(Swift) Get OAuth2 Access Token for Azure Registered App

Demonstrates how to get OAuth2 access token for an Azure Registered App from a desktop application or script. This example demonstrates the OAuth2 authorization flow.

This example requires Chilkat v10.1.2 or greater.

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func chilkatTest() {
    // To further clarify, see OAuth 2.0 Authorization Flow

    let oauth2 = CkoOAuth2()!

    // This should be the port in the localhost callback URL for your app.  
    // The callback URL would look like "http://localhost:3017/" if the port number is 3017.
    oauth2.listenPort = 3017

    // ----------------------------------------------------------------------------------------------------------
    // The screenshot at the bottom of this page shows how we created the Azure App Registration for this example.
    // ----------------------------------------------------------------------------------------------------------

    // Note: The endpoint depends on the Azure App Registration.
    // See How to Choose the Correct Endpoints for your Azure App Registration
    oauth2.authorizationEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/authorize"
    oauth2.tokenEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/token"

    // Replace these with actual values.
    oauth2.clientId = "CLIENT_ID"

    // This is for Require Proof Key for Code Exchange (PKCE)
    // See OAuth2 PKCE Explained
    oauth2.codeChallenge = true
    oauth2.codeChallengeMethod = "S256"

    // Provide a SPACE separated list of scopes.
    // See https://developer.microsoft.com/en-us/graph/docs/authorization/permission_scopes 

    // Important: To get a refresh token in the final response, ask for "offline_access" scope
    oauth2.scope = "openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite"

    // Begin the OAuth2 three-legged 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
    }

    // 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
    }

    print("OAuth2 authorization granted!")
    print("Access Token = \(oauth2.accessToken!)")

    // When the token is near expiration, your app can refresh as shown here:
    // Refresh Expiring OAuth2 Access Token for Azure Registered App

    // Get the full JSON response:
    let json = CkoJsonObject()!
    json.load(oauth2.accessTokenResponse)
    json.emitCompact = false

    // The JSON response looks like this:

    // {
    //   "token_type": "Bearer",
    //   "scope": "User.Read Mail.ReadWrite Mail.Send",
    //   "expires_in": 3600,
    //   "ext_expires_in": 0,
    //   "access_token": "EwBAA8l6B...",
    //   "refresh_token": "MCRMdbe...",
    //   "id_token": "eyJ0eXA..."
    // }

    // If an "expires_on" member does not exist, then add the JSON member by
    // getting the current system date/time and adding the "expires_in" seconds.
    // This way we'll know when the token expires.
    if json.hasMember("expires_on") != true {
        let dtExpire = CkoDateTime()!
        dtExpire.setFromCurrentSystemTime()
        dtExpire.addSeconds(json.int(of: "expires_in").intValue)
        json.append("expires_on", value: dtExpire.getAsUnixTimeStr(false))
    }

    print("\(json.emit()!)")

    // Save the JSON to a file for future requests.
    let fac = CkoFileAccess()!
    fac.writeEntireTextFile("qa_data/tokens/_myAzureApp.json", fileData: json.emit(), charset: "utf-8", includePreamble: false)

    // This is a screenshot of how we created the Azure App for this example:
    // 

}