Fix parsing minified code with PEG (#363) (#365)

Update JS function name parsing

Use a custom PyParsing grammar to extract function names
from JavaScript names rather than a basic and somewhat
flawed regex pattern.

Author: KyleKing

README-developers.md

@@ -13,7 +13,7 @@ Create a dev virtual environment. Your process for doing this may vary, but migh
 
 ```bash
 python3 -m venv venv
-./venv/bin/activate
+source venv/bin/activate
 ```
 
 We support Python 3.6+ so developers should ideally run their tests against the latest minor version of each major version we support from there. Tox is configured to run tests against each major version we support. In order to run tox fully, you will need to install multiple versions of Python. See the pinned minor versions in `.python-version`.

eel/__init__.py

@@ -10,6 +10,7 @@
 import re as rgx
 import os
 import eel.browsers as brw
+import pyparsing as pp
 import random as rnd
 import sys
 import pkg_resources as pkg
@@ -83,6 +84,22 @@ def decorator(function):
         return function
 
 
+# PyParsing grammar for parsing exposed functions in JavaScript code
+# Examples: `eel.expose(w, "func_name")`, `eel.expose(func_name)`, `eel.expose((function (e){}), "func_name")`
+EXPOSED_JS_FUNCTIONS = pp.ZeroOrMore(
+    pp.Suppress(
+        pp.SkipTo(pp.Literal('eel.expose('))
+        + pp.Literal('eel.expose(')
+        + pp.Optional(
+            pp.Or([pp.nestedExpr(), pp.Word(pp.printables, excludeChars=',')]) + pp.Literal(',')
+        )
+    )
+    + pp.Suppress(pp.Regex(r'["\']?'))
+    + pp.Word(pp.printables, excludeChars='"\')')
+    + pp.Suppress(pp.Regex(r'["\']?\s*\)')),
+)
+
+
 def init(path, allowed_extensions=['.js', '.html', '.txt', '.htm',
                                    '.xhtml', '.vue'], js_result_timeout=10000):
     global root_path, _js_functions, _js_result_timeout
@@ -98,12 +115,8 @@ def init(path, allowed_extensions=['.js', '.html', '.txt', '.htm',
                 with open(os.path.join(root, name), encoding='utf-8') as file:
                     contents = file.read()
                     expose_calls = set()
-                    finder = rgx.findall(r'eel\.expose\(([^\)]+)\)', contents)
-                    for expose_call in finder:
-                        # If name specified in 2nd argument, strip quotes and store as function name
-                        if ',' in expose_call:
-                            expose_call = rgx.sub(r'["\']', '', expose_call.split(',')[1])
-                        expose_call = expose_call.strip()
+                    matches = EXPOSED_JS_FUNCTIONS.parseString(contents).asList()
+                    for expose_call in matches:
                         # Verify that function name is valid
                         msg = "eel.expose() call contains '(' or '='"
                         assert rgx.findall(r'[\(=]', expose_call) == [], msg

examples/07 - CreateReactApp/eel_CRA.py

@@ -55,6 +55,8 @@ def start_eel(develop):
     say_hello_py('Python World!')
     eel.say_hello_js('Python World!')   # Call a JavaScript function (must be after `eel.init()`)
 
+    eel.show_log('https://github.com/samuelhwilliams/Eel/issues/363 (show_log)')
+
     eel_kwargs = dict(
         host='localhost',
         port=8080,

examples/07 - CreateReactApp/src/App.tsx

@@ -13,6 +13,12 @@ function sayHelloJS( x: any ) {
 // WARN: must use window.eel to keep parse-able eel.expose{...}
 window.eel.expose( sayHelloJS, 'say_hello_js' )
 
+// Test anonymous function when minimized. See https://github.com/samuelhwilliams/Eel/issues/363
+function show_log(msg:string) {
+  console.log(msg)
+}
+window.eel.expose(show_log, 'show_log')
+
 // Test calling sayHelloJS, then call the corresponding Python function
 sayHelloJS( 'Javascript World!' )
 eel.say_hello_py( 'Javascript World!' )

requirements.txt

@@ -3,4 +3,5 @@ bottle-websocket==0.2.9
 gevent==1.3.6
 gevent-websocket==0.10.1
 greenlet==0.4.15
+pyparsing==2.4.7
 whichcraft==0.4.1

setup.py

@@ -14,7 +14,7 @@
     package_data={
         'eel': ['eel.js'],
     },
-    install_requires=['bottle', 'bottle-websocket', 'future', 'whichcraft'],
+    install_requires=['bottle', 'bottle-websocket', 'future', 'pyparsing', 'whichcraft'],
     extras_require={
         "jinja2": ['jinja2>=2.10']
     },

tests/conftest.py

@@ -21,7 +21,7 @@ def driver():
     # Firefox doesn't currently supported pulling JavaScript console logs, which we currently scan to affirm that
     # JS/Python can communicate in some places. So for now, we can't really use firefox/geckodriver during testing.
     # This may be added in the future: https://github.com/mozilla/geckodriver/issues/284
-    
+
     # elif TEST_BROWSER == "firefox":
     #     options = webdriver.FirefoxOptions()
     #     options.headless = True

tests/data/init_test/App.tsx

@@ -0,0 +1,58 @@
+import React, { Component } from 'react';
+import logo from './logo.svg';
+import './App.css';
+
+// Point Eel web socket to the instance
+export const eel = window.eel
+eel.set_host( 'ws://localhost:8080' )
+
+// Expose the `sayHelloJS` function to Python as `say_hello_js`
+function sayHelloJS( x: any ) {
+  console.log( 'Hello from ' + x )
+}
+// WARN: must use window.eel to keep parse-able eel.expose{...}
+window.eel.expose( sayHelloJS, 'say_hello_js' )
+
+// Test anonymous function when minimized. See https://github.com/samuelhwilliams/Eel/issues/363
+function show_log(msg:string) {
+  console.log(msg)
+}
+window.eel.expose(show_log, 'show_log')
+
+// Test calling sayHelloJS, then call the corresponding Python function
+sayHelloJS( 'Javascript World!' )
+eel.say_hello_py( 'Javascript World!' )
+
+// Set the default path. Would be a text input, but this is a basic example after all
+const defPath = '~'
+
+interface IAppState {
+  message: string
+  path: string
+}
+
+export class App extends Component<{}, {}> {
+  public state: IAppState = {
+    message: `Click button to choose a random file from the user's system`,
+    path: defPath,
+  }
+
+  public pickFile = () => {
+    eel.pick_file(defPath)(( message: string ) => this.setState( { message } ) )
+  }
+
+  public render() {
+    eel.expand_user(defPath)(( path: string ) => this.setState( { path } ) )
+    return (
+      <div className="App">
+        <header className="App-header">
+          <img src={logo} className="App-logo" alt="logo" />
+          <p>{this.state.message}</p>
+          <button className='App-button' onClick={this.pickFile}>Pick Random File From `{this.state.path}`</button>
+        </header>
+      </div>
+    );
+  }
+}
+
+export default App;

tests/data/init_test/hello.html

@@ -0,0 +1,27 @@
+{% extends 'base.html' %} 
+{% block title %}Hello, World!{% endblock %}
+{% block head_scripts %}        
+    eel.expose(say_hello_js);               // Expose this function to Python
+        function say_hello_js(x) {
+        console.log("Hello from " + x);
+    }
+
+    eel.expose(js_random);
+    function js_random() {
+        return Math.random();
+    }
+
+    function print_num(n) {
+        console.log('Got this from Python: ' + n);
+    }
+
+    eel.py_random()(print_num);
+        
+    say_hello_js("Javascript World!");
+    eel.say_hello_py("Javascript World!");  // Call a Python function
+{% endblock %}
+{% block content %}
+    Hello, World!
+    <br />
+    <a href="page2.html">Page 2</a>
+{% endblock %}