(DataFlex) Get Firebase Access Token from JSON Service Account Private Key

Demonstrates how to get a Firebase access token using a JSON service account private key. Your Firebase service account can be used to authenticate multiple Firebase features, such as Database, Storage and Auth, programmatically.

A Firebase JSON service account private key can be created in the Firebase settings/admin portion of the console.firebase.google.com site as shown here:

Scroll down to see the example code...

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoFac
    String sJsonKey
    Handle hoGAuth
    Variant vTlsSock
    Handle hoTlsSock
    Boolean iSuccess
    String sTemp1
    Boolean bTemp1

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

    // First load the Firebase JSON private key into a string.
    Get Create (RefClass(cComCkFileAccess)) To hoFac
    If (Not(IsComObjectCreated(hoFac))) Begin
        Send CreateComObject of hoFac
    End
    Get ComReadEntireTextFile Of hoFac "qa_data/firebase/firebase-chilkat-firebase-adminsdk-n28n4-1b664ee163.json" "utf-8" To sJsonKey
    Get ComLastMethodSuccess Of hoFac To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoFac To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // A Firebase JSON private key should look something like this:

    // { 
    //   "type": "service_account",
    //   "project_id": "firebase-chilkat",
    //   "private_key_id": "1c664ee164907413c91ddefcf5b765ecba8779e2",
    //   "private_key": "-----BEGIN PRIVATE KEY-----\nMIIEvQIBA ... Ya2UZii/lXn73/ZOK8=\n-----END PRIVATE KEY-----\n",
    //   "client_email": "firebase-adminsdk-n28n4@firebase-chilkat.iam.gserviceaccount.com",
    //   "client_id": "134846322329335418431",
    //   "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    //   "token_uri": "https://accounts.google.com/o/oauth2/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/firebase-adminsdk-n28n4%40firebase-chilkat.iam.gserviceaccount.com"
    // } 
    // 

    Get Create (RefClass(cComChilkatAuthGoogle)) To hoGAuth
    If (Not(IsComObjectCreated(hoGAuth))) Begin
        Send CreateComObject of hoGAuth
    End
    Set ComJsonKey Of hoGAuth To sJsonKey

    // Choose a scope.
    // The scope could be "https://www.googleapis.com/auth/firebase.database"
    // or a space-delimited list of scopes:
    // "https://www.googleapis.com/auth/firebase.database https://www.googleapis.com/auth/userinfo.email"

    Set ComScope Of hoGAuth To "https://www.googleapis.com/auth/firebase.database https://www.googleapis.com/auth/userinfo.email"

    // Request an access token that is valid for this many seconds.
    Set ComExpireNumSeconds Of hoGAuth To 3600

    // If the application is requesting delegated access:
    // The email address of the user for which the application is requesting delegated access,
    // then set the email address here. (Otherwise leave it empty.)
    Set ComSubEmailAddress Of hoGAuth To ""

    // Connect to www.googleapis.com using TLS (TLS 1.2 is the default.)
    // The Chilkat socket object is used so that the connection can be established
    // through proxies or an SSH tunnel if desired.
    Get Create (RefClass(cComChilkatSocket)) To hoTlsSock
    If (Not(IsComObjectCreated(hoTlsSock))) Begin
        Send CreateComObject of hoTlsSock
    End
    Get ComConnect Of hoTlsSock "www.googleapis.com" 443 True 5000 To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoTlsSock To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Send the request to obtain the access token.
    Get pvComObject of hoTlsSock to vTlsSock
    Get ComObtainAccessToken Of hoGAuth vTlsSock To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoGAuth To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Examine the access token:
    Get ComAccessToken Of hoGAuth To sTemp1
    Showln "Firebase Access Token: " sTemp1

    // Save the token to a file (or wherever desired).  This token is valid for 1 hour.
    Get ComAccessToken Of hoGAuth To sTemp1
    Get ComWriteEntireTextFile Of hoFac "qa_data/tokens/firebaseToken.txt" sTemp1 "utf-8" False To iSuccess


End_Procedure