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Flash Media Server Resources |
LoadVars classContents [Hide]The LoadVars class lets you send all the variables in an object to a specified URL and lets you load all the variables at a specified URL into an object. It also lets you send specific variables, rather than all variables, which can make your application more efficient. You can use the LoadVars.onLoad() handler to ensure that your application runs when data is loaded, and not before. The LoadVars class works much like the XML class; it uses the load(), send(), and sendAndLoad() methods to communicate with a server. The main difference between the LoadVars class and the XML class is that LoadVars transfers ActionScript name-value pairs, rather than an XML Document Object Model (DOM) tree stored in the XML object. The LoadVars class follows the same security restrictions as the XML class. Property summary
Method summary
Event handler summary
LoadVars.addRequestHeader()myLoadVars.addRequestHeader(header, headerValue) Adds or changes HTTP request headers (such as Content-Type or SOAPAction) sent with POST actions. There are two possible use cases for this method: you can pass two strings, header and headerValue, or you can pass an array of strings, alternating header names and header values. If multiple calls are made to set the same header name, each successive value replaces the value set in the previous call. The following standard HTTP headers cannot be added or changed with this method: Accept-Ranges, Age, Allow, Allowed, Connection, Content-Length, Content-Location, Content-Range, ETag, Host, Last-Modified, Locations, Max-Forwards, Proxy-Authenticate, Proxy-Authorization, Public, Range, Retry-After, Server, TE, Trailer, Transfer-Encoding, Upgrade, URI, Vary, Via, Warning, and WWW-Authenticate. Parameters
ExampleThe following example adds a custom HTTP header named SOAPAction with a value of Foo to the my_lv object: var my_lv = new LoadVars();
my_lv.addRequestHeader("SOAPAction", "'Foo'");
The following example creates an array named headers that contains two alternating HTTP headers and their associated values. The array is passed as a parameter to the addRequestHeader() method. var my_lv = new LoadVars(); var headers = ["Content-Type", "text/plain", "X-ClientAppVersion", "2.0"]; my_lv.addRequestHeader(headers); The following example creates a new LoadVars object that adds a request header called FLASH-UUID. The header contains a variable that the server can check. var my_lv = new LoadVars();
my_lv.addRequestHeader("FLASH-UUID", "41472");
my_lv.name = "Mort";
my_lv.age = 26;
my_lv.send("http://flash-mx.com/mm/cgivars.cfm", "_blank", "POST");
LoadVars.contentTypemyLoadVars.contentType The MIME type sent to the server when you call the LoadVars.send() or LoadVars.sendAndLoad() method. The default is application/x-www-urlform-encoded. ExampleThe following example creates a LoadVars object and displays the default content type of the data that is sent to the server: application.onConnect = function(client){
this.acceptConnection(client);
var my_lv = new LoadVars();
trace(my_lv.contentType);
};
// Output to Live Log: application/x-www-form-urlencoded
LoadVars.decode()myLoadVars.decode(queryString) Converts the query string to properties of the specified LoadVars object. This method is used internally by the LoadVars.onData() event handler. Most users do not need to call this method directly. If you override the LoadVars.onData() event handler, you can explicitly call LoadVars.decode() to parse a string of variables. ExampleThe following example traces the three variables: application.onConnect = function(client){
this.acceptConnection(client);
// Create a new LoadVars object.
var my_lv = new LoadVars();
//Convert the variable string to properties.
my_lv.decode("name=Mort&score=250000");
trace(my_lv.toString());
// Iterate over properties in my_lv.
for (var prop in my_lv) {
trace(prop+" -> "+my_lv[prop]);
}
};
The following is output to the Live Log panel in the Administration Console: name=Mort&score=250000 name -> Mort score -> 250000 contentType -> application/x-www-form-urlencoded loaded -> false LoadVars.getBytesLoaded()myLoadVars.getByesLoaded() Returns the number of bytes loaded from the last or current LoadVars.load() or LoadVars.sendAndLoad() method call. The value of the contentType property does not affect the value of getBytesLoaded(). LoadVars.getBytesTotal()myLoadVars.getBytesTotal() Returns the total number of bytes loaded into an object during allLoadVars.load() or LoadVars.sendAndLoad() LoadVars.load() or LoadVars.sendAndLoad()method calls. Each time a call to load() or sendAndLoad() is issued, the getBytesLoaded() method is reset, but the getBytesTotal() method continues to grow. The value of the contentType property does not affect the value of getBytesLoaded(). LoadVars.load()myLoadVars.load(url) Downloads variables from the specified URL, parses the variable data, and places the resulting variables into the LoadVars object that calls the method. You can load variables from a remote URL or from a URL in the local file system; the same encoding standards apply to both. Any properties in the myLoadVars object that have the same names as downloaded variables are overwritten. The downloaded data must be in the MIME content type and be application/x-www-urlform-encoded. The LoadVars.load() method call is asynchronous. ExampleThe following code defines an onLoad() handler function that signals when data is returned: application.onConnect = function(client){
this.acceptConnection(client);
var my_lv = new LoadVars();
my_lv.onLoad = function(success) {
if (success) {
trace(this.toString());
} else {
trace("Error loading/parsing LoadVars.");
}
};
my_lv.load("http://www.helpexamples.com/flash/params.txt");
};
LoadVars.loadedmyLoadVars.loaded A boolean value that indicates whether a LoadVars.load() or LoadVars.sendAndLoad() operation has completed (true) or not (false). LoadVars.onData()myLoadVars.onData(src){}
Invoked when data has completely downloaded from the server or when an error occurs while data is downloading from a server. Parameters
DetailsThis handler is invoked before the data is parsed and can be used to call a custom parsing routine instead of the one built in to Flash Player. The value of the src parameter that is passed to the function assigned to LoadVars.onData() can be either undefined or a string that contains the URL-encoded name-value pairs downloaded from the server. If the src parameter is undefined, an error occurred while downloading the data from the server. The default implementation of LoadVars.onData() invokes LoadVars.onLoad(). You can override this default implementation by assigning a custom function to LoadVars.onData(), but LoadVars.onLoad() is not called unless you call it in your implementation of LoadVars.onData(). LoadVars.onHTTPStatus()myLoadVars.onHTTPStatus(httpStatus){}
Invoked when Flash Media Interactive Server receives an HTTP status code from the server. This handler lets you capture and act on HTTP status codes. Parameters
DetailsThe onHTTPStatus() handler is invoked before onData(), which triggers calls to onLoad() with a value of undefined if the load fails. After onHTTPStatus() is triggered, onData() is always triggered, whether or not you override onHTTPStatus(). To best use the onHTTPStatus() handler, you should write a function to catch the result of the onHTTPStatus() call; you can then use the result in your onData() and onLoad() handlers. If onHTTPStatus() is not invoked, this indicates that Flash Media Interactive Server did not try to make the URL request. If Flash Media Interactive Server cannot get a status code, or if it cannot communicate with the server, the default value of 0 is passed to your ActionScript code. ExampleThe following example shows how to use onHTTPStatus() to help with debugging. The example collects HTTP status codes and assigns their value and type to an instance of the LoadVars object. (Notice that this example creates the instance members this.httpStatus and this.httpStatusType at runtime.) The onData() handler uses these instance members to trace information about the HTTP response that can be useful in debugging. var myLoadVars = new LoadVars();
myLoadVars.onHTTPStatus = function(httpStatus) {
this.httpStatus = httpStatus;
if(httpStatus < 100) {
this.httpStatusType = "flashError";
}
else if(httpStatus < 200) {
this.httpStatusType = "informational";
}
else if(httpStatus < 300) {
this.httpStatusType = "successful";
}
else if(httpStatus < 400) {
this.httpStatusType = "redirection";
}
else if(httpStatus < 500) {
this.httpStatusType = "clientError";
}
else if(httpStatus < 600) {
this.httpStatusType = "serverError";
}
}
myLoadVars.onData = function(src) {
trace(">> " + this.httpStatusType + ": " + this.httpStatus);
if(src != undefined) {
this.decode(src);
this.loaded = true;
this.onLoad(true);
}
else {
this.onLoad(false);
}
}
myLoadVars.onLoad = function(success) {}
myLoadVars.load("http://weblogs.macromedia.com/mxna/flashservices/getMostRecentPosts.cfm");
LoadVars.onLoad()myLoadVars.onLoad(success){}
Invoked when a LoadVars.load() or LoadVars.sendAndLoad() operation has completed. If the variables load successfully, the success parameter is true. If the variables were not received, or if an error occurred in receiving the response from the server, the success parameter is false. If the success parameter is true, the myLoadVars object is populated with variables downloaded by the LoadVars.load() or LoadVars.sendAndLoad() operation, and these variables are available when the onLoad() handler is invoked. Parameters
ExampleThe following example creates a new LoadVars object, attempts to load variables into it from a remote URL, and prints the result: myLoadVars = new LoadVars();
myLoadVars.onLoad = function(result){
trace("myLoadVars load success is " + result);
}
myLoadVars.load("http://www.someurl.com/somedata.txt");
LoadVars.send()myLoadVars.send(url [, target, method]) Sends the variables in the myLoadVars object to the specified URL. All enumerable variables in the myLoadVars object are concatenated into a string that is posted to the URL by using the HTTP POST method. The MIME content type sent in the HTTP request headers is the value of LoadVars.contentType. Parameters
LoadVars.sendAndLoad()myLoadVars.sendAndLoad(url, target[, method ]) Posts the variables in the myLoadVars object to the specified URL. The server response is downloaded and parsed as variable data, and the resulting variables are placed in the target object. Variables are posted in the same way as LoadVars.send(). Variables are downloaded into target in the same way as LoadVars.load(). LoadVars.toString()myLoadVars.toString() Returns a string containing all enumerable variables in myLoadVars, in the MIME content encoding application/x-www-form-urlencoded. 
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