topic Re: HTTP Post request to Power automate in Product Forum

HTTP Post request to Power automate

Christopher — Tue, 25 Apr 2023 08:55:00 GMT

I am attempting to send a post request from Blue Prism to our power automate platform, but I am encountering some difficulties. While the request works perfectly fine in Postman, I am uncertain as to why Blue Prism is unable to successfully send the same request.

I have attached screenshots containing information from both Postman and Blue Prism. Despite making some changes to the headers to resolve errors, I am now receiving a generic Blue Prism error message stating that an object reference is not set to an instance of an object.

If anyone has any insights or ideas on how to resolve this issue, I would greatly appreciate it.

Re: HTTP Post request to Power automate

harish.mogulluri — Tue, 25 Apr 2023 10:46:55 GMT

Hi christopher

Not sure whether you are using the latest utility http vbo. I recommend to download the vbo from digital exchange.

https://digitalexchange.blueprism.com/dx/entry/3439/solution/utility---http

Re: HTTP Post request to Power automate

shashank.kumar280 — Tue, 25 Apr 2023 10:53:14 GMT

@Christopher

Can you try like below. I am assuming you only need to pass URL parameters and the Body is blank.
The URL params can be set in the Address URL as shown in the screenshot.

Re: HTTP Post request to Power automate

Christopher — Tue, 25 Apr 2023 11:52:56 GMT

So after a little more adjustments and updating BO (Thank you Harish)

we get a more detailed error message:

The remote server returned an error: (411) Length Required

Which indicates that we are missing that header in the collection, i have tried every combination of 'Content length' 'ContentLength' and so on and giving it the value 0 which i can see is the correct thing, but i get the error 411 every time.

Re: HTTP Post request to Power automate

harish.mogulluri — Tue, 25 Apr 2023 12:13:21 GMT

Hello christopher

You can try the action shashank kumar mentioned.

I had very good success rate using that action.

Also if you want to still try to understand and work around for 411 error check the below article.

https://kinsta.com/knowledgebase/411-length-required/

Re: HTTP Post request to Power automate

Christopher — Tue, 25 Apr 2023 12:27:34 GMT

Hi,

Both actions give the same error, i do understand the meaning of the content-length header, it is also sent in the postman request with a value of 0, but blue prism will not accept it.

Re: HTTP Post request to Power automate

shashank.kumar280 — Tue, 25 Apr 2023 14:39:15 GMT

I believe setting the Content-Type to blank should resolve the error as there is no Body.

Re: HTTP Post request to Power automate

Christopher — Fri, 28 Apr 2023 08:51:13 GMT

Still getting same errors, been trying all variants of the headers and so on.
Creating a ticket for it, they must have a proper explanation what is needed to make that request work instead of a generic error.

Re: HTTP Post request to Power automate

harish.mogulluri — Fri, 28 Apr 2023 12:37:00 GMT

Hi christopher,

Did you get chance to try web api in system tab?
I dont think it will give any different result but that is some thing i would try.

Re: HTTP Post request to Power automate

ewilson — Fri, 28 Apr 2023 17:55:37 GMT

@Christopher

One thing I'd recommend is downloading a copy of Fiddler and then run both your Postman and BP tests again while Fiddler captures the full network traffic. Then we should be able to see a good comparison of all the headers that are being included against both requests. I typically use Fiddler Classic.

Cheers,
Eric

Re: HTTP Post request to Power automate

Christopher — Mon, 08 May 2023 09:21:47 GMT

I gave up on using any native Blue prism solutions, so i used Curl instead and it works like a charm.
Thanks for all the suggestions though