engine.js

实现自动刷新页面 本例实现页面自动刷新的效果

/*
 * Copyright 2005 Joe Walker
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Declare an object to which we can add real functions.
 */
if (dwr == null) var dwr = {};
if (dwr.engine == null) dwr.engine = {};
if (DWREngine == null) var DWREngine = dwr.engine;

/**
 * Set an alternative error handler from the default alert box.
 * @see getahead.org/dwr/browser/engine/errors
 */
dwr.engine.setErrorHandler = function(handler) {
  dwr.engine._errorHandler = handler;
};

/**
 * Set an alternative warning handler from the default alert box.
 * @see getahead.org/dwr/browser/engine/errors
 */
dwr.engine.setWarningHandler = function(handler) {
  dwr.engine._warningHandler = handler;
};

/**
 * Setter for the text/html handler - what happens if a DWR request gets an HTML
 * reply rather than the expected Javascript. Often due to login timeout
 */
dwr.engine.setTextHtmlHandler = function(handler) {
  dwr.engine._textHtmlHandler = handler;
}

/**
 * Set a default timeout value for all calls. 0 (the default) turns timeouts off.
 * @see getahead.org/dwr/browser/engine/errors
 */
dwr.engine.setTimeout = function(timeout) {
  dwr.engine._timeout = timeout;
};

/**
 * The Pre-Hook is called before any DWR remoting is done.
 * @see getahead.org/dwr/browser/engine/hooks
 */
dwr.engine.setPreHook = function(handler) {
  dwr.engine._preHook = handler;
};

/**
 * The Post-Hook is called after any DWR remoting is done.
 * @see getahead.org/dwr/browser/engine/hooks
 */
dwr.engine.setPostHook = function(handler) {
  dwr.engine._postHook = handler;
};

/**
 * Custom headers for all DWR calls
 * @see getahead.org/dwr/????
 */
dwr.engine.setHeaders = function(headers) {
  dwr.engine._headers = headers;
};

/**
 * Custom parameters for all DWR calls
 * @see getahead.org/dwr/????
 */
dwr.engine.setParameters = function(parameters) {
  dwr.engine._parameters = parameters;
};

/** XHR remoting type constant. See dwr.engine.set[Rpc|Poll]Type() */
dwr.engine.XMLHttpRequest = 1;

/** XHR remoting type constant. See dwr.engine.set[Rpc|Poll]Type() */
dwr.engine.IFrame = 2;

/** XHR remoting type constant. See dwr.engine.setRpcType() */
dwr.engine.ScriptTag = 3;

/**
 * Set the preferred remoting type.
 * @param newType One of dwr.engine.XMLHttpRequest or dwr.engine.IFrame or dwr.engine.ScriptTag
 * @see getahead.org/dwr/browser/engine/options
 */
dwr.engine.setRpcType = function(newType) {
  if (newType != dwr.engine.XMLHttpRequest && newType != dwr.engine.IFrame && newType != dwr.engine.ScriptTag) {
    dwr.engine._handleError(null, { name:"dwr.engine.invalidRpcType", message:"RpcType must be one of dwr.engine.XMLHttpRequest or dwr.engine.IFrame or dwr.engine.ScriptTag" });
    return;
  }
  dwr.engine._rpcType = newType;
};

/**
 * Which HTTP method do we use to send results? Must be one of "GET" or "POST".
 * @see getahead.org/dwr/browser/engine/options
 */
dwr.engine.setHttpMethod = function(httpMethod) {
  if (httpMethod != "GET" && httpMethod != "POST") {
    dwr.engine._handleError(null, { name:"dwr.engine.invalidHttpMethod", message:"Remoting method must be one of GET or POST" });
    return;
  }
  dwr.engine._httpMethod = httpMethod;
};

/**
 * Ensure that remote calls happen in the order in which they were sent? (Default: false)
 * @see getahead.org/dwr/browser/engine/ordering
 */
dwr.engine.setOrdered = function(ordered) {
  dwr.engine._ordered = ordered;
};

/**
 * Do we ask the XHR object to be asynchronous? (Default: true)
 * @see getahead.org/dwr/browser/engine/options
 */
dwr.engine.setAsync = function(async) {
  dwr.engine._async = async;
};

/**
 * Does DWR poll the server for updates? (Default: false)
 * @see getahead.org/dwr/browser/engine/options
 */
dwr.engine.setActiveReverseAjax = function(activeReverseAjax) {
  if (activeReverseAjax) {
    // Bail if we are already started
    if (dwr.engine._activeReverseAjax) return;
    dwr.engine._activeReverseAjax = true;
    dwr.engine._poll();
  }
  else {
    // Can we cancel an existing request?
    if (dwr.engine._activeReverseAjax && dwr.engine._pollReq) dwr.engine._pollReq.abort();
    dwr.engine._activeReverseAjax = false;
  }
  // TODO: in iframe mode, if we start, stop, start then the second start may
  // well kick off a second iframe while the first is still about to return
  // we should cope with this but we don't
};

/**
 * Set the preferred polling type.
 * @param newPollType One of dwr.engine.XMLHttpRequest or dwr.engine.IFrame
 * @see getahead.org/dwr/browser/engine/options
 */
dwr.engine.setPollType = function(newPollType) {
  if (newPollType != dwr.engine.XMLHttpRequest && newPollType != dwr.engine.IFrame) {
    dwr.engine._handleError(null, { name:"dwr.engine.invalidPollType", message:"PollType must be one of dwr.engine.XMLHttpRequest or dwr.engine.IFrame"  });
    return;
  }
  dwr.engine._pollType = newPollType;
};

/**
 * The default message handler.
 * @see getahead.org/dwr/browser/engine/errors
 */
dwr.engine.defaultErrorHandler = function(message, ex) {
  dwr.engine._debug("Error: " + ex.name + ", " + ex.message, true);

  if (message == null || message == "") alert("A server error has occured. More information may be available in the console.");
  // Ignore NS_ERROR_NOT_AVAILABLE if Mozilla is being narky
  else if (message.indexOf("0x80040111") != -1) dwr.engine._debug(message);
  else alert(message);
};

/**
 * The default warning handler.
 * @see getahead.org/dwr/browser/engine/errors
 */
dwr.engine.defaultWarningHandler = function(message, ex) {
  dwr.engine._debug(message);
};

/**
 * For reduced latency you can group several remote calls together using a batch.
 * @see getahead.org/dwr/browser/engine/batch
 */
dwr.engine.beginBatch = function() {
  if (dwr.engine._batch) {
    dwr.engine._handleError(null, { name:"dwr.engine.batchBegun", message:"Batch already begun" });
    return;
  }
  dwr.engine._batch = dwr.engine._createBatch();
};

/**
 * Finished grouping a set of remote calls together. Go and execute them all.
 * @see getahead.org/dwr/browser/engine/batch
 */
dwr.engine.endBatch = function(options) {
  var batch = dwr.engine._batch;
  if (batch == null) {
    dwr.engine._handleError(null, { name:"dwr.engine.batchNotBegun", message:"No batch in progress" });
    return;
  }
  dwr.engine._batch = null;
  if (batch.map.callCount == 0) return;

  // The hooks need to be merged carefully to preserve ordering
  if (options) dwr.engine._mergeBatch(batch, options);

  // In ordered mode, we don't send unless the list of sent items is empty
  if (dwr.engine._ordered && dwr.engine._batchesLength != 0) {
    dwr.engine._batchQueue[dwr.engine._batchQueue.length] = batch;
  }
  else {
    dwr.engine._sendData(batch);
  }
};

/** @deprecated */
dwr.engine.setPollMethod = function(type) { dwr.engine.setPollType(type); };
dwr.engine.setMethod = function(type) { dwr.engine.setRpcType(type); };
dwr.engine.setVerb = function(verb) { dwr.engine.setHttpMethod(verb); };

//==============================================================================
// Only private stuff below here
//==============================================================================

/** The original page id sent from the server */
dwr.engine._origScriptSessionId = "47857D9F260C82871FC4D06192ACECEC";

/** The session cookie name */
dwr.engine._sessionCookieName = "JSESSIONID"; // JSESSIONID

/** Is GET enabled for the benefit of Safari? */
dwr.engine._allowGetForSafariButMakeForgeryEasier = "false";

/** The script prefix to strip in the case of scriptTagProtection. */
dwr.engine._scriptTagProtection = "throw 'allowScriptTagRemoting is false.';";

/** The default path to the DWR servlet */
dwr.engine._defaultPath = "/ajax_8/dwr";

/** The read page id that we calculate */
dwr.engine._scriptSessionId = null;

/** The function that we use to fetch/calculate a session id */
dwr.engine._getScriptSessionId = function() {
  if (dwr.engine._scriptSessionId == null) {
    dwr.engine._scriptSessionId = dwr.engine._origScriptSessionId + Math.floor(Math.random() * 1000);
  }
  return dwr.engine._scriptSessionId;
};

/** A function to call if something fails. */
dwr.engine._errorHandler = dwr.engine.defaultErrorHandler;

/** For debugging when something unexplained happens. */
dwr.engine._warningHandler = dwr.engine.defaultWarningHandler;

/** A function to be called before requests are marshalled. Can be null. */
dwr.engine._preHook = null;

/** A function to be called after replies are received. Can be null. */
dwr.engine._postHook = null;

/** An map of the batches that we have sent and are awaiting a reply on. */
dwr.engine._batches = {};

/** A count of the number of outstanding batches. Should be == to _batches.length unless prototype has messed things up */
dwr.engine._batchesLength = 0;

/** In ordered mode, the array of batches waiting to be sent */
dwr.engine._batchQueue = [];

/** What is the default rpc type */
dwr.engine._rpcType = dwr.engine.XMLHttpRequest;

/** What is the default remoting method (ie GET or POST) */
dwr.engine._httpMethod = "POST";

/** Do we attempt to ensure that calls happen in the order in which they were sent? */
dwr.engine._ordered = false;

/** Do we make the calls async? */
dwr.engine._async = true;

/** The current batch (if we are in batch mode) */
dwr.engine._batch = null;

/** The global timeout */
dwr.engine._timeout = 0;

/** ActiveX objects to use when we want to convert an xml string into a DOM object. */
dwr.engine._DOMDocument = ["Msxml2.DOMDocument.6.0", "Msxml2.DOMDocument.5.0", "Msxml2.DOMDocument.4.0", "Msxml2.DOMDocument.3.0", "MSXML2.DOMDocument", "MSXML.DOMDocument", "Microsoft.XMLDOM"];

/** The ActiveX objects to use when we want to do an XMLHttpRequest call. */
dwr.engine._XMLHTTP = ["Msxml2.XMLHTTP.6.0", "Msxml2.XMLHTTP.5.0", "Msxml2.XMLHTTP.4.0", "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP"];

/** Are we doing comet or polling? */
dwr.engine._activeReverseAjax = false;

/** What is the default polling type */
dwr.engine._pollType = dwr.engine.XMLHttpRequest;
//dwr.engine._pollType = dwr.engine.IFrame;

/** The iframe that we are using to poll */
dwr.engine._outstandingIFrames = [];

/** The xhr object that we are using to poll */
dwr.engine._pollReq = null;

/** How many milliseconds between internal comet polls */
dwr.engine._pollCometInterval = 200;

/** How many times have we re-tried to poll? */
dwr.engine._pollRetries = 0;
dwr.engine._maxPollRetries = 0;

/** Do we do a document.reload if we get a text/html reply? */
dwr.engine._textHtmlHandler = null;

/** If you wish to send custom headers with every request */
dwr.engine._headers = null;

/** If you wish to send extra custom request parameters with each request */
dwr.engine._parameters = null;

/** Undocumented interceptors - do not use */
dwr.engine._postSeperator = "\n";
dwr.engine._defaultInterceptor = function(data) {return data;}
dwr.engine._urlRewriteHandler = dwr.engine._defaultInterceptor;
dwr.engine._contentRewriteHandler = dwr.engine._defaultInterceptor;
dwr.engine._replyRewriteHandler = dwr.engine._defaultInterceptor;

/** Batch ids allow us to know which batch the server is answering */
dwr.engine._nextBatchId = 0;

/** A list of the properties that need merging from calls to a batch */
dwr.engine._propnames = [ "rpcType", "httpMethod", "async", "timeout", "errorHandler", "warningHandler", "textHtmlHandler" ];

/** Do we stream, or can be hacked to do so? */
dwr.engine._partialResponseNo = 0;
dwr.engine._partialResponseYes = 1;
dwr.engine._partialResponseFlush = 2;

/**
 * @private Send a request. Called by the Javascript interface stub
 * @param path part of URL after the host and before the exec bit without leading or trailing /s
 * @param scriptName The class to execute
 * @param methodName The method on said class to execute
 * @param func The callback function to which any returned data should be passed
 *       if this is null, any returned data will be ignored
 * @param vararg_params The parameters to pass to the above class
 */
dwr.engine._execute = function(path, scriptName, methodName, vararg_params) {
  var singleShot = false;
  if (dwr.engine._batch == null) {
    dwr.engine.beginBatch();
    singleShot = true;
  }
  var batch = dwr.engine._batch;
  // To make them easy to manipulate we copy the arguments into an args array
  var args = [];
  for (var i = 0; i < arguments.length - 3; i++) {
    args[i] = arguments[i + 3];
  }
  // All the paths MUST be to the same servlet
  if (batch.path == null) {
    batch.path = path;
  }
  else {
    if (batch.path != path) {
      dwr.engine._handleError(batch, { name:"dwr.engine.multipleServlets", message:"Can't batch requests to multiple DWR Servlets." });
      return;
    }
  }
  // From the other params, work out which is the function (or object with
  // call meta-data) and which is the call parameters
  var callData;
  var lastArg = args[args.length - 1];
  if (typeof lastArg == "function" || lastArg == null) callData = { callback:args.pop() };
  else callData = args.pop();

  // Merge from the callData into the batch
  dwr.engine._mergeBatch(batch, callData);
  batch.handlers[batch.map.callCount] = {
    exceptionHandler:callData.exceptionHandler,
    callback:callData.callback
  };

  // 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;
  for (i = 0; i < args.length; i++) {
    dwr.engine._serializeAll(batch, [], args[i], prefix + "param" + i);
  }

  // Now we have finished remembering the call, we incr the call count
  batch.map.callCount++;
  if (singleShot) dwr.engine.endBatch();
};