B4X Requires Chilkat v10.1.2+
Slack OAuth2

Chilkat B4X Downloads

B4X
Dim success As Boolean = False

'  For more information about the OAuth2, see OAuth 2.0 Authorization Flow

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

'  This example is for desktop applicatons (it is not for code that runs on a web server).

'  Your applicaton must use your own public web server as an intermediate
'  to receive and forward the redirect to localhost.
'  See Using Your Web Server as an Intermediary for OAuth2 Redirect to localhost

'  This is the Redirect URL defined for your Slack App in the Slack developer portal, and contains the above PHP.
oauth2.AppCallbackUrl = "https://yourwebserver.com/oauth2_redirect"
oauth2.ListenPort = 3017

oauth2.AuthorizationEndpoint = "https://slack.com/oauth/authorize"
oauth2.TokenEndpoint = "https://slack.com/api/oauth.access"

'  Replace these with actual values.
oauth2.ClientId = "CLIENT_ID"
oauth2.ClientSecret = "CLIENT_SECRET"

oauth2.Scope = "team:read users:read"

'  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:

'  {
'    "ok": true,
'    "access_token": "xoxp-348475395242-348621810805-4768936228341-9f512b295124e7c9846ce63cb1464c4d",
'    "scope": "identify,team:read,users:read",
'    "user_id": "UA8HZRUPP",
'    "team_id": "TA3DZBN74",
'    "enterprise_id": null,
'    "team_name": "Chilkat Testing"
'  }

Log(json.Emit)

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