Zig Requires Chilkat v10.1.2+

Shopify OAuth2 Authentication

See more OAuth2 Examples

This example shows how to obtain an initial access token for a Shopify application using OAuth2 authentication specifically for non-web applications. This process requires displaying a browser window to secure user authorization. In contrast, web-based applications use a different method to obtain an OAuth2 token, as they redirect back to the application via a URL. Note: Once you have the access token, all subsequent Chilkat examples that rely on an already-obtained token are applicable to both web and non-web applications. Zig

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

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

    // To further clarify, 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.
    // Make sure that "http://localhost:3017/" is listed in your Whitelisted Redirection URLs for your Shopify app.
    oauth2.setListenPort(3017);

    // The full content of the Authorization Endpoin for Shopify looks like this:
    // https://{shop}.myshopify.com/admin/oauth/authorize?client_id={api_key}&scope={scopes}&redirect_uri={redirect_uri}&state={nonce}&grant_options[]={option}

    // Replace "chilkat" with your shop name.
    oauth2.setAuthorizationEndpoint("https://chilkat.myshopify.com/admin/oauth/authorize");
    oauth2.setTokenEndpoint("https://chilkat.myshopify.com/admin/oauth/access_token");

    // Replace this with your actual API KEY (client ID)
    oauth2.setClientId("SHOPIFY_API_KEY");

    // This is for Require Proof Key for Code Exchange (PKCE)
    // See OAuth2 PKCE Explained
    oauth2.setCodeChallenge(true);
    oauth2.setCodeChallengeMethod("S256");

    // Set requested scopes.  See https://help.shopify.com/api/getting-started/authentication/oauth
    oauth2.setScope("read_product_listings,read_customers,read_orders,read_draft_orders");

    // 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;
    };

    // 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)});

    // Save the full JSON access token response to a file.
    const sb_json = try chilkat.StringBuilder.init();
    defer sb_json.deinit();
    sb_json.append(try oauth2.getAccessTokenResponse(alloc)) catch {};
    sb_json.writeFile("qa_data/tokens/shopify-access-token.json", "utf-8", false) catch {};

    // The saved JSON response looks like this:

    // {
    //   "access_token": "1364e43a5332583188cb27bc85469b1f",
    //   "scope": "read_product_listings,read_customers,read_orders,read_draft_orders"
    // }
}