feat(epub): add EPUB3 generator and zip packager

src-tauri/src/epub.rs

@@ -0,0 +1,47 @@
+use base64::Engine;
+use base64::engine::general_purpose::STANDARD;
+use serde::Deserialize;
+use std::io::Write;
+use zip::write::SimpleFileOptions;
+use zip::{CompressionMethod, ZipWriter};
+
+#[derive(Deserialize)]
+pub struct EpubFile {
+    path: String,
+    data: String,
+    encoding: String,
+}
+
+fn build(files: &[EpubFile]) -> Result<Vec<u8>, String> {
+    let buffer = std::io::Cursor::new(Vec::new());
+    let mut zip = ZipWriter::new(buffer);
+
+    let stored = SimpleFileOptions::default().compression_method(CompressionMethod::Stored);
+    zip.start_file("mimetype", stored)
+        .map_err(|e| e.to_string())?;
+    zip.write_all(b"application/epub+zip")
+        .map_err(|e| e.to_string())?;
+
+    let deflated = SimpleFileOptions::default().compression_method(CompressionMethod::Deflated);
+    for file in files {
+        if file.path == "mimetype" {
+            continue;
+        }
+        let bytes = match file.encoding.as_str() {
+            "base64" => STANDARD
+                .decode(file.data.as_bytes())
+                .map_err(|e| format!("failed to decode \"{}\": {e}", file.path))?,
+            _ => file.data.as_bytes().to_vec(),
+        };
+        zip.start_file(&file.path, deflated)
+            .map_err(|e| e.to_string())?;
+        zip.write_all(&bytes).map_err(|e| e.to_string())?;
+    }
+
+    Ok(zip.finish().map_err(|e| e.to_string())?.into_inner())
+}
+
+#[tauri::command]
+pub fn package_epub(files: Vec<EpubFile>) -> Result<tauri::ipc::Response, String> {
+    build(&files).map(tauri::ipc::Response::new)
+}

src-tauri/src/lib.rs

@@ -1,3 +1,4 @@
+mod epub;
 mod pdf;
 mod project;
 
@@ -7,6 +8,7 @@ pub fn run() {
         .plugin(tauri_plugin_opener::init())
         .plugin(tauri_plugin_dialog::init())
         .invoke_handler(tauri::generate_handler![
+            epub::package_epub,
             pdf::compile_pdf,
             project::read_file,
             project::write_file,