APIM redirect to another API based on Host

Question

APIM redirect to another API based on Host

Rahul Prabhu 46

I have a private APIM (hostname: apim.custom.com) with 2 APIs, dev1 and dev2 with similar set of operations(api/v1)

How can I redirect request from dev1.apim.custom.com/api/v1 to dev1/api/v1 api operation and dev2.apim.custom.com/api/v1 to dev2/api/v1?

*.apim.custom.com is mapped to private IP of APIM in the Private DNS Zone

MuthuKumaranMurugaachari-MSFT 22,451 Reputation points Moderator

2022-08-18T19:25:08.99+00:00

@Rahul Prabhu Thank you for reaching out to Microsoft Q&A. As per my understanding, you have two APIs defined as dev1/api/v1 & dev2/api/v1 and with custom domain apim.custom.com configured, both APIs can be accessed as apim.custom.com/dev1/api/v1 and apim.custom.com/dev2/api/v1 respectively. Instead of this, you would like to set up custom domains to redirect requests to API level. Is that correct?

Unfortunately, this is not possible. Custom domains cannot be set up at Product or API level and only at gateway level (see [similar discussion][1]). Which means, you can only create additional domains: dev1.apim.custom.com & dev2.apim.custom.com for a same APIM instance gateway and set up a unique URL suffix like app1, app2 for each APIs (or dev1, dev2 if you like to use same name reference). Then restrict each custom domain to a specific API as mentioned in [other thread][1]. (This might appear similar to what you currently have but it enables different domain names for each developer area)

I understand it would be great useful to define a custom domain/endpoint at API or product level in your use case. Please share your feedback with our product team via aka.ms/apimwish so that other users who are in need to similar feature can upvote it.

I hope this answers your question and feel free to add if you have any questions. Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.
Rahul Prabhu 46 Reputation points

2022-08-19T10:04:24.487+00:00

Can we make use of Inbound policy to redirect requests?

For eg; There can be 3 APIs defined api/v1, dev1/api/v1 and dev2/api/v1

Every request will be made to api/v1 api and a inbound policy will redirect to dev1 or dev2 api based on the Hostname

<inbound>
<choose>
<when condition="@(context.Request.Url.Host.Contains("dev1") ? false : true)">
<redirect logic to dev1 API>
</when>
<when condition="@(context.Request.Url.Host.Contains("dev2") ? false : true)">
<redirect logic to dev2 API>
</when>
<otherwise />
</choose>
</inbound>

Does APIM policy supports this feature?

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MuthuKumaranMurugaachari-MSFT 22,451 Reputation points Moderator

2022-08-18T19:25:08.99+00:00

@Rahul Prabhu Thank you for reaching out to Microsoft Q&A. As per my understanding, you have two APIs defined as dev1/api/v1 & dev2/api/v1 and with custom domain apim.custom.com configured, both APIs can be accessed as apim.custom.com/dev1/api/v1 and apim.custom.com/dev2/api/v1 respectively. Instead of this, you would like to set up custom domains to redirect requests to API level. Is that correct?

Unfortunately, this is not possible. Custom domains cannot be set up at Product or API level and only at gateway level (see [similar discussion][1]). Which means, you can only create additional domains: dev1.apim.custom.com & dev2.apim.custom.com for a same APIM instance gateway and set up a unique URL suffix like app1, app2 for each APIs (or dev1, dev2 if you like to use same name reference). Then restrict each custom domain to a specific API as mentioned in [other thread][1]. (This might appear similar to what you currently have but it enables different domain names for each developer area)

I understand it would be great useful to define a custom domain/endpoint at API or product level in your use case. Please share your feedback with our product team via aka.ms/apimwish so that other users who are in need to similar feature can upvote it.

I hope this answers your question and feel free to add if you have any questions. Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.
Rahul Prabhu 46 Reputation points

2022-08-19T10:04:24.487+00:00

Can we make use of Inbound policy to redirect requests?

For eg; There can be 3 APIs defined api/v1, dev1/api/v1 and dev2/api/v1

Every request will be made to api/v1 api and a inbound policy will redirect to dev1 or dev2 api based on the Hostname

<inbound>
<choose>
<when condition="@(context.Request.Url.Host.Contains("dev1") ? false : true)">
<redirect logic to dev1 API>
</when>
<when condition="@(context.Request.Url.Host.Contains("dev2") ? false : true)">
<redirect logic to dev2 API>
</when>
<otherwise />
</choose>
</inbound>

Does APIM policy supports this feature?

Answer 1

@Rahul Prabhu Thank you for your reply. Yes, you can create a new API with default API URL suffix (empty) or api/v1 simply for the purpose of redirection. In that API, you can define an operation with URL as "/" and set inbound policy with return-response like below:

    <inbound>  
                <choose>  
                    <when condition="@(context.Request.OriginalUrl.Host == "dev1.apim.custom.com")">  
                        <return-response>  
                            <set-status code="303" />  
                            <set-header name="Location" exists-action="override">  
                                <value>@("https://" + context.Request.OriginalUrl.Host + "/dev1/api/v1")</value>  
                            </set-header>  
                        </return-response>  
                    </when>  
                    <when condition="@(context.Request.OriginalUrl.Host == "dev2.apim.custom.com")">  
                        <return-response>  
                            <set-status code="303" />  
                            <set-header name="Location" exists-action="override">  
                                <value>@("https://" + context.Request.OriginalUrl.Host + "/dev2/api/v1")</value>  
                            </set-header>  
                        </return-response>  
                    </when>  
                </choose>  
                <base />  
            </inbound>

Please make sure to set redirect policy logic above base element.

This way whenever you hit dev1.apim.custom.com/api/v1, based on the condition it should redirect to dev1/api/v1 and similarly for dev2.apim.custom.com/api/v1, it goes to dev2/api/v1. Please validate and let me know if you ran into any issues.

Just a note, make sure that API(s) is grouped accordingly if you enable a subscription key for the product. Also, if needed, restrict other domains from accessing API directly (dev1.apim.custom.com/dev2/api/v1 or dev2.apim.custom.com/dev1/api/v1) as mentioned here.

I hope this answers your question and feel free to add if you have any questions. Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.

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APIM redirect to another API based on Host

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