. Read only. Example:
'GET'
, 'DELETE'
.
message.rawHeaders#
The raw request/response headers list exactly as they were received.
Note that the keys and values are in the same list. It is not a list of tuples. So, the even-numbered offsets are key values, and the odd-numbered offsets are the associated values.
Header names are not lowercased, and duplicates are not merged.
// Prints something like:
//
// [ 'user-agent',
// 'this is invalid because there can be only one',
// 'User-Agent',
// 'curl/7.22.0',
// 'Host',
// '127.0.0.1:8000',
// 'ACCEPT',
// '*/*' ]
console.log(request.rawHeaders);
message.rawTrailers#
The raw request/response trailer keys and values exactly as they were
received. Only populated at the 'end'
event.
message.setTimeout(msecs, callback)#
msecs
<number>callback
<Function>
Calls message.connection.setTimeout(msecs, callback)
.
Returns message
.
message.socket#
The net.Socket
object associated with the connection.
With HTTPS support, use request.socket.getPeerCertificate()
to obtain the
client's authentication details.
message.statusCode#
Only valid for response obtained from http.ClientRequest
.
The 3-digit HTTP response status code. E.G. 404
.
message.statusMessage#
Only valid for response obtained from http.ClientRequest
.
The HTTP response status message (reason phrase). E.G. OK
or Internal Server Error
.
message.trailers#
The request/response trailers object. Only populated at the 'end'
event.
message.url#
Only valid for request obtained from http.Server
.
Request URL string. This contains only the URL that is present in the actual HTTP request. If the request is:
GET /status?name=ryan HTTP/1.1\r\n
Accept: text/plain\r\n
\r\n
Then request.url
will be:
'/status?name=ryan'
To parse the url into its parts require('url').parse(request.url)
can be used. Example:
$ node
> require('url').parse('/status?name=ryan')
Url {
protocol: null,
slashes: null,
auth: null,
host: null,
port: null,
hostname: null,
hash: null,
search: '?name=ryan',
query: 'name=ryan',
pathname: '/status',
path: '/status?name=ryan',
href: '/status?name=ryan' }
To extract the parameters from the query string, the
require('querystring').parse
function can be used, or
true
can be passed as the second argument to require('url').parse
.
Example:
$ node
> require('url').parse('/status?name=ryan', true)
Url {
protocol: null,
slashes: null,
auth: null,
host: null,
port: null,
hostname: null,
hash: null,
search: '?name=ryan',
query: { name: 'ryan' },
pathname: '/status',
path: '/status?name=ryan',
href: '/status?name=ryan' }
http.METHODS#
A list of the HTTP methods that are supported by the parser.
http.STATUS_CODES#
A collection of all the standard HTTP response status codes, and the
short description of each. For example, http.STATUS_CODES[404] === 'Not
Found'
.
http.createServer([options][, requestListener])#
options
<Object>IncomingMessage
<http.IncomingMessage> Specifies the IncomingMessage class to be used. Useful for extending the originalIncomingMessage
. Defaults to:IncomingMessage
ServerResponse
<http.ServerResponse> Specifies the ServerResponse class to be used. Useful for extending the originalServerResponse
. Defaults to:ServerResponse
requestListener
<Function>Returns: <http.Server>
Returns a new instance of http.Server
.
The requestListener
is a function which is automatically
added to the 'request'
event.
http.get(options[, callback])#
options
<Object> | <string> | <URL> Accepts the sameoptions
ashttp.request()
, with themethod
always set toGET
. Properties that are inherited from the prototype are ignored.callback
<Function>- Returns: <http.ClientRequest>
Since most requests are GET requests without bodies, Node.js provides this
convenience method. The only difference between this method and
http.request()
is that it sets the method to GET and calls req.end()
automatically. Note that the callback must take care to consume the response
data for reasons stated in http.ClientRequest
section.
The callback
is invoked with a single argument that is an instance of
http.IncomingMessage
JSON Fetching Example:
http.get('http://nodejs.org/dist/index.json', (res) => {
const { statusCode } = res;
const contentType = res.headers['content-type'];
let error;
if (statusCode !== 200) {
error = new Error('Request Failed.\n' +
`Status Code: ${statusCode}`);
} else if (!/^application\/json/.test(contentType)) {
error = new Error('Invalid content-type.\n' +
`Expected application/json but received ${contentType}`);
}
if (error) {
console.error(error.message);
// consume response data to free up memory
res.resume();
return;
}
res.setEncoding('utf8');
let rawData = '';
res.on('data', (chunk) => { rawData += chunk; });
res.on('end', () => {
try {
const parsedData = JSON.parse(rawData);
console.log(parsedData);
} catch (e) {
console.error(e.message);
}
});
}).on('error', (e) => {
console.error(`Got error: ${e.message}`);
});
http.globalAgent#
Global instance of Agent
which is used as the default for all HTTP client
requests.
http.request(options[, callback])#
options
<Object> | <string> | <URL>protocol
<string> Protocol to use. Defaults tohttp:
.host
<string> A domain name or IP address of the server to issue the request to. Defaults tolocalhost
.hostname
<string> Alias forhost
. To supporturl.parse()
,hostname
is preferred overhost
.family
<number> IP address family to use when resolvinghost
andhostname
. Valid values are4
or6
. When unspecified, both IP v4 and v6 will be used.port
<number> Port of remote server. Defaults to 80.localAddress
<string> Local interface to bind for network connections.socketPath
<string> Unix Domain Socket (use one of host:port or socketPath).method
<string> A string specifying the HTTP request method. Defaults to'GET'
.path
<string> Request path. Defaults to'/'
. Should include query string if any. E.G.'/index.html?page=12'
. An exception is thrown when the request path contains illegal characters. Currently, only spaces are rejected but that may change in the future.headers
<Object> An object containing request headers.auth
<string> Basic authentication i.e.'user:password'
to compute an Authorization header.agent
<http.Agent> | <boolean> ControlsAgent
behavior. Possible values:undefined
(default): usehttp.globalAgent
for this host and port.Agent
object: explicitly use the passed inAgent
.false
: causes a newAgent
with default values to be used.
createConnection
<Function> A function that produces a socket/stream to use for the request when theagent
option is not used. This can be used to avoid creating a customAgent
class just to override the defaultcreateConnection
function. Seeagent.createConnection()
for more details. AnyDuplex
stream is a valid return value.timeout
<number>: A number specifying the socket timeout in milliseconds. This will set the timeout before the socket is connected.
callback
<Function>- Returns: <http.ClientRequest>
Node.js maintains several connections per server to make HTTP requests. This function allows one to transparently issue requests.
options
can be an object, a string, or a URL
object. If options
is a
string, it is automatically parsed with url.parse()
. If it is a URL
object, it will be automatically converted to an ordinary options
object.
The optional callback
parameter will be added as a one-time listener for
the 'response'
event.
http.request()
returns an instance of the http.ClientRequest
class. The ClientRequest
instance is a writable stream. If one needs to
upload a file with a POST request, then write to the ClientRequest
object.
Example:
const postData = querystring.stringify({
'msg': 'Hello World!'
});
const options = {
hostname: 'www.google.com',
port: 80,
path: '/upload',
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded',
'Content-Length': Buffer.byteLength(postData)
}
};
const req = http.request(options, (res) => {
console.log(`STATUS: ${res.statusCode}`);
console.log(`HEADERS: ${JSON.stringify(res.headers)}`);
res.setEncoding('utf8');
res.on('data', (chunk) => {
console.log(`BODY: ${chunk}`);
});
res.on('end', () => {
console.log('No more data in response.');
});
});
req.on('error', (e) => {
console.error(`problem with request: ${e.message}`);
});
// write data to request body
req.write(postData);
req.end();
Note that in the example req.end()
was called. With http.request()
one
must always call req.end()
to signify the end of the request -
even if there is no data being written to the request body.
If any error is encountered during the request (be that with DNS resolution,
TCP level errors, or actual HTTP parse errors) an 'error'
event is emitted
on the returned request object. As with all 'error'
events, if no listeners
are registered the error will be thrown.
There are a few special headers that should be noted.
Sending a 'Connection: keep-alive' will notify Node.js that the connection to the server should be persisted until the next request.
Sending a 'Content-Length' header will disable the default chunked encoding.
Sending an 'Expect' header will immediately send the request headers. Usually, when sending 'Expect: 100-continue', both a timeout and a listener for the
continue
event should be set. See RFC2616 Section 8.2.3 for more information.Sending an Authorization header will override using the
auth
option to compute basic authentication.
Example using a URL
as options
:
const { URL } = require('url');
const options = new URL('http://abc:[email protected]');
const req = http.request(options, (res) => {
// ...
});
In a successful request, the following events will be emitted in the following order:
socket
response
data
any number of times, on theres
object (data
will not be emitted at all if the response body is empty, for instance, in most redirects)end
on theres
object
close
In the case of a connection error, the following events will be emitted:
socket
error
close
If req.abort()
is called before the connection succeeds, the following events
will be emitted in the following order:
socket
- (
req.abort()
called here) abort
close
error
with an error with messageError: socket hang up
and codeECONNRESET
If req.abort()
is called after the response is received, the following events
will be emitted in the following order:
socket
response
data
any number of times, on theres
object
- (
req.abort()
called here) abort
close
aborted
on theres
objectend
on theres
objectclose
on theres
object
Note that setting the timeout
option or using the setTimeout
function will
not abort the request or do anything besides add a timeout
event.