322 lines
11 KiB
Markdown
322 lines
11 KiB
Markdown
# net
|
|
|
|
> Issue HTTP/HTTPS requests.
|
|
|
|
The `net` module is a client-side API for issuing HTTP(S) requests. It is
|
|
similar to the [HTTP](https://nodejs.org/api/http.html) and
|
|
[HTTPS](https://nodejs.org/api/https.html) modules of Node.js but uses
|
|
Chromium native networking library instead of the Node.js implementation
|
|
offering therefore a much greater support regarding web proxies.
|
|
|
|
Following is a non-exhaustive list of why you may consider using the `net`
|
|
module instead of the native Node.js modules:
|
|
* Automatic management of system proxy configuration, support of the wpad
|
|
protocol and proxy pac configuration files.
|
|
* Automatic tunneling of HTTPS requests.
|
|
* Support for authenticating proxies using basic, digest, NTLM, Kerberos or
|
|
negotiate authentication schemes.
|
|
* Support for traffic monitoring proxies: Fiddler-like proxies used for access
|
|
control and monitoring.
|
|
|
|
The `net` module API has been specifically designed to mimic, as closely as
|
|
possible, the familiar Node.js API. The API components including classes,
|
|
methods, properties and event names are similar to those commonly used in
|
|
Node.js.
|
|
|
|
For instance, the following example quickly shows how the `net` API might be
|
|
used:
|
|
|
|
```javascript
|
|
const {app} = require('electron')
|
|
app.on('ready', () => {
|
|
const {net} = require('electron')
|
|
const request = net.request('https://github.com')
|
|
request.on('response', (response) => {
|
|
console.log(`STATUS: ${response.statusCode}`)
|
|
console.log(`HEADERS: ${JSON.stringify(response.headers)}`)
|
|
response.on('data', (chunk) => {
|
|
console.log(`BODY: ${chunk}`)
|
|
})
|
|
response.on('end', () => {
|
|
console.log('No more data in response.')
|
|
})
|
|
})
|
|
request.end()
|
|
})
|
|
```
|
|
|
|
By the way, it is almost identical to how you would normally use the
|
|
[HTTP](https://nodejs.org/api/http.html)/[HTTPS](https://nodejs.org/api/https.html)
|
|
modules of Node.js
|
|
|
|
The `net` API can be used only after the application emits the `ready` event.
|
|
Trying to use the module before the `ready` event will throw an error.
|
|
|
|
## Methods
|
|
|
|
The `net` module has the following methods:
|
|
|
|
### `net.request(options)`
|
|
|
|
* `options`: Object or String - The `ClientRequest` constructor options.
|
|
|
|
Returns `ClientRequest`
|
|
|
|
Creates a `ClientRequest` instance using the provided `options` which are
|
|
directly forwarded to the `ClientRequest` constructor. The `net.request` method
|
|
would be used to issue both secure and insecure HTTP requests according to the
|
|
specified protocol scheme in the `options` object.
|
|
|
|
## Class: ClientRequest
|
|
|
|
`ClientRequest` implements the [Writable Stream](https://nodejs.org/api/stream.html#stream_writable_streams)
|
|
interface and it is therefore an [EventEmitter](https://nodejs.org/api/events.html#events_class_eventemitter).
|
|
|
|
### `new ClientRequest(options)`
|
|
|
|
* `options` Object or String - If `options` is a String, it is interpreted as
|
|
the request URL.
|
|
If it is an object, it is expected to fully specify an HTTP request via the
|
|
following properties:
|
|
* `method` String (optional) - The HTTP request method. Defaults to the GET
|
|
method.
|
|
* `url` String (optional) - The request URL. Must be provided in the absolute
|
|
form with the protocol scheme specified as http or https.
|
|
* `session` Object (optional) - The [`Session`](session.md) instance with
|
|
which the request is associated.
|
|
* `partition` String (optional) - The name of the [`partition`](session.md)
|
|
with which the request is associated. Defaults to the empty string. The
|
|
`session` option prevails on `partition`. Thus if a `session` is explicitly
|
|
specified, `partition` is ignored.
|
|
* `protocol` String (optional) - The protocol scheme in the form 'scheme:'.
|
|
Currently supported values are 'http:' or 'https:'. Defaults to 'http:'.
|
|
* `host` String (optional) - The server host provided as a concatenation of
|
|
the hostname and the port number 'hostname:port'
|
|
* `hostname` String (optional) - The server host name.
|
|
* `port` Integer (optional) - The server's listening port number.
|
|
* `path` String (optional) - The path part of the request URL.
|
|
|
|
`options` properties such as `protocol`, `host`, `hostname`, `port` and `path`
|
|
strictly follow the Node.js model as described in the
|
|
[URL](https://nodejs.org/api/url.html) module.
|
|
|
|
For instance, we could have created the same request to 'github.com' as follows:
|
|
|
|
```JavaScript
|
|
const request = net.request({
|
|
method: 'GET',
|
|
protocol: 'https:',
|
|
hostname: 'github.com',
|
|
port: 443,
|
|
path: '/'
|
|
})
|
|
```
|
|
|
|
### Instance Events
|
|
|
|
#### Event: 'response'
|
|
|
|
Returns:
|
|
|
|
* `response` IncomingMessage - An object representing the HTTP response message.
|
|
|
|
#### Event: 'login'
|
|
|
|
Returns:
|
|
|
|
* `authInfo` Object
|
|
* `isProxy` Boolean
|
|
* `scheme` String
|
|
* `host` String
|
|
* `port` Integer
|
|
* `realm` String
|
|
* `callback` Function
|
|
|
|
Emitted when an authenticating proxy is asking for user credentials.
|
|
|
|
The `callback` function is expected to be called back with user credentials:
|
|
|
|
* `usrename` String
|
|
* `password` String
|
|
|
|
```JavaScript
|
|
request.on('login', (authInfo, callback) => {
|
|
callback('username', 'password')
|
|
})
|
|
```
|
|
Providing empty credentials will cancel the request and report an authentication
|
|
error on the response object:
|
|
|
|
```JavaScript
|
|
request.on('response', (response) => {
|
|
console.log(`STATUS: ${response.statusCode}`);
|
|
response.on('error', (error) => {
|
|
console.log(`ERROR: ${JSON.stringify(error)}`)
|
|
})
|
|
})
|
|
request.on('login', (authInfo, callback) => {
|
|
callback()
|
|
})
|
|
```
|
|
|
|
#### Event: 'finish'
|
|
|
|
Emitted just after the last chunk of the `request`'s data has been written into
|
|
the `request` object.
|
|
|
|
#### Event: 'abort'
|
|
|
|
Emitted when the `request` is aborted. The `abort` event will not be fired if
|
|
the `request` is already closed.
|
|
|
|
#### Event: 'error'
|
|
|
|
Returns:
|
|
|
|
* `error` Error - an error object providing some information about the failure.
|
|
|
|
Emitted when the `net` module fails to issue a network request. Typically when
|
|
the `request` object emits an `error` event, a `close` event will subsequently
|
|
follow and no response object will be provided.
|
|
|
|
#### Event: 'close'
|
|
|
|
Emitted as the last event in the HTTP request-response transaction. The `close`
|
|
event indicates that no more events will be emitted on either the `request` or
|
|
`response` objects.
|
|
|
|
### Instance Properties
|
|
|
|
#### `request.chunkedEncoding`
|
|
|
|
A Boolean specifying whether the request will use HTTP chunked transfer encoding
|
|
or not. Defaults to false. The property is readable and writable, however it can
|
|
be set only before the first write operation as the HTTP headers are not yet put
|
|
on the wire. Trying to set the `chunkedEncoding` property after the first write
|
|
will throw an error.
|
|
|
|
Using chunked encoding is strongly recommended if you need to send a large
|
|
request body as data will be streamed in small chunks instead of being
|
|
internally buffered inside Electron process memory.
|
|
|
|
### Instance Methods
|
|
|
|
#### `request.setHeader(name, value)`
|
|
|
|
* `name` String - An extra HTTP header name.
|
|
* `value` String - An extra HTTP header value.
|
|
|
|
Adds an extra HTTP header. The header name will issued as it is without
|
|
lowercasing. It can be called only before first write. Calling this method after
|
|
the first write will throw an error.
|
|
|
|
#### `request.getHeader(name)`
|
|
|
|
* `name` String - Specify an extra header name.
|
|
|
|
Returns String - The value of a previously set extra header name.
|
|
|
|
#### `request.removeHeader(name)`
|
|
|
|
* `name` String - Specify an extra header name.
|
|
|
|
Removes a previously set extra header name. This method can be called only
|
|
before first write. Trying to call it after the first write will throw an error.
|
|
|
|
#### `request.write(chunk[, encoding][, callback])`
|
|
|
|
* `chunk` String or Buffer - A chunk of the request body's data. If it is a
|
|
string, it is converted into a Buffer using the specified encoding.
|
|
* `encoding` String (optional) - Used to convert string chunks into Buffer
|
|
objects. Defaults to 'utf-8'.
|
|
* `callback` Function (optional) - Called after the write operation ends.
|
|
`callback` is essentially a dummy function introduced in the purpose of keeping
|
|
similarity with the Node.js API. It is called asynchronously in the next tick
|
|
after `chunk` content have been delivered to the Chromium networking layer.
|
|
Contrary to the Node.js implementation, it is not guaranteed that `chunk`
|
|
content have been flushed on the wire before `callback` is called.
|
|
|
|
Adds a chunk of data to the request body. The first write operation may cause
|
|
the request headers to be issued on the wire. After the first write operation,
|
|
it is not allowed to add or remove a custom header.
|
|
|
|
#### `request.end([chunk][, encoding][, callback])`
|
|
|
|
* `chunk` String or Buffer (optional)
|
|
* `encoding` String (optional)
|
|
* `callback` Function (optional)
|
|
|
|
Sends the last chunk of the request data. Subsequent write or end operations
|
|
will not be allowed. The `finish` event is emitted just after the end operation.
|
|
|
|
#### `request.abort()`
|
|
|
|
Cancels an ongoing HTTP transaction. If the request has already emitted the
|
|
`close` event, the abort operation will have no effect. Otherwise an ongoing
|
|
event will emit `abort` and `close` events. Additionally, if there is an ongoing
|
|
response object,it will emit the `aborted` event.
|
|
|
|
|
|
## Class: IncomingMessage
|
|
|
|
`IncomingMessage` represents an HTTP response message.
|
|
It is a [Readable Stream](https://nodejs.org/api/stream.html#stream_readable_streams)
|
|
and consequently an [EventEmitter](https://nodejs.org/api/events.html#events_class_eventemitter).
|
|
|
|
### Instance Events
|
|
|
|
#### Event 'data'
|
|
|
|
Returns:
|
|
|
|
* `chunk`: Buffer - A chunk of response body's data.
|
|
|
|
The `data` event is the usual method of transferring response data into
|
|
applicative code.
|
|
|
|
#### Event 'end'
|
|
|
|
Indicates that response body has ended.
|
|
|
|
#### Event 'aborted'
|
|
|
|
Emitted when a request has been canceled during an ongoing HTTP transaction.
|
|
|
|
#### Event 'error'
|
|
|
|
Returns:
|
|
|
|
`error` Error - Typically holds an error string identifying failure root cause.
|
|
|
|
Emitted when an error was encountered while streaming response data events. For
|
|
instance, if the server closes the underlying while the response is still
|
|
streaming, an `error` event will be emitted on the response object and a `close`
|
|
event will subsequently follow on the request object.
|
|
|
|
### Instance properties
|
|
|
|
An `IncomingMessage` instance has the following readable properties:
|
|
|
|
#### `response.statusCode`
|
|
|
|
An Integer indicating the HTTP response status code.
|
|
|
|
#### `response.statusMessage`
|
|
|
|
A String representing the HTTP status message.
|
|
|
|
#### `response.headers`
|
|
|
|
An Object representing the response HTTP headers. The `headers` object is
|
|
formatted as follows:
|
|
|
|
* All header names are lowercased.
|
|
* Each header name produces an array-valued property on the headers object.
|
|
* Each header value is pushed into the array associated with its header name.
|
|
|
|
#### `response.httpVersion`
|
|
|
|
A String indicating the HTTP protocol version number. Typical values are '1.0'
|
|
or '1.1'. Additionally `httpVersionMajor` and `httpVersionMinor` are two
|
|
Integer-valued readable properties that return respectively the HTTP major and
|
|
minor version numbers.
|