How to avoid hardcoding ServiceUrl in AD B2C custom policy API connector?

Question

I have a REST API connector in my B2C custom policy. All examples I have seen hard code the value of the ServiceUrl metadata item in the REST technical profile. For example:

<ClaimsProvider>
      <DisplayName>REST APIs</DisplayName>
      <TechnicalProfiles>
        <TechnicalProfile Id="REST-MyApiConnector">
          <DisplayName>This an example of my API connector</DisplayName>
          <Protocol Name="Proprietary" Handler="Web.TPEngine.Providers.RestfulProvider, Web.TPEngine, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
          <Metadata>
            <Item Key="ServiceUrl">https://someapi.com/api/endpoint</Item>
            <Item Key="SendClaimsIn">Url</Item>
            <Item Key="AuthenticationType">Basic</Item>
            <Item Key="AllowInsecureAuthInProduction">false</Item>
          </Metadata>
          <CryptographicKeys>
            <Key Id="BasicAuthenticationUsername" StorageReferenceId="B2C_1A_RestApiUsername" />
            <Key Id="BasicAuthenticationPassword" StorageReferenceId="B2C_1A_RestApiPassword" />
          </CryptographicKeys>
          <InputClaims>
          </InputClaims>
          <OutputClaims>
          </OutputClaims>
          <UseTechnicalProfileForSessionManagement ReferenceId="SM-Noop" />
        </TechnicalProfile>
      </TechnicalProfiles>
    </ClaimsProvider>  

I have seen a snippet on a GitHub issue (https://github.com/MicrosoftDocs/azure-docs/issues/58267) where the poster seems to have pulled the ServiceUrl from some external settings:

<Item Key="ServiceUrl">{Settings:CID-ApiUrl}/{user_id}</Item>

I can't seem to find any further information on this. Is there a way to store things like the ServiceUrl in some external settings that can then be accessed within the custom policy to avoid having to hardcode the URL?

Answer 1

It’s not dynamic. They would be using CICD pipeline to populate them before uploading into the tenant.

Answer 2

Loading the ServiceUrl dynamically is not possible once it is deployed to B2C. But there is a very useful VS Code extension which should help during development. Go to the policy settings section from the following documentation: Azure AD B2C Tools for VSCode

In short, it helps to define variables, and replace them based on values stored in an appsettings.json file. You can have multiple sets of settings for different environments. Then use a single command to replace all variables and get the final policies to another folder.

You can then deploy them to your b2c tenant. Another option is to replace the variables from a CI/CD pipelines and deploy them to the tenant.