Zig

Download GMail Message Attachment by ID

See more GMail REST API Examples

Demonstrates how to download a GMail email attachment by the attachment ID. 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 http = try chilkat.Http.init();
    defer http.deinit();

    http.setAuthToken("ACCESS_TOKEN");
    http.setAccept("application/json");

    // See the following example:  Get GMail Message (format=full)
    // It shows how to download an email by message ID, and it shows how to parse the JSON
    // response which includes attachment names, ids, and other information.

    // This example will assume we already have the attachment id and filename.

    // This is the attachment ID for a file named "helloWorld.pdf".
    const attachment_id = "ANGjdJ-oy3aCuZISJKLAhUdaEksCEklbAPyMaWzFgqOMGbPCRkgwgeu_Kttd99C17OBTHROkDZGekibTKWXGfscB5ww7fw4E65_V1dQ-jHhb2TD1Cdm58-BbNw2iDxzptco8iILPiSnLLfFn5Ps7nsRcxHaGTt3r0yqFKCuIYNnPK1vM04BXI_cfzo-HnI4I3tD6oHNHOGVQrL01MdShFQjPELPUjXM8z1qs7Kom-QyvV1iOldUN-66UuhynsmDX-CMM5TIdB-8KD_lmdhf-0DqG8JnCA20XpXyfqwS8XFkPA-t-QSjb7SdkHQFtQ4lz2PcBREFzZ2eI5j0l0Y_dQHRPYTeMwkVl1yl4MfFT4C4iso3VSF-eqaIjiFCbXKCFNyeEIW5WFsv189dhlSqU";

    const message_id = "1712bc1dc22da2a2";

    http.setUrlVar("messageId", message_id) catch {};
    http.setUrlVar("attachmentId", attachment_id) catch {};

    const url = "https://www.googleapis.com/gmail/v1/users/userId/messages/{$messageId}/attachments/{$attachmentId}";

    // When we download, the response is JSON that contains the attachment data base64url encoded, like this:
    // {
    //  "size": 934,
    //  "data": "JVBERi0xLjM ... CiUlRU9GCg=="
    // }

    // Download into a StringBuilder.
    const sb_json = try chilkat.StringBuilder.init();
    defer sb_json.deinit();
    http.downloadSb(url, "utf-8", sb_json) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    if (http.getLastStatus() != 200) {
        // Something failed.
        // the JSON contains an error message.
        std.debug.print("{s}\n", .{try sb_json.getAsString(alloc)});
        return;
    }

    // Load into a Chilkat JSON object.
    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    try json.loadSb(sb_json);

    // Extract the base64url data into a BinData.
    const bd = try chilkat.BinData.init();
    defer bd.deinit();
    try json.bytesOf("data", "base64url", bd);

    // Save the data to a file.
    try bd.writeFile("qa_output/helloWorld.pdf");

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