(PureBasic) Twitter API v2 - Get OAuth2 Access Token

See more Twitter API v2 Examples

Demonstrates how to get a Twitter API v2 OAuth2 access token from a desktop application or script.

For more information, see https://developer.twitter.com/en/docs/authentication/oauth-2-0/user-access-token

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkFileAccess.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkOAuth2.pb"

Procedure ChilkatExample()

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

    oauth2.i = CkOAuth2::ckCreate()
    If oauth2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i

    ; This should be the port in the localhost callback URI for your App (defined in the Twitter Developer Portal)
    ; The Callback URI / Redirect URL should be "http://localhost:3017/" if the port number is 3017.
    CkOAuth2::setCkListenPort(oauth2, 3017)

    CkOAuth2::setCkAuthorizationEndpoint(oauth2, "https://twitter.com/i/oauth2/authorize")
    CkOAuth2::setCkTokenEndpoint(oauth2, "https://api.twitter.com/2/oauth2/token")

    ; Replace these with actual values.
    CkOAuth2::setCkClientId(oauth2, "CLIENT_ID")
    CkOAuth2::setCkClientSecret(oauth2, "CLIENT_SECRET")

    CkOAuth2::setCkScope(oauth2, "tweet.read users.read follows.read follows.write")

    CkOAuth2::ckAddAuthQueryParam(oauth2,"offline.access","")
    CkOAuth2::ckAddAuthQueryParam(oauth2,"state","state")
    CkOAuth2::setCkCodeChallenge(oauth2, 1)
    CkOAuth2::setCkCodeChallengeMethod(oauth2, "plain")
    CkOAuth2::setCkUseBasicAuth(oauth2, 1)

    ; Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
    url.s = CkOAuth2::ckStartAuth(oauth2)
    If CkOAuth2::ckLastMethodSuccess(oauth2) <> 1
        Debug CkOAuth2::ckLastErrorText(oauth2)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    Debug url

    ; At this point, your application should load the URL in a browser.
    ; For example, 
    ; in C#: System.Diagnostics.Process.Start(url);
    ; in Java: Desktop.getDesktop().browse(new URI(url));
    ; in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
    ;              wsh.Run url
    ; in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
    ; in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
    ; The Microsoft account owner would interactively accept or deny the authorization request.

    ; Add the code to load the url in a web browser here...
    ; Add the code to load the url in a web browser here...
    ; Add the code to load the url in a web browser here...

    ; Now wait for the authorization.
    ; We'll wait for a max of 60 seconds.
    numMsWaited.i = 0
    While (numMsWaited < 60000) AND (CkOAuth2::ckAuthFlowState(oauth2) < 3)
        CkOAuth2::ckSleepMs(oauth2,100)
        numMsWaited = numMsWaited + 100
    Wend

    ; If there was no response from the browser within 60 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 CkOAuth2::ckAuthFlowState(oauth2) < 3
        CkOAuth2::ckCancel(oauth2)
        Debug "No response from the browser!"
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    ; 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 CkOAuth2::ckAuthFlowState(oauth2) = 5
        Debug "OAuth2 failed to complete."
        Debug CkOAuth2::ckFailureInfo(oauth2)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    If CkOAuth2::ckAuthFlowState(oauth2) = 4
        Debug "OAuth2 authorization was denied."
        Debug CkOAuth2::ckAccessTokenResponse(oauth2)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    If CkOAuth2::ckAuthFlowState(oauth2) <> 3
        Debug "Unexpected AuthFlowState:" + Str(CkOAuth2::ckAuthFlowState(oauth2))
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    Debug "OAuth2 authorization granted!"
    Debug "Access Token = " + CkOAuth2::ckAccessToken(oauth2)

    ; Get the full JSON response:
    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckLoad(json,CkOAuth2::ckAccessTokenResponse(oauth2))
    CkJsonObject::setCkEmitCompact(json, 0)

    ; The JSON response looks like this:

    ; {
    ;   "token_type": "bearer",
    ;   "expires_in": 7200,
    ;   "access_token": "NnAfRUxCVWhLNDB3MFRvd25yQlNnelRZY1F1WkFlQqVfNXYwOEVobVNqR0VfOjf2NTg4NDk0MjMxnzE6MTowOmF2OjE",
    ;   "scope": "users.read follows.read tweet.read follows.write"
    ; }

    Debug CkJsonObject::ckEmit(json)

    ; Save the JSON to a file for future requests.
    fac.i = CkFileAccess::ckCreate()
    If fac.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkFileAccess::ckWriteEntireTextFile(fac,"qa_data/tokens/twitter_v2_oauth2.json",CkJsonObject::ckEmit(json),"utf-8",0)


    CkOAuth2::ckDispose(oauth2)
    CkJsonObject::ckDispose(json)
    CkFileAccess::ckDispose(fac)


    ProcedureReturn
EndProcedure