Smaller scope for try/catch block to detect 404

src/lambda-handler.ts

@@ -40,61 +40,64 @@ const streamify_handler: StreamifyHandler = async ( event, response ) => {
 		delete args.presign;
 	}
 
-	try {
-		let s3_response = await getS3File( config, key, args );
-		if ( ! s3_response.Body ) {
-			throw new Error( 'No body in file.' );
-		}
-		let buffer = Buffer.from( await s3_response.Body.transformToByteArray() );
-
-		let { info, data } = await resizeBuffer( buffer, args );
-		// If this is a signed URL, we need to calculate the max-age of the image.
-		let maxAge = 31536000;
-		if ( args['X-Amz-Expires'] ) {
-			// Date format of X-Amz-Date is YYYYMMDDTHHMMSSZ, which is not parsable by Date.
-			const dateString = args['X-Amz-Date']!.replace(
-				/(\d{4})(\d{2})(\d{2})T(\d{2})(\d{2})(\d{2})Z/,
-				'$1-$2-$3T$4:$5:$6Z'
-			);
-			const date = new Date( dateString );
-
-			// Calculate when the signed URL will expire, as we'll set the max-age
-			// cache control to this value.
-			const expires = date.getTime() / 1000 + Number( args['X-Amz-Expires'] );
-
-			// Mage age is the date the URL expires minus the current time.
-			maxAge = Math.round( expires - new Date().getTime() / 1000 ); // eslint-disable-line no-unused-vars
-		}
-
-		// Somewhat undocumented API on how to pass headers to a stream response.
-		response = awslambda.HttpResponseStream.from( response, {
-			statusCode: 200,
-			headers: {
-				'Cache-Control': `max-age=${ maxAge }`,
-				'Last-Modified': ( new Date() ).toUTCString(),
-				'Content-Type': 'image/' + info.format,
-			},
-		} );
+	let s3_response;
 
-		response.write( data );
-		response.end();
+	try {
+		s3_response = await getS3File( config, key, args );
 	} catch ( e: any ) {
 		// An AccessDenied error means the file is either protected, or doesn't exist.
 		if ( e.Code === 'AccessDenied' ) {
 			const metadata = {
 				statusCode: 404,
 				headers: {
-					'Content-Type': 'text/html',
-					'Cache-Control': 'no-cache',
+					'Content-Type': 'text/html'
 				},
 			};
 			response = awslambda.HttpResponseStream.from( response, metadata );
 			response.write( 'File not found.' );
 			response.end();
-		} else {
-			throw e;
-		}
+			return;
+		} 
+		throw e;
 	}
+
+	if ( ! s3_response.Body ) {
+		throw new Error( 'No body in file.' );
+	}
+
+	let buffer = Buffer.from( await s3_response.Body.transformToByteArray() );
+
+	let { info, data } = await resizeBuffer( buffer, args );
+	// If this is a signed URL, we need to calculate the max-age of the image.
+	let maxAge = 31536000;
+	if ( args['X-Amz-Expires'] ) {
+		// Date format of X-Amz-Date is YYYYMMDDTHHMMSSZ, which is not parsable by Date.
+		const dateString = args['X-Amz-Date']!.replace(
+			/(\d{4})(\d{2})(\d{2})T(\d{2})(\d{2})(\d{2})Z/,
+			'$1-$2-$3T$4:$5:$6Z'
+		);
+		const date = new Date( dateString );
+
+		// Calculate when the signed URL will expire, as we'll set the max-age
+		// cache control to this value.
+		const expires = date.getTime() / 1000 + Number( args['X-Amz-Expires'] );
+
+		// Mage age is the date the URL expires minus the current time.
+		maxAge = Math.round( expires - new Date().getTime() / 1000 ); // eslint-disable-line no-unused-vars
+	}
+
+	// Somewhat undocumented API on how to pass headers to a stream response.
+	response = awslambda.HttpResponseStream.from( response, {
+		statusCode: 200,
+		headers: {
+			'Cache-Control': `max-age=${ maxAge }`,
+			'Last-Modified': ( new Date() ).toUTCString(),
+			'Content-Type': 'image/' + info.format,
+		},
+	} );
+
+	response.write( data );
+	response.end();
 };
 
 if ( typeof awslambda === 'undefined' ) {