Merge branch 'worker_improvements' into 'master'

Don't block async when processing images

See merge request !5

src/bin/worker.rs

@@ -10,6 +10,7 @@ use std::fs::File;
 use std::io::prelude::*;
 use std::io::Cursor;
 use std::path::Path;
+use tokio::task;
 
 async fn download_file(url: &str) -> Option<Bytes> {
 	let resp = reqwest::get(url).await.ok()?;
@@ -27,35 +28,40 @@ fn write_file(path: &Path, bytes: &[u8]) -> Option<()> {
 
 async fn process_file(
 	url: &str,
-	output_directory: &str,
-	output_id: &str,
-	formats: &[Format],
+	output_directory: String,
+	output_id: String,
+	formats: Vec<Format>,
 ) -> Option<String> {
 	let content = download_file(url).await?;
 
-	let reader = ImageReader::new(Cursor::new(content))
-		.with_guessed_format()
-		.ok()?;
-	let img_format = reader.format()?;
-	let extension = img_format.extensions_str()[0];
-	let img = reader.decode().ok()?;
-
-	for format in formats {
-		let img = img.resize(
-			format.width.unwrap_or_else(|| img.width()),
-			format.height.unwrap_or_else(|| img.height()),
-			FilterType::Triangle,
-		);
-
-		let mut buffer = Vec::new();
-		img.write_to(&mut buffer, img_format).ok()?;
-
-		write_file(
-			&Path::new(output_directory)
-				.join(&format!("{}_{}.{}", output_id, format.name, extension)),
-			&buffer,
-		)?;
-	}
+	let extension = task::spawn_blocking(move || {
+		let reader = ImageReader::new(Cursor::new(content))
+			.with_guessed_format()
+			.ok()?;
+		let img_format = reader.format()?;
+		let extension = img_format.extensions_str()[0];
+		let img = reader.decode().ok()?;
+
+		for format in formats {
+			let img = img.resize(
+				format.width.unwrap_or_else(|| img.width()),
+				format.height.unwrap_or_else(|| img.height()),
+				FilterType::Triangle,
+			);
+
+			let mut buffer = Vec::new();
+			img.write_to(&mut buffer, img_format).ok()?;
+
+			write_file(
+				&Path::new(&output_directory)
+					.join(&format!("{}_{}.{}", output_id, format.name, extension)),
+				&buffer,
+			)?;
+		}
+		Some(extension)
+	})
+	.await
+	.unwrap()?; // Propagate any panics
 
 	Some(extension.to_string())
 }
@@ -92,9 +98,9 @@ async fn main() {
 			|(row, pool)| async move {
 				let extension = match process_file(
 					&row.original_url,
-					image_directory,
-					&row.id.to_string(),
-					&formats,
+					image_directory.to_string(),
+					row.id.to_string(),
+					formats.clone(),
 				)
 				.await
 				{