(C) OAuth2 using an HTTP Proxy (for a Desktop Application)

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

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#include <C_CkSocket.h>
#include <C_CkOAuth2.h>
#include <C_CkJsonObject.h>
#include <C_CkDateTime.h>
#include <C_CkFileAccess.h>

void ChilkatSample(void)
    {
    HCkSocket socket;
    HCkOAuth2 oauth2;
    BOOL success;
    const char *url;
    int numMsWaited;
    HCkJsonObject json;
    HCkDateTime dtExpire;
    HCkFileAccess fac;

    // 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.
    socket = CkSocket_Create();
    // Use your HTTP proxy server domain or IP address.
    CkSocket_putHttpProxyHostname(socket,"myproxyserver.com");
    // Change this to the listening port of your HTTP proxy server (if necessary)
    CkSocket_putHttpProxyPort(socket,808);
    // Specify login/password if needed.
    CkSocket_putHttpProxyUsername(socket,"myProxyLogin");
    CkSocket_putHttpProxyPassword(socket,"myProxyPassword");
    CkSocket_putHttpProxyForHttp(socket,TRUE);

    oauth2 = CkOAuth2_Create();

    // We don't need to connect the socket beforehand.
    // Just tell oauth2 to use the socket which has the HTTP proxy properties.
    success = CkOAuth2_UseConnection(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_putListenPort(oauth2,3017);

    CkOAuth2_putAuthorizationEndpoint(oauth2,"https://login.microsoftonline.com/common/oauth2/v2.0/authorize");
    CkOAuth2_putTokenEndpoint(oauth2,"https://login.microsoftonline.com/common/oauth2/v2.0/token");

    // Replace these with actual values.
    CkOAuth2_putClientId(oauth2,"MICROSOFT-GRAPH-CLIENT-ID");
    // This is your app password:
    CkOAuth2_putClientSecret(oauth2,"MICROSOFT-GRAPH-CLIENT-SECRET");

    CkOAuth2_putCodeChallenge(oauth2,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
    CkOAuth2_putScope(oauth2,"openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite");

    // Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
    url = CkOAuth2_startAuth(oauth2);
    if (CkOAuth2_getLastMethodSuccess(oauth2) != TRUE) {
        printf("%s\n",CkOAuth2_lastErrorText(oauth2));
        CkSocket_Dispose(socket);
        CkOAuth2_Dispose(oauth2);
        return;
    }

    // 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 30 seconds.
    numMsWaited = 0;
    while ((numMsWaited < 30000) && (CkOAuth2_getAuthFlowState(oauth2) < 3)) {
        CkOAuth2_SleepMs(oauth2,100);
        numMsWaited = numMsWaited + 100;
    }

    // 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 (CkOAuth2_getAuthFlowState(oauth2) < 3) {
        CkOAuth2_Cancel(oauth2);
        printf("No response from the browser!\n");
        CkSocket_Dispose(socket);
        CkOAuth2_Dispose(oauth2);
        return;
    }

    // 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_getAuthFlowState(oauth2) == 5) {
        printf("OAuth2 failed to complete.\n");
        printf("%s\n",CkOAuth2_failureInfo(oauth2));
        CkSocket_Dispose(socket);
        CkOAuth2_Dispose(oauth2);
        return;
    }

    if (CkOAuth2_getAuthFlowState(oauth2) == 4) {
        printf("OAuth2 authorization was denied.\n");
        printf("%s\n",CkOAuth2_accessTokenResponse(oauth2));
        CkSocket_Dispose(socket);
        CkOAuth2_Dispose(oauth2);
        return;
    }

    if (CkOAuth2_getAuthFlowState(oauth2) != 3) {
        printf("Unexpected AuthFlowState:%d\n",CkOAuth2_getAuthFlowState(oauth2));
        CkSocket_Dispose(socket);
        CkOAuth2_Dispose(oauth2);
        return;
    }

    printf("OAuth2 authorization granted!\n");
    printf("Access Token = %s\n",CkOAuth2_accessToken(oauth2));

    // Get the full JSON response:
    json = CkJsonObject_Create();
    CkJsonObject_Load(json,CkOAuth2_accessTokenResponse(oauth2));
    CkJsonObject_putEmitCompact(json,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 (CkJsonObject_HasMember(json,"expires_on") != TRUE) {
        dtExpire = CkDateTime_Create();
        CkDateTime_SetFromCurrentSystemTime(dtExpire);
        CkDateTime_AddSeconds(dtExpire,CkJsonObject_IntOf(json,"expires_in"));
        CkJsonObject_AppendString(json,"expires_on",CkDateTime_getAsUnixTimeStr(dtExpire,FALSE));
    }

    printf("%s\n",CkJsonObject_emit(json));

    // Save the JSON to a file for future requests.
    fac = CkFileAccess_Create();
    CkFileAccess_WriteEntireTextFile(fac,"qa_data/tokens/microsoftGraph.json",CkJsonObject_emit(json),"utf-8",FALSE);


    CkSocket_Dispose(socket);
    CkOAuth2_Dispose(oauth2);
    CkJsonObject_Dispose(json);
    CkDateTime_Dispose(dtExpire);
    CkFileAccess_Dispose(fac);

    }