dart:html
HttpRequest class
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) {
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
- @Native("XMLHttpRequest")
Constructors
- HttpRequest()
factory
- General constructor for any type of request (GET, POST, etc). [...]
Properties
- onReadyStateChange → Stream<Event>
read-only
- Event listeners to be notified every time the HttpRequest object's
readyState changes values. - readyState → int
final
- Indicator of the current state of the request: [...]
- response → dynamic
@SupportedBrowser(SupportedBrowser.CHROME), @SupportedBrowser(SupportedBrowser.FIREFOX), @SupportedBrowser(SupportedBrowser.IE, '10'), @SupportedBrowser(SupportedBrowser.SAFARI), read-only
- The data received as a reponse from the request. [...]
- Returns all response headers as a key-value map. [...]
- responseText → String
final
- The response in String form or empty String on failure.
- responseType ↔ String
read / write
- String telling the server the desired response format. [...]
- responseUrl → String
@JSName('responseURL'), final
- responseXml → Document
@JSName('responseXML'), final
- The request response, or null on failure. [...]
- status → int
final
- The HTTP result code from the request (200, 404, etc). See also: HTTP Status Codes
- statusText → String
final
- The request response string (such as "OK"). See also: HTTP Status Codes
- timeout ↔ int
read / write
- Length of time in milliseconds before a request is automatically terminated. [...]
- upload → HttpRequestUpload
@Unstable(), final
- 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. [...]
- hashCode → int
read-only, inherited
- The hash code for this object. [...]
- 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>
@SupportedBrowser(SupportedBrowser.CHROME), @SupportedBrowser(SupportedBrowser.FIREFOX), @SupportedBrowser(SupportedBrowser.IE, '10'), @SupportedBrowser(SupportedBrowser.SAFARI), 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>
@SupportedBrowser(SupportedBrowser.CHROME), @SupportedBrowser(SupportedBrowser.FIREFOX), @SupportedBrowser(SupportedBrowser.IE, '10'), @SupportedBrowser(SupportedBrowser.SAFARI), read-only, inherited
- Stream of
progress events handled by this HttpRequestEventTarget. - onTimeout → Stream<ProgressEvent>
read-only, inherited
- Stream of
timeout events handled by this HttpRequestEventTarget. - runtimeType → Type
read-only, inherited
- A representation of the runtime type of the object.
Methods
- abort() → void
- Stop the current request. [...]
- Retrieve all the response headers from a request. [...]
- 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 mime) → void
@SupportedBrowser(SupportedBrowser.CHROME), @SupportedBrowser(SupportedBrowser.FIREFOX), @SupportedBrowser(SupportedBrowser.SAFARI)
- Specify a particular MIME type (such as
text/xml) desired for the response. [...] - send([dynamic body_OR_data ]) → void
- Send the request with any given
data. [...] - Sets the value of an HTTP request header. [...]
- addEventListener(String type, EventListener listener, [ bool useCapture ]) → void
inherited
- dispatchEvent(Event event) → bool
inherited
- noSuchMethod(Invocation invocation) → dynamic
inherited
- Invoked when a non-existent method or property is accessed. [...]
- removeEventListener(String type, EventListener listener, [ bool useCapture ]) → void
inherited
- toString() → String
inherited
- Returns a string representation of this object.
Operators
- operator ==(dynamic other) → bool
inherited
- The equality operator. [...]
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, 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
- DONE → const int
-
4
-
2
- LOADING → const int
-
3
- OPENED → const int
-
1
- readyStateChangeEvent → const EventStreamProvider<Event>
- Static factory designed to expose
readystatechange events to event handlers that are not necessarily instances of HttpRequest. [...] const EventStreamProvider<Event>('readystatechange')
- UNSENT → const int
-
0