frontend_server_common/lib/src/asset_server.dart - webdev - Git at Google

 // Copyright 2020 The Dart Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 // Note: this is a copy from flutter tools, updated to work with dwds tests

 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:typed_data';

 import 'package:dwds/asset_reader.dart';
 import 'package:dwds/config.dart';
 import 'package:file/file.dart';
 import 'package:logging/logging.dart';
 import 'package:mime/mime.dart' as mime;
 import 'package:shelf/shelf.dart' as shelf;
 import 'package:test_common/test_sdk_layout.dart';

 class TestAssetServer implements AssetReader {
   late final String _basePath;
   final String index;

   final _logger = Logger('TestAssetServer');

   // Fallback to "application/octet-stream" on null which
   // makes no claims as to the structure of the data.
   static const String _defaultMimeType = 'application/octet-stream';
   final FileSystem _fileSystem;
   final HttpServer _httpServer;
   final Map<String, Uint8List> _files = {};
   final Map<String, Uint8List> _sourceMaps = {};
   final Map<String, Uint8List> _metadata = {};
   late String _mergedMetadata;
   final PackageUriMapper _packageUriMapper;
   final InternetAddress internetAddress;
   final TestSdkLayout _sdkLayout;

   TestAssetServer(
     this.index,
     this._httpServer,
     this._packageUriMapper,
     this.internetAddress,
     this._fileSystem,
     this._sdkLayout,
   ) {
     _basePath = _parseBasePathFromIndexHtml(index);
   }

   @override
   String get basePath => _basePath;

   bool hasFile(String path) => _files.containsKey(path);
   Uint8List getFile(String path) => _files[path]!;

   bool hasSourceMap(String path) => _sourceMaps.containsKey(path);
   Uint8List getSourceMap(String path) => _sourceMaps[path]!;

   bool hasMetadata(String path) => _metadata.containsKey(path);
   Uint8List getMetadata(String path) => _metadata[path]!;

   /// Start the web asset server on a [hostname] and [port].
   ///
   /// Unhandled exceptions will throw a exception with the error and stack
   /// trace.
   static Future<TestAssetServer> start(
     String sdkDirectory,
     FileSystem fileSystem,
     String index,
     String hostname,
     int port,
     UrlEncoder? urlTunneler,
     PackageUriMapper packageUriMapper,
   ) async {
     final address = (await InternetAddress.lookup(hostname)).first;
     final httpServer = await HttpServer.bind(address, port);
     final sdkLayout = TestSdkLayout.createDefault(sdkDirectory);
     final server = TestAssetServer(
         index, httpServer, packageUriMapper, address, fileSystem, sdkLayout);
     return server;
   }

   // handle requests for JavaScript source, dart sources maps, or asset files.
   Future<shelf.Response> handleRequest(shelf.Request request) async {
     if (request.method != 'GET') {
       // Assets are served via GET only.
       return shelf.Response.notFound('');
     }
     final requestPath = _stripBasePath(request.url.path, basePath);
     if (requestPath == null) {
       return shelf.Response.notFound('');
     }

     var headers = <String, String>{};

     if (request.url.path.endsWith('.html')) {
       var indexFile = _fileSystem.file(index);
       if (indexFile.existsSync()) {
         headers[HttpHeaders.contentTypeHeader] = 'text/html';
         headers[HttpHeaders.contentLengthHeader] =
             indexFile.lengthSync().toString();
         return shelf.Response.ok(indexFile.openRead(), headers: headers);
       }
       return shelf.Response.notFound('');
     }

     // If this is a JavaScript file, it must be in the in-memory cache.
     // Attempt to look up the file by URI.
     if (hasFile(requestPath)) {
       final List<int> bytes = getFile(requestPath);
       headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
       headers[HttpHeaders.contentTypeHeader] = 'application/javascript';
       return shelf.Response.ok(bytes, headers: headers);
     }
     // If this is a sourcemap file, then it might be in the in-memory cache.
     // Attempt to lookup the file by URI.
     if (hasSourceMap(requestPath)) {
       final List<int> bytes = getSourceMap(requestPath);
       headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
       headers[HttpHeaders.contentTypeHeader] = 'application/json';
       return shelf.Response.ok(bytes, headers: headers);
     }
     // If this is a metadata file, then it might be in the in-memory cache.
     // Attempt to lookup the file by URI.
     if (hasMetadata(requestPath)) {
       final List<int> bytes = getMetadata(requestPath);
       headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
       headers[HttpHeaders.contentTypeHeader] = 'application/json';
       return shelf.Response.ok(bytes, headers: headers);
     }

     var file = _resolveDartFile(requestPath);
     if (!file.existsSync()) {
       return shelf.Response.notFound('');
     }

     var length = file.lengthSync();
     // Attempt to determine the file's mime type. if this is not provided some
     // browsers will refuse to render images/show video et cetera. If the tool
     // cannot determine a mime type, fall back to application/octet-stream.
     String? mimeType;
     if (length >= 12) {
       mimeType = mime.lookupMimeType(
         file.path,
         headerBytes: await file.openRead(0, 12).first,
       );
     }
     mimeType ??= _defaultMimeType;
     headers[HttpHeaders.contentLengthHeader] = length.toString();
     headers[HttpHeaders.contentTypeHeader] = mimeType;
     return shelf.Response.ok(file.openRead(), headers: headers);
   }

   /// Tear down the http server running.
   @override
   Future<void> close() {
     return _httpServer.close();
   }

   /// Write a single file into the in-memory cache.
   void writeFile(String filePath, String contents) {
     _files[filePath] = Uint8List.fromList(utf8.encode(contents));
   }

   /// Update the in-memory asset server with the provided source and manifest files.
   ///
   /// Returns a list of updated modules.
   List<String> write(
       File codeFile, File manifestFile, File sourcemapFile, File metadataFile) {
     var modules = <String>[];
     var codeBytes = codeFile.readAsBytesSync();
     var sourcemapBytes = sourcemapFile.readAsBytesSync();
     var metadataBytes = metadataFile.readAsBytesSync();
     var manifest =
         _castStringKeyedMap(json.decode(manifestFile.readAsStringSync()));
     for (var filePath in manifest.keys) {
       var offsets = _castStringKeyedMap(manifest[filePath]);
       var codeOffsets = (offsets['code'] as List<dynamic>).cast<int>();
       var sourcemapOffsets =
           (offsets['sourcemap'] as List<dynamic>).cast<int>();
       var metadataOffsets = (offsets['metadata'] as List<dynamic>).cast<int>();
       if (codeOffsets.length != 2 ||
           sourcemapOffsets.length != 2 ||
           metadataOffsets.length != 2) {
         _logger.severe('Invalid manifest byte offsets: $offsets');
         continue;
       }

       var codeStart = codeOffsets[0];
       var codeEnd = codeOffsets[1];
       if (codeStart < 0 || codeEnd > codeBytes.lengthInBytes) {
         _logger.severe('Invalid byte index: [$codeStart, $codeEnd]');
         continue;
       }
       var byteView = Uint8List.view(
         codeBytes.buffer,
         codeStart,
         codeEnd - codeStart,
       );

       final fileName =
           filePath.startsWith('/') ? filePath.substring(1) : filePath;
       _files[fileName] = byteView;

       var sourcemapStart = sourcemapOffsets[0];
       var sourcemapEnd = sourcemapOffsets[1];
       if (sourcemapStart < 0 || sourcemapEnd > sourcemapBytes.lengthInBytes) {
         _logger.severe('Invalid byte index: [$sourcemapStart, $sourcemapEnd]');
         continue;
       }
       var sourcemapView = Uint8List.view(
         sourcemapBytes.buffer,
         sourcemapStart,
         sourcemapEnd - sourcemapStart,
       );
       _sourceMaps['$fileName.map'] = sourcemapView;

       var metadataStart = metadataOffsets[0];
       var metadataEnd = metadataOffsets[1];
       if (metadataStart < 0 || metadataEnd > metadataBytes.lengthInBytes) {
         _logger.severe('Invalid byte index: [$metadataStart, $metadataEnd]');
         continue;
       }
       var metadataView = Uint8List.view(
         metadataBytes.buffer,
         metadataStart,
         metadataEnd - metadataStart,
       );
       _metadata['$fileName.metadata'] = metadataView;

       modules.add(fileName);
     }

     _mergedMetadata = _metadata.values
         .map((Uint8List encoded) => utf8.decode(encoded))
         .join('\n');

     return modules;
   }

   // Attempt to resolve `path` to a dart file.
   File _resolveDartFile(String path) {
     // If this is a dart file, it must be on the local file system and is
     // likely coming from a source map request. The tool doesn't currently
     // consider the case of Dart files as assets.
     final dartFile =
         _fileSystem.file(_fileSystem.currentDirectory.uri.resolve(path));
     if (dartFile.existsSync()) {
       return dartFile;
     }

     final segments = path.split('/');

     // The file might have been a package file which is signaled by a
     // `/packages/<package>/<path>` request.
     if (segments.first == 'packages') {
       final resolved = _packageUriMapper.serverPathToResolvedUri(path);
       final packageFile = _fileSystem.file(resolved);
       if (packageFile.existsSync()) {
         return packageFile;
       }
       _logger.severe('Package file not found: $path ($packageFile)');
     }

     // Otherwise it must be a Dart SDK source.
     var dartSdkParent = _fileSystem.directory(_sdkLayout.sdkDirectory).parent;
     var dartSdkFile = _fileSystem.file(
         _fileSystem.path.joinAll(<String>[dartSdkParent.path, ...segments]));
     return dartSdkFile;
   }

   @override
   Future<String?> dartSourceContents(String serverPath) async {
     final stripped = _stripBasePath(serverPath, basePath);
     if (stripped != null) {
       var result = _resolveDartFile(stripped);
       if (result.existsSync()) {
         return result.readAsString();
       }
     }
     _logger.severe('Source not found: $serverPath');
     return null;
   }

   @override
   Future<String?> sourceMapContents(String serverPath) async {
     final stripped = _stripBasePath(serverPath, basePath);
     if (stripped != null) {
       if (hasSourceMap(stripped)) {
         return utf8.decode(getSourceMap(stripped));
       }
     }
     _logger.severe('Source map not found: $serverPath');
     return null;
   }

   @override
   Future<String?> metadataContents(String serverPath) async {
     final stripped = _stripBasePath(serverPath, basePath);
     if (stripped != null) {
       if (stripped.endsWith('.ddc_merged_metadata')) {
         return _mergedMetadata;
       }
       if (hasMetadata(stripped)) {
         return utf8.decode(getMetadata(stripped));
       }
     }
     _logger.severe('Metadata not found: $serverPath');
     return null;
   }

   String _parseBasePathFromIndexHtml(String index) {
     final file = _fileSystem.file(index);
     if (!file.existsSync()) {
       throw StateError('Index file $index is not found');
     }
     final contents = file.readAsStringSync();
     final matches = RegExp(r'<base href="/([^>]*)/">').allMatches(contents);
     if (matches.isEmpty) return '';
     return matches.first.group(1) ?? '';
   }

   String? _stripBasePath(String path, String basePath) {
     path = stripLeadingSlashes(path);
     if (path.startsWith(basePath)) {
       path = path.substring(basePath.length);
     } else {
       // The given path isn't under base path, return null to indicate that.
       _logger.severe('Path is not under $basePath: $path');
       return null;
     }
     return stripLeadingSlashes(path);
   }
 }

 /// Given a data structure which is a Map of String to dynamic values, return
 /// the same structure (`Map<String, dynamic>`) with the correct runtime types.
 Map<String, dynamic> _castStringKeyedMap(dynamic untyped) {
   var map = untyped as Map<dynamic, dynamic>;
   return map.cast<String, dynamic>();
 }
	// Copyright 2020 The Dart Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	// Note: this is a copy from flutter tools, updated to work with dwds tests

	import 'dart:async';
	import 'dart:convert';
	import 'dart:io';
	import 'dart:typed_data';

	import 'package:dwds/asset_reader.dart';
	import 'package:dwds/config.dart';
	import 'package:file/file.dart';
	import 'package:logging/logging.dart';
	import 'package:mime/mime.dart' as mime;
	import 'package:shelf/shelf.dart' as shelf;
	import 'package:test_common/test_sdk_layout.dart';

	class TestAssetServer implements AssetReader {
	late final String _basePath;
	final String index;

	final _logger = Logger('TestAssetServer');

	// Fallback to "application/octet-stream" on null which
	// makes no claims as to the structure of the data.
	static const String _defaultMimeType = 'application/octet-stream';
	final FileSystem _fileSystem;
	final HttpServer _httpServer;
	final Map<String, Uint8List> _files = {};
	final Map<String, Uint8List> _sourceMaps = {};
	final Map<String, Uint8List> _metadata = {};
	late String _mergedMetadata;
	final PackageUriMapper _packageUriMapper;
	final InternetAddress internetAddress;
	final TestSdkLayout _sdkLayout;

	TestAssetServer(
	this.index,
	this._httpServer,
	this._packageUriMapper,
	this.internetAddress,
	this._fileSystem,
	this._sdkLayout,
	) {
	_basePath = _parseBasePathFromIndexHtml(index);
	}

	@override
	String get basePath => _basePath;

	bool hasFile(String path) => _files.containsKey(path);
	Uint8List getFile(String path) => _files[path]!;

	bool hasSourceMap(String path) => _sourceMaps.containsKey(path);
	Uint8List getSourceMap(String path) => _sourceMaps[path]!;

	bool hasMetadata(String path) => _metadata.containsKey(path);
	Uint8List getMetadata(String path) => _metadata[path]!;

	/// Start the web asset server on a [hostname] and [port].
	///
	/// Unhandled exceptions will throw a exception with the error and stack
	/// trace.
	static Future<TestAssetServer> start(
	String sdkDirectory,
	FileSystem fileSystem,
	String index,
	String hostname,
	int port,
	UrlEncoder? urlTunneler,
	PackageUriMapper packageUriMapper,
	) async {
	final address = (await InternetAddress.lookup(hostname)).first;
	final httpServer = await HttpServer.bind(address, port);
	final sdkLayout = TestSdkLayout.createDefault(sdkDirectory);
	final server = TestAssetServer(
	index, httpServer, packageUriMapper, address, fileSystem, sdkLayout);
	return server;
	}

	// handle requests for JavaScript source, dart sources maps, or asset files.
	Future<shelf.Response> handleRequest(shelf.Request request) async {
	if (request.method != 'GET') {
	// Assets are served via GET only.
	return shelf.Response.notFound('');
	}
	final requestPath = _stripBasePath(request.url.path, basePath);
	if (requestPath == null) {
	return shelf.Response.notFound('');
	}

	var headers = <String, String>{};

	if (request.url.path.endsWith('.html')) {
	var indexFile = _fileSystem.file(index);
	if (indexFile.existsSync()) {
	headers[HttpHeaders.contentTypeHeader] = 'text/html';
	headers[HttpHeaders.contentLengthHeader] =
	indexFile.lengthSync().toString();
	return shelf.Response.ok(indexFile.openRead(), headers: headers);
	}
	return shelf.Response.notFound('');
	}

	// If this is a JavaScript file, it must be in the in-memory cache.
	// Attempt to look up the file by URI.
	if (hasFile(requestPath)) {
	final List<int> bytes = getFile(requestPath);
	headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
	headers[HttpHeaders.contentTypeHeader] = 'application/javascript';
	return shelf.Response.ok(bytes, headers: headers);
	}
	// If this is a sourcemap file, then it might be in the in-memory cache.
	// Attempt to lookup the file by URI.
	if (hasSourceMap(requestPath)) {
	final List<int> bytes = getSourceMap(requestPath);
	headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
	headers[HttpHeaders.contentTypeHeader] = 'application/json';
	return shelf.Response.ok(bytes, headers: headers);
	}
	// If this is a metadata file, then it might be in the in-memory cache.
	// Attempt to lookup the file by URI.
	if (hasMetadata(requestPath)) {
	final List<int> bytes = getMetadata(requestPath);
	headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
	headers[HttpHeaders.contentTypeHeader] = 'application/json';
	return shelf.Response.ok(bytes, headers: headers);
	}

	var file = _resolveDartFile(requestPath);
	if (!file.existsSync()) {
	return shelf.Response.notFound('');
	}

	var length = file.lengthSync();
	// Attempt to determine the file's mime type. if this is not provided some
	// browsers will refuse to render images/show video et cetera. If the tool
	// cannot determine a mime type, fall back to application/octet-stream.
	String? mimeType;
	if (length >= 12) {
	mimeType = mime.lookupMimeType(
	file.path,
	headerBytes: await file.openRead(0, 12).first,
	);
	}
	mimeType ??= _defaultMimeType;
	headers[HttpHeaders.contentLengthHeader] = length.toString();
	headers[HttpHeaders.contentTypeHeader] = mimeType;
	return shelf.Response.ok(file.openRead(), headers: headers);
	}

	/// Tear down the http server running.
	@override
	Future<void> close() {
	return _httpServer.close();
	}

	/// Write a single file into the in-memory cache.
	void writeFile(String filePath, String contents) {
	_files[filePath] = Uint8List.fromList(utf8.encode(contents));
	}

	/// Update the in-memory asset server with the provided source and manifest files.
	///
	/// Returns a list of updated modules.
	List<String> write(
	File codeFile, File manifestFile, File sourcemapFile, File metadataFile) {
	var modules = <String>[];
	var codeBytes = codeFile.readAsBytesSync();
	var sourcemapBytes = sourcemapFile.readAsBytesSync();
	var metadataBytes = metadataFile.readAsBytesSync();
	var manifest =
	_castStringKeyedMap(json.decode(manifestFile.readAsStringSync()));
	for (var filePath in manifest.keys) {
	var offsets = _castStringKeyedMap(manifest[filePath]);
	var codeOffsets = (offsets['code'] as List<dynamic>).cast<int>();
	var sourcemapOffsets =
	(offsets['sourcemap'] as List<dynamic>).cast<int>();
	var metadataOffsets = (offsets['metadata'] as List<dynamic>).cast<int>();
	if (codeOffsets.length != 2 \|\|
	sourcemapOffsets.length != 2 \|\|
	metadataOffsets.length != 2) {
	_logger.severe('Invalid manifest byte offsets: $offsets');
	continue;
	}

	var codeStart = codeOffsets[0];
	var codeEnd = codeOffsets[1];
	if (codeStart < 0 \|\| codeEnd > codeBytes.lengthInBytes) {
	_logger.severe('Invalid byte index: [$codeStart, $codeEnd]');
	continue;
	}
	var byteView = Uint8List.view(
	codeBytes.buffer,
	codeStart,
	codeEnd - codeStart,
	);

	final fileName =
	filePath.startsWith('/') ? filePath.substring(1) : filePath;
	_files[fileName] = byteView;

	var sourcemapStart = sourcemapOffsets[0];
	var sourcemapEnd = sourcemapOffsets[1];
	if (sourcemapStart < 0 \|\| sourcemapEnd > sourcemapBytes.lengthInBytes) {
	_logger.severe('Invalid byte index: [$sourcemapStart, $sourcemapEnd]');
	continue;
	}
	var sourcemapView = Uint8List.view(
	sourcemapBytes.buffer,
	sourcemapStart,
	sourcemapEnd - sourcemapStart,
	);
	_sourceMaps['$fileName.map'] = sourcemapView;

	var metadataStart = metadataOffsets[0];
	var metadataEnd = metadataOffsets[1];
	if (metadataStart < 0 \|\| metadataEnd > metadataBytes.lengthInBytes) {
	_logger.severe('Invalid byte index: [$metadataStart, $metadataEnd]');
	continue;
	}
	var metadataView = Uint8List.view(
	metadataBytes.buffer,
	metadataStart,
	metadataEnd - metadataStart,
	);
	_metadata['$fileName.metadata'] = metadataView;

	modules.add(fileName);
	}

	_mergedMetadata = _metadata.values
	.map((Uint8List encoded) => utf8.decode(encoded))
	.join('\n');

	return modules;
	}

	// Attempt to resolve `path` to a dart file.
	File _resolveDartFile(String path) {
	// If this is a dart file, it must be on the local file system and is
	// likely coming from a source map request. The tool doesn't currently
	// consider the case of Dart files as assets.
	final dartFile =
	_fileSystem.file(_fileSystem.currentDirectory.uri.resolve(path));
	if (dartFile.existsSync()) {
	return dartFile;
	}

	final segments = path.split('/');

	// The file might have been a package file which is signaled by a
	// `/packages/<package>/<path>` request.
	if (segments.first == 'packages') {
	final resolved = _packageUriMapper.serverPathToResolvedUri(path);
	final packageFile = _fileSystem.file(resolved);
	if (packageFile.existsSync()) {
	return packageFile;
	}
	_logger.severe('Package file not found: $path ($packageFile)');
	}

	// Otherwise it must be a Dart SDK source.
	var dartSdkParent = _fileSystem.directory(_sdkLayout.sdkDirectory).parent;
	var dartSdkFile = _fileSystem.file(
	_fileSystem.path.joinAll(<String>[dartSdkParent.path, ...segments]));
	return dartSdkFile;
	}

	@override
	Future<String?> dartSourceContents(String serverPath) async {
	final stripped = _stripBasePath(serverPath, basePath);
	if (stripped != null) {
	var result = _resolveDartFile(stripped);
	if (result.existsSync()) {
	return result.readAsString();
	}
	}
	_logger.severe('Source not found: $serverPath');
	return null;
	}

	@override
	Future<String?> sourceMapContents(String serverPath) async {
	final stripped = _stripBasePath(serverPath, basePath);
	if (stripped != null) {
	if (hasSourceMap(stripped)) {
	return utf8.decode(getSourceMap(stripped));
	}
	}
	_logger.severe('Source map not found: $serverPath');
	return null;
	}

	@override
	Future<String?> metadataContents(String serverPath) async {
	final stripped = _stripBasePath(serverPath, basePath);
	if (stripped != null) {
	if (stripped.endsWith('.ddc_merged_metadata')) {
	return _mergedMetadata;
	}
	if (hasMetadata(stripped)) {
	return utf8.decode(getMetadata(stripped));
	}
	}
	_logger.severe('Metadata not found: $serverPath');
	return null;
	}

	String _parseBasePathFromIndexHtml(String index) {
	final file = _fileSystem.file(index);
	if (!file.existsSync()) {
	throw StateError('Index file $index is not found');
	}
	final contents = file.readAsStringSync();
	final matches = RegExp(r'<base href="/([^>]*)/">').allMatches(contents);
	if (matches.isEmpty) return '';
	return matches.first.group(1) ?? '';
	}

	String? _stripBasePath(String path, String basePath) {
	path = stripLeadingSlashes(path);
	if (path.startsWith(basePath)) {
	path = path.substring(basePath.length);
	} else {
	// The given path isn't under base path, return null to indicate that.
	_logger.severe('Path is not under $basePath: $path');
	return null;
	}
	return stripLeadingSlashes(path);
	}
	}

	/// Given a data structure which is a Map of String to dynamic values, return
	/// the same structure (`Map<String, dynamic>`) with the correct runtime types.
	Map<String, dynamic> _castStringKeyedMap(dynamic untyped) {
	var map = untyped as Map<dynamic, dynamic>;
	return map.cast<String, dynamic>();
	}