Add epub extractor

crates/pile-dataset/src/extract/epub/epub_meta.rs

@@ -0,0 +1,76 @@
+use epub::doc::EpubDoc;
+use pile_config::Label;
+use std::{collections::HashMap, io::Cursor, sync::OnceLock};
+use tracing::debug;
+
+use crate::{Item, PileValue, extract::Extractor};
+
+pub struct EpubMetaExtractor<'a> {
+	item: &'a Item,
+	output: OnceLock<HashMap<Label, PileValue<'a>>>,
+}
+
+impl<'a> EpubMetaExtractor<'a> {
+	pub fn new(item: &'a Item) -> Self {
+		Self {
+			item,
+			output: OnceLock::new(),
+		}
+	}
+
+	async fn get_inner(&self) -> Result<&HashMap<Label, PileValue<'a>>, std::io::Error> {
+		if let Some(x) = self.output.get() {
+			return Ok(x);
+		}
+
+		let bytes = self.item.read().await?.read_to_end().await?;
+
+		let cursor = Cursor::new(bytes);
+		let doc = match EpubDoc::from_reader(cursor) {
+			Ok(x) => x,
+			Err(error) => {
+				debug!(message = "Could not process epub", ?error, key = ?self.item.key());
+				return Ok(self.output.get_or_init(HashMap::new));
+			}
+		};
+
+		let mut output: HashMap<Label, PileValue<'a>> = HashMap::new();
+
+		let fields = &[
+			"title",
+			"creator",
+			"description",
+			"language",
+			"publisher",
+			"date",
+			"subject",
+			"identifier",
+		];
+
+		#[expect(clippy::unwrap_used)]
+		for key in fields {
+			let label = Label::new(*key).unwrap();
+			let value = match doc.mdata(key) {
+				Some(s) => PileValue::String(s.into()),
+				None => PileValue::Null,
+			};
+			output.insert(label, value);
+		}
+
+		return Ok(self.output.get_or_init(|| output));
+	}
+}
+
+#[async_trait::async_trait]
+impl Extractor for EpubMetaExtractor<'_> {
+	async fn field<'a>(
+		&'a self,
+		name: &Label,
+	) -> Result<Option<&'a PileValue<'a>>, std::io::Error> {
+		Ok(self.get_inner().await?.get(name))
+	}
+
+	async fn fields(&self) -> Result<Vec<Label>, std::io::Error> {
+		Ok(self.get_inner().await?.keys().cloned().collect())
+	}
+}

crates/pile-dataset/src/extract/epub/epub_text.rs

@@ -0,0 +1,88 @@
+use epub::doc::EpubDoc;
+use pile_config::Label;
+use std::{collections::HashMap, io::Cursor, sync::OnceLock};
+use tracing::debug;
+
+use crate::{Item, PileValue, extract::Extractor};
+
+pub struct EpubTextExtractor<'a> {
+	item: &'a Item,
+	output: OnceLock<HashMap<Label, PileValue<'a>>>,
+}
+
+impl<'a> EpubTextExtractor<'a> {
+	pub fn new(item: &'a Item) -> Self {
+		Self {
+			item,
+			output: OnceLock::new(),
+		}
+	}
+
+	async fn get_inner(&self) -> Result<&HashMap<Label, PileValue<'a>>, std::io::Error> {
+		if let Some(x) = self.output.get() {
+			return Ok(x);
+		}
+
+		let bytes = self.item.read().await?.read_to_end().await?;
+
+		let cursor = Cursor::new(bytes);
+		let mut doc = match EpubDoc::from_reader(cursor) {
+			Ok(x) => x,
+			Err(error) => {
+				debug!(message = "Could not process epub", ?error, key = ?self.item.key());
+				return Ok(self.output.get_or_init(HashMap::new));
+			}
+		};
+
+		let mut text_parts: Vec<String> = Vec::new();
+
+		loop {
+			if let Ok(content) = doc.get_current_str() {
+				text_parts.push(strip_html(&content));
+			}
+			if doc.go_next().is_err() {
+				break;
+			}
+		}
+
+		let text = text_parts.join(" ");
+
+		#[expect(clippy::unwrap_used)]
+		let output = HashMap::from([(Label::new("text").unwrap(), PileValue::String(text.into()))]);
+
+		let _ = self.output.set(output);
+		#[expect(clippy::unwrap_used)]
+		return Ok(self.output.get().unwrap());
+	}
+}
+
+/// Strip HTML/XHTML tags from a string, leaving only text nodes.
+fn strip_html(html: &str) -> String {
+	let mut result = String::with_capacity(html.len());
+	let mut in_tag = false;
+
+	for c in html.chars() {
+		match c {
+			'<' => in_tag = true,
+			'>' => in_tag = false,
+			_ if !in_tag => result.push(c),
+			_ => {}
+		}
+	}
+
+	result
+}
+
+#[async_trait::async_trait]
+impl Extractor for EpubTextExtractor<'_> {
+	async fn field<'a>(
+		&'a self,
+		name: &Label,
+	) -> Result<Option<&'a PileValue<'a>>, std::io::Error> {
+		Ok(self.get_inner().await?.get(name))
+	}
+
+	async fn fields(&self) -> Result<Vec<Label>, std::io::Error> {
+		Ok(self.get_inner().await?.keys().cloned().collect())
+	}
+}

crates/pile-dataset/src/extract/epub/mod.rs

@@ -0,0 +1,63 @@
+use pile_config::Label;
+use std::{collections::HashMap, sync::Arc};
+
+mod epub_meta;
+pub use epub_meta::*;
+
+mod epub_text;
+pub use epub_text::*;
+
+use crate::{
+	Item, PileValue,
+	extract::{Extractor, MapExtractor},
+};
+
+pub struct EpubExtractor<'a> {
+	inner: MapExtractor<'a>,
+}
+
+impl<'a> EpubExtractor<'a> {
+	#[expect(clippy::unwrap_used)]
+	pub fn new(item: &'a Item) -> Self {
+		let inner = MapExtractor {
+			inner: HashMap::from([
+				(
+					Label::new("text").unwrap(),
+					PileValue::Extractor(Arc::new(EpubTextExtractor::new(item))),
+				),
+				(
+					Label::new("meta").unwrap(),
+					PileValue::Extractor(Arc::new(EpubMetaExtractor::new(item))),
+				),
+			]),
+		};
+
+		Self { inner }
+	}
+}
+
+#[async_trait::async_trait]
+impl Extractor for EpubExtractor<'_> {
+	async fn field<'a>(
+		&'a self,
+		name: &pile_config::Label,
+	) -> Result<Option<&'a PileValue<'a>>, std::io::Error> {
+		#[expect(clippy::unwrap_used)]
+		if name.as_str() == "text" {
+			match self.inner.inner.get(name).unwrap() {
+				PileValue::Extractor(x) => return x.field(name).await,
+				_ => unreachable!(),
+			};
+		}
+
+		self.inner.field(name).await
+	}
+
+	#[expect(clippy::unwrap_used)]
+	async fn fields(&self) -> Result<Vec<Label>, std::io::Error> {
+		Ok(vec![
+			Label::new("text").unwrap(),
+			Label::new("meta").unwrap(),
+		])
+	}
+}

crates/pile-dataset/src/extract/mod.rs

@@ -10,6 +10,9 @@ pub use id3::*;
 mod fs;
 pub use fs::*;
 
+mod epub;
+pub use epub::*;
+
 mod pdf;
 pub use pdf::*;
 
@@ -69,6 +72,10 @@ impl<'a> MetaExtractor<'a> {
 					Label::new("fs").unwrap(),
 					crate::PileValue::Extractor(Arc::new(FsExtractor::new(item))),
 				),
+				(
+					Label::new("epub").unwrap(),
+					crate::PileValue::Extractor(Arc::new(EpubExtractor::new(item))),
+				),
 				(
 					Label::new("pdf").unwrap(),
 					crate::PileValue::Extractor(Arc::new(PdfExtractor::new(item))),
@@ -103,6 +110,7 @@ impl Extractor for MetaExtractor<'_> {
 			Label::new("flac").unwrap(),
 			Label::new("id3").unwrap(),
 			Label::new("fs").unwrap(),
+			Label::new("epub").unwrap(),
 			Label::new("pdf").unwrap(),
 			Label::new("sidecar").unwrap(),
 		]);