Merge pull request #56 from readur/fix/pdf-thumbnail-generation

feat(server): actually render PDF thumbnails
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Jon Fuller 2025-06-26 14:14:25 -07:00 committed by GitHub
commit 1c02dd480e
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3 changed files with 70 additions and 13 deletions

4
Cargo.lock generated
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@ -2621,7 +2621,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "07033963ba89ebaf1584d767badaa2e8fcec21aedea6b8c0346d487d49c28667"
dependencies = [
"cfg-if",
"windows-targets 0.48.5",
"windows-targets 0.52.6",
]
[[package]]
@ -5626,7 +5626,7 @@ version = "0.1.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
dependencies = [
"windows-sys 0.48.0",
"windows-sys 0.59.0",
]
[[package]]

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@ -10,7 +10,7 @@ RUN npm run build
# --- Backend build stage ---
FROM rust:1.87-bookworm as backend-builder
# Install system dependencies for OCR
# Install system dependencies for OCR and PDF processing
RUN apt-get update && apt-get install -y \
tesseract-ocr \
tesseract-ocr-eng \
@ -19,6 +19,7 @@ RUN apt-get update && apt-get install -y \
pkg-config \
libclang-dev \
clang \
poppler-utils \
&& rm -rf /var/lib/apt/lists/*
WORKDIR /app
@ -35,6 +36,7 @@ RUN apt-get update && apt-get install -y \
tesseract-ocr \
tesseract-ocr-eng \
ca-certificates \
poppler-utils \
&& rm -rf /var/lib/apt/lists/*
WORKDIR /app

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@ -320,18 +320,73 @@ impl FileService {
#[cfg(feature = "ocr")]
async fn generate_pdf_thumbnail(&self, file_data: &[u8]) -> Result<Vec<u8>> {
use image::Rgb;
use std::process::Command;
use tokio::fs;
use uuid::Uuid;
// Try to extract first page as image using pdf-extract with panic protection
match catch_unwind(AssertUnwindSafe(|| {
pdf_extract::extract_text_from_mem(file_data)
})) {
Ok(Ok(text)) => {
// If we can extract text, create a text-based thumbnail
self.generate_text_based_thumbnail(&text, "PDF", Rgb([220, 38, 27])).await
// Create a temporary file for the PDF
let temp_id = Uuid::new_v4();
let temp_pdf_path = format!("/tmp/pdf_thumb_{}.pdf", temp_id);
let temp_png_path = format!("/tmp/pdf_thumb_{}.png", temp_id);
// Write PDF data to temporary file
if let Err(e) = fs::write(&temp_pdf_path, file_data).await {
error!("Failed to write temporary PDF file: {}", e);
return self.generate_placeholder_thumbnail("PDF").await;
}
// Use pdftoppm to convert first page to PNG
let output = Command::new("pdftoppm")
.arg("-f").arg("1") // First page only
.arg("-l").arg("1") // Last page (same as first)
.arg("-scale-to").arg("200") // Scale to 200px width
.arg("-png") // Output as PNG
.arg(&temp_pdf_path)
.arg(&format!("/tmp/pdf_thumb_{}", temp_id)) // Output prefix
.output();
// Clean up temporary PDF file
let _ = fs::remove_file(&temp_pdf_path).await;
match output {
Ok(result) if result.status.success() => {
// pdftoppm adds "-1" to the filename for the first page
let actual_png_path = format!("/tmp/pdf_thumb_{}-1.png", temp_id);
// Read the generated PNG file
match fs::read(&actual_png_path).await {
Ok(png_data) => {
// Clean up temporary PNG file
let _ = fs::remove_file(&actual_png_path).await;
// Convert PNG to JPEG thumbnail
match image::load_from_memory(&png_data) {
Ok(img) => {
// Resize to 200x200 maintaining aspect ratio
let thumbnail = img.resize(200, 200, image::imageops::FilterType::Lanczos3);
// Convert to JPEG
let mut buffer = Vec::new();
let mut cursor = std::io::Cursor::new(&mut buffer);
if thumbnail.write_to(&mut cursor, ImageFormat::Jpeg).is_ok() {
Ok(buffer)
} else {
self.generate_placeholder_thumbnail("PDF").await
}
}
Err(_) => self.generate_placeholder_thumbnail("PDF").await,
}
}
Err(_) => {
let _ = fs::remove_file(&actual_png_path).await;
self.generate_placeholder_thumbnail("PDF").await
}
}
}
Ok(Err(_)) | Err(_) => {
// Fall back to placeholder if PDF extraction fails or panics
_ => {
// Clean up any potential PNG files
let _ = fs::remove_file(&temp_png_path).await;
let _ = fs::remove_file(&format!("/tmp/pdf_thumb_{}-1.png", temp_id)).await;
self.generate_placeholder_thumbnail("PDF").await
}
}