FAQ at SWX: SWF Data Format

Frequently asked questions about SWX, SWX RPC, SWX PHP, and the SWX ActionScript Library.

Why am I getting Security Sandbox Violations in the Flash IDE when running the sample applications or my own applications?

Last modified on 2008-04-20 07:39:14 GMT. 1 comment. Top.

Summary: This warning only occurs when testing your applications from the Flash IDE. Cross-domain data exchange will work correctly when you run your applications from a web server. You can ignore this warning.

SWX RPC lets you to make cross-domain data calls (you can turn this off by setting the allowDomain option in the SWX PHP configuration file at php/swx_config.php to false). This means, for example. that you can have a SWF running on your development server or on your shared host somewhere and you can still consume the SWX RPC services (APIs) on the Public SWX Gateway on swxformat.org.

The Flash IDE, however, will display a Security Sandbox Violation when you run SWX applications in the IDE. This is because applications that run in the IDE use the file:// protocol as opposed to http://. Rest assured that your applications will work correctly when tested from a web server using the http:// protocol.

In short, you can safely ignore this warning.

For a longer explanation, read on.

The way SWX RPC enables cross-domain data exchange is by writing an allowDomain statement to the exact URL of the SWF that called it (your application) in the SWX data SWF that it sends back. The SWX ActionScript Library sends this URL in the SWX RPC call for you.

If you are using the native method via loadMovie(), you need to send the value of _url in a parameter called url in your SWX RPC call manually. Alternatively, when using the native method, if you don't send a url parameter, you can specifically allowDomain the loaded SWX data SWF from the main application and it, in turn, it will allowDomain its parent (your application) if it doesn't receive the url. This second method is discouraged, however, as the SWX data SWF should not require access to your application (if only does so to allow your application access to itself by calling allowDomain on _parent) and a fake SWX data SWF from an untrusted SWX RPC gateway could possibly access data and/or alter your main application when using this method.

To summarize, you can ignore this warning and you should either send a url parameter when using the native method via loadMovie() in SWX RPC or, even simpler, use the SWX ActionScript Library when your applications need to access data across domains.

Why are my string values sometimes incorrectly interpreted as numbers in the SWX Service Explorer?

Last modified on 2008-04-20 07:39:37 GMT. 0 comments. Top.

When entering string values for method arguments in the SWX Service Explorer, please enclose them in quotation marks, especially if they contain numbers. Otherwise, strings that start with numeric digits or are made up of a long sequence of numeric digits (such as IDs, etc.) will get interpreted as a number.

You can read more about this issue in the post titled Question: When's a string not a string.

This is a known issue and one that I will hopefully be addressing in the near future (post 1.0). In the meanwhile, to be on the safe side, please enclose all string values in the SWX Service Explorer in quotation marks.

Can I use a folder other than /php/services to hold my SWX PHP service classes?

Last modified on 2008-03-22 08:14:25 GMT. 0 comments. Top.

You sure can. All you need to do is change a setting in the SWX configuration file (swx_config.php). You can find the file in the php folder.

In it, just change the $servicesPath variable to point to where your services are (relative to the SWX gateway).

// Service Path: Put your service classes in this folder.
// Is relative to the SWX gateway (swx.php).
$servicesPath = "services/";

Why is my SWX PHP Start Page messed up?

Last modified on 2007-09-12 23:32:33 GMT. 0 comments. Top.

Tom Beaver reported that his SWX PHP Start Page was broken when he installed SWX PHP 1.0 under Apache on OS X although it was working fine with the SWX MAMP Bundle. After some investigation, I realized that it was because I was using PHP short tags in Version 1.0. If short tags are turned off in the PHP configuration file, the SWX PHP Start Page will not display correctly.

You should only run into this problem if you downloaded SWX PHP on September 11th or 12th (GMT) and your PHP instance is configured to disallow short tags.

If this problem affects you, please download the latest release of SWX PHP (Version 1.01 or later) which has been updated to use long tags throughout the SWX PHP Start Page.

Althernatively, you can turn short_open_tag on in the PHP configuration file (php.ini). Instructions on how to do this are available in the PHP Manual.

How do you pronounce SWX?

Last modified on 2007-08-25 11:49:12 GMT. 0 comments. Top.

It's pronounced "swix".

Who’s the cute little guy, then?

Last modified on 2007-09-14 06:59:28 GMT. 0 comments. Top.

If you’re asking about the SWX mascot/logo, his name’s Datum. He lives in a SWF shell.

Download the Adobe Illustrator file for Datum. You can also print your own SWX Moo cards and SWX Stickers that feature Datum.

Why do we need a new data format?

Last modified on 2007-09-27 13:53:14 GMT. 9 comments. Top.

When I first announced SWX, Patrick Mineault, lead developer of AMFPHP, questioned whether SWX was reinventing the wheel. Why, he asked, do we need SWX when there is AMFPHP? (AMFPHP is a PHP implementation of a Flash Remoting gateway).

To start with, comparing SWX and AMFPHP is like comparing apples and oranges. As I stated earlier, SWX is a new data format for Flash and SWX RPC is a remote procedure call protocol encoded in SWX. As such, we can compare SWX to AMF (the data format) and SWX RCP to Flash Remoting (the RPC protocol) and SWX PHP (my PHP implementation of SWX RPC) to AMF PHP.

So the real question becomes, does the Flash Platform need a new data format and a new RPC protocol? I believe it does and here are some reasons why:

Existing formats are non-native, complicated, require parsing and/or writing plumbing code e.g., XML, variable-encoded strings (LoadVars, loadVariables), Flash Remoting, etc.
SWX files have low processor overhead when parsed by the Flash Player as they are native (SWF bytecode)
SWX RPC is the only RPC solution for Flash Lite 2.0 and 2.1 (and thus for mobile Flash applications). Flash Remoting does not work with Flash Lite.
Most important: SWX, being native, has inherent advantages such as cross-platform data exchange (via allowDomain support for SWF files), simplicity (no ActionScript library is necessary to use it, although there is a high-level library if you want to use it), etc.

It's my first belief that every platform can benefit from a native data format that does not require parsing. The main advantage of SWX over other data formats and of SWX RPC over other RPC solutions is ease of use. I hope that this ease of use will spur a wealth of development of data-driven applications and mashups on the Flash Platform by developers who may traditionally have shied away from creating such applications because it was just too darn hard to do so.

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