A client-side XHR request for getting data from a URL, formally known as XMLHttpRequest.

HttpRequest can be used to obtain data from HTTP and FTP protocols, and is useful for AJAX-style page updates.

The simplest way to get the contents of a text file, such as a JSON-formatted file, is with getString. For example, the following code gets the contents of a JSON file and prints its length:

var path = 'myData.json';
HttpRequest.getString(path)
    .then((String fileContents) {
      print(fileContents.length);
    })
    .catchError((Error error) {
      print(error.toString());
    });

Fetching data from other servers

For security reasons, browsers impose restrictions on requests made by embedded apps. With the default behavior of this class, the code making the request must be served from the same origin (domain name, port, and application layer protocol) as the requested resource. In the example above, the myData.json file must be co-located with the app that uses it. You might be able to get around this restriction by using CORS headers or JSONP.

Other resources

Inheritance
Annotations
  • DomName('XMLHttpRequest')

Constants

int DONE = 4
const

int HEADERS_RECEIVED = 2
const

int LOADING = 3
const

int OPENED = 1
const

EventStreamProvider<ProgressEvent> readyStateChangeEvent = const EventStreamProvider<ProgressEvent>('readystatechange')
const

Static factory designed to expose readystatechange events to event handlers that are not necessarily instances of HttpRequest.…

int UNSENT = 0
const

Static Properties

supportsCrossOrigin → bool
read-only

Checks to see if the current platform supports making cross origin requests.…

supportsLoadEndEvent → bool
read-only

Checks to see if the LoadEnd event is supported on the current platform.

supportsOverrideMimeType → bool
read-only

Checks to see if the overrideMimeType method is supported on the current platform.

supportsProgressEvent → bool
read-only

Checks to see if the Progress event is supported on the current platform.

Static Methods

getString(String url, {bool withCredentials, void onProgress(ProgressEvent e)}) → Future<String>

Creates a GET request for the specified url.…

postFormData(String url, Map<String,String> data, {bool withCredentials, String responseType, Map<String,String> requestHeaders, void onProgress(ProgressEvent e)}) → Future<HttpRequest>

Makes a server POST request with the specified data encoded as form data.…

request(String url, {String method, bool withCredentials, String responseType, String mimeType, Map<String,String> requestHeaders, sendData, void onProgress(ProgressEvent e)}) → Future<HttpRequest>

Creates and sends a URL request for the specified url.…

requestCrossOrigin(String url, {String method, String sendData}) → Future<String>

Makes a cross-origin request to the specified URL.…

Properties

on → Events
read-only, inherited

This is an ease-of-use accessor for event streams which should only be used when an explicit accessor is not available.

onAbort → Stream<ProgressEvent>
read-only, inherited

Stream of abort events handled by this HttpRequestEventTarget.

onError → Stream<ProgressEvent>
read-only, inherited

Stream of error events handled by this HttpRequestEventTarget.

onLoad → Stream<ProgressEvent>
read-only, inherited

Stream of load events handled by this HttpRequestEventTarget.

onLoadEnd → Stream<ProgressEvent>
read-only, inherited

Stream of loadend events handled by this HttpRequestEventTarget.

onLoadStart → Stream<ProgressEvent>
read-only, inherited

Stream of loadstart events handled by this HttpRequestEventTarget.

onProgress → Stream<ProgressEvent>
read-only, inherited

Stream of progress events handled by this HttpRequestEventTarget.

onReadyStateChange → Stream<ProgressEvent>
read-only

Event listeners to be notified every time the HttpRequest object's readyState changes values.

onTimeout → Stream<ProgressEvent>
read-only, inherited

Stream of timeout events handled by this HttpRequestEventTarget.

readyState → int
read-only

Indicator of the current state of the request:…

response → Object
read-only

The data received as a reponse from the request.…

responseHeaders → Map<String,String>
read-only

Returns all response headers as a key-value map.…

responseText → String
read-only

The response in String form or empty String on failure.

responseType → String
read / write

String telling the server the desired response format.…

responseUrl → String
read-only

responseXml → Document
read-only

The request response, or null on failure.…

status → int
read-only

The http result code from the request (200, 404, etc). See also: Http Status Codes

statusText → String
read-only

The request response string (such as \"200 OK\"). See also: Http Status Codes

timeout → int
read / write

Length of time before a request is automatically terminated.…

upload → HttpRequestUpload
read-only

EventTarget that can hold listeners to track the progress of the request. The events fired will be members of HttpRequestUploadEvents.

withCredentials → bool
read / write

True if cross-site requests should use credentials such as cookies or authorization headers; false otherwise.…

Constructors

HttpRequest()

General constructor for any type of request (GET, POST, etc).…

Methods

abort() → void

Stop the current request.…

addEventListener(String type, dynamic listener(Event event), [bool useCapture]) → void
inherited

dispatchEvent(Event event) → bool
inherited

getAllResponseHeaders() → String

Retrieve all the response headers from a request.…

getResponseHeader(String header) → String

Return the response header named header, or null if not found.…

open(String method, String url, {bool async, String user, String password}) → void

Specify the desired url, and method to use in making the request.…

overrideMimeType(String override) → void

Specify a particular MIME type (such as text/xml) desired for the response.…

removeEventListener(String type, dynamic listener(Event event), [bool useCapture]) → void
inherited

send([data]) → void

Send the request with any given data.…

setRequestHeader(String header, String value) → void

Sets the value of an HTTP requst header.…