electron/docs/api/client-request.md

Class: ClientRequest

Make HTTP/HTTPS requests.

Process: Main

ClientRequest implements the Writable Stream interface and is therefore an EventEmitter.

new ClientRequest(options)

• options (Object | 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 instance with which the request is associated.
  • partition String (optional) - The name of the partition 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.
  • redirect String (optional) - The redirect mode for this request. Should be one of follow, error or manual. Defaults to follow. When mode is error, any redirection will be aborted. When mode is manual the redirection will be deferred until request.followRedirect is invoked. Listen for the redirect event in this mode to get more details about the redirect request.

options properties such as protocol, host, hostname, port and path strictly follow the Node.js model as described in the URL module.

For instance, we could have created the same request to 'github.com' as follows:

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
  • username String
  • password String

Emitted when an authenticating proxy is asking for user credentials.

The callback function is expected to be called back with user credentials:

• username String
• password String

request.on('login', (authInfo, callback) => {
  callback('username', 'password')
})

Providing empty credentials will cancel the request and report an authentication error on the response object:

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.

Event: 'redirect'

Returns:

• statusCode Integer
• method String
• redirectUrl String
• responseHeaders Object

Emitted when there is redirection and the mode is manual. Calling request.followRedirect will continue with the redirection.

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 Object - 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. If the passed value is not a String, its toString() method will be called to obtain the final value.

request.getHeader(name)

• name String - Specify an extra header name.

Returns Object - 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 | 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 | 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.

request.followRedirect()

Continues any deferred redirection request when the redirection mode is manual.

request.getUploadProgress()

Returns Object:

• active Boolean - Whether the request is currently active. If this is false no other properties will be set
• started Boolean - Whether the upload has started. If this is false both current and total will be set to 0.
• current Integer - The number of bytes that have been uploaded so far
• total Integer - The number of bytes that will be uploaded this request

You can use this method in conjunction with POST requests to get the progress of a file upload or other data transfer.