Zig

Get Google Cloud Storage Access Token using Service Account JSON Private Key

See more Google Cloud Storage Examples

Demonstrates how to get a Google Cloud Storage access token using a JSON service account private key. Obtaining an access token for a service account requires no user interaction (it does not require a browser, nor callback URI's, etc.).

When an access token expires, an application can be (and should be) designed to automatically fetch a new access token.

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.

    // First load the JSON key into a string.
    const fac = try chilkat.FileAccess.init();
    defer fac.deinit();
    const json_key = fac.readEntireTextFile(alloc, "qa_data/googleApi/ChilkatCloud-13a07a2e8b3f.json", "utf-8") catch {
        std.debug.print("{s}\n", .{try fac.getLastErrorText(alloc)});
        return;
    };

    // A JSON private key should look something like this:

    //     {
    //       "type": "service_account",
    //       "project_id": "chilkattest-1350",
    //       "private_key_id": "fa2e36ee26986eab628b59868af8bec1d1c64c38",
    //       "private_key": "-----BEGIN PRIVATE KEY-----\nMIIEvgIjFa...28N64N2n1E4FYzBZjSdy\n-----END PRIVATE KEY-----\n",
    //       "client_email": "598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a@developer.gserviceaccount.com",
    //       "client_id": "598922945226-00rb0ppfg0snd9jo7bhvd4v17jtj2d3a.apps.googleusercontent.com",
    //       "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    //       "token_uri": "https://accounts.google.com/o/oauth2/token",
    //       "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
    //       "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a%40developer.gserviceaccount.com"
    //     }

    const g_auth = try chilkat.AuthGoogle.init();
    defer g_auth.deinit();
    g_auth.setJsonKey(json_key);

    // Choose a scope.
    g_auth.setScope("https://www.googleapis.com/auth/cloud-platform");

    // Request an access token that is valid for this many seconds.
    g_auth.setExpireNumSeconds(3600);

    // If the application is requesting delegated access:
    // The email address of the user for which the application is requesting delegated access,
    // then set the email address here. (Otherwise leave it empty.)
    g_auth.setSubEmailAddress("");

    // Connect to www.googleapis.com using TLS (TLS 1.2 is the default.)
    // The Chilkat socket object is used so that the connection can be established
    // through proxies or an SSH tunnel if desired.
    const tls_sock = try chilkat.Socket.init();
    defer tls_sock.deinit();
    tls_sock.connect("www.googleapis.com", 443, true, 5000) catch {
        std.debug.print("{s}\n", .{try tls_sock.getLastErrorText(alloc)});
        return;
    };

    // Send the request to obtain the access token.
    g_auth.obtainAccessToken(tls_sock) catch {
        std.debug.print("{s}\n", .{try g_auth.getLastErrorText(alloc)});
        return;
    };

    // Examine the access token:
    std.debug.print("Access Token: {s}\n", .{try g_auth.getAccessToken(alloc)});

    // We're going to save this access token to a file to be used
    // by other examples.
    const sb_token = try chilkat.StringBuilder.init();
    defer sb_token.deinit();
    sb_token.append(try g_auth.getAccessToken(alloc)) catch {};
    sb_token.writeFile("qa_data/tokens/googleCloudStorageAccessToken.txt", "utf-8", false) catch {};
}