How to make synchronous DataSource/DMI calls

[leonardoeloy]

Hi,

I'm implementing some custom FormItems and it just happens I need to make a synchronous call to a DataSource (or perhaps I could arrange to do that within a DMI call). It that possible?

Thanks,
Leonardo Eloy

[Isomorphic]

Hi Leonardo,

SmartClient doesn't currently provide for synchronous xmlHttpRequest calls. We do plan to provide support for it, however, using it reduces the number of browsers your application supports, because synchronous xmlHttpRequests are flaky on some older browsers, and it is still necessary to switch back to frames-based communication for cases like IE6 with ActiveX disabled.

How did you arrive at the need for a synchronous call? Maybe there's a simpler approach. If not, you could always do an xmlHttpRequest outside of SmartClient.

[mjamesb]

synchronous DataSource

Any progress on synchronous calls in a datasource?

[Isomorphic]

Hi mjamesb,
The SmartClient 6.0 release includes some simple code intended to support this, enabled by setting blocking to true on the RPCRequest object.
Feel free to experiment with it, but be aware that this is not a supported feature at this stage, and may not be fully functional.

You can see the source for this functionality under

/source/client/communications/Comm.jsp

- search for the "sendXMLHttpRequest" function.

Also - we'd be interested in hearing what your use case is that's requiring this functionality, as this would help us gauge whether we should be prioritizing this feature differently.

Thanks
Isomorphic Software