Sample passwordless phone number authentication with IdentityServer4 in ASP.NET Core 3.1

ATTENTION: This implementation is not fully rfc6749 complient, for creating custom grant_type's follow instructions in section 8.3

NOTE: To be able to test locally you can change "ReturnVerifyTokenForTesting : true" on appsettings.json it will returns us verify_token on response, however in production usages it must be removed and you should add real SMS service (Twilio, Nexmo, etc..) by implementing ISmsServices

curl -H "Content-Type: application/json" \ 
     -X POST \ 
     -d '{"phonenumber":"+198989822"}' \ 
     http://localhost:62537/api/verify_phone_number

{
    "resend_token": "CfDJ8F2fHxOfr9xAtc...",
    "verify_token": "373635"
}

Authentication by verification token

curl -H "Content-Type: application/x-www-form-urlencoded" \
     -X POST \ 
     -d 'grant_type=phone_number_token&client_id=phone_number_authentication&client_secret=secret&phone_number=%2B198989822&verification_token=373635' \ 
      http://localhost:62537/connect/token

{
    "access_token": "CfDJ8F2fHxOfr9xAtc......",
    "expires_in": 3600,
    "token_type": "Bearer",
    "refresh_token": "CfDJ8F2fHxOfr9xAtc...."
}

Test your api controller by Bearer token

curl -i http://localhost:62732/api/Identity \
     -H "Authorization: Bearer CfDJ8F2fHxOfr9xAtc......"

{
    "type": "phone_number",
    "value": "+198989822"
}