Xbase++

Get Firebase Access Token from JSON Service Account Private Key

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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...

Xbase++

LOCAL nSuccess
LOCAL oFac
LOCAL cJsonKey
LOCAL oGAuth
LOCAL oTlsSock

nSuccess := 0

//  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.
oFac := CreateObject("Chilkat.FileAccess")
cJsonKey := oFac:ReadEntireTextFile("qa_data/firebase/firebase-chilkat-firebase-adminsdk-n28n4-1b664ee163.json", "utf-8")
IF (oFac:LastMethodSuccess != 1)
    ? oFac:LastErrorText
    oFac:destroy()
    RETURN
ENDIF

//  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"
//  } 
//  

oGAuth := CreateObject("Chilkat.AuthGoogle")
oGAuth:JsonKey := cJsonKey

//  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"

oGAuth:Scope := "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.
oGAuth:ExpireNumSeconds := 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.)
oGAuth:SubEmailAddress := ""

//  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.
oTlsSock := CreateObject("Chilkat.Socket")
nSuccess := oTlsSock:Connect("www.googleapis.com", 443, 1, 5000)
IF (nSuccess != 1)
    ? oTlsSock:LastErrorText
    oFac:destroy()
    oGAuth:destroy()
    oTlsSock:destroy()
    RETURN
ENDIF

//  Send the request to obtain the access token.
nSuccess := oGAuth:ObtainAccessToken(oTlsSock)
IF (nSuccess != 1)
    ? oGAuth:LastErrorText
    oFac:destroy()
    oGAuth:destroy()
    oTlsSock:destroy()
    RETURN
ENDIF

//  Examine the access token:
? "Firebase Access Token: " + oGAuth:AccessToken

//  Save the token to a file (or wherever desired).  This token is valid for 1 hour.
oFac:WriteEntireTextFile("qa_data/tokens/firebaseToken.txt", oGAuth:AccessToken, "utf-8", 0)

oFac:destroy()
oGAuth:destroy()
oTlsSock:destroy()