jquery/jquery

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src/ajax/xhr.js

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define( [
    "../core",
    "../var/support",
    "../ajax"
], function( jQuery, support ) {

"use strict";

jQuery.ajaxSettings.xhr = function() {
    try {
        return new window.XMLHttpRequest();
    } catch ( e ) {}
};

var xhrSuccessStatus = {

        // File protocol always yields status code 0, assume 200
        0: 200,

        // Support: IE <=9 only
        // #1450: sometimes IE returns 1223 when it should be 204
        1223: 204
    },
    xhrSupported = jQuery.ajaxSettings.xhr();

support.cors = !!xhrSupported && ( "withCredentials" in xhrSupported );
support.ajax = xhrSupported = !!xhrSupported;

jQuery.ajaxTransport( function( options ) {
    var callback, errorCallback;

    // Cross domain only allowed if supported through XMLHttpRequest
    if ( support.cors || xhrSupported && !options.crossDomain ) {
        return {
            send: function( headers, complete ) {
                var i,
                    xhr = options.xhr();

                xhr.open(
                    options.type,
                    options.url,
                    options.async,
                    options.username,
                    options.password
                );

                // Apply custom fields if provided
                if ( options.xhrFields ) {
                    for ( i in options.xhrFields ) {
                        xhr[ i ] = options.xhrFields[ i ];
                    }
                }

                // Override mime type if needed
                if ( options.mimeType && xhr.overrideMimeType ) {
                    xhr.overrideMimeType( options.mimeType );
                }

                // X-Requested-With header
                // For cross-domain requests, seeing as conditions for a preflight are
                // akin to a jigsaw puzzle, we simply never set it to be sure.
                // (it can always be set on a per-request basis or even using ajaxSetup)
                // For same-domain requests, won't change header if already provided.
                if ( !options.crossDomain && !headers[ "X-Requested-With" ] ) {
                    headers[ "X-Requested-With" ] = "XMLHttpRequest";
                }

                // Set headers
                for ( i in headers ) {
                    xhr.setRequestHeader( i, headers[ i ] );
                }

                // Callback
                callback = function( type ) {
                    return function() {
                        if ( callback ) {
                            callback = errorCallback = xhr.onload =
                                xhr.onerror = xhr.onabort = xhr.ontimeout =
                                    xhr.onreadystatechange = null;

                            if ( type === "abort" ) {
                                xhr.abort();
                            } else if ( type === "error" ) {

                                // Support: IE <=9 only
                                // On a manual native abort, IE9 throws
                                // errors on any property access that is not readyState
                                if ( typeof xhr.status !== "number" ) {
                                    complete( 0, "error" );
                                } else {
                                    complete(

                                        // File: protocol always yields status 0; see #8605, #14207
                                        xhr.status,
                                        xhr.statusText
                                    );
                                }
                            } else {
                                complete(
                                    xhrSuccessStatus[ xhr.status ] || xhr.status,
                                    xhr.statusText,

                                    // Support: IE <=9 only
                                    // IE9 has no XHR2 but throws on binary (trac-11426)
                                    // For XHR2 non-text, let the caller handle it (gh-2498)
                                    ( xhr.responseType || "text" ) !== "text"  ||
                                    typeof xhr.responseText !== "string" ?
                                        { binary: xhr.response } :
                                        { text: xhr.responseText },
                                    xhr.getAllResponseHeaders()
                                );
                            }
                        }
                    };
                };

                // Listen to events
                xhr.onload = callback();
                errorCallback = xhr.onerror = xhr.ontimeout = callback( "error" );

                // Support: IE 9 only
                // Use onreadystatechange to replace onabort
                // to handle uncaught aborts
                if ( xhr.onabort !== undefined ) {
                    xhr.onabort = errorCallback;
                } else {
                    xhr.onreadystatechange = function() {

                        // Check readyState before timeout as it changes
                        if ( xhr.readyState === 4 ) {

                            // Allow onerror to be called first,
                            // but that will not handle a native abort
                            // Also, save errorCallback to a variable
                            // as xhr.onerror cannot be accessed
                            window.setTimeout( function() {
                                if ( callback ) {
                                    errorCallback();
                                }
                            } );
                        }
                    };
                }

                // Create the abort callback
                callback = callback( "abort" );

                try {

                    // Do send the request (this may raise an exception)
                    xhr.send( options.hasContent && options.data || null );
                } catch ( e ) {

                    // #14683: Only rethrow if this hasn't been notified as an error yet
                    if ( callback ) {
                        throw e;
                    }
                }
            },

            abort: function() {
                if ( callback ) {
                    callback();
                }
            }
        };
    }
} );

} );