78 lines
2.7 KiB
Rust
78 lines
2.7 KiB
Rust
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//! PDF text extraction.
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//!
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//! Primary path: [`pdf_extract::extract_text`], which handles most modern PDFs
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//! and is simple to call. It can panic or hard-error on malformed files; any
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//! failure is surfaced to the caller and marks the file's content state as
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//! failed. Properties (title, author, etc.) from the PDF `Info` dictionary
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//! are pulled via `lopdf` where available.
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use std::path::Path;
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use lopdf::{Document as LopdfDocument, Object};
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use super::{ExtractError, ExtractedContent, Extractor};
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pub struct PdfExtractor;
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impl Extractor for PdfExtractor {
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fn supports(&self, mime: &str) -> bool {
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mime == "application/pdf"
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}
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fn extract(&self, path: &Path) -> Result<ExtractedContent, ExtractError> {
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// Text. Catch panics from pdf_extract (some PDFs crash its parser).
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let path_buf = path.to_path_buf();
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let text = std::panic::catch_unwind(move || pdf_extract::extract_text(&path_buf))
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.map_err(|_| "pdf_extract panicked".to_string())?
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.map_err(|e| format!("pdf_extract: {}", e))?;
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let mut out = ExtractedContent::with_text(text);
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// Info dictionary via lopdf. Soft-fail: if lopdf can't open the file
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// we still return the text.
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if let Ok(doc) = LopdfDocument::load(path) {
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if let Ok(info_ref) = doc.trailer.get(b"Info") {
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if let Ok(info_id) = info_ref.as_reference() {
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if let Ok(info) = doc.get_object(info_id) {
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if let Ok(dict) = info.as_dict() {
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for key in ["Title", "Author", "Subject", "Keywords", "Creator", "Producer"] {
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if let Ok(val) = dict.get(key.as_bytes()) {
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if let Some(s) = object_to_string(val) {
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if !s.is_empty() {
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out.properties.insert(key.to_ascii_lowercase(), s);
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}
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}
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}
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}
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}
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}
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}
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}
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}
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Ok(out)
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}
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}
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fn object_to_string(obj: &Object) -> Option<String> {
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match obj {
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Object::String(bytes, _) => {
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// Try UTF-8; fall back to lossy decoding.
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Some(String::from_utf8_lossy(bytes).into_owned())
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}
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Object::Name(bytes) => Some(String::from_utf8_lossy(bytes).into_owned()),
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_ => None,
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn supports_pdf_mime() {
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assert!(PdfExtractor.supports("application/pdf"));
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assert!(!PdfExtractor.supports("application/zip"));
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}
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}
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