Passing current login user of Microsoft Dynamics CRM Portal to external web app

You can get the detail of current login user in liquid template va user liquid object. There is another way you can get the current login user via XHR call.

Microsoft CRM Portal has built-in API to generate JWT of current login user. The API is at https://<crm portal url>/_services/auth/token and returns JWT. This JWT is nothing but a JSON object encrypted using RS256 algorithm. So, anyone can decode it. Other words, anyone can encode it also.

You sometimes need to pass the current login user information to external web app. Since it takes very little effort to generate a JWT and pass it to your external website, it is very easy to bypass the security. Therefore, you will definitely want to verify the authenticity of generated token too ensure the token is generated from trusted source (in this case, your CRM portal).

The beauty with JWT is you can verify the signature of token using public key. If you are not familiar with PKI, the process generally involves the source or CRM portal which generates a token using its private key (which is already handled in CRM portal), and the target or your external web app which verifies the authenticity of the token using public key. To do this, get  the public key of your CRM portal at https://<crm portal url>/_services/auth/publickey.

The order of the whole process is

  1. Pass JWT token as a parameter in a web request/link to your external web app
  2. In your external web app, get public key from CRM portal and verify the signature of the JWT contained in web request

That’s easy, simple and neat. Right?

Next time, we will have a look at Azure AD B2C configuration to authenticate users, which requires more configurations and adds a little bit of complexity.

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