nsIXMLHttpRequest

IID:7b3b3c62-9d53-4abc-bc89-c33ce78f439f
Inherits From:nsISupports

Mozilla's XMLHttpRequest is modelled after Microsoft's IXMLHttpRequest object. The goal has been to make Mozilla's version match Microsoft's version as closely as possible, but there are bound to be some differences.

In general, Microsoft's documentation for IXMLHttpRequest can be used. Mozilla's interface definitions provide some additional documentation. The web page to look at is http://www.mozilla.org/xmlextras/

Mozilla's XMLHttpRequest object can be created in JavaScript like this: new XMLHttpRequest() compare to Internet Explorer: new ActiveXObject("Msxml2.XMLHTTP")

From JavaScript, the methods and properties visible in the XMLHttpRequest object are a combination of nsIXMLHttpRequest and nsIJSXMLHttpRequest; there is no need to differentiate between those interfaces.

From native code, the way to set up onload and onerror handlers is a bit different. Here is a comment from Johnny Stenback :

The mozilla implementation of nsIXMLHttpRequest implements the interface nsIDOMEventTarget and that's how you're supported to add event listeners. Try something like this:

NsCOMPtr target(do_QueryInterface(myxmlhttpreq));

Target->AddEventListener(NS_LITERAL_STRING("load"), mylistener, PR_FALSE)

Where mylistener is your event listener object that implements the interface nsIDOMEventListener.

The 'onload' and 'onerror' attributes moved to nsIJSXMLHttRequest, but if you're coding in C++ you should avoid using those.

Properties

readonly nsIChannel channel

The request uses a channel in order to perform the request. This attribute represents the channel used for the request. NULL if the channel has not yet been created.

In a multipart request case, this is the initial channel, not the different parts in the multipart request.

Mozilla only. Requires elevated privileges to access.

PRBool multipart

Set to true if the response is expected to be a stream of possibly multiple (XML) documents. If set to true, the content type of the initial response must be multipart/x-mixed-replace or an error will be triggerd. All requests must be asynchronous.

This enables server push. For each XML document that's written to this request, a new XML DOM document is created and the onload handler is called inbetween documents. Note that when this is set, the onload handler and other event handlers are not reset after the first XML document is loaded, and the onload handler will be called as each part of the response is received.

readonly PRInt32 readyState

The state of the request.

Possible values: 0 UNINITIALIZED open() has not been called yet. 1 LOADING send() has not been called yet. 2 LOADED send() has been called, headers and status are available. 3 INTERACTIVE Downloading, responseText holds the partial data. 4 COMPLETED Finished with all operations.

readonly AString responseText

The response to the request as text. NULL if the request is unsuccessful or has not yet been sent.

readonly nsIDOMDocument responseXML

The response to the request is parsed as if it were a text/xml stream. This attributes represents the response as a DOM Document object. NULL if the request is unsuccessful or has not yet been sent.

readonly PRUint32 status

The status of the response to the request for HTTP requests.

readonly AUTF8String statusText

The string representing the status of the response for HTTP requests.

Methods

void abort ( ) char* getAllResponseHeaders ( ) ACString getResponseHeader ( AUTF8String header ) void open ( AUTF8String method , AUTF8String url ) [noscript] void openRequest ( AUTF8String method , AUTF8String url , PRBool async , AString user , AString password ) void overrideMimeType ( AUTF8String mimetype ) void send ( nsIVariant body ) void setRequestHeader ( AUTF8String header , AUTF8String value )

void abort ( )

If the request has been sent already, this method will abort the request.

char* getAllResponseHeaders ( )

Returns all of the response headers as a string for HTTP requests.

Note that this will return all the headers from the *current* part of a multipart request, not from the original channel.

ACString getResponseHeader ( AUTF8String header )

Returns the text of the header with the specified name for HTTP requests.

Arguments:
header: The name of the header to retrieve

void open ( AUTF8String method , AUTF8String url )

Meant to be a script-only method for initializing a request. The parameters are similar to the ones detailed in the description of openRequest, but the last 3 are optional.

Will abort currently active loads.

After the initial response, all event listeners will be cleared. Call open() before setting new event listeners.

Arguments:
method: The HTTP method - either "POST" or "GET". Ignored if the URL is not a HTTP URL.
url: The URL to which to send the request.

void openRequest ( AUTF8String method , AUTF8String url , PRBool async , AString user , AString password )

Native (non-script) method to initialize a request. Note that the request is not sent until the send method is invoked.

Will abort currently active loads.

After the initial response, all event listeners will be cleared. Call open() before setting new event listeners.

Arguments:
method: The HTTP method, for example "POST" or "GET". Ignored if the URL is not a HTTP(S) URL.
url: The URL to which to send the request.
async: Whether the request is synchronous or asynchronous i.e. whether send returns only after the response is received or if it returns immediately after sending the request. In the latter case, notification of completion is sent through the event listeners. This argument must be true if the multipart attribute has been set to true, or an exception will be thrown.
user: A username for authentication if necessary.
password: A password for authentication if necessary.

void overrideMimeType ( AUTF8String mimetype )

Override the mime type returned by the server (if any). This may be used, for example, to force a stream to be treated and parsed as text/xml, even if the server does not report it as such. This must be done before the send method is invoked.

Arguments:
mimetype: The type used to override that returned by the server (if any).

void send ( nsIVariant body )

Sends the request. If the request is asynchronous, returns immediately after sending the request. If it is synchronous returns only after the response has been received.

After the initial response, all event listeners will be cleared. Call open() before setting new event listeners.

Arguments:
body: Either an instance of nsIDOMDocument, nsIInputStream or a string (nsISupportsString in the native calling case). This is used to populate the body of the HTTP request if the HTTP request method is "POST". If the parameter is a nsIDOMDocument, it is serialized. If the parameter is a nsIInputStream, then it must be compatible with nsIUploadChannel.setUploadStream, and a Content-Length header will be added to the HTTP request with a value given by nsIInputStream.available. Any headers included at the top of the stream will be treated as part of the message body. The MIME type of the stream should be specified by setting the Content- Type header via the setRequestHeader method before calling send.

void setRequestHeader ( AUTF8String header , AUTF8String value )

Sets a HTTP request header for HTTP requests. You must call open before setting the request headers.

Arguments:
header: The name of the header to set in the request.
value: The body of the header.

References

This interface is passed as an argument to the following methods:

nsIUpdateCheckListener.onCheckComplete, nsIUpdateCheckListener.onError, nsIUpdateCheckListener.onProgress

Reference documentation is generated from Mozilla's source.