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Annotation.Biorxiv

Scrapes metadata from bioRxiv and medRxiv preprint pages using Dublin Core meta tags

Pathbuild/Annotation/Biorxiv.hs
LanguageHaskell
Lines59
Sourcebuild/Annotation/Biorxiv.hs
at 406d3e423

Read this when Use this page when tracing the Haskell build pipeline, generators, metadata code, or backend utility behavior around Annotation.Biorxiv.

Overview​

This module extracts bibliographic metadata from bioRxiv and medRxiv preprint pages. Both preprint servers share the same codebase and embed Dublin Core metadata in HTML <meta> tags, which this module parses using TagSoup after fetching the page via curl.

The scraper extracts title, authors, date, DOI, and abstract from the HTML. It handles several bioRxiv-specific quirks: broken quote encoding in abstracts (stray 9s -> s), and two different tag formats for abstracts (citation_abstract vs DC.Description). The extracted abstract is cleaned and optionally split into paragraphs by the LLM-based paragraphizer.

This module is one of several domain-specific scrapers under Annotation/ that feed into the central Annotation.linkDispatcher routing system.

Public API​

biorxiv :: Metadata -> Path -> IO (Either Failure (Path, MetadataItem))​

Main entry point. Fetches and parses a bioRxiv/medRxiv URL, returning structured metadata.

biorxiv md "https://www.biorxiv.org/content/10.1101/2020.04.03.024554.full"
-- → Right ("https://www.biorxiv.org/content/...", ("Title", "Authors", "2020-04-03", "", [("doi","10.1101/...")], [], "<p>Abstract...</p>"))

Called by: Annotation.linkDispatcherURL (when URL matches https://www.biorxiv.org/content/ or https://www.medrxiv.org/content/)

Calls:

  • runShellCommand — curl fetch
  • parseTags — HTML parsing
  • cleanAuthors — author name normalization
  • processDOI — DOI cleanup
  • cleanAbstractsHTML — abstract HTML cleanup
  • processParagraphizer — LLM-based paragraph splitting

Returns:

  • Right (url, MetadataItem) — success with 7-tuple: (title, author, date, created, [(key,value)], tags, abstract)
  • Left Permanent — parse failure (title empty)
  • Left Temporary — abstract empty after processing

Internal Architecture​

Data Flow​

URL → curl fetch → TagSoup parse → filter <meta> tags → extract by name attribute → clean/transform → MetadataItem

Key Internal Functions​

parseMetadataTagsoup :: String -> [Tag String] -> [String]​

Extracts values from meta tags where the name attribute matches the key. Returns the content attribute value from the first attribute position.

-- For: <meta name="DC.Title" content="Paper Title">
parseMetadataTagsoup "DC.Title" metas  -- → ["Paper Title"]

parseMetadataTagsoupSecond :: String -> [Tag String] -> [String]​

Similar to above but reads from the second attribute position. Used for citation_abstract which has lang before content.

-- For: <meta name="citation_abstract" lang="en" content="Abstract text">
parseMetadataTagsoupSecond "citation_abstract" metas  -- → ["Abstract text"]

safeKeyList / safeKeyList2​

Low-level extractors that pattern match on TagOpen with attribute lists. Error on malformed tags (partial function).

Dublin Core Tags Extracted​

Meta NameFieldNotes
DC.TitletitleRequired; empty triggers parse failure
DC.ContributorauthorMultiple tags joined with ,
DC.DatedatePublication date
DC.DescriptionabstractFallback if citation_abstract empty
citation_abstractabstractPrimary source (second attr position)
citation_doiDOIStored in key-value list
Key Patterns

PDF URL Short-Circuit​

PDF URLs are immediately returned with empty metadata rather than fetched:

if ".pdf" `isInfixOf` p then return (Right (p, ("", "", "", "", [], [], "")))

This avoids downloading PDFs when the abstract page should be used instead.

Broken Quote Encoding Workaround​

BioRxiv has a known bug producing broken quote encoding in abstracts, leaving a stray 9 before possessive s (e.g., "patient9s"). The code works around this by simply replacing "9s" with "s":

replace "9s" "s"  -- BUG: BioRxiv abstracts have broken quote encoding

This is noted as reported but unfixed for 2+ years.

Fallback Abstract Source​

The scraper tries citation_abstract first (using the second attribute parser), then falls back to DC.Description:

let abstractRaw' = if not (null abstractRaw) then abstractRaw
                   else concat $ parseMetadataTagsoup "DC.Description" metas
Configuration

No direct configuration. Behavior is controlled by:

  • User-Agent: Hardcoded to gwern+biorxivscraping@gwern.net for curl requests
  • Abstract processing: Delegated to cleanAbstractsHTML (config in Config.Metadata.Format)
  • Abstract processing: Delegated to cleanAbstractsHTML and processParagraphizer

Integration Points​

Events / State​

None. Pure scraper with no global state or event system.

Module Dependencies​

Imports:

  • LinkMetadataTypes — Failure, MetadataItem, Path, Metadata types
  • Metadata.Format — checkURL, cleanAbstractsHTML, processDOI
  • Metadata.Author — cleanAuthors
  • Metadata.Format — cleanAbstractsHTML
  • Paragraph — processParagraphizer
  • Utils — printRed, replace

External:

  • curl — fetched via runShellCommand
  • Text.HTML.TagSoup — HTML parsing

URL Routing​

Triggered by Annotation.linkDispatcherURL for URLs matching:

anyPrefix l ["https://www.biorxiv.org/content/", "https://www.medrxiv.org/content/"]

Output Format​

Returns standard MetadataItem 7-tuple:

(title, author, date, "", [("doi", doi)], [], abstract)
--  ^      ^      ^    ^        ^          ^      ^
--  |      |      |    |        |          |      Cleaned HTML with <p> tags
--  |      |      |    |        |          Tags (empty, TODO for ML)
--  |      |      |    |        Key-value pairs
--  |      |      |    Date created (empty, set later)
--  |      |      Publication date
--  |      Comma-separated authors
--  Title string
See Also