Where should I store data about the server in a Flex app?

I am a Flex newbie and I'm developing a Flex application that needs to talk to an AMF server in order to authenticate the user.

Where should I store the server URL? I don't want to hardcode it in the source 开发者_如何学Ccode, but the URL should be fixed at compile time, because when I compile the app it should be tied to a specific server.

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If you need the URL at compile time but you don't want to "hardcode" it, the best thing to do is to store it in inline constants. They work as #IFDEF or #define on C/C++ and you can easy change the URL without changing the application (just re-compiling it).

You have to add something like this into your compiler options:

-define+=APP::amfServerUrl,'http://localhost/some/path/'

And then, on your app code:

private static const AMF_SERVER_URL:String = APP::amfServerUrl;

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If it's not AIR, you could give your flash the server URL via FlashVars

HTML

<script type="text/javascript">
    var flashvars = {gateway:'http://myserver/amfphp'
    };
    var params = { 
        menu: "false",
        scale: "showAll",
        allowFullscreen: "true",
        allowScriptAccess: "always",
        quality:"best",
        bgcolor: "#FFFFFF"
    };
    var attributes = {
        id:"main", name:"main"
    };
    swfobject.embedSWF("main.swf", "altContent", "100%", "100%", "10.0.0", "expressInstall.swf", flashvars, params, attributes);

</script>

Then to retrieve this parameter, use:

AS3

var gatewayUrl:String = stage.loaderInfo.parameters["gateway"];

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I use an external config.xml file that resides on the server. My swf/wrapper are in the root, and the config is in a folder there named 'config'. Here is code from my current project that uses this config: .

override protected function doStart() : void {
    var xmlLoader : URLLoader = new URLLoader();

    xmlLoader.addEventListener(Event.COMPLETE, result, false, EventPriority.DEFAULT_HANDLER, true);
    xmlLoader.addEventListener(IOErrorEvent.IO_ERROR, fault, false, EventPriority.DEFAULT_HANDLER, true);

    xmlLoader.load(new URLRequest("config/config.xml"));
}

public function fault(info : *) : void {
    error("Failed to load config file.");
    trace("Error Loading Configuration");
}

public function result(data : Event) : void {
    var xml : XML = new XML(data.target.data);
    var settings : Object = XMLMapperUtil.mapAppSettingsModelFromXML(xml);
    var appSettingsModel : AppSettingsModel = AppSettingsModel.getInstance();

    ExObjectUtil.copyObjectProperties(appSettingsModel, settings);

    var secureString : String = (appSettingsModel.serverProtocol == 'https') ? "secure" : "";

    var firstURLSegment : String =
        appSettingsModel.serverProtocol
        + "://"
        + appSettingsModel.serverIP
        + ":"
        + appSettingsModel.serverPort
        + "/FlexClient/messagebroker/";

    var remotingURL : String  = firstURLSegment + "amf" + secureString;
    var messagingURL : String = firstURLSegment + secureString + "streamingamf";

    var remotingChannelSet : ChannelSet = new ChannelSet();
    var messagingChannelSet : ChannelSet = new ChannelSet();

    if (appSettingsModel.serverProtocol == 'https') {
        remotingChannelSet.addChannel(new SecureAMFChannel("my-secure-amf", remotingURL));
        messagingChannelSet.addChannel(new SecureStreamingAMFChannel("my-secure-amf-stream", messagingURL));
    }
    else {
        remotingChannelSet.addChannel(new AMFChannel("my-amf", remotingURL));
        messagingChannelSet.addChannel(new StreamingAMFChannel("my-streaming-amf", messagingURL));
    }

    appSettingsModel.remoteObject_ChannelSet = remotingChannelSet;
    appSettingsModel.messaging_ChannelSet = messagingChannelSet;

    complete();
}

My result function uses SpiceLab's XMLObjectMapper, a singleton, and a special property copying function to get the settings from the XML into a global object that I can use (appSettingsModel). All you really need to do is get that XML, parse it all out, and create some channels with the results. Oh, here is my XML file:

<AppSettingsModelXML 
    serverIP = "123.123.123.123"
    serverPort = "8080"
    serverProtocol = "http"/>