Zig Requires Chilkat v10.1.2+

Dropbox: OAuth2 Authorization to Obtain an Access Token

See more Dropbox Examples

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

This example runs the OAuth 2.0 authorization flow that lets the user sign in to Dropbox and authorize your app.

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();

    // The port should match the Authorized Redirect URL in your Dropbox app,
    // which would look like "http://localhost:3017/"
    oauth2.setListenPort(3017);

    // IMPORTANT: One of the OAuth2 redirect URIs for your Dropbox app must be
    // exactly this string:  http://localhost:3017/

    oauth2.setAuthorizationEndpoint("https://www.dropbox.com/oauth2/authorize");
    oauth2.setTokenEndpoint("https://api.dropboxapi.com/oauth2/token");

    // Replace this with your actual Dropbox App Key
    oauth2.setClientId("DROPBOX_APP_KEY");

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

    // Add token_access_type=offline to also get a refresh token in the response
    oauth2.addAuthQueryParam("token_access_type", "offline") catch {};

    // 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", .{});

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.load(try oauth2.getAccessTokenResponse(alloc)) catch {};
    json.setEmitCompact(false);

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

    // A sample access token response:

    // {
    //   "access_token": "...",
    //   "token_type": "bearer",
    //   "expires_in": 14399,
    //   "refresh_token": "...",
    //   "scope": "account_info.read",
    //   "uid": "562542581",
    //   "account_id": "dbid:AACQhDS0E3_Vb72Ynd0F-GxGWdTI2qcTHzA"
    // }

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

    // Save the JSON access token response to a file for subsequent use..
    json.writeFile("qa_data/tokens/dropbox.json") catch {};
}