User identity throttling example does not work.

[leftler]

In the example User identity throttling it has the following code example.

<rate-limit-by-key calls="10"
    renewal-period="60"
    counter-key="@(context.Request.Headers.GetValueOrDefault("Authorization","").AsJwt()?.Subject)" />

This will not work as the value of Authorization will be something like Bearer eyJ0eXAiO... this causes .AsJwt() to return null. To get this to work I had to do

 context.Request.Headers.GetValueOrDefault("Authorization","").Substring("Bearer ".Length).AsJwt()

to get .AsJwt() to not return null. Is this a error in the documentation or is this a error in the .AsJwt() call?

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Document Details

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• ID: c64c31f4-ee3f-1482-14a8-3585ff5ef2de
• Version Independent ID: 8e50e224-bfd8-061c-3203-4d19016d16dd
• Content: Advanced request throttling with Azure API Management
• Content Source: articles/api-management/api-management-sample-flexible-throttling.md
• Service: api-management
• GitHub Login: @vladvino
• Microsoft Alias: apimpm

[AdamS-MSFT]

@leftler Thanks for the feedback! I have assigned the issue to the content author to evaluate and update as appropriate.

[vladvino]

@leftler example is correct and doesn't work due to a regression. Bug fix will be deployed in the coming weeks. Thank you for the heads up!

[vladvino]

#please-close

[seanperera]

I experienced the issue where the jwt token didn't have the sub(subject) claim and APIM was throwing a 500 internal error with the message "Expression value is invalid. The counter-key field is required." The error recorded in AppInsights when i enabled diagnostics logging for APIM.

Registered claims (iss (issuer), exp (expiration time), sub (subject), aud (audience)) in jwt token is not mandatory but recommended. so fix the jwt token to include sub claim (the user) and the following worked.

<rate-limit-by-key calls="10"
renewal-period="60"
counter-key="@(context.Request.Headers.GetValueOrDefault("Authorization","").AsJwt()?.Subject)" />