(PureBasic) Auth0 Server-to-Server Access Token (Client Credentials flow)

Demonstrates how to obtain an Auth0 access token using client credentials (client_id and client_secret).

This is just a matter of duplicating this CURL command:

curl --request POST
  --url 'https://chilkat.auth0.com/oauth/token' \
  --header 'content-type: application/json' \
  --data '{"grant_type":"client_credentials","client_id": "xxxx","client_secret": "xxxx","audience": "https://api.example.com/geocoding/v1/"}'

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkHttpResponse.pb"
IncludeFile "CkHttp.pb"
IncludeFile "CkJsonObject.pb"

Procedure ChilkatExample()

    success.i = 0

    ; This example assumes the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    ; We want to duplicate this curl command:
    ; 
    ; curl --request POST
    ;   --url 'https://chilkat.auth0.com/oauth/token' \
    ;   --header 'content-type: application/json' \
    ;   --data '{"grant_type":"client_credentials","client_id": "my_client_id","client_secret": "my_client_secret","audience": "https://api.example.com/geocoding/v1/"}'

    ; Build the JSON body of the request.
    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckUpdateString(json,"grant_type","client_credentials")
    CkJsonObject::ckUpdateString(json,"client_id","AUTH0-CLIENT-ID")
    CkJsonObject::ckUpdateString(json,"client_secret","AUTH0-CLIENT-SECRET")
    CkJsonObject::ckUpdateString(json,"audience","https://api.example.com/geocoding/v1/")

    ; IMPORTANT: You would use your own url.  You would not use "chilkat.auth0.com".  
    ; Instead you would use "your_name.auth0.com"
    http.i = CkHttp::ckCreate()
    If http.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    resp.i = CkHttpResponse::ckCreate()
    If resp.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkHttp::ckHttpJson(http,"POST","https://chilkat.auth0.com/oauth/token",json,"application/json",resp)
    If success = 0
        Debug CkHttp::ckLastErrorText(http)
        CkJsonObject::ckDispose(json)
        CkHttp::ckDispose(http)
        CkHttpResponse::ckDispose(resp)
        ProcedureReturn
    EndIf

    ; A 200 response status code indicates success.  In the success case, the response body
    ; contains the JSON access token, such as: 
    ; {
    ;   "access_token": "eyJz93a...k4laUWw",
    ;   "token_type":"Bearer",
    ;   "expires_in":86400
    ; }
    ; 

    Debug "response status code = " + Str(CkHttpResponse::ckStatusCode(resp))

    ; The repsonse is JSON if successful and also JSON for errors.
    jsonResp.i = CkJsonObject::ckCreate()
    If jsonResp.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(jsonResp, 0)
    CkJsonObject::ckLoad(jsonResp,CkHttpResponse::ckBodyStr(resp))

    If CkHttpResponse::ckStatusCode(resp) <> 200
        ; The response body contains error information in JSON format.
        Debug CkJsonObject::ckEmit(jsonResp)

        ; An example of an error response:
        ; 		{
        ; 		  "error": "access_denied",
        ; 		  "error_description": "Client is not authorized to access \"https://api.example.com/geocoding/v1/\". You might probably want to create a \"client-grant\" associated to this API. See: https://auth0.com/docs/api/v2#!/Client_Grants/post_client_grants"
        ; 		}
        CkJsonObject::ckDispose(json)
        CkHttp::ckDispose(http)
        CkHttpResponse::ckDispose(resp)
        CkJsonObject::ckDispose(jsonResp)
        ProcedureReturn
    EndIf

    Debug "Success!"
    Debug CkJsonObject::ckEmit(jsonResp)

    ; A successful JSON response body looks like this:

    ; {
    ;   "access_token": "eyJz93a...k4laUWw",
    ;   "token_type":"Bearer",
    ;   "expires_in":86400
    ; }


    CkJsonObject::ckDispose(json)
    CkHttp::ckDispose(http)
    CkHttpResponse::ckDispose(resp)
    CkJsonObject::ckDispose(jsonResp)


    ProcedureReturn
EndProcedure