`pdf_metadata`

Extract metadata from a PDF file (document info dictionary + page count).

Parameters

pathstringone of path or source_key: PDF file path
source_keystringone of path or source_key: Context key containing a file path, artifact URI, or artifact descriptor
output_keystringdefault "metadata": Prefix for output key

Providing both path and source_key is an error. Artifact inputs are opened and SHA-256 verified inside the tracked blocking worker; PDF parsing consumes that same rewound handle rather than a resolved store pathname.

Resource contract

The source must be a regular file and is capped by IRONFLOW_MAX_PDF_BYTES (default 100 MiB) before and while it is read; a file that grows after the initial metadata check cannot cross the limit. On Unix and Windows the final path component may not be a symlink/reparse point. Loading and metadata traversal run on a tracked blocking worker with cancellation checkpoints around and during input reads. lopdf still constructs its document object model in memory, so the byte ceiling bounds raw input rather than promising that parser RSS equals file size.

Shared PDF loading additionally enforces IRONFLOW_MAX_PDF_DECOMPRESSED_STREAM_BYTES (64 MiB) per object/cross-reference stream and IRONFLOW_MAX_PDF_OBJECTS (250000) after parsing. Strict loading and bounded recovery checks reject oversized streams instead of returning partial metadata. These are independent limits, not a cumulative memory ceiling.

Context Output

<output_key> — object containing metadata:
- pages — page count
- title, author, subject, keywords, creator, producer, created, modified when present

Example

local flow = Flow.new("pdf_metadata_demo")

flow:step("meta", nodes.pdf_metadata({
    path = "examples/fixtures/ironflow-sample.pdf",
    output_key = "pdf_meta"
}))

-- Interpolation does not evaluate fallback expressions, so normalize the
-- optional field in an explicit workflow step.
flow:step("metadata_defaults", function(ctx)
    return {
        pdf_creator = ctx.pdf_meta.creator or "unknown"
    }
end):depends_on("meta")

flow:step("log", nodes.log({
    message = "PDF has ${ctx.pdf_meta.pages} page(s), produced by ${ctx.pdf_creator}"
})):depends_on("metadata_defaults")

return flow