Java

Download GMail Message Attachment by ID

See more GMail REST API Examples

Demonstrates how to download a GMail email attachment by the attachment ID. Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Http;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Http http = new Http();

        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".
        String attachmentId = "ANGjdJ-oy3aCuZISJKLAhUdaEksCEklbAPyMaWzFgqOMGbPCRkgwgeu_Kttd99C17OBTHROkDZGekibTKWXGfscB5ww7fw4E65_V1dQ-jHhb2TD1Cdm58-BbNw2iDxzptco8iILPiSnLLfFn5Ps7nsRcxHaGTt3r0yqFKCuIYNnPK1vM04BXI_cfzo-HnI4I3tD6oHNHOGVQrL01MdShFQjPELPUjXM8z1qs7Kom-QyvV1iOldUN-66UuhynsmDX-CMM5TIdB-8KD_lmdhf-0DqG8JnCA20XpXyfqwS8XFkPA-t-QSjb7SdkHQFtQ4lz2PcBREFzZ2eI5j0l0Y_dQHRPYTeMwkVl1yl4MfFT4C4iso3VSF-eqaIjiFCbXKCFNyeEIW5WFsv189dhlSqU";

        String messageId = "1712bc1dc22da2a2";

        http.setUrlVar("messageId", messageId);
        http.setUrlVar("attachmentId", attachmentId);

        String 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=="
        // }

        String outputFilePath = "qa_output/helloWorld.pdf";

        // Download into a StringBuilder.
        StringBuilder sbJson = new StringBuilder();
        try {
            http.downloadSb(url, "utf-8", sbJson);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        if (http.getLastStatus() != 200) {
            // Something failed.
            // the JSON contains an error message.
            System.out.println(sbJson.getAsString());
            return;
        }

        // Load into a Chilkat JSON object.
        JsonObject json = new JsonObject();
        json.loadSb(sbJson);

        // Extract the base64url data into a BinData.
        BinData bd = new BinData();
        json.bytesOf("data", "base64url", bd);

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

        System.out.println("Success.");
    }
}