connection.js

数据库系统教材中附录的课程设计accomodation宿舍管理系统源码

/*
 * Ext JS Library 2.0 Beta 1
 * Copyright(c) 2006-2007, Ext JS, LLC.
 * [e-mail]
 * 
 * http://extjs.com/license
 */

/**
 * @class Ext.data.Connection
 * @extends Ext.util.Observable
 * The class encapsulates a connection to the page's originating domain, allowing requests to be made
 * either to a configured URL, or to a URL specified at request time.<br><br>
 * <p>
 * Requests made by this class are asynchronous, and will return immediately. No data from
 * the server will be available to the statement immediately following the {@link #request} call.
 * To process returned data, use a callback in the request options object, or an event listener.</p><br>
 * <p>
 * Note: If you are doing a file upload, you will not get a normal response object sent back to
 * your callback or event handler.  Since the upload is handled via in IFRAME, there is no XMLHttpRequest.
 * The response object is created using the innerHTML of the IFRAME's document as the responseText
 * property and, if present, the IFRAME's XML document as the responseXML property.</p><br>
 * This means that a valid XML or HTML document must be returned. If JSON data is required, it is suggested
 * that it be placed either inside a &lt;textarea> in an HTML document and retrieved from the responseText
 * using a regex, or inside a CDATA section in an XML document and retrieved from the responseXML using
 * standard DOM methods.
 * @constructor
 * @param {Object} config a configuration object.
 */
Ext.data.Connection = function(config){
    Ext.apply(this, config);
    this.addEvents({
        /**
         * @event beforerequest
         * Fires before a network request is made to retrieve a data object.
         * @param {Connection} conn This Connection object.
         * @param {Object} options The options config object passed to the {@link #request} method.
         */
        "beforerequest" : true,
        /**
         * @event requestcomplete
         * Fires if the request was successfully completed.
         * @param {Connection} conn This Connection object.
         * @param {Object} response The XHR object containing the response data.
         * See <a href="http://www.w3.org/TR/XMLHttpRequest/">The XMLHttpRequest Object</a>
         * for details.
         * @param {Object} options The options config object passed to the {@link #request} method.
         */
        "requestcomplete" : true,
        /**
         * @event requestexception
         * Fires if an error HTTP status was returned from the server.
         * See <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html>HTTP Status Code Definitions</a>
         * for details of HTTP status codes.
         * @param {Connection} conn This Connection object.
         * @param {Object} response The XHR object containing the response data.
         * See <a href="http://www.w3.org/TR/XMLHttpRequest/">The XMLHttpRequest Object</a>
         * for details.
         * @param {Object} options The options config object passed to the {@link #request} method.
         */
        "requestexception" : true
    });
    Ext.data.Connection.superclass.constructor.call(this);
};

Ext.extend(Ext.data.Connection, Ext.util.Observable, {
    /**
     * @cfg {String} url (Optional) The default URL to be used for requests to the server. (defaults to undefined)
     */
    /**
     * @cfg {Object} extraParams (Optional) An object containing properties which are used as
     * extra parameters to each request made by this object. (defaults to undefined)
     */
    /**
     * @cfg {Object} defaultHeaders (Optional) An object containing request headers which are added
     *  to each request made by this object. (defaults to undefined)
     */
    /**
     * @cfg {String} method (Optional) The default HTTP method to be used for requests. (defaults to undefined; if not set but parms are present will use POST, otherwise GET)
     */
    /**
     * @cfg {Number} timeout (Optional) The timeout in milliseconds to be used for requests. (defaults to 30000)
     */
    timeout : 30000,
    /**
     * @cfg {Boolean} autoAbort (Optional) Whether this request should abort any pending requests. (defaults to false)
     * @type Boolean
     */
    autoAbort:false,

    /**
     * @cfg {Boolean} disableCaching (Optional) True to add a unique cache-buster param to GET requests. (defaults to true)
     * @type Boolean
     */
    disableCaching: true,

    /**
     * Sends an HTTP request to a remote server.
     * @param {Object} options An object which may contain the following properties:<ul>
     * <li><b>url</b> {String} (Optional) The URL to which to send the request. Defaults to configured URL</li>
     * <li><b>params</b> {Object/String/Function} (Optional) An object containing properties which are used as parameters to the
     * request, a url encoded string or a function to call to get either.</li>
     * <li><b>method</b> {String} (Optional) The HTTP method to use for the request. Defaults to the configured method, or
     * if no method was configured, "GET" if no parameters are being sent, and "POST" if parameters are being sent.</li>
     * <li><b>callback</b> {Function} (Optional) The function to be called upon receipt of the HTTP response.
     * The callback is called regardless of success or failure and is passed the following parameters:<ul>
     * <li>options {Object} The parameter to the request call.</li>
     * <li>success {Boolean} True if the request succeeded.</li>
     * <li>response {Object} The XMLHttpRequest object containing the response data.</li>
     * </ul></li>
     * <li><b>success</b> {Function} (Optional) The function to be called upon success of the request.
     * The callback is passed the following parameters:<ul>
     * <li>response {Object} The XMLHttpRequest object containing the response data.</li>
     * <li>options {Object} The parameter to the request call.</li>
     * </ul></li>
     * <li><b>failure</b> {Function} (Optional) The function to be called upon failure of the request.
     * The callback is passed the following parameters:<ul>
     * <li>response {Object} The XMLHttpRequest object containing the response data.</li>
     * <li>options {Object} The parameter to the request call.</li>
     * </ul></li>
     * <li><b>scope</b> {Object} (Optional) The scope in which to execute the callbacks: The "this" object
     * for the callback function. Defaults to the browser window.</li>
     * <li><b>form</b> {Object/String} (Optional) A form object or id to pull parameters from.</li>
     * <li><b>isUpload</b> {Boolean} (Optional) True if the form object is a file upload (will usually be automatically detected).</li>
     * <li><b>headers</b> {Object} (Optional) Request headers to set for the request.</li>
     * <li><b>xmlData</b> {Object} (Optional) XML document to use for the post. Note: This will be used instead of
     * params for the post data. Any params will be appended to the URL.</li>
     * <li><b>disableCaching</b> {Boolean} (Optional) True to add a unique cache-buster param to GET requests.</li>
     * </ul>
     * @return {Number} transactionId
     */
    request : function(o){
        if(this.fireEvent("beforerequest", this, o) !== false){
            var p = o.params;

            if(typeof p == "function"){
                p = p.call(o.scope||window, o);
            }
            if(typeof p == "object"){
                p = Ext.urlEncode(o.params);
            }
            if(this.extraParams){
                var extras = Ext.urlEncode(this.extraParams);
                p = p ? (p + '&' + extras) : extras;
            }

            var url = o.url || this.url;
            if(typeof url == 'function'){
                url = url.call(o.scope||window, o);
            }

            if(o.form){
                var form = Ext.getDom(o.form);
                url = url || form.action;

                var enctype = form.getAttribute("enctype");
                if(o.isUpload || (enctype && enctype.toLowerCase() == 'multipart/form-data')){
                    return this.doFormUpload(o, p, url);
                }
                var f = Ext.lib.Ajax.serializeForm(form);
                p = p ? (p + '&' + f) : f;
            }

            var hs = o.headers;
            if(this.defaultHeaders){
                hs = Ext.apply(hs || {}, this.defaultHeaders);
                if(!o.headers){
                    o.headers = hs;
                }
            }

            var cb = {
                success: this.handleResponse,
                failure: this.handleFailure,
                scope: this,
                argument: {options: o},
                timeout : this.timeout
            };

            var method = o.method||this.method||(p ? "POST" : "GET");

            if(method == 'GET' && (this.disableCaching && o.disableCaching !== false) || o.disableCaching === true){
                url += (url.indexOf('?') != -1 ? '&' : '?') + '_dc=' + (new Date().getTime());
            }

            if(typeof o.autoAbort == 'boolean'){ // options gets top priority
                if(o.autoAbort){
                    this.abort();
                }
            }else if(this.autoAbort !== false){
                this.abort();
            }
            if((method == 'GET' && p) || o.xmlData){
                url += (url.indexOf('?') != -1 ? '&' : '?') + p;
                p = '';
            }
            this.transId = Ext.lib.Ajax.request(method, url, cb, p, o);
            return this.transId;
        }else{
            Ext.callback(o.callback, o.scope, [o, null, null]);
            return null;
        }
    },

    /**
     * Determine whether this object has a request outstanding.
     * @param {Number} transactionId (Optional) defaults to the last transaction
     * @return {Boolean} True if there is an outstanding request.
     */
    isLoading : function(transId){
        if(transId){
            return Ext.lib.Ajax.isCallInProgress(transId);
        }else{
            return this.transId ? true : false;
        }
    },

    /**
     * Aborts any outstanding request.
     * @param {Number} transactionId (Optional) defaults to the last transaction