Zig

Google Photos OAuth2 Access Token

See more Google Photos Examples

Demonstrates how to get a Google Photos 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();

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

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

    // For Google OAuth2, set the listen port equal to the port used
    // in the Authorized Redirect URL for the Client ID.
    // For example, in this case the Authorized Redirect URL would be http://localhost:3017/
    // Your app should choose a port not likely not used by any other application.
    oauth2.setListenPort(3017);

    oauth2.setAuthorizationEndpoint("https://accounts.google.com/o/oauth2/v2/auth");
    oauth2.setTokenEndpoint("https://www.googleapis.com/oauth2/v4/token");

    // Replace these with actual values.
    oauth2.setClientId("GOOGLE-CLIENT-ID");
    oauth2.setClientSecret("GOOGLE-CLIENT-SECRET");

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

    // This is a scope for Google Photos.  See https://developers.google.com/photos/library/guides/authentication-authorization
    // This scope provides read/write access but not sharing.
    oauth2.setScope("https://www.googleapis.com/auth/photoslibrary");

    // Begin the OAuth2 three-legged 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 system's default browser navigated to the URL.
    oauth2.launchBrowser(url) catch {
        std.debug.print("{s}\n", .{try oauth2.getLastErrorText(alloc)});
        return;
    };

    // Now wait for the authorization.
    // We'll wait for a max of 120 seconds.
    var num_ms_waited: i32 = 0;
    while ((num_ms_waited < 120000) and (oauth2.getAuthFlowState() < 3)) {
        oauth2.sleepMs(100);
        num_ms_waited = num_ms_waited + 100;
    }

    // If there was no response from the browser within 120 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 (oauth2.getAuthFlowState() < 3) {
        oauth2.cancel() catch {};
        std.debug.print("No response from the browser!\n", .{});
        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 (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;
    }

    // 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/googlePhotos.json", "utf-8", false) catch {};

    // The saved JSON response looks like this:
    // {
    //   "access_token": "ya29.GlamBqWR6cp8lEfJMmTHVEua45912XLKoq4djyHl_Z3CEIzsPLIZkJSGie5oOrbaggy1rjJHn1zW5bjqSesGr5MEYIp9Hx-0CuvjVYf8srg2jeaDMwMACvzemp43",
    //   "expires_in": 3600,
    //   "refresh_token": "1/rl6k16nysDl9Bp1EhRH9F1WyRIoiSQAvko49Z4yY694MT5V1QXLj2ibNZGaRgek0",
    //   "scope": "https://www.googleapis.com/auth/photoslibrary",
    //   "token_type": "Bearer"
    // }

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