datasource.js

这是YUI的源码及相关示例。里面有很多很炫的Javascript效果。

/**
 * Receives raw data response and type converts to XML, JSON, etc as necessary.
 * Forwards oFullResponse to appropriate parsing function to get turned into
 * oParsedResponse. Calls doBeforeCallback() and adds oParsedResponse to 
 * the cache when appropriate before calling issueCallback().
 * 
 * The oParsedResponse object literal has the following properties:
 * <dl>
 *     <dd><dt>tId {Number}</dt> Unique transaction ID</dd>
 *     <dd><dt>results {Array}</dt> Array of parsed data results</dd>
 *     <dd><dt>meta {Object}</dt> Object literal of meta values</dd> 
 *     <dd><dt>error {Boolean}</dt> (optional) True if there was an error</dd>
 *     <dd><dt>cached {Boolean}</dt> (optional) True if response was cached</dd>
 * </dl>
 *
 * @method handleResponse
 * @param oRequest {Object} Request object
 * @param oRawResponse {Object} The raw response from the live database.
 * @param oCallback {Object} Callback object literal.
 * @param oCaller {Object} (deprecated) Use oCallback.scope.
 * @param tId {Number} Transaction ID.
 */
handleResponse : function(oRequest, oRawResponse, oCallback, oCaller, tId) {
    this.fireEvent("responseEvent", {tId:tId, request:oRequest, response:oRawResponse,
            callback:oCallback, caller:oCaller});
    var xhr = (this.dataType == DS.TYPE_XHR) ? true : false;
    var oParsedResponse = null;
    var oFullResponse = oRawResponse;
    
    // Try to sniff data type if it has not been defined
    if(this.responseType === DS.TYPE_UNKNOWN) {
        var ctype = (oRawResponse && oRawResponse.getResponseHeader) ? oRawResponse.getResponseHeader["Content-Type"] : null;
        if(ctype) {
             // xml
            if(ctype.indexOf("text/xml") > -1) {
                this.responseType = DS.TYPE_XML;
            }
            else if(ctype.indexOf("application/json") > -1) { // json
                this.responseType = DS.TYPE_JSON;
            }
            else if(ctype.indexOf("text/plain") > -1) { // text
                this.responseType = DS.TYPE_TEXT;
            }
        }
        else {
            if(YAHOO.lang.isArray(oRawResponse)) { // array
                this.responseType = DS.TYPE_JSARRAY;
            }
             // xml
            else if(oRawResponse && oRawResponse.nodeType && oRawResponse.nodeType == 9) {
                this.responseType = DS.TYPE_XML;
            }
            else if(oRawResponse && oRawResponse.nodeName && (oRawResponse.nodeName.toLowerCase() == "table")) { // table
                this.responseType = DS.TYPE_HTMLTABLE;
            }    
            else if(YAHOO.lang.isObject(oRawResponse)) { // json
                this.responseType = DS.TYPE_JSON;
            }
            else if(YAHOO.lang.isString(oRawResponse)) { // text
                this.responseType = DS.TYPE_TEXT;
            }
        }
    }

    switch(this.responseType) {
        case DS.TYPE_JSARRAY:
            if(xhr && oRawResponse && oRawResponse.responseText) {
                oFullResponse = oRawResponse.responseText; 
            }
            oFullResponse = this.doBeforeParseData(oRequest, oFullResponse, oCallback);
            oParsedResponse = this.parseArrayData(oRequest, oFullResponse);
            break;
        case DS.TYPE_JSON:
            if(xhr && oRawResponse && oRawResponse.responseText) {
                oFullResponse = oRawResponse.responseText;
            }
            try {
                // Convert to JSON object if it's a string
                if(lang.isString(oFullResponse)) {
                    // Check for YUI JSON Util
                    if(lang.JSON) {
                        oFullResponse = lang.JSON.parse(oFullResponse);
                    }
                    // Look for JSON parsers using an API similar to json2.js
                    else if(window.JSON && JSON.parse) {
                        oFullResponse = JSON.parse(oFullResponse);
                    }
                    // Look for JSON parsers using an API similar to json.js
                    else if(oFullResponse.parseJSON) {
                        oFullResponse = oFullResponse.parseJSON();
                    }
                    // No JSON lib found so parse the string
                    else {
                        // Trim leading spaces
                        while (oFullResponse.length > 0 &&
                                (oFullResponse.charAt(0) != "{") &&
                                (oFullResponse.charAt(0) != "[")) {
                            oFullResponse = oFullResponse.substring(1, oFullResponse.length);
                        }
    
                        if(oFullResponse.length > 0) {
                            // Strip extraneous stuff at the end
                            var objEnd = Math.max(oFullResponse.lastIndexOf("]"),oFullResponse.lastIndexOf("}"));
                            oFullResponse = oFullResponse.substring(0,objEnd+1);
    
                            // Turn the string into an object literal...
                            // ...eval is necessary here
                            oFullResponse = eval("(" + oFullResponse + ")");
    
                        }
                    }
                }
            }
            catch(e) {
            }

            oFullResponse = this.doBeforeParseData(oRequest, oFullResponse, oCallback);
            oParsedResponse = this.parseJSONData(oRequest, oFullResponse);
            break;
        case DS.TYPE_HTMLTABLE:
            if(xhr && oRawResponse.responseText) {
                oFullResponse = oRawResponse.responseText;
            }
            oFullResponse = this.doBeforeParseData(oRequest, oFullResponse, oCallback);
            oParsedResponse = this.parseHTMLTableData(oRequest, oFullResponse);
            break;
        case DS.TYPE_XML:
            if(xhr && oRawResponse.responseXML) {
                oFullResponse = oRawResponse.responseXML;
            }
            oFullResponse = this.doBeforeParseData(oRequest, oFullResponse, oCallback);
            oParsedResponse = this.parseXMLData(oRequest, oFullResponse);
            break;
        case DS.TYPE_TEXT:
            if(xhr && lang.isString(oRawResponse.responseText)) {
                oFullResponse = oRawResponse.responseText;
            }
            oFullResponse = this.doBeforeParseData(oRequest, oFullResponse, oCallback);
            oParsedResponse = this.parseTextData(oRequest, oFullResponse);
            break;
        default:
            oFullResponse = this.doBeforeParseData(oRequest, oFullResponse, oCallback);
            oParsedResponse = this.parseData(oRequest, oFullResponse);
            break;
    }


    // Clean up for consistent signature
    oParsedResponse = oParsedResponse || {};
    if(!oParsedResponse.results) {
        oParsedResponse.results = [];
    }
    if(!oParsedResponse.meta) {
        oParsedResponse.meta = {};
    }

    // Success
    if(oParsedResponse && !oParsedResponse.error) {
        // Last chance to touch the raw response or the parsed response
        oParsedResponse = this.doBeforeCallback(oRequest, oFullResponse, oParsedResponse, oCallback);
        this.fireEvent("responseParseEvent", {request:oRequest,
                response:oParsedResponse, callback:oCallback, caller:oCaller});
        // Cache the response
        this.addToCache(oRequest, oParsedResponse);
    }
    // Error
    else {
        // Be sure the error flag is on
        oParsedResponse.error = true;
        this.fireEvent("dataErrorEvent", {request:oRequest, response: oRawResponse, callback:oCallback, 
                caller:oCaller, message:DS.ERROR_DATANULL});
    }

    // Send the response back to the caller
    oParsedResponse.tId = tId;
    DS.issueCallback(oCallback,[oRequest,oParsedResponse],oParsedResponse.error,oCaller);
},

/**
 * Overridable method gives implementers access to the original full response
 * before the data gets parsed. Implementers should take care not to return an
 * unparsable or otherwise invalid response.
 *
 * @method doBeforeParseData
 * @param oRequest {Object} Request object.
 * @param oFullResponse {Object} The full response from the live database.
 * @param oCallback {Object} The callback object.  
 * @return {Object} Full response for parsing.
  
 */
doBeforeParseData : function(oRequest, oFullResponse, oCallback) {
    return oFullResponse;
},

/**
 * Overridable method gives implementers access to the original full response and
 * the parsed response (parsed against the given schema) before the data
 * is added to the cache (if applicable) and then sent back to callback function.
 * This is your chance to access the raw response and/or populate the parsed
 * response with any custom data.
 *
 * @method doBeforeCallback
 * @param oRequest {Object} Request object.
 * @param oFullResponse {Object} The full response from the live database.
 * @param oParsedResponse {Object} The parsed response to return to calling object.
 * @param oCallback {Object} The callback object. 
 * @return {Object} Parsed response object.
 */
doBeforeCallback : function(oRequest, oFullResponse, oParsedResponse, oCallback) {
    return oParsedResponse;
},

/**
 * Overridable method parses data of generic RESPONSE_TYPE into a response object.
 *
 * @method parseData
 * @param oRequest {Object} Request object.
 * @param oFullResponse {Object} The full Array from the live database.
 * @return {Object} Parsed response object with the following properties:<br>
 *     - results {Array} Array of parsed data results<br>
 *     - meta {Object} Object literal of meta values<br>
 *     - error {Boolean} (optional) True if there was an error<br>
 */
parseData : function(oRequest, oFullResponse) {
    if(lang.isValue(oFullResponse)) {
        var oParsedResponse = {results:oFullResponse,meta:{}};
        return oParsedResponse;

    }
    return null;
},

/**
 * Overridable method parses Array data into a response object.
 *
 * @method parseArrayData
 * @param oRequest {Object} Request object.
 * @param oFullResponse {Object} The full Array from the live database.
 * @return {Object} Parsed response object with the following properties:<br>
 *     - results (Array) Array of parsed data results<br>
 *     - error (Boolean) True if there was an error
 */
parseArrayData : function(oRequest, oFullResponse) {
    if(lang.isArray(oFullResponse)) {
        var results = [],
            i, j,
            rec, field, data;
        
        // Parse for fields
        if(lang.isArray(this.responseSchema.fields)) {
            var fields = this.responseSchema.fields;
            for (i = fields.length - 1; i >= 0; --i) {
                if (typeof fields[i] !== 'object') {
                    fields[i] = { key : fields[i] };
                }
            }

            var parsers = {}, p;
            for (i = fields.length - 1; i >= 0; --i) {
                p = (typeof fields[i].parser === 'function' ?
                          fields[i].parser :
                          DS.Parser[fields[i].parser+'']) || fields[i].converter;
                if (p) {
                    parsers[fields[i].key] = p;
                }
            }

            var arrType = lang.isArray(oFullResponse[0]);
            for(i=oFullResponse.length-1; i>-1; i--) {
                var oResult = {};
                rec = oFullResponse[i];
                if (typeof rec === 'object') {
                    for(j=fields.length-1; j>-1; j--) {
                        field = fields[j];
                        data = arrType ? rec[j] : rec[field.key];

                        if (parsers[field.key]) {
                            data = parsers[field.key].call(this,data);
                        }

                        // Safety measure
                        if(data === undefined) {
                            data = null;
                        }

                        oResult[field.key] = data;
                    }
                }
                else if (lang.isString(rec)) {
                    for(j=fields.length-1; j>-1; j--) {
                        field = fields[j];
                        data = rec;

                        if (parsers[field.key]) {
                            data = parsers[field.key].call(this,data);
                        }

                        // Safety measure
                        if(data === undefined) {
                            data = null;
                        }

                        oResult[field.key] = data;
                    }                
                }
                results[i] = oResult;
            }    
        }
        // Return entire data set
        else {
            results = oFullResponse;
        }
        var oParsedResponse = {results:results};
        return oParsedResponse;

    }
    return null;
},

/**
 * Overridable method parses plain text data into a response object.
 *
 * @method parseTextData
 * @param oRequest {Object} Request object.
 * @param oFullResponse {Object} The full text response from the live database.
 * @return {Object} Parsed response object with the following properties:<br>
 *     - results (Array) Array of parsed data results<br>
 *     - error (Boolean) True if there was an error
 */
parseTextData : function(oRequest, oFullResponse) {
    if(lang.isString(oFullResponse)) {
        if(lang.isString(this.responseSchema.recordDelim) &&
                lang.isString(this.responseSchema.fieldDelim)) {
            var oParsedResponse = {results:[]};
            var recDelim = this.responseSchema.recordDelim;
            var fieldDelim = this.responseSchema.fieldDelim;
            if(oFullResponse.length > 0) {
                // Delete the last line delimiter at the end of the data if it exists
                var newLength = oFullResponse.length-recDelim.length;
                if(oFullResponse.substr(newLength) == recDelim) {
                    oFullResponse = oFullResponse.substr(0, newLength);
                }
                if(oFullResponse.length > 0) {
                    // Split along record delimiter to get an array of strings
                    var recordsarray = oFullResponse.split(recDelim);
                    // Cycle through each record
                    for(var i = 0, len = recordsarray.length, recIdx = 0; i < len; ++i) {
                        var bError = false,
                            sRecord = recordsarray[i];
                        if (lang.isString(sRecord) && (sRecord.length > 0)) {
                            // Split each record along field delimiter to get data
                            var fielddataarray = recordsarray[i].split(fieldDelim);
                            var oResult = {};
                            
                            // Filter for fields data
                            if(lang.isArray(this.responseSchema.fields)) {
                                var fields = this.responseSchema.fields;
                                for(var j=fields.length-1; j>-1; j--) {
                                    try {
                                        // Remove quotation marks from edges, if applicable
                                        var data = fielddataarray[j];
                                        if (lang.isString(data)) {
                                            if(data.charAt(0) == "\"") {
                                                data = data.substr(1);
                                            }
                                            if(data.charAt(data.length-1) == "\"") {
                                                data = data.substr(0,data.length-1);
                                            }
                                            var field = fields[j];
                                            var key = (lang.isValue(field.key)) ? field.key : field;
                                            // Backward compatibility
                                            if(!field.parser && field.converter) {
                                                field.parser = field.converter;
                                            }
                                            var parser = (typeof field.parser === 'function') ?
                                                field.parser :
                                                DS.Parser[field.parser+''];
                                            if(parser) {
                                                data = parser.call(this, data);
                                            }
                                            // Safety measure
                                            if(data === undefined) {
                                                data = null;
                                            }
                                            oResult[key] = data;
                                        }
                                        else {
                                            bError = true;
                                        }
                                    }
                                    catch(e) {
                                        bError = true;
                                    }
                                }
                            }            
                            // No fields defined so pass along all data as an array
                            else {
                                oResult = fielddataarray;
                            }
                            if(!bError) {
                                oParsedResponse.results[recIdx++] = oResult;
                            }
                        }
                    }
                }
            }