XML-RPC Client for LabVIEW

[Christian_L]

Document to share XML-RPC client VIs for LabVIEW and provide feedback, suggestions, request, etc.

What is XML-RPC?

Specification

The first VI is a very simple XML-RPC client that sends a method call with numeric parameters to a server and receives the response.

[1/17/2010] Added a LV 8.0 version of the code. This VI includes a custom version of the HTTP Post VI as HTTP Post didn't exist in LabVIEW 8.0.

[James_McN]

This looks really useful.  My interest is that I would really like to see a Robotic Operating System (ROS) interface in LabVIEW and this is certainly the first step.

[mrutm]

Please save in LabVIEW 9.0 because it was saved in LabVIEW 10. Thanks

[Christian_L]

I added a version of the code saved in LV 8.0.

[Christian_L]

Dave,   

The following and other similar headers are the HTTP header, and not part of the XML. Basically they are what make the HTTP Post call to the HTTP server running on the device you are talking to.   

POST /server.php HTTP/1.0 
User-Agent: National Instruments LabVIEW 
Host: phpxmlrpc.sourceforge.net 
Content-Type: application/x-www-form-urlencoded 
Content-Length: 160    

HTTP is a protocol based on top of TCP, which is based on top of IP which is based on top of Ethernet.  In short there are about five layers of nested protocols. For your application, assuming the HTTP Post function is written correctly, you should not need to worry about anything other than the XML to be sent to your device.  In the case where the header starts with the following:   

POST /RPC2 HTTP/1.0   

/RPC2 represents the location on the server where the XML-RPC engine/parser/interpreter is located. In my example this was /server.php, but it may need to be /RPC2 in your case. You specify this location as part of the URL passed to the HTTP Post function and do not need to modify the HTTP Post itself.  If your server is located at 'localhost' the URL would be 

http://localhost/RPC2

In addition the port of the HTTP server is specified in the URL. By default it is port 80. If you need to use a different port (e.g. 8080) then it becomes part of the URL like this: 

localhost:8080/RPC2

I have updated the HTTP Post function for LV 80 and will upload the new VI to this document. The previous version did not support adding a non default port to the URL.  

Addition: I just found another issue that the SNAPConnect server may be sensitive to. The HTTP header contains a field called Content-Type. For XML-RPC this should be set to text/xml. My code does not do this. My test server did not care about this field, but the SNAPConnect server may. I will need to make another update to the VIs, but don't have time to do that right now. I'll get to it later tonight or tomorrow.  Is there some documentation available online for the SNAPConnect XML-RPC interface?

[Christian_L]

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[Christian_L]

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[Gasson]

Hi,

I need to communicate to RPC server running on port 7700 with a username and password. How do I this in labview? Does anyone have any examples?

As the example below?