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HTTP calls to Azure Cognitive services - Operation-Location value as a variable

Dear community,


Hope you can help me with an issue I've been struggling with. 


I'm accessing the Azure Cognitive Services FormRecognizer service pre-built invoice model from PowerAutomate using HTTP POST and GET actions. The file input is PDF invoices. I run the POST call, copy and paste the Operation-Location value that is returned in the POST response into the URI field of the GET call, save, run my flow, all is well. 

However, when instead of a literal copy/paste, I construct a text variable containing that very same Operation-Location string and provide that variable reference in the GET action URI field, the GET call still completes without error, but the GET response reports that the FormRecognizer service is either notStarted or running, and does not return any further output.


As soon as i revert the text variable in the GET action URI field back to the literal copy and paste Operation-Location string value, things start working normally again. 


I need to construct this Operation-Location value dynamically as I understand the service Operation-Location URI links expire after a certain amount of time, and my service calls would not continue to run.  Please advise?

Power Apps
Power Apps

Hi @rvanraamsdonk,


Thanks for posting this question. 

Since this is the AI Builder forum, can I ask if you have considered using AI Builder? 🙂 A good number of AI Builder models are powered by Azure Form Recognizer. Since AI Builder is part of the Power Platform it's usage in a Power Automate flow is very simple. 

If you have considered AI Builder but still want to build your own solution with Azure, I'd love to understand if its because a feature gap or other reason. 


I can recommend the following video from @ThatAPIGuy that shows how to call Azure Form Recognizer from the Power Platform:

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