Adding web support to serious_python

Author: SebieF

src/serious_python/lib/serious_python.dart

@@ -1,8 +1,10 @@
-import 'dart:io';
-
+import 'package:flutter/foundation.dart';
 import 'package:path/path.dart' as path;
 import 'package:serious_python_platform_interface/serious_python_platform_interface.dart';
 
+// Conditional import for IO operations
+import 'src/io_stub.dart' if (dart.library.io) 'src/io_impl.dart';
+
 export 'package:serious_python_platform_interface/src/utils.dart';
 
 /// Provides cross-platform functionality for running Python programs.
@@ -15,56 +17,80 @@ class SeriousPython {
   }
 
   /// Runs Python program from an asset.
-  ///
-  /// [assetPath] is the path to an asset which is a zip archive
-  /// with a Python program. When the app starts the archive is unpacked
-  /// to a temporary directory and Serious Python plugin will try to run
-  /// `main.py` in the root of the archive. Current directory is changed to
-  /// a temporary directory.
-  ///
-  /// If a Python app has a different entry point
-  /// it could be specified with [appFileName] parameter.
-  ///
-  /// Environment variables that must be available to a Python program could
-  /// be passed in [environmentVariables].
-  ///
-  /// By default, Serious Python expects Python dependencies installed into
-  /// `__pypackages__` directory in the root of app directory. Additional paths
-  /// to look for 3rd-party packages can be specified with [modulePaths] parameter.
-  ///
-  /// Set [sync] to `true` to sychronously run Python program; otherwise the
-  /// program starts in a new thread.
   static Future<String?> run(String assetPath,
       {String? appFileName,
-      List<String>? modulePaths,
-      Map<String, String>? environmentVariables,
-      bool? sync}) async {
-    // unpack app from asset
+        List<String>? modulePaths,
+        Map<String, String>? environmentVariables,
+        bool? sync}) async {
+    // Handle web platform differently
+    if (kIsWeb) {
+      return _runWeb(assetPath,
+          appFileName: appFileName,
+          modulePaths: modulePaths,
+          environmentVariables: environmentVariables,
+          sync: sync);
+    } else {
+      return _runDesktop(assetPath,
+          appFileName: appFileName,
+          modulePaths: modulePaths,
+          environmentVariables: environmentVariables,
+          sync: sync);
+    }
+  }
+
+  /// Web-specific implementation
+  static Future<String?> _runWeb(String assetPath,
+      {String? appFileName,
+        List<String>? modulePaths,
+        Map<String, String>? environmentVariables,
+        bool? sync}) async {
+
+    String virtualPath;
+    if (path.extension(assetPath) == ".zip") {
+      virtualPath = assetPath.replaceAll(".zip", "");
+      // TODO Check if path exists and except with unzip hint if not
+    } else {
+      virtualPath = assetPath;
+    }
+
+    if (appFileName != null) {
+      virtualPath = '$virtualPath/$appFileName';
+    } else {
+      virtualPath = '$virtualPath/main.py';
+    }
+
+    return runProgram(virtualPath,
+        modulePaths: modulePaths,
+        environmentVariables: environmentVariables,
+        sync: sync);
+  }
+
+  /// Desktop-specific implementation
+  static Future<String?> _runDesktop(String assetPath,
+      {String? appFileName,
+        List<String>? modulePaths,
+        Map<String, String>? environmentVariables,
+        bool? sync}) async {
     String appPath = "";
     if (path.extension(assetPath) == ".zip") {
       appPath = await extractAssetZip(assetPath);
       if (appFileName != null) {
         appPath = path.join(appPath, appFileName);
-      } else if (await File(path.join(appPath, "main.pyc")).exists()) {
-        appPath = path.join(appPath, "main.pyc");
-      } else if (await File(path.join(appPath, "main.py")).exists()) {
-        appPath = path.join(appPath, "main.py");
       } else {
-        throw Exception(
-            "App archive must contain either `main.py` or `main.pyc`; otherwise `appFileName` must be specified.");
+        appPath = await FileSystem.findMainFile(appPath);
       }
     } else {
       appPath = await extractAsset(assetPath);
     }
 
     // set current directory to app path
-    Directory.current = path.dirname(appPath);
+    await FileSystem.setCurrentDirectory(path.dirname(appPath));
 
     // run python program
     return runProgram(appPath,
         modulePaths: modulePaths,
         environmentVariables: environmentVariables,
-        script: Platform.isWindows ? "" : null,
+        script: FileSystem.isWindows ? "" : null,
         sync: sync);
   }
 
@@ -82,14 +108,13 @@ class SeriousPython {
   /// `__pypackages__` directory in the root of app directory. Additional paths
   /// to look for 3rd-party packages can be specified with [modulePaths] parameter.
   ///
-  /// Set [sync] to `true` to sychronously run Python program; otherwise the
+  /// Set [sync] to `true` to synchronously run Python program; otherwise the
   /// program starts in a new thread.
   static Future<String?> runProgram(String appPath,
       {String? script,
-      List<String>? modulePaths,
-      Map<String, String>? environmentVariables,
-      bool? sync}) async {
-    // run python program
+        List<String>? modulePaths,
+        Map<String, String>? environmentVariables,
+        bool? sync}) async {
     return SeriousPythonPlatform.instance.run(appPath,
         script: script,
         modulePaths: modulePaths,
@@ -100,4 +125,4 @@ class SeriousPython {
   static void terminate() {
     SeriousPythonPlatform.instance.terminate();
   }
-}
+}

src/serious_python/lib/src/io_impl.dart

@@ -0,0 +1,20 @@
+import 'dart:io';
+import 'package:path/path.dart' as path;
+
+class FileSystem {
+  static Future<String> findMainFile(String appPath) async {
+    if (await File(path.join(appPath, "main.pyc")).exists()) {
+      return path.join(appPath, "main.pyc");
+    } else if (await File(path.join(appPath, "main.py")).exists()) {
+      return path.join(appPath, "main.py");
+    }
+    throw Exception(
+        "App archive must contain either `main.py` or `main.pyc`; otherwise `appFileName` must be specified.");
+  }
+
+  static Future<void> setCurrentDirectory(String path) async {
+    Directory.current = path;
+  }
+
+  static bool get isWindows => Platform.isWindows;
+}

src/serious_python/lib/src/io_stub.dart

@@ -0,0 +1,12 @@
+// Stub implementation for web
+class FileSystem {
+  static Future<String> findMainFile(String appPath) async {
+    return '$appPath/main.py';
+  }
+
+  static Future<void> setCurrentDirectory(String path) async {
+    // No-op for web
+  }
+
+  static bool get isWindows => false;
+}