HttpRequest class - dart:html library (original) (raw)
A client-side XHR request for getting data from a URL, formally known as XMLHttpRequest.
Note: You should avoid directly using HttpRequest to make HTTP requests. You can use HttpRequest indirectly through theBrowserClientadapter in package:http.
Using a higher-level library, likepackage:http, allows you to switch implementations with minimal changes to your code. For example,package:http Clienthas implementations for the browser and implementations that use platform native HTTP clients on Android and iOS.
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) {
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.
Other resources
- Fetch data dynamically, a tutorial shows how to load data from a static file or from a server.
- Dart article on using HttpRequests
- JS XMLHttpRequest
- Using XMLHttpRequest
Inheritance
- Object
- EventTarget
- HttpRequestEventTarget
- HttpRequest
Annotations
- @Native("XMLHttpRequest")
Constructors
General constructor for any type of request (GET, POST, etc).
factory
Properties
The hash code for this object.
no setterinherited
This is an ease-of-use accessor for event streams which should only be used when an explicit accessor is not available.
no setterinherited
onAbort → Stream<ProgressEvent>
Stream of abort events handled by this HttpRequestEventTarget.
no setterinherited
onError → Stream<ProgressEvent>
Stream of error events handled by this HttpRequestEventTarget.
no setterinherited
onLoad → Stream<ProgressEvent>
Stream of load events handled by this HttpRequestEventTarget.
no setterinherited
onLoadEnd → Stream<ProgressEvent>
Stream of loadend events handled by this HttpRequestEventTarget.
no setterinherited
onLoadStart → Stream<ProgressEvent>
Stream of loadstart events handled by this HttpRequestEventTarget.
no setterinherited
onProgress → Stream<ProgressEvent>
Stream of progress events handled by this HttpRequestEventTarget.
no setterinherited
onReadyStateChange → Stream<Event>
Event listeners to be notified every time the HttpRequestobject's readyState changes values.
no setter
onTimeout → Stream<ProgressEvent>
Stream of timeout events handled by this HttpRequestEventTarget.
no setterinherited
Indicator of the current state of the request:
no setter
response → dynamic
The data received as a reponse from the request.
no setter
Returns all response headers as a key-value map.
no setter
The response in String form or empty String on failure.
no setter
String telling the server the desired response format.
getter/setter pair
no setter
The request response, or null on failure.
no setter
A representation of the runtime type of the object.
no setterinherited
The HTTP result code from the request (200, 404, etc). See also: HTTP Status Codes
no setter
statusText → String?
The request response string (such as "OK"). See also: HTTP Status Codes
no setter
Length of time in milliseconds before a request is automatically terminated.
getter/setter pair
EventTarget that can hold listeners to track the progress of the request.
no setter
True if cross-site requests should use credentials such as cookies or authorization headers; false otherwise.
getter/setter pair
Methods
abort()→ void
Stop the current request.
addEventListener(String type, EventListener? listener, [bool? useCapture])→ void
inherited
dispatchEvent(Event event)→ bool
inherited
Retrieve all the response headers from a request.
Return the response header named header, or null if not found.
noSuchMethod(Invocation invocation)→ dynamic
Invoked when a nonexistent method or property is accessed.
inherited
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 mime)→ void
Specify a particular MIME type (such as text/xml) desired for the response.
removeEventListener(String type, EventListener? listener, [bool? useCapture])→ void
inherited
send([dynamic body_OR_data])→ void
Send the request with any given data.
Sets the value of an HTTP request header.
A string representation of this object.
inherited
Operators
operator ==(Object other)→ bool
The equality operator.
inherited
Static Properties
Checks to see if the current platform supports making cross origin requests.
no setter
Checks to see if the LoadEnd event is supported on the current platform.
no setter
supportsOverrideMimeType → bool
Checks to see if the overrideMimeType method is supported on the current platform.
no setter
Checks to see if the Progress event is supported on the current platform.
no setter
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, 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, dynamic 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.
Constants
readyStateChangeEvent → const EventStreamProvider<Event>
Static factory designed to expose readystatechange events to event handlers that are not necessarily instances of HttpRequest.