Getting access to Soap Faults

[rmarp]

Folks,



I am using the WebService object in Flex/AS3. The
documentation states the following:

quote:

---

NOTE: You must use the Flex proxy, which is part of Flex Data
Services, to ensure that HTTP status codes are returned correctly
from HTTP services and web services. On web browsers, when a
service returns any status code other than 200, Adobe Flash Player
cannot read the body of the response. If the status code is 500 and
the body contains a fault, there is no way to get to the fault. The
proxy works around this issue by forcing the status code for faults
to 200; the player passes the body of the response along with the
fault intact.

---

Ok so this makes sense in principle. But the documentation is
very weak in explaining what exactly the proxy mechanism is and how
to configure it. Does anybody have any ideas?



Without this, any soap fault that occurs during a web service
call (which is very valid behavior) will never get properly handled
by Flash and thus just returns a generic "HTTP request error".

[aglosband]

To make your web service request go through the proxy, you
set the useProxy property of your web service to true, so



myService.useProxy = true;



If you set the wsdl property on the web service rather than
specifying a destination, the destination DefaultHTTP that is
defined in the proxy-config.xml file gets used. The destination has
<dynamic-url> properties which contain url patterns that
determine which urls the proxy lets through.



<destination id="DefaultHTTP">

<properties>

<dynamic-url>
http://myserver.com/myservice/*</dynamic-url><dynamic-url>*</dynamic-url>

</properties>

</destination>



So, to wrap up. To use the proxy, set useProxy to true on
your web service. Then edit the DefaultHTTP destination in
proxy-config.xml and add a dynamic-url property that will allow
your web service request to go through.



If you want to configure a destination on the server rather
than using the wsdl property, look at the Configuring RPC Services
-> Configuring destination properties -> Web service
properties section in the developers guide. The doc on this is
pretty good.

[rmarp]

Thanks for the information Alex. The only thing that's still
a bit foggy for me is where I am supposed to place this
proxy-config.xml file? Do I just put it in the same folder on my
web server as the SWF file for my flex application? I've seen
people mention putting it in WEB-INF/flex but that seems to be a
Java-specific folder. What if the site that hosts my SWF is ASP.NET
or something?



Ryan

[aglosband]

Ok. I think I see what the confusion is. The WEB-INF/flex
directory is a Java-specific folder. It's part of Flex Data
Services, which is a j2ee web application. If you're not running
the web application then you can't use the proxy.

[rmarp]

Alex - thank you for clarifying this with me. I was confused
over this point. I have seen reference to Flex Data Services and
now I understand this part. I guess I'm just left with this
question then ...



If I'm not using Data Services, do I not have any way of
handing soap faults other than recieving an HTTP request error? If
this is the case, this would be quite disappointing as this seems
to kill the whole web services scenario.

[seth_hodgson]

This issue is a limitation of the plugin API provided by the
browser.



Using FDS to proxy web service calls allows us to make the
proxied call on your behalf from the server where this limitation
doesn't exist. A 500 fault response can be returned as a 200
reponse that is readable by Flash.



If using FDS to proxy web service calls isn't an option and
you need access to the information in SOAP faults, you'd need to do
custom work on the server to reset the status code to 200 for the
fault responses returned to Flash clients.



Best,

Seth

[rmarp]

Seth - this is interesting info. So you are saying that when
Flash makes external communication via the mx.rpc.http/soap objects
that is uses an API on the web browser? Does the same apply to the
flash.net objects?

[seth_hodgson]

The plugin player (non-IE) uses the browser plugin API to
make its network calls. The IE player uses the Windows network
stack to make its calls. This is true of the flash.net classes, as
well as the mx.rpc classes (whose functionality is built on top of
flash.net).



Best,

Seth