Zig

Download Object from Google Cloud Storage

See more Google Cloud Storage Examples

Demonstrates how to download an object from Google Cloud Storage to a file. 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.

    // This example uses a previously obtained access token having permission for the
    // scope "https://www.googleapis.com/auth/cloud-platform"

    // In this example, Get Google Cloud Storage OAuth2 Access Token,
    // the service account access token was saved to a text file.  This example fetches the access token from the file..
    const sb_token = try chilkat.StringBuilder.init();
    defer sb_token.deinit();
    sb_token.loadFile("qa_data/tokens/googleCloudStorageAccessToken.txt", "utf-8") catch {};

    // Send a GET equivalent to this curl command.

    // curl -X GET \
    //     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
    //     -o "[SAVE_TO_LOCATION]" \
    //     "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/[OBJECT_NAME]?alt=media"

    const http = try chilkat.Http.init();
    defer http.deinit();

    http.setAuthToken(try sb_token.getAsString(alloc));

    // Construct a URL to download an object named "starfish.jpg" from the "chilkat-ocean" bucket.
    http.setUrlVar("bucket_name", "chilkat-ocean") catch {};
    http.setUrlVar("object_name", "starfish.jpg") catch {};
    const url = "https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?alt=media";

    // If there is an error response, then we didn't actually download the file data,
    // but instead we downloaded an error response..
    const file_data = try chilkat.BinData.init();
    defer file_data.deinit();
    http.downloadBd(url, file_data) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    const sb_error_response = try chilkat.StringBuilder.init();
    defer sb_error_response.deinit();
    const response_code = http.getLastStatus();
    if (response_code == 401) {
        std.debug.print("If invalid credentials, then it is likely the access token expired.\n", .{});
        std.debug.print("Your app should automatically fetch a new access token and re-try.\n", .{});
    }

    if (response_code != 200) {
        // Get the error response
        sb_error_response.appendBd(file_data, "utf-8", 0, 0) catch {};
        std.debug.print("Error response code = {d}\n", .{response_code});
        std.debug.print("Error:\n", .{});
        std.debug.print("{s}\n", .{try sb_error_response.getAsString(alloc)});
        return;
    }

    std.debug.print("Success.\n", .{});

    // Save the downloaded data to a file.
    try file_data.writeFile("qa_output/starfish.jpg");
}