How-to guides/Metadata

Read PDF metadata fields in Rust

Read standard document information fields and XMP metadata from any PDF. Covers title, author, creation date, subject, and custom XMP properties.

rust
use pdfluent::PdfDocument;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let doc = PdfDocument::open("document.pdf")?;
    let meta = doc.metadata()?;

    println!("Title:   {}", meta.title.as_deref().unwrap_or("(none)"));
    println!("Author:  {}", meta.author.as_deref().unwrap_or("(none)"));
    println!("Created: {:?}", meta.creation_date);
    Ok(())
}
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Step by step

1

Open the PDF

Open the document. Metadata is read from the Info dictionary, which is loaded during the initial parse.

rust
use pdfluent::PdfDocument;

let doc = PdfDocument::open("report.pdf")?;
2

Read standard Info dictionary fields

Call doc.metadata() to get a PdfMetadata struct. All standard fields are Option<String> because they may not be present in every PDF.

rust
let meta = doc.metadata()?;

println!("Title:    {}", meta.title.as_deref().unwrap_or(""));
println!("Author:   {}", meta.author.as_deref().unwrap_or(""));
println!("Subject:  {}", meta.subject.as_deref().unwrap_or(""));
println!("Keywords: {}", meta.keywords.as_deref().unwrap_or(""));
println!("Creator:  {}", meta.creator.as_deref().unwrap_or(""));
println!("Producer: {}", meta.producer.as_deref().unwrap_or(""));
3

Read creation and modification dates

Dates in the Info dictionary are stored as PDF date strings. PDFluent parses them into chrono::DateTime<FixedOffset> values.

rust
if let Some(created) = meta.creation_date {
    println!("Created: {}", created.format("%Y-%m-%d %H:%M:%S %Z"));
}
if let Some(modified) = meta.modification_date {
    println!("Modified: {}", modified.format("%Y-%m-%d %H:%M:%S %Z"));
}
4

Read XMP metadata

If the PDF has an XMP metadata stream, access it via doc.xmp_metadata(). This returns the raw XMP XML string.

rust
if let Some(xmp) = doc.xmp_metadata()? {
    println!("XMP length: {} bytes", xmp.len());
    // Parse with your preferred XML library
    println!("{}", &xmp[..xmp.len().min(500)]);
}
5

Read custom metadata properties

The Info dictionary may contain non-standard keys added by the authoring tool. Access them via meta.custom.

rust
for (key, value) in &meta.custom {
    println!("Custom[{}] = {}", key, value);
}

Notes and tips

  • Standard field names are case-sensitive in the PDF spec. PDFluent reads them by their canonical names.
  • If a PDF has both an Info dictionary and an XMP stream, the XMP values take precedence for display in PDF viewers.
  • Some tools write malformed date strings. PDFluent returns None for unparseable dates rather than returning an error.

Why PDFluent for this

Pure Rust

No JVM, no runtime, no DLL dependencies. Ships as a single native binary or WASM module.

Memory safe

Rust's ownership model prevents buffer overflows and use-after-free. No segfaults in PDF parsing.

Runs anywhere

Same code runs server-side, in Docker, on AWS Lambda, on Cloudflare Workers, or in the browser via WASM.

Frequently asked questions

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