B4X Requires Chilkat v10.1.2+

OAuth2 using an HTTP Proxy (for a Desktop Application)

See more OAuth2 Examples

Shows how to send OAuth2 communications through an HTTP proxy in a desktop application, using Microsoft Graph as an example. This method applies to all OAuth2 applications. B4X

Dim success As Boolean = False

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

'  To use an HTTP proxy with OAuth2, create a Chilkat socket object and specify the details.
Dim socket As ChilkatSocket
socket.Initialize("socket")
'  Use your HTTP proxy server domain or IP address.
socket.HttpProxyHostname = "myproxyserver.com"
'  Change this to the listening port of your HTTP proxy server (if necessary)
socket.HttpProxyPort = 808
'  Specify login/password if needed.
socket.HttpProxyUsername = "myProxyLogin"
socket.HttpProxyPassword = "myProxyPassword"
socket.HttpProxyForHttp = True

Dim oauth2 As ChilkatOAuth2
oauth2.Initialize("oauth2")

'  We don't need to connect the socket beforehand.
'  Just tell oauth2 to use the socket which has the HTTP proxy properties.
success = oauth2.UseConnection(socket)

'  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

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 = "MICROSOFT-GRAPH-CLIENT-ID"
'  This is your app password:
oauth2.ClientSecret = "MICROSOFT-GRAPH-CLIENT-SECRET"

oauth2.CodeChallenge = False
'  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, you have to ask for "offline_access" scope
oauth2.Scope = "openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite"

'  Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
Dim url As String = oauth2.StartAuth
If oauth2.LastMethodSuccess <> True Then
    Log(oauth2.LastErrorText)
    Return
End If


Log("url = " & url)

'  Launch the default browser on the system and navigate to the url.
'  The LaunchBrowser method was added in Chilkat v10.1.2.
success = oauth2.LaunchBrowser(url)
If success = False Then
    Log(oauth2.LastErrorText)
    Return
End If


'  Wait for the user to approve or deny authorization in the browser.
Dim numMsWaited As Int = 0
Do While (numMsWaited < 90000) And (oauth2.AuthFlowState < 3)
    oauth2.SleepMs(100)
    numMsWaited = numMsWaited + 100
Loop

'  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 < 3 Then
    oauth2.Cancel
    Log("No response from the browser!")
    Return
End If


'  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 = 5 Then
    Log("OAuth2 failed to complete.")
    Log(oauth2.FailureInfo)
    Return
End If


If oauth2.AuthFlowState = 4 Then
    Log("OAuth2 authorization was denied.")
    Log(oauth2.AccessTokenResponse)
    Return
End If


If oauth2.AuthFlowState <> 3 Then
    Log("Unexpected AuthFlowState:" & oauth2.AuthFlowState)
    Return
End If


Log("OAuth2 authorization granted!")
Log("Access Token = " & oauth2.AccessToken)

'  Get the full JSON response:
Dim json As ChilkatJsonObject
json.Initialize
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 Then
    Dim dtExpire As ChilkatDateTime
    dtExpire.Initialize
    dtExpire.SetFromCurrentSystemTime
    dtExpire.AddSeconds(json.IntOf("expires_in"))
    json.AppendString("expires_on", dtExpire.GetAsUnixTimeStr(False))
End If


Log(json.Emit)

'  Save the JSON to a file for future requests.
Dim fac As ChilkatFileAccess
fac.Initialize
fac.WriteEntireTextFile("qa_data/tokens/microsoftGraph.json", json.Emit, "utf-8", False)