dwr-engine.js

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  var batch = dwr.engine._createBatch();
  batch.map.id = 0; // TODO: Do we need this??
  batch.map.callCount = 1;
  batch.map.partialResponse = (document.all) ? "false" : "true";
  batch.isPoll = true;
  batch.rpcType = dwr.engine._pollType;
  batch.httpMethod = "POST";
  batch.async = true;
  batch.timeout = 0;
  batch.path = (overridePath) ? overridePath : dwr.engine._defaultPath;
  batch.preHooks = [];
  batch.postHooks = [];
  batch.handlers[0] = {
    callback:function(pause) {
      dwr.engine._cometBatch = null;
      setTimeout("dwr.engine._poll()", pause);
    }
  };

  // Send the data
  dwr.engine._sendData(batch);
  if (batch.map.partialResponse == "true") {
    dwr.engine._cometBatch = batch;
    dwr.engine._checkCometPoll();
  }
};

/** @private Generate a new standard batch */
dwr.engine._createBatch = function() {
  var batch = {
    map:{
      callCount:0,
      page:window.location.pathname,
      httpSessionId:dwr.engine._getJSessionId(),
      scriptSessionId:dwr.engine._getScriptSessionId()
    },
    paramCount:0, // TODO: What's this for?
    isPoll:false, headers:{}, handlers:{}, preHooks:[], postHooks:[],
    rpcType:dwr.engine._rpcType,
    httpMethod:dwr.engine._httpMethod,
    async:dwr.engine._async,
    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);
  var propname, data;
  if (dwr.engine._headers) {
    for (propname in dwr.engine._headers) {
      data = dwr.engine._headers[propname];
      if (typeof data != "function") batch.headers[propname] = "" + data;
    }
  }
  if (dwr.engine._parameters) {
    for (propname in dwr.engine._parameters) {
      data = dwr.engine._parameters[propname];
      if (typeof data != "function") batch.parameters[propname] = "" + data;
    }
  }
  return batch;
}

/** @private Take further options and merge them into */
dwr.engine._mergeBatch = 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[propname];
      if (typeof data != "function") batch.headers[propname] = "" + data;
    }
  }
  if (overrides.parameters) {
    for (propname in overrides.parameters) {
      data = overrides[propname];
      if (typeof data != "function") batch.map[propname] = "" + data;
    }
  }
};

/** @private What is our session id? */
dwr.engine._getJSessionId =  function() {
  var cookies = document.cookie.split(';');
  for (var i = 0; i < cookies.length; i++) {
    var cookie = cookies[i];
    while (cookie.charAt(0) == ' ') cookie = cookie.substring(1, cookie.length);
    if (cookie.indexOf(dwr.engine._sessionCookieName + "=") == 0) {
      return cookie.substring(11, cookie.length);
    }
  }
  return "";
}

/** @private Check for reverse Ajax activity */
dwr.engine._checkCometPoll = function() {
  if (dwr.engine._pollComet) {
    // If the poll resources are still there, come back again
    //if (dwr.engine._pollFrame || dwr.engine._pollReq) {
    //  setTimeout("dwr.engine._checkCometPoll()", dwr.engine._pollCometInterval);
    //}
    try {
      dwr.engine._receivedBatch = dwr.engine._cometBatch;
      if (dwr.engine._pollFrame) {
        var text = dwr.engine._getTextFromCometIFrame();
        dwr.engine._processCometResponse(text);
      }
      else if (dwr.engine._pollReq) {
        var xhrtext = dwr.engine._pollReq.responseText;
        dwr.engine._processCometResponse(xhrtext);
      }
      dwr.engine._receivedBatch = null;
    }
    catch (ex) {
      // IE complains for no good reason for both options above. Ignore.
    }
    // If the poll resources are still there, come back again
    if (dwr.engine._pollFrame || dwr.engine._pollReq) {
      setTimeout("dwr.engine._checkCometPoll()", dwr.engine._pollCometInterval);
    }
  }
};

/** @private Extract the whole (executed an all) text from the current iframe */
dwr.engine._getTextFromCometIFrame = function() {
  var frameDocument;
  if (dwr.engine._pollFrame.contentDocument) {
    frameDocument = dwr.engine._pollFrame.contentDocument.defaultView.document;
  }
  else if (dwr.engine._pollFrame.contentWindow) {
    frameDocument = dwr.engine._pollFrame.contentWindow.document;
  }
  else {
    return "";
  }
  var bodyNodes = frameDocument.getElementsByTagName("body");
  if (bodyNodes == null || bodyNodes.length == 0) return "";
  if (bodyNodes[0] == null) return "";
  var text = bodyNodes[0].innerHTML.toString();
  // IE plays silly-pants and adds <PRE>...</PRE> for some unknown reason
  if (text.indexOf("<PRE>") == 0) text = text.substring(5, text.length - 7);
  return text;
};

/** @private Some more text might have come in, test and execute the new stuff */
dwr.engine._processCometResponse = function(response) {
  if (dwr.engine._cometProcessed != response.length) {
    if (response.length == 0) {
      dwr.engine._cometProcessed = 0;
    }
    else {
      // dwr.engine._debug("response.length=" + response.length + ", cometProcessed=" + dwr.engine._cometProcessed + ", extra chars=" + (response.length - dwr.engine._cometProcessed));
      var firstStartTag = response.indexOf("//#DWR-START#", dwr.engine._cometProcessed);
      // dwr.engine._debug("firstStartTag='" + firstStartTag + "'");
      if (firstStartTag == -1) {
        // dwr.engine._debug("Failed to find start tag when starting at " + firstStartTag + ". Dropping: " + (response.length - dwr.engine._cometProcessed) + " characters");
        dwr.engine._cometProcessed = response.length;
      }
      else {
        var lastEndTag = response.lastIndexOf("//#DWR-END#");
        // dwr.engine._debug("lastEndTag='" + lastEndTag + "'");
        if (lastEndTag != -1) {
          var exec = response.substring(firstStartTag + 13, lastEndTag);
          // Skip the end tag too for next time, remembering CR and LF
          if (response.charCodeAt(lastEndTag + 11) == 13 && response.charCodeAt(lastEndTag + 12) == 10) {
            dwr.engine._cometProcessed = lastEndTag + 13;
          }
          else {
            dwr.engine._cometProcessed = lastEndTag + 11;
          }
          dwr.engine._eval(exec);
          // dwr.engine._debug("setting _cometProcessed='" + dwr.engine._cometProcessed + "'");
        }
        // else {
        //   dwr.engine._debug("No end tag. (yet) '" + response + "'");
        // }
      }
    }
  }
};

/** @private Actually send the block of data in the batch object. */
dwr.engine._sendData = function(batch) {
  batch.map.batchId = dwr.engine._nextBatchId++;
  dwr.engine._batches[batch.map.batchId] = batch;
  dwr.engine._batchesLength++;
  batch.completed = false;

  for (var i = 0; i < batch.preHooks.length; i++) {
    batch.preHooks[i]();
  }
  batch.preHooks = null;
  // Set a timeout
  if (batch.timeout && batch.timeout != 0) {
    batch.interval = setInterval(function() { dwr.engine._abortRequest(batch); }, batch.timeout);
  }
  // Get setup for XMLHttpRequest if possible
  if (batch.rpcType == dwr.engine.XMLHttpRequest) {
    if (window.XMLHttpRequest) {
      batch.req = new XMLHttpRequest();
    }
    // IE5 for the mac claims to support window.ActiveXObject, but throws an error when it's used
    else if (window.ActiveXObject && !(navigator.userAgent.indexOf("Mac") >= 0 && navigator.userAgent.indexOf("MSIE") >= 0)) {
      batch.req = dwr.engine._newActiveXObject(dwr.engine._XMLHTTP);
    }
  }

  var prop, request;
  if (batch.req) {
    // Proceed using XMLHttpRequest
    if (batch.async) {
      batch.req.onreadystatechange = function() { dwr.engine._stateChange(batch); };
    }
    // If we're polling, record this for monitoring
    if (batch.isPoll) dwr.engine._pollReq = batch.req;
    // Workaround for Safari 1.x POST bug
    var indexSafari = navigator.userAgent.indexOf("Safari/");
    if (indexSafari >= 0) {
      if (dwr.engine._allowGetForSafariButMakeForgeryEasier)
      {
        var version = navigator.userAgent.substring(indexSafari + 7);
        if (parseInt(version, 10) < 400) batch.httpMethod = "GET";
      }
      else {
        dwr.engine._handleWarning(batch, { name:"dwr.engine.oldSafari", message:"Safari GET support disabled. See http://getahead.ltd.uk/dwr/server/servlet and allowGetForSafariButMakeForgeryEasier." });
      }
    }
    batch.mode = batch.isPoll ? dwr.engine._ModePlainPoll : dwr.engine._ModePlainCall;
    request = dwr.engine._constructRequest(batch);
    try {
      batch.req.open(batch.httpMethod, request.url, batch.async);
      try {
        for (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) dwr.engine._stateChange(batch);
    }
    catch (ex) {
      dwr.engine._handleError(batch, ex);
    }
  }
  else if (batch.rpcType != dwr.engine.ScriptTag) {
    var idname = "dwr-if-" + batch.map["c0-id"];
    // Proceed using iframe
    batch.div = document.createElement("div");
    batch.div.innerHTML = "<iframe src='javascript:void(0)' frameborder='0' width='0' height='0' id='" + idname + "' name='" + idname + "'></iframe>";
    document.body.appendChild(batch.div);
    batch.iframe = document.getElementById(idname);
    batch.iframe.setAttribute("style", "width:0px; height:0px; border:0px;");
    batch.iframe.batch = batch;
    batch.mode = batch.isPoll ? dwr.engine._ModeHtmlPoll : dwr.engine._ModeHtmlCall;
    if (batch.isPoll) {
      // Settings that vary if we are polling
      dwr.engine._pollFrame = batch.iframe;
      dwr.engine._cometProcessed = 0;
    }
    request = dwr.engine._constructRequest(batch);
    if (batch.httpMethod == "GET") {
      batch.iframe.setAttribute("src", request.url);
      document.body.appendChild(batch.iframe);
    }
    else {
      batch.form = document.createElement("form");
      batch.form.setAttribute("id", "dwr-form");
      batch.form.setAttribute("action", request.url);
      batch.form.setAttribute("target", idname);
      batch.form.target = idname;
      batch.form.setAttribute("method", batch.httpMethod);
      for (prop in batch.map) {
        var value = batch.map[prop];
        if (typeof value != "function") {
          var formInput = document.createElement("input");
          formInput.setAttribute("type", "hidden");
          formInput.setAttribute("name", prop);
          formInput.setAttribute("value", value);
          batch.form.appendChild(formInput);
        }
      }
      document.body.appendChild(batch.form);
      batch.form.submit();
    }
  }
  else {
    batch.httpMethod = "GET"; // There's no such thing as ScriptTag using POST
    batch.mode = batch.isPoll ? dwr.engine._ModePlainPoll : dwr.engine._ModePlainCall;
    request = dwr.engine._constructRequest(batch);
    batch.script = document.createElement("script");
    batch.script.id = "dwr-st-" + batch.map["c0-id"];
    batch.script.src = request.url;
    document.body.appendChild(batch.script);
  }
};

dwr.engine._ModePlainCall = "/call/plaincall/";
dwr.engine._ModeHtmlCall = "/call/htmlcall/";
dwr.engine._ModePlainPoll = "/call/plainpoll/";
dwr.engine._ModeHtmlPoll = "/call/htmlpoll/";

/** @private Work out what the URL should look like */
dwr.engine._constructRequest = function(batch) {
  // A quick string to help people that use web log analysers
  var request = { url:batch.path + batch.mode, body:null };
  if (batch.isPoll == true) {
    request.url += "ReverseAjax.dwr";
  }
  else if (batch.map.callCount == 1) {
    request.url += batch.map["c0-scriptName"] + "." + batch.map["c0-methodName"] + ".dwr";
  }
  else {
    request.url += "Multiple." + batch.map.callCount + ".dwr";
  }
  // Play nice with url re-writing
  var sessionMatch = location.href.match(/jsessionid=(\w+)/);
  if (sessionMatch != null) {
    request.url += ";jsessionid=" + sessionMatch[1];
  }

  var prop;
  if (batch.httpMethod == "GET") {
    // Some browsers (Opera/Safari2) seem to fail to convert the callCount value
    // to a string in the loop below so we do it manually here.
    batch.map.callCount = "" + batch.map.callCount;
    request.url += "?";
    for (prop in batch.map) {
      if (typeof batch.map[prop] != "function") {
        request.url += encodeURIComponent(prop) + "=" + encodeURIComponent(batch.map[prop]) + "&";
      }
    }
    request.url = request.url.substring(0, request.url.length - 1);
  }
  else {
    // PERFORMANCE: for iframe mode this is thrown away.
    request.body = "";
    for (prop in batch.map) {
      if (typeof batch.map[prop] != "function") {
        request.body += prop + "=" + batch.map[prop] + dwr.engine._postSeperator;
      }
    }
    request.body = dwr.engine._contentRewriteHandler(request.body);
  }
  request.url = dwr.engine._urlRewriteHandler(request.url);
  return request;
};

/** @private Called by XMLHttpRequest to indicate that something has happened */
dwr.engine._stateChange = function(batch) {
  var toEval;

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

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

  try {
    var reply = batch.req.responseText;
    reply = dwr.engine._replyRewriteHandler(reply);
    var status = batch.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:batch.req.statusText });
    }
    else {
      var contentType = batch.req.getResponseHeader("Content-Type");
      if (!contentType.match(/^text\/plain/) && !contentType.match(/^text\/javascript/)) {
        if (contentType.match(/^text\/html/) && typeof batch.textHtmlHandler == "function") {
          batch.textHtmlHandler();
        }
        else {
          dwr.engine._handleWarning(batch, { name:"dwr.engine.invalidMimeType", message:"Invalid content type: '" + contentType + "'" });
        }
      }
      else {
        // Comet replies might have already partially executed
        if (batch.req == dwr.engine._pollReq && batch.map.partialResponse == "true") {
          dwr.engine._receivedBatch = batch;
          dwr.engine._processCometResponse(reply);
          dwr.engine._receivedBatch = null;
        }
        else {
          if (reply.search("//#DWR") == -1) {