(Swift 3,4,5...) Google Drive Refresh Access Token

Demonstrates how to automatically refresh the access token when it expires.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

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

    var success: Bool = true

    // This example uses a previously obtained access token having permission for the 
    // Google Drive scope.

    // The access token (and refresh token) was previously saved to a JSON file with this format:
    // See Get Google Drive OAuth2 Access Token

    // {
    //   "access_token": "ya29.Gls-BsdxTWuenChv ... yzVIrXikkLxu5T6dy4I6GjADFardoz4Lruw",
    //   "expires_in": 3600,
    //   "refresh_token": "1/tMBJ ... 27D-Hk6rpQYBA",
    //   "scope": "https://www.googleapis.com/auth/drive",
    //   "token_type": "Bearer"
    // }

    let json = CkoJsonObject()!
    var tokenFilePath: String? = "qa_data/tokens/googleDrive.json"
    json.loadFile(tokenFilePath)

    let oauth2 = CkoOAuth2()!
    oauth2.accessToken = json.string(of: "access_token")
    oauth2.refreshToken = json.string(of: "refresh_token")

    oauth2.authorizationEndpoint = "https://accounts.google.com/o/oauth2/v2/auth"
    oauth2.tokenEndpoint = "https://www.googleapis.com/oauth2/v4/token"

    //  Replace these with actual values.
    oauth2.clientId = "GOOGLE-CLIENT-ID"
    oauth2.clientSecret = "GOOGLE-CLIENT-SECRET"
    oauth2.scope = "https://www.googleapis.com/auth/drive"

    // Use OAuth2 to refresh the access token.
    success = oauth2.refreshAccessToken()
    if success != true {
        print("\(oauth2.lastErrorText!)")
        return
    }

    print("\(oauth2.accessTokenResponse!)")

    // Save the new access token to our JSON file (so we can refresh it again when needed).
    json.update("access_token", value: oauth2.accessToken)

    let fac = CkoFileAccess()!
    fac.writeEntireTextFile(tokenFilePath, fileData: json.emit(), charset: "utf-8", includePreamble: false)

    print("Access Token Refreshed!")

}