(Swift) Get a Xero OAuth2 Access Token

Gets a Xero OAuth2 access token.

Note: This example requires Chilkat v10.1.2 or greater.

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func chilkatTest() {
    // For more information about the OAuth2, see OAuth 2.0 Authorization Flow

    let oauth2 = CkoOAuth2()!

    // For Xero OAuth2, set the listen port equal to the port used
    // in the Authorized Redirect URL for the Client ID.
    // For example, in this case the Authorized Redirect URL would be http://localhost:55568/
    // Your app should choose a port not likely not used by any other application.
    // See Xero OAuth2 for Desktop Apps for more information.
    oauth2.listenPort = 55568

    oauth2.authorizationEndpoint = "https://login.xero.com/identity/connect/authorize"
    oauth2.tokenEndpoint = "https://identity.xero.com/connect/token"

    // Replace these with actual values.
    oauth2.clientId = "XERO_APP_OAUTH2_CLIENT_ID"
    oauth2.clientSecret = "XERO_APP_OAUTH2_CLIENT_SECRET"
    oauth2.useBasicAuth = true

    // See https://developer.xero.com/documentation/oauth2/scopes for a complete list of scopes.
    // You will need to change the scopes depending on what access is needed..
    oauth2.scope = "openid profile email accounting.transactions accounting.attachments accounting.settings payroll.employees offline_access"

    // Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
    var url: String? = oauth2.start()
    if oauth2.lastMethodSuccess != true {
        print("\(oauth2.lastErrorText!)")
        return
    }

    print("url = \(url!)")

    // Launch the default browser on the system and navigate to the url.
    // The LaunchBrowser method was added in Chilkat v10.1.2.
    var success: Bool = oauth2.launchBrowser(url)
    if success == false {
        print("\(oauth2.lastErrorText!)")
        return
    }

    // Wait for the user to approve or deny authorization in the browser.
    var numMsWaited: Int = 0
    while (numMsWaited < 90000) && (oauth2.authFlowState.intValue < 3) {
        oauth2.sleepMs(100)
        numMsWaited = numMsWaited + 100
    }

    // If the browser does not respond within the specified time, AuthFlowState will be:
    // 
    // 1: Waiting for Redirect - The OAuth2 background thread is waiting for the browser's redirect request.
    // 2: Waiting for Final Response - The thread is awaiting the final access token response.
    // In either case, cancel the background task initiated by StartAuth.

    if oauth2.authFlowState.intValue < 3 {
        oauth2.cancel()
        print("No response from the browser!")
        return
    }

    // Check AuthFlowState to determine if authorization was granted, denied, or failed:
    // 
    // 3: Success - OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
    // 4: Access Denied - OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
    // 5: Failure - OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

    if oauth2.authFlowState.intValue == 5 {
        print("OAuth2 failed to complete.")
        print("\(oauth2.failureInfo!)")
        return
    }

    if oauth2.authFlowState.intValue == 4 {
        print("OAuth2 authorization was denied.")
        print("\(oauth2.accessTokenResponse!)")
        return
    }

    if oauth2.authFlowState.intValue != 3 {
        print("Unexpected AuthFlowState:\(oauth2.authFlowState.intValue)")
        return
    }

    // Save the full JSON access token response to a file.
    let sbJson = CkoStringBuilder()!
    sbJson.append(oauth2.accessTokenResponse)
    sbJson.writeFile("qa_data/tokens/xero-access-token.json", charset: "utf-8", emitBom: false)

    // The saved JSON response looks like this:

    // 	{
    // 	 "access_token": "...",
    // 	 "token_type": "Bearer",
    // 	 "expires_in": 3600,
    // 	 "refresh_token": "..."
    // 	}
    // 
    print("OAuth2 authorization granted!")
    print("Access Token = \(oauth2.accessToken!)")

}