Set Doc Info Metadata

This guide will explain the process of setting docinfo metadata step by step.

Before you begin #

First of all you should get your API key from your UniCloud account.

If this is your first time using UniPDF SDK, follow this guide to set up a local development environment.

Project setup #

Clone the project repository #

In your terminal, clone examples repository. It contains the Go code we will be using for this guide.

git clone https://github.com/unidoc/unipdf-examples.git

Navigate to the metadata folder in the unipdf-examples directory.

cd unipdf-examples/metadata

Configure environment variables #

Replace the UNIDOC_LICENSE_API_KEY with your API credentials from your UniCloud account.

Linux/Mac #

export UNIDOC_LICENSE_API_KEY=PUT_YOUR_API_KEY_HERE

Windows #

set UNIDOC_LICENSE_API_KEY=PUT_YOUR_API_KEY_HERE

How it works #

The import section in lines 10-17 imports unipdf packages and other necessary libraries. The init function loads your metered License API key and authenticates your library request.

In lines 28-84 the main function is defined. Here in lines 29-33 the number of command lines arguments is checked. The document’s author is set in lines 35-36. In lines 38-48 a new model.PdfReader is constructed.

In lines 51-53 a new ReaderToWriterOpts is initialized and the SkipInfo attribute is set to true to avoid copying document info. In lines 56-60 a new model.PdfWriter is initialized from the model.PdfReader using pdfReader.ToWriter(opt) method.

In line 65 a copy of the defaultPdfWriter is set to customPdfWriter for later use with custom document info. The content of the defaultPdfWriter is written to file in line 65-69. In lines 72-77 a custom info is added to the writer using customPdfWriter. Finally in lines 79-83 the document is written to a file.

Run the code #

go run pdf_metadata_set_docinfo.go <input.pdf>