HTTP trigger does not handle redirects on external calling point

Question

HTTP trigger does not handle redirects on external calling point

Jagjit Singh 0

Hello all,

Please would someone be able to guide me on this issue? I am trying to send GET request to an external HTTP endpoint from Logic App. The authentication to this external endpoint is Basic with a username and password. However, this external endpoint seems to have an Access policy manager (F5) in front which redirects this request to another location along with cookie and session details (MRHSession). When I try this HTTP trigger from Logic App, it stops after the first redirect. However, when I try the same trigger from Postman, the Postman handles the redirect and it automatically tries the new location and cookies - and all goes well. There are three redirects for this single GET request - and Postman manages all these but HTTP trigger from Logic App can't?

One solution that I have been advised is to parse the HTTP header from the first GET request to get the location and cookie, and then create additional GET requests to follow through all the redirects. This may work but sounds more of a workaround. Isn't there a better way for Azure/Logic App to manage the redirects? Could I use Application Gateway or APIM or something similar for calling this external HTTP Endpoint?

I am hoping that someone has come across similar situation where external HTTPS endpoints have an Access policy manager and will be able to help me here.

Thank you for your time to review my questions and help.

Jagjit

Jagjit Singh 0 Reputation points

2023-02-07T11:42:03.6566667+00:00

Any thoughts on this question from anyone please? Thank you.
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-02-28T04:22:47.5266667+00:00

Hi @Jagjit Singh

I hope the answer and comment clears things up. Feel free to get back to me if you need any assistance.

Please accept as "Yes" if the answer is helpful so that it can help others in the community. If you need any help/clarification/concerns/follow up questions, then please click on "Add Comment" on my answer and provide more details.

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Jagjit Singh 0 Reputation points

2023-02-07T11:42:03.6566667+00:00

Any thoughts on this question from anyone please? Thank you.
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-02-28T04:22:47.5266667+00:00

Hi @Jagjit Singh

I hope the answer and comment clears things up. Feel free to get back to me if you need any assistance.

Please accept as "Yes" if the answer is helpful so that it can help others in the community. If you need any help/clarification/concerns/follow up questions, then please click on "Add Comment" on my answer and provide more details.

Answer 1

MayankBargali-MSFT 70,936 Moderator

@Jagjit Singh Thanks for reaching out. The logic app HTTP action will fail if the return code is other than 2xx and this is the expected behavior. The one possible solution to handle this is to configure the run after behavior for the failed HTTP action and check for the status code as 301 or some other code as per your HTTP call and then get the required details from the request and create a new request as you have mentioned. APIM would not be able to handle the redirects as it will return the same response as it is from your backend service. I am not an expert in application gateway but looking into the document it does handle the redirects and this may be possible by configure URL rewrite. I have added the azure application gateway tag for the expert to confirm if the redirects can be handled or not in application gateway as per your scenario.

Jagjit Singh 0 Reputation points

2023-02-15T08:34:42.08+00:00

Dear @MayankBargali-MSFT thank you for your suggestions above. I have tried to configure run after but failed as this external HTTP endpoint is causing two subsequent redirects. Is there not a way in Logic app to set followRedirect to true or that wouldn't make any difference? Or alternatively, is there a way to use custom/Inline Javascript instead of in-built HTTP request?

Thanks again.

Jagjit
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-02-15T11:45:53.9466667+00:00

@Jagjit Singh Run after behaviour is only makes sure that your next action runs in case of different result (is successful, has time out, is skipped, has failed). For two subsequent redirects you need to make two more HTTP calls for the redirect. There is no way for Logic app to set followRedirect to true as logic app treats redirect 301/302 as failure. The inline code in logic app only supports Standard built-in objects as document here. I don't see any build in object to make the HTTP call from inline code in logic app.

The workaround will be creating the function or your custom service to handle this. I can see HTTPWebRequest has the property AllowAutoRedirect which can help you with the redirection. Now your logic app will call the azure function and your function will make the HTTPRequest with the redirect and return the response to logic app.

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HTTP trigger does not handle redirects on external calling point

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