Zig

Add File Attachments to a PDF

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Demonstrates how to attach files to a PDF. This is also known as embedding a file within a PDF.

Note: This example requires Chilkat v9.5.0.97 or greater.

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 pdf = try chilkat.Pdf.init();
    defer pdf.deinit();

    // We'll be adding attachments to this PDF file..
    // Note: We are loading the PDF file into memory.  The PDF file is not kept open at this point.
    pdf.loadFile("qa_data/pdf/helloWorld.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    // Note: The ability to attach files to a PDF was added in Chilkat v9.5.0.97

    // Build JSON to provide information about the files to be embedded in the PDF.
    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.setEmitCompact(false);

    var i: i32 = 0;

    // We can attach multiple files in one operation.

    // Here we specify the local relative file path of the 1st file to be embedded.
    json.setI(i);
    json.updateString("files[i].description", "Hello World") catch {};
    json.updateString("files[i].localFilePath", "qa_data/xml/helloWorld.xml") catch {};
    i = i + 1;

    // Specify the 2nd file to be attached.
    json.setI(i);
    json.updateString("files[i].description", "Image of starfish") catch {};
    json.updateString("files[i].localFilePath", "qa_data/jpg/starfish.jpg") catch {};
    // You can explicitly specify the subType (i.e. MIME type) of the file.
    // Otherwise Chilkat will use the default MIME type based on the filename extension.
    // If no default MIME type exists, then "application/octet-stream" is used.
    json.updateString("files[i].subType", "image/jpeg") catch {};
    i = i + 1;

    // You can alternatively provide the file data from base64 encoded data rather than from a local file.
    json.setI(i);
    json.updateString("files[i].description", "Hello World from Data") catch {};
    json.updateString("files[i].fileData", "SGVsbG8gV29ybGQsIEhlbGxvIFdvcmxkLCBIZWxsbyBXb3JsZCwgSGVsbG8gV29ybGQsIEhlbGxvIFdvcmxk") catch {};
    json.updateString("files[i].embeddedFilename", "abc.txt") catch {};
    i = i + 1;

    // By default, the filename used within the PDF is the filename part of the local file path.
    // You can change it by specifying the embeddedFilename.
    json.setI(i);
    json.updateString("files[i].description", "Invoice") catch {};
    json.updateString("files[i].localFilePath", "qa_data/xml/invoice.xml") catch {};
    json.updateString("files[i].embeddedFilename", "invoice_1234.xml") catch {};
    json.updateString("files[i].subType", "application/xml") catch {};

    // The above JSON provides instructions for attaching 4 files to the PDF.
    // Let's attach the files..
    // It is perfectly acceptable to write over the PDF file that was loaded,
    // but in this example we'll write the PDF with attachments to a new PDF file.
    pdf.addEmbeddedFiles(json, "qa_output/helloWorld_withAttachments.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    // You can alternatively write the PDF file with attachments to a Chilkat BinData object..
    const bd = try chilkat.BinData.init();
    defer bd.deinit();
    pdf.addEmbeddedFilesBd(json, bd) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    // Then you can do what you want with the BinData, which contains the binary image of the PDF with attachments.

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