Reading/Writing Additional Metadata in Mako

📌 Overview

This article addresses issues regarding the retrieval and modification of additional metadata in documents using Mako.

Issue Description

For certain documents, Acrobat displays metadata such as:

• Copyright information (Status, Notice and Info URL)

• “Description Writer”

• “Fast Web View”

The customer wanted to know if these are directly accessible or modifiable using Mako's current capabilities.

💡 Solution

To retrieve and modify metadata using Mako, follow these steps:

1. Accessing Metadata

   • Use the Mako SDK to parse the document and access the metadata section.

   • Implement custom functions to extract specific metadata fields.

2. Modifying Metadata

   • Once the metadata is accessed, use Mako's API to modify the fields as required.

   • Ensure that changes are saved back to the document correctly.

3. Exceptional cases: Edit XMP packet

   • Some metadata fields may not be available using Mako’s APIs, See the table below for what properties are accessible with Mako.

   • In this case you will need update the XMP packet using a third party library

🗺️ Metadata Property Mapping

⌨️ Sample Code

Below is a sample code snippet to get you started with accessing and modifying metadata. There is a longer example on our GitHub, MakoPDFMetadata.cpp, which makes use of these APIs, and also shows how to retrieve and edit the XMP data. To parse the XML in the XMP packet, you will need an XML library.

const auto mako = IJawsMako::create();
mako->enableAllFeatures(mako);
const auto assembly = IInput::create(mako, eFFPDF)->open("path/to/your/document.pdf");

// Get Metadata
auto metadata = assembly->getJobMetadata();
PValue pVal;
metadata->getProperty(IDOMMetadata::eDocumentInfo, "Title", pVal);
auto titleString = pVal.getString();
std::wcout << "The title of this PDF is: " << titleString << '
';

// Set Metadata
metadata->setProperty(IDOMMetadata::eDocumentInfo, "Title", PValue("New title for this PDF"));

// Check if metadata is null and create if necessary
if (metadata == nullptr)
{
    metadata = IDOMMetadata::create(mako); 
    metadata->setProperty(IDOMMetadata::eDocumentInfo, "Title", PValue("New title for this PDF"));
    assembly->setJobMetadata(metadata);
}

☑️ Conclusion

While Mako provides robust tools for document manipulation, accessing and modifying certain metadata fields may require additional custom development. For further assistance, please contact Mako support.

📚 Additional Resources

If you need additional help, see our API documentation for detailed information on class/method usage, or raise a support ticket via our customer portal.

• MakoPDFMetadata.cpp

• Mako API Documentation

• Contact Mako Support