engine.js

dwr3第一个学习例子

        var request = dwr.engine.batch.constructRequest(batch, batch.httpMethod);
        if (batch.httpMethod == "GET") {
          batch.iframe.setAttribute("src", request.url);
        }
        else {
          // TODO: On firefox we can now get the values of file fields, maybe we should use this
          // See http://soakedandsoaped.com/articles/read/firefox-3-native-ajax-file-upload
          // setting enctype via the DOM does not work in IE, create the form using innerHTML instead
          var formHtml = "<form id='dwr-form' action='" + request.url + "' target='" + idname + "' style='display:none;' method='" + batch.httpMethod + "'";
          if (batch.encType) formHtml += " enctype='" + batch.encType + "'";
          formHtml += "></form>";
          var div = batch.document.createElement("div");
          div.innerHTML = formHtml;
          batch.form = div.firstChild;
          for (var prop in batch.map) {
            var value = batch.map[prop];
            if (typeof value != "function") {
              if (value.tagName && value.tagName.toLowerCase() == "input" && value.type && value.type.toLowerCase() == "file") {
                // Since we can not set the value of a file object, we must post the actual file object
                // that the user clicked browse on. We will put a clone in it's place.
                var clone = value.cloneNode(true);
                value.removeAttribute("id", prop);
                value.setAttribute("name", prop);
                value.parentNode.insertBefore(clone, value);
                value.parentNode.removeChild(value);
                batch.form.appendChild(value);
              } else {
                var formInput = batch.document.createElement("input");
                formInput.setAttribute("type", "hidden");
                formInput.setAttribute("name", prop);
                formInput.setAttribute("value", value);
                batch.form.appendChild(formInput);
              }
            }
          }
          batch.document.body.appendChild(batch.form);
          batch.form.submit();
        }
      },

      /**
       * Called from iframe onload, check batch using batch-id
       * @private
       * @param {int} batchId The id of the batch that has loaded
       */
      loadingComplete:function(batchId) {
        var batch = dwr.engine._batches[batchId];
        if (batch) dwr.engine.batch.validate(batch);
      },

      /**
       * Functions designed to be called by the server
       */
      remote:{
        /**
         * Called by the server: An IFrame reply is about to start
         * @private
         * @param {Object} iframe
         * @param {int} batchId
         */
        beginIFrameResponse:function(iframe, batchId) {
          if (iframe != null) dwr.engine._receivedBatch = iframe.batch;
          dwr.engine._callPostHooks(dwr.engine._receivedBatch);
        },

        /**
         * Called by the server: An IFrame reply is just completing
         * @private
         * @param {int} batchId
         */
        endIFrameResponse:function(batchId) {
          dwr.engine.batch.remove(dwr.engine._receivedBatch);
          dwr.engine._receivedBatch = null;
        }
      },

      remove:function(batch) {
        // TODO: make it so that we don't need these if statements
        if (batch.div) {
            batch.div.parentNode.removeChild(batch.div);
        }
        if (batch.iframe) {
          batch.iframe.parentNode.removeChild(batch.iframe);
        }
        if (batch.form) {
          batch.form.parentNode.removeChild(batch.form);
        }
      }

      /*
      // If we have an iframe comet solution where we need to read data streamed
      // into an iframe then we need code like this to slurp the data out.
      // Compare this with xhr.checkCometPoll()
      outstandingIFrames:[],

      checkCometPoll:function() {
        for (var i = 0; i < dwr.engine.transport.iframe.outstandingIFrames.length; i++) {
          var text = "";
          var iframe = dwr.engine.transport.iframe.outstandingIFrames[i];
          try {
            text = dwr.engine.transport.iframe.getTextFromCometIFrame(iframe);
          }
          catch (ex) {
            dwr.engine._handleWarning(iframe.batch, ex);
          }
          if (text != "") dwr.engine.transport.xhr.processCometResponse(text, iframe.batch);
        }

        if (dwr.engine.transport.iframe.outstandingIFrames.length > 0) {
          setTimeout(dwr.engine.transport.iframe.checkCometPoll, dwr.engine._pollCometInterval);
        }
      }

      // We probably also need to update dwr.engine.remote.beginIFrameResponse()
      // to call checkCometPoll.

      // Extract the whole (executed and all) text from the current iframe
      getTextFromCometIFrame:function(frameEle) {
        var body = frameEle.contentWindow.document.body;
        if (body == null) return "";
        var text = body.innerHTML;
        // We need to prevent IE from stripping line feeds
        if (text.indexOf("<PRE>") == 0 || text.indexOf("<pre>") == 0) {
          text = text.substring(5, text.length - 7);
        }
        return text;
      };

      // And an addition to iframe.remove():
      {
        if (batch.iframe) {
          // If this is a poll frame then stop comet polling
          for (var i = 0; i < dwr.engine.transport.iframe.outstandingIFrames.length; i++) {
            if (dwr.engine.transport.iframe.outstandingIFrames[i] == batch.iframe) {
              dwr.engine.transport.iframe.outstandingIFrames.splice(i, 1);
            }
          }
        }
      }
      */
    },

    /**
     * Functions for remoting through Script Tags
     */
    scriptTag:{
      /**
       * Setup a batch for transfer through a script tag
       * @param {Object} batch The batch to alter for script tag transmit
       */
      send:function(batch) {
        batch.mode = batch.isPoll ? dwr.engine._ModePlainPoll : dwr.engine._ModePlainCall;
        var request = dwr.engine.batch.constructRequest(batch, "GET");
        // The best option is DOM manipulation, but this only works after onload
        // has completed
        if (document.body) {
          batch.script = document.createElement("script");
          batch.script.id = "dwr-st-" + batch.map.batchId;
          batch.script.src = request.url;
          batch.script.type = "text/javascript";
          document.body.appendChild(batch.script);
        }
        else {
          document.writeln("<scr" + "ipt type='text/javascript' id='dwr-st-" + batch.map["c0-id"] + "' src='" + request.url + "'> </scr" + "ipt>");
        }
      }
    },

    /**
     * Remoting through IE's htmlfile ActiveX control
     */
    htmlfile:{
      /**
       * Setup a batch for transfer through htmlfile
       * @param {Object} batch The batch to alter for htmlfile transmit
       */
      send:function(batch) {
        var idname = dwr.engine.transport.iframe.getId(batch);
        batch.htmlfile = new window.ActiveXObject("htmlfile");
        batch.htmlfile.open();
        batch.htmlfile.write("<" + "html>");
        batch.htmlfile.write("<div><iframe className='wibble' src='javascript:void(0)' id='" + idname + "' name='" + idname + "' onload='dwr.engine.transport.iframe.loadingComplete(" + batch.map.batchId + ");'></iframe></div>");
        batch.htmlfile.write("</" + "html>");
        batch.htmlfile.close();
        batch.htmlfile.parentWindow.dwr = dwr;
        batch.document = batch.htmlfile;

        dwr.engine.transport.iframe.beginLoader(batch, idname);
      }
    }
  };

  /**
   * Functions to manipulate batches
   * @private
   */
  dwr.engine.batch = {
    /**
     * Generate a new standard batch
     * @private
     */
    create:function() {
      var batch = {
        async:dwr.engine._async,
        charsProcessed:0,
        handlers:[],
        isPoll:false,
        map:{ callCount:0, windowName:window.name },
        paramCount:0,
        preHooks:[],
        postHooks:[],
        timeout:dwr.engine._timeout,
        errorHandler:dwr.engine._errorHandler,
        warningHandler:dwr.engine._warningHandler,
        textHtmlHandler:dwr.engine._textHtmlHandler
      };

      if (dwr.engine._preHook) {
        batch.preHooks.push(dwr.engine._preHook);
      }
      if (dwr.engine._postHook) {
        batch.postHooks.push(dwr.engine._postHook);
      }

      dwr.engine.batch.populateHeadersAndParameters(batch);
      return batch;
    },

    /**
     * Generate a new batch for polling
     * @private
     * @see dwr.engine.batch.create()
     */
    createPoll:function() {
      var batch = {
        async:true,
        charsProcessed:0,
        handlers:[{
          callback:function(pause) {
            dwr.engine._pollRetries = 0;
            setTimeout(dwr.engine._poll, pause);
          }
        }],
        isPoll:true,
        map:{ windowName:window.name },
        paramCount:0,
        path:dwr.engine._pathToDwrServlet,
        preHooks:[],
        postHooks:[],
        timeout:0,
        windowName:window.name,
        errorHandler:dwr.engine._pollErrorHandler,
        warningHandler:dwr.engine._pollErrorHandler,
        textHtmlHandler:dwr.engine._textHtmlHandler
      };

      dwr.engine.batch.populateHeadersAndParameters(batch);
      return batch;
    },

    /**
     * Copy the global headers and parameters into this batch object
     * @private
     * @param {Object} batch The destination
     */
    populateHeadersAndParameters:function(batch) {
      var propname, data;
      batch.headers = {};
      if (dwr.engine._headers) {
        for (propname in dwr.engine._headers) {
          data = dwr.engine._headers[propname];
          if (typeof data != "function") batch.headers[propname] = data;
        }
      }
      batch.parameters = {};
      if (dwr.engine._parameters) {
        for (propname in dwr.engine._parameters) {
          data = dwr.engine._parameters[propname];
          if (typeof data != "function") batch.parameters[propname] = data;
        }
      }
    },

    /**
     * Augment this batch with a new call
     * @private
     */
    addCall:function(batch, scriptName, methodName, args) {
      // From the other params, work out which is the function (or object with
      // call meta-data) and which is the call parameters
      var callData, stopAt;
      var lastArg = args[args.length - 1];
      if (lastArg == null || typeof lastArg == "function") {
        callData = { callback:lastArg };
        stopAt = args.length - 1;
      }
      else if (typeof lastArg == "object" && (typeof lastArg.callback == "function"
        || typeof lastArg.exceptionHandler == "function" || typeof lastArg.callbackHandler == "function"
        || typeof lastArg.errorHandler == "function" || typeof lastArg.warningHandler == "function" )) {
        callData = lastArg;
        stopAt = args.length - 1;
      }
      else {
        callData = {};
        stopAt = args.length;
      }

      // Merge from the callData into the batch
      dwr.engine.batch.merge(batch, callData);
      batch.handlers[batch.map.callCount] = {
        exceptionHandler:callData.exceptionHandler,
        exceptionArg:callData.exceptionArg || callData.arg || null,
        exceptionScope:callData.exceptionScope || callData.scope || window,
        callback:callData.callbackHandler || callData.callback,
        callbackArg:callData.callbackArg || callData.arg || null,      
        callbackScope:callData.callbackScope || callData.scope || window          
      };

      // Copy to the map the things that need serializing
      var prefix = "c" + batch.map.callCount + "-";
      batch.map[prefix + "scriptName"] = scriptName;
      batch.map[prefix + "methodName"] = methodName;
      batch.map[prefix + "id"] = batch.map.callCount;
      var converted = [];
      for (var i = 0; i < stopAt; i++) {
        dwr.engine.serialize.convert(batch, converted, args[i], prefix + "param" + i, 0);
      }
    },

    /**
     * Take further options and merge them into a batch
     * @private
     * @param {Object} batch The batch that we are altering
     * @param {Object} overrides The object containing properties to copy into batch
     */
    merge:function(batch, overrides) {
      var propname, data;
      for (var i = 0; i < dwr.engine._propnames.length; i++) {
        propname = dwr.engine._propnames[i];
        if (overrides[propname] != null) batch[propname] = overrides[propname];
      }
      if (overrides.preHook != null) batch.preHooks.unshift(overrides.preHook);
      if (overrides.postHook != null) batch.postHooks.push(overrides.postHook);
      if (overrides.headers) {
        for (propname in overrides.headers) {
          data = overrides.headers[propname];
          if (typeof data != "function") batch.headers[propname] = data;
        }
      }
      if (overrides.parameters) {
        for (propname in overrides.parameters) {
          data = overrides.parameters[propname];
          if (typeof data != "function") batch.map["p-" + propname] = "" + data;
        }
      }
    },

    /**
     * Executed just before a transport sends the batch
     * @private
     * @param {Object} batch The batch to prepare for sending
     */
    prepareToSend:function(batch) {
      batch.map.batchId = dwr.engine._nextBatchId;
      dwr.engine._nextBatchId++;
      dwr.engine._batches[batch.map.batchId] = batch;
      dwr.engine._batchesLength++;
      batch.completed = false;

      // security details are