Azure API Management
An Azure service that provides a hybrid, multi-cloud management platform for APIs.
2,405 questions
Azure Api Management throws System.Exception: Content length mismatch
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Clemens Tan
1
Reputation point
Hello,
an Azure Function is responding to an HTTP PUT request an 400 error with a body which contains some error text. When calling the Azure Function HTTP directly from the Azure function, the HTTP trigger responses correctly. If called through the ApiManagement, the API Management discards the body and throws
System.Exception: Content length mismatch
I can't figure out, what is going wrong here. Same with 422 response code. With response code 200, the body is sent correclty.
Azure API Management
{count} votes
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MayankBargali-MSFT 70,921 Reputation points Moderator2021-08-13T03:57:12.84+00:00 @Clemens Tan I will suggest you to review the traces and verify whether the exact failure is either from Inbound, Backend or Outbound section and verify whether there could be any policy causing the issue.
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Clemens Tan 1 Reputation point
2021-08-13T06:31:55.027+00:00 We found a "bug". It seems that there is a 64kb limit in the response body, whenever a return code is not 200. I guess it is a bug. I could not find any limitations in the documentation.
The Azure Function returns the full body, but the APIManagement ha a problem, with a payload above 64kbWe are using the consumption plan of the API Management. With the Basic Tier, the problem does not occure.
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MayankBargali-MSFT 70,921 Reputation points Moderator
2021-08-19T05:13:36.77+00:00 @Clemens Tan Thanks for your respose. I have tried to reproduce the issue at my end but couldn't observe the error : System.Exception: Content length mismatch but I do see 500 error when the return code is not 200 and the patyload is more than 64KB. I will reach out to my team on the confirmaton if this is expected behaviour.
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Clemens Tan 1 Reputation point
2021-08-19T08:02:35.867+00:00 Hi MayankBargali,
the problem does only occur with the consumption sku plan of the api management.
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Warren Kinley 61 Reputation points2022-11-02T08:15:40.82+00:00 Hi, sorry to jump on this old thread but I cannot find any information out there apart from this question.
I am seeing this 422 message in APIM. I think it is to do with the size of the mocked response i.e. 2.8 Mb. The actually mocking is working perfectly from outside of APIM, however, when I try and update the API I see this 422 exception in APIM. Also, the endpoint does not even load in APIM, it times out with a "Could not load details for operation...".My question is, what are the limits here, mocking responses? I only see a 64 Kb limit on a validation schema policy within APIM.
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