(PureBasic) Get Access Token for Google Tasks using Service Account JSON Key

Demonstrates how to get an access token for the Google Tasks API using a Service Account JSON key.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkSocket.pb"
IncludeFile "CkAuthGoogle.pb"
IncludeFile "CkFileAccess.pb"

Procedure ChilkatExample()

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

    ; First load the JSON key into a string.
    fac.i = CkFileAccess::ckCreate()
    If fac.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    jsonKey.s = CkFileAccess::ckReadEntireTextFile(fac,"qa_data/googleSvcAccountKeys/ChilkatCloud-48f7737c7505.json","utf-8")
    If CkFileAccess::ckLastMethodSuccess(fac) <> 1
        Debug CkFileAccess::ckLastErrorText(fac)
        CkFileAccess::ckDispose(fac)
        ProcedureReturn
    EndIf

    ; A JSON private key should look like this:

    ; {
    ;   "type": "service_account",
    ;   "project_id": "chilkatcloud",
    ;   "private_key_id": "48f7737c7505bb88eee6a20d09993e10605d466e",
    ;   "private_key": "-----BEGIN PRIVATE KEY----- ... -----END PRIVATE KEY-----\n",
    ;   "client_email": "pip-564@chilkatcloud.iam.gserviceaccount.com",
    ;   "client_id": "109982228323456925225",
    ;   "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    ;   "token_uri": "https://oauth2.googleapis.com/token",
    ;   "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
    ;   "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/pip-564%40chilkatcloud.iam.gserviceaccount.com"
    ; }

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

    CkAuthGoogle::setCkJsonKey(gAuth, jsonKey)

    ; Choose the scope for read/write access.
    CkAuthGoogle::setCkScope(gAuth, "https://www.googleapis.com/auth/tasks")

    ; Request an access token that is valid for this many seconds.
    CkAuthGoogle::setCkExpireNumSeconds(gAuth, 3600)

    CkAuthGoogle::setCkSubEmailAddress(gAuth, "")

    ; Connect to www.googleapis.com using TLS
    tlsSock.i = CkSocket::ckCreate()
    If tlsSock.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkSocket::ckConnect(tlsSock,"www.googleapis.com",443,1,5000)
    If success <> 1
        Debug CkSocket::ckLastErrorText(tlsSock)
        CkFileAccess::ckDispose(fac)
        CkAuthGoogle::ckDispose(gAuth)
        CkSocket::ckDispose(tlsSock)
        ProcedureReturn
    EndIf

    ; Send the request to obtain the access token.
    success = CkAuthGoogle::ckObtainAccessToken(gAuth,tlsSock)
    If success <> 1
        Debug CkAuthGoogle::ckLastErrorText(gAuth)
        CkFileAccess::ckDispose(fac)
        CkAuthGoogle::ckDispose(gAuth)
        CkSocket::ckDispose(tlsSock)
        ProcedureReturn
    EndIf

    ; Examine the access token:
    Debug "Access Token: " + CkAuthGoogle::ckAccessToken(gAuth)

    ; Save our access token to a file.
    success = CkFileAccess::ckWriteEntireTextFile(fac,"qa_data/tokens/googleTasks.txt",CkAuthGoogle::ckAccessToken(gAuth),"utf-8",0)


    CkFileAccess::ckDispose(fac)
    CkAuthGoogle::ckDispose(gAuth)
    CkSocket::ckDispose(tlsSock)


    ProcedureReturn
EndProcedure