B4X

Square OAuth2 Access Token

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Demonstrates how to get an access token for the Square API. This example is for desktop apps only (not web apps). B4X

Dim success As Boolean = False

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

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

'  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

'  To use the production system, change the domains here to "connect.squareup.com"
oauth2.AuthorizationEndpoint = "https://connect.squareupsandbox.com/oauth2/authorize"
oauth2.TokenEndpoint = "https://connect.squareupsandbox.com/oauth2/token"

'  Replace these with actual values.
oauth2.ClientId = "APPLICATION_ID"
oauth2.ClientSecret = "APPLICATION_SECRET"

'  Make sure to include the scopes you'll need.
oauth2.Scope = "ITEMS_WRITE ITEMS_READ"

'  Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
Dim url As String = oauth2.StartAuth
If oauth2.LastMethodSuccess = False Then
    Log(oauth2.LastErrorText)
    Return
End If


'  Add the session=False query param to the URL.
Dim sbUrl As ChilkatStringBuilder
sbUrl.Initialize
sbUrl.Append(url)
sbUrl.Append("&session=False")
'  Launch this URL in the browser.
url = sbUrl.GetAsString

'  Launch the system's default browser navigated to the URL.
success = oauth2.LaunchBrowser(url)
If success = False Then
    Log(oauth2.LastErrorText)
    Return
End If


'  Now wait for the authorization.
'  We'll wait for a max of 30 seconds.
Dim numMsWaited As Int = 0
Do While (numMsWaited < 30000) And (oauth2.AuthFlowState < 3)
    oauth2.SleepMs(100)
    numMsWaited = numMsWaited + 100
Loop

'  If there was no response from the browser within 30 seconds, then 
'  the AuthFlowState will be equal to 1 or 2.
'  1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
'  2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
'  In that case, cancel the background task started in the call to StartAuth.
If oauth2.AuthFlowState < 3 Then
    oauth2.Cancel
    Log("No response from the browser!")
    Return
End If


'  Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
'  The possible AuthFlowState values are:
'  3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
'  4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
'  5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
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:

'  {
'    "access_token": "EAAAE...depV",
'    "token_type": "bearer",
'    "expires_at": "2020-09-04T23:30:18Z",
'    "merchant_id": "MLQA83866KSR5",
'    "refresh_token": "EQAAEE...jeVfD6MV"
'  }

Log(json.Emit)

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