engine.js

dwr3第一个学习例子

          throw new Error("Cross domain file uploads are not possible with this release of DWR");
        }
        batch.transport = dwr.engine.transport.iframe;
      }
      else if (isCrossDomain && !dwr.engine.isJaxerServer) {
        batch.transport = dwr.engine.transport.scriptTag;
      }
      // else if (batch.isPoll && dwr.engine.isIE) {
      //   batch.transport = dwr.engine.transport.htmlfile;
      // }
      else {
        batch.transport = dwr.engine.transport.xhr;
      }

      return batch.transport.send(batch);
    },

    /**
     * A generic function to remove all remoting artifacts
     * @param {Object} batch The batch that has completed
     */
    remove:function(batch) {
      dwr.engine.transport.iframe.remove(batch);
      dwr.engine.transport.xhr.remove(batch);
    },

    /**
     * Called as a result of a request timeout
     * @private
     * @param {Object} batch The batch that is aborting
     */
    abort:function(batch) {
      if (batch && !batch.completed) {
        dwr.engine.batch.remove(batch);

        if (batch.req) {
          batch.req.abort();
        }

        dwr.engine.transport.remove(batch);
        dwr.engine._handleError(batch, { name:"dwr.engine.timeout", message:"Timeout" });
      }
    },

    /**
     * Remoting through XHR
     */
    xhr:{
      /**
       * The default HTTP method to use
       */
      httpMethod:"POST",

      /**
       * The ActiveX objects to use when we want to do an XMLHttpRequest call.
       * TODO: We arrived at this by trial and error. Other toolkits use
       * different strings, maybe there is an officially correct version?
       */
      XMLHTTP:["Msxml2.XMLHTTP.6.0", "Msxml2.XMLHTTP.5.0", "Msxml2.XMLHTTP.4.0", "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP"],

      /**
       * Setup a batch for transfer through XHR
       * @param {Object} batch The batch to alter for XHR transmit
       */
      send:function(batch) {
        if (batch.isPoll) {
          batch.map.partialResponse = dwr.engine._partialResponseYes;
        }

        // Do proxies or IE force us to use early closing mode?
        if (batch.isPoll && dwr.engine._pollWithXhr == "true") {
          batch.map.partialResponse = dwr.engine._partialResponseNo;
        }
        if (batch.isPoll && dwr.engine.isIE) {
          batch.map.partialResponse = dwr.engine._partialResponseNo;
        }

        if (window.XMLHttpRequest) {
          batch.req = new XMLHttpRequest();
        }
        else if (window.ActiveXObject) {
          batch.req = dwr.engine.util.newActiveXObject(dwr.engine.transport.xhr.XMLHTTP);
        }

        // Proceed using XMLHttpRequest
        if (batch.async == true) {
          batch.req.onreadystatechange = function() {
            if (typeof dwr != 'undefined') {
              dwr.engine.transport.xhr.stateChange(batch);
            }
          };
        }

        // If we're polling, record this for monitoring
        if (batch.isPoll) {
          dwr.engine._pollReq = batch.req;
          // In IE XHR is an ActiveX control so you can't augment it like this
          if (!dwr.engine.isIE) batch.req.batch = batch;
        }

        httpMethod = dwr.engine.transport.xhr.httpMethod;

        // Workaround for Safari 1.x POST bug
        var indexSafari = navigator.userAgent.indexOf("Safari/");
        if (indexSafari >= 0) {
          var version = navigator.userAgent.substring(indexSafari + 7);
          if (parseInt(version, 10) < 400) {
            if (dwr.engine._allowGetForSafariButMakeForgeryEasier == "true") {
              httpMethod = "GET";
            }
            else {
              dwr.engine._handleWarning(batch, {
                name: "dwr.engine.oldSafari",
                message: "Safari GET support disabled. See getahead.org/dwr/server/servlet and allowGetForSafariButMakeForgeryEasier."
              });
            }
          }
        }

        batch.mode = batch.isPoll ? dwr.engine._ModePlainPoll : dwr.engine._ModePlainCall;
        var request = dwr.engine.batch.constructRequest(batch, httpMethod);

        try {
          batch.req.open(httpMethod, request.url, batch.async);
          try {
            for (var prop in batch.headers) {
              var value = batch.headers[prop];
              if (typeof value == "string") {
                batch.req.setRequestHeader(prop, value);
              }
            }
            if (!batch.headers["Content-Type"]) {
              batch.req.setRequestHeader("Content-Type", "text/plain");
            }
          }
          catch (ex) {
            dwr.engine._handleWarning(batch, ex);
          }
          batch.req.send(request.body);
          if (batch.async == false) {
            dwr.engine.transport.xhr.stateChange(batch);
          }
        }
        catch (ex) {
          dwr.engine._handleError(batch, ex);
        }

        if (batch.isPoll && batch.map.partialResponse == dwr.engine._partialResponseYes) {
          dwr.engine.transport.xhr.checkCometPoll();
        }

        // This is only of any use in sync mode to return the reply data
        return batch.reply;
      },

      /**
       * Called by XMLHttpRequest to indicate that something has happened
       * @private
       * @param {Object} batch The current remote operation
       */
      stateChange:function(batch) {
        var toEval;

        if (batch.completed) {
          dwr.engine._debug("Error: _stateChange() with batch.completed");
          return;
        }

        var req = batch.req;
        try {
          var readyState = req.readyState;
          var notReady = (req.readyState != 4);
          if (notReady) {
            return;
          }
        }
        catch (ex) {
          dwr.engine._handleWarning(batch, ex);
          // It's broken - clear up and forget this call
          dwr.engine.batch.remove(batch);
          return;
        }

        if (dwr.engine._unloading && !dwr.engine.isJaxerServer) {
          dwr.engine._debug("Ignoring reply from server as page is unloading.");
          return;
        }

        try {
          var reply = req.responseText;
          reply = dwr.engine._replyRewriteHandler(reply);
          var status = req.status; // causes Mozilla to except on page moves

          if (reply == null || reply == "") {
            dwr.engine._handleWarning(batch, { name:"dwr.engine.missingData", message:"No data received from server" });
          }
          else if (status != 200) {
            dwr.engine._handleError(batch, { name:"dwr.engine.http." + status, message:req.statusText });
          }
          else {
            var contentType = req.getResponseHeader("Content-Type");
            if (dwr.engine.isJaxerServer) {
              // HACK! Jaxer does something b0rken with Content-Type
              contentType = "text/javascript";
            }
            if (!contentType.match(/^text\/plain/) && !contentType.match(/^text\/javascript/)) {
              if (contentType.match(/^text\/html/) && typeof batch.textHtmlHandler == "function") {
                batch.textHtmlHandler({ status:status, responseText:reply, contentType:contentType });
              }
              else {
                dwr.engine._handleWarning(batch, { name:"dwr.engine.invalidMimeType", message:"Invalid content type: '" + contentType + "'" });
              }
            }
            else {
              // Comet replies might have already partially executed
             if (batch.isPoll && batch.map.partialResponse == dwr.engine._partialResponseYes) {
                dwr.engine.transport.xhr.processCometResponse(reply, batch);
              }
              else {
                if (reply.search("//#DWR") == -1) {
                  dwr.engine._handleWarning(batch, { name:"dwr.engine.invalidReply", message:"Invalid reply from server" });
                }
                else {
                  toEval = reply;
                }
              }
            }
          }
        }
        catch (ex) {
          dwr.engine._handleWarning(batch, ex);
        }

        dwr.engine._callPostHooks(batch);

        // Outside of the try/catch so errors propagate normally:
        dwr.engine._receivedBatch = batch;
        if (toEval != null) toEval = toEval.replace(dwr.engine._scriptTagProtection, "");
        dwr.engine._eval(toEval);
        dwr.engine._receivedBatch = null;
        dwr.engine.batch.validate(batch);
        if (!batch.completed) dwr.engine.batch.remove(batch);
      },

      /**
       * Check for reverse Ajax activity
       * @private
       */
      checkCometPoll:function() {
        if (dwr.engine._pollReq) {
          var req = dwr.engine._pollReq;
          var text = req.responseText;
          if (text != null) {
            dwr.engine.transport.xhr.processCometResponse(text, req.batch);
          }
        }

        // If the poll resources are still there, come back again
        if (dwr.engine._pollReq) {
          setTimeout(dwr.engine.transport.xhr.checkCometPoll, dwr.engine._pollCometInterval);
        }
      },

      /**
       * Some more text might have come in, test and execute the new stuff.
       * This method could also be called by the iframe transport
       * @private
       * @param {Object} response from xhr.responseText
       * @param {Object} batch The batch that the XHR object pertains to
       */
      processCometResponse:function(response, batch) {
        if (batch.charsProcessed == response.length) return;
        if (response.length == 0) {
          batch.charsProcessed = 0;
          return;
        }

        var firstStartTag = response.indexOf("//#DWR-START#", batch.charsProcessed);
        if (firstStartTag == -1) {
          // dwr.engine._debug("No start tag (search from " + batch.charsProcessed + "). skipping '" + response.substring(batch.charsProcessed) + "'");
          batch.charsProcessed = response.length;
          return;
        }
        // if (firstStartTag > 0) {
        //   dwr.engine._debug("Start tag not at start (search from " + batch.charsProcessed + "). skipping '" + response.substring(batch.charsProcessed, firstStartTag) + "'");
        // }

        var lastEndTag = response.lastIndexOf("//#DWR-END#");
        if (lastEndTag == -1) {
          // dwr.engine._debug("No end tag. unchanged charsProcessed=" + batch.charsProcessed);
          return;
        }

        // Skip the end tag too for next time, remembering CR and LF
        if (response.charCodeAt(lastEndTag + 11) == 13 && response.charCodeAt(lastEndTag + 12) == 10) {
         batch.charsProcessed = lastEndTag + 13;
        }
        else {
          batch.charsProcessed = lastEndTag + 11;
        }

        var exec = response.substring(firstStartTag + 13, lastEndTag);

        try {
          dwr.engine._receivedBatch = batch;
          dwr.engine._eval(exec);
          dwr.engine._receivedBatch = null;
        }
        catch (ex) {
          // This is one of these annoying points where we might be executing
          // while the window is being destroyed. If dwr == null, bail out.
          if (dwr != null) {
            dwr.engine._handleError(batch, ex);
          }
        }
      },

      /**
       * Tidy-up when an XHR call is done
       * @param {Object} batch
       */
      remove:function(batch) {
        // XHR tidyup: avoid IE handles increase
        if (batch.req) {
          // If this is a poll frame then stop comet polling
          if (batch.req == dwr.engine._pollReq) dwr.engine._pollReq = null;
          delete batch.req;
        }
      }
    },

    /**
     * Functions for remoting through IFrame
     */
    iframe:{
      /**
       * Setup a batch for transfer through IFrame
       * @param {Object} batch The batch to alter for IFrame transmit
       */
      send:function(batch) {
        if (batch.fileUpload) {
          batch.httpMethod = "POST";
          batch.encType = "multipart/form-data";
        }
        var idname = dwr.engine.transport.iframe.getId(batch);
        batch.div = document.createElement("div");
        // Add the div to the document first, otherwise IE 6 will ignore onload handler.
        document.body.appendChild(batch.div);
        batch.div.innerHTML = "<iframe src='javascript:void(0)' frameborder='0' style='width:0px;height:0px;border:0;' id='" + idname + "' name='" + idname + "' onload='dwr.engine.transport.iframe.loadingComplete(" + batch.map.batchId + ");'></iframe>";
        batch.document = document;
        dwr.engine.transport.iframe.beginLoader(batch, idname);
      },

      /**
       * Create a unique ID so multiple iframes can fire at the same time
       * @param {Object} batch A source of a unique number for the batch
       * @return {String} a name prefix for created elements
       */
      getId:function(batch) {
        return batch.isPoll ? "dwr-if-poll-" + batch.map.batchId : "dwr-if-" + batch.map.batchId;
      },

      /**
       * Setup a form or construct a src attribute to use the iframe.
       * This is abstracted from send() because the same logic will do for htmlfile
       * @param {Object} batch
       */
      beginLoader:function(batch, idname) {
        batch.iframe = batch.document.getElementById(idname);
        batch.iframe.batch = batch;
        batch.mode = batch.isPoll ? dwr.engine._ModeHtmlPoll : dwr.engine._ModeHtmlCall;
        if (batch.isPoll) dwr.engine._outstandingIFrames.push(batch.iframe);