Zig Requires Chilkat v10.1.2+

Twinfield OAuth2 for Desktop App or Script

See more OAuth2 Examples

Demonstrates how to get a Twinfield OAuth2 access token from a desktop application or script. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const oauth2 = try chilkat.OAuth2.init();
    defer oauth2.deinit();

    // 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.setListenPort(3017);

    oauth2.setAuthorizationEndpoint("https://login.twinfield.com/auth/authentication/connect/authorize");
    oauth2.setTokenEndpoint("https://login.twinfield.com/auth/authentication/connect/token");

    // Replace these with actual values.
    oauth2.setClientId("CLIENT_ID");
    oauth2.setClientSecret("CLIENT_SECRET");

    oauth2.setScope("openid twf.user twf.organisation twf.organisationUser offline_access");

    oauth2.setCodeChallenge(true);
    oauth2.setCodeChallengeMethod("S256");

    // Twinfield requires that the request to exchange the authorization code for a token must be a GET.
    // (In most cases, OAuth2 is implemented where the exchange for token HTTP request is a POST.)
    // Note: The exchange-for-token happens within Chilkat in a background thread.  After the user interactively
    // accepts or denies authorization, the browser receives the response and redirects to localhost:<port>,
    // where Chilkat is waiting on a background thread to receive the redirect, process it, and then send the HTTP request
    // to exchange the code for a token.  This happens internally while your code below is waiting for the authorization..)
    oauth2.setUncommonOptions("EXCHANGE_CODE_FOR_TOKEN_USING_GET");

    // Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
    const url = oauth2.startAuth(alloc) catch {
        std.debug.print("{s}\n", .{try oauth2.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("url = {s}\n", .{url});

    // Launch the default browser on the system and navigate to the url.
    // The LaunchBrowser method was added in Chilkat v10.1.2.
    oauth2.launchBrowser(url) catch {
        std.debug.print("{s}\n", .{try oauth2.getLastErrorText(alloc)});
        return;
    };

    // Wait for the user to approve or deny authorization in the browser.
    var num_ms_waited: i32 = 0;
    while ((num_ms_waited < 90000) and (oauth2.getAuthFlowState() < 3)) {
        oauth2.sleepMs(100);
        num_ms_waited = num_ms_waited + 100;
    }

    // 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.getAuthFlowState() < 3) {
        oauth2.cancel() catch {};
        std.debug.print("No response from the browser!\n", .{});
        return;
    }

    // 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.getAuthFlowState() == 5) {
        std.debug.print("OAuth2 failed to complete.\n", .{});
        std.debug.print("{s}\n", .{try oauth2.getFailureInfo(alloc)});
        return;
    }

    if (oauth2.getAuthFlowState() == 4) {
        std.debug.print("OAuth2 authorization was denied.\n", .{});
        std.debug.print("{s}\n", .{try oauth2.getAccessTokenResponse(alloc)});
        return;
    }

    if (oauth2.getAuthFlowState() != 3) {
        std.debug.print("Unexpected AuthFlowState:{d}\n", .{oauth2.getAuthFlowState()});
        return;
    }

    std.debug.print("OAuth2 authorization granted!\n", .{});
    std.debug.print("Access Token = {s}\n", .{try oauth2.getAccessToken(alloc)});

    // Get the full JSON response:
    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.load(try oauth2.getAccessTokenResponse(alloc)) catch {};
    json.setEmitCompact(false);

    // The JSON response looks like this:

    std.debug.print("{s}\n", .{try json.emit(alloc)});

    // Save the JSON to a file for future requests.
    const fac = try chilkat.FileAccess.init();
    defer fac.deinit();
    fac.writeEntireTextFile("qa_data/tokens/twinfield.json", try json.emit(alloc), "utf-8", false) catch {};
}