(PureBasic) OAuth2 using a SOCKS Proxy (for a Desktop Application)

Demonstrates how to send OAuth2 communications through a SOCKS proxy for a desktop application. The technique is the same for all OAuth2 applications. This one happens to demonstrate for Microsoft Graph.

Note: This example requires Chilkat v10.1.2 or greater.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkSocket.pb"
IncludeFile "CkFileAccess.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkOAuth2.pb"
IncludeFile "CkDateTime.pb"

Procedure ChilkatExample()

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

    ; To use a SOCKS proxy with OAuth2, create a Chilkat socket object and specify the details for the
    ; SOCKS proxy server (SOCKS4 or SOCKS5).
    socket.i = CkSocket::ckCreate()
    If socket.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Use your SOCKS proxy server domain or IP address.
    CkSocket::setCkSocksHostname(socket, "mysocksproxyserver.com")
    ; Change this to the listening port of your SOCKS proxy server (if necessary)
    CkSocket::setCkSocksPort(socket, 1080)
    CkSocket::setCkSocksUsername(socket, "myProxyLogin")
    CkSocket::setCkSocksPassword(socket, "myProxyPassword")
    ; Set the SOCKS version to 4 or 5 based on the version
    ; of the SOCKS proxy server:
    CkSocket::setCkSocksVersion(socket, 5)
    ; Note: SOCKS4 servers only support usernames without passwords.
    ; SOCKS5 servers support full login/password authentication.

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

    ; We don't need to connect the socket beforehand.
    ; Just tell oauth2 to use the socket which has the SOCKS proxy properties.
    success.i = CkOAuth2::ckUseConnection(oauth2,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.
    CkOAuth2::setCkListenPort(oauth2, 3017)

    CkOAuth2::setCkAuthorizationEndpoint(oauth2, "https://login.microsoftonline.com/common/oauth2/v2.0/authorize")
    CkOAuth2::setCkTokenEndpoint(oauth2, "https://login.microsoftonline.com/common/oauth2/v2.0/token")

    ; Replace these with actual values.
    CkOAuth2::setCkClientId(oauth2, "MICROSOFT-GRAPH-CLIENT-ID")
    ; This is your app password:
    CkOAuth2::setCkClientSecret(oauth2, "MICROSOFT-GRAPH-CLIENT-SECRET")

    CkOAuth2::setCkCodeChallenge(oauth2, 0)
    ; 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
    CkOAuth2::setCkScope(oauth2, "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.
    url.s = CkOAuth2::ckStartAuth(oauth2)
    If CkOAuth2::ckLastMethodSuccess(oauth2) <> 1
        Debug CkOAuth2::ckLastErrorText(oauth2)
        CkSocket::ckDispose(socket)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    Debug "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 = CkOAuth2::ckLaunchBrowser(oauth2,url)
    If success = 0
        Debug CkOAuth2::ckLastErrorText(oauth2)
        CkSocket::ckDispose(socket)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    ; Wait for the user to approve or deny authorization in the browser.
    numMsWaited.i = 0
    While (numMsWaited < 90000) AND (CkOAuth2::ckAuthFlowState(oauth2) < 3)
        CkOAuth2::ckSleepMs(oauth2,100)
        numMsWaited = numMsWaited + 100
    Wend

    ; 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 CkOAuth2::ckAuthFlowState(oauth2) < 3
        CkOAuth2::ckCancel(oauth2)
        Debug "No response from the browser!"
        CkSocket::ckDispose(socket)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

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

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

    If CkOAuth2::ckAuthFlowState(oauth2) <> 3
        Debug "Unexpected AuthFlowState:" + Str(CkOAuth2::ckAuthFlowState(oauth2))
        CkSocket::ckDispose(socket)
        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",
    ;   "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 CkJsonObject::ckHasMember(json,"expires_on") <> 1
        dtExpire.i = CkDateTime::ckCreate()
        If dtExpire.i = 0
            Debug "Failed to create object."
            ProcedureReturn
        EndIf

        CkDateTime::ckSetFromCurrentSystemTime(dtExpire)
        CkDateTime::ckAddSeconds(dtExpire,CkJsonObject::ckIntOf(json,"expires_in"))
        CkJsonObject::ckAppendString(json,"expires_on",CkDateTime::ckGetAsUnixTimeStr(dtExpire,0))
    EndIf

    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/microsoftGraph.json",CkJsonObject::ckEmit(json),"utf-8",0)


    CkSocket::ckDispose(socket)
    CkOAuth2::ckDispose(oauth2)
    CkJsonObject::ckDispose(json)
    CkDateTime::ckDispose(dtExpire)
    CkFileAccess::ckDispose(fac)


    ProcedureReturn
EndProcedure