feat(regex): add .NET regex validation via PowerShell and integrate into frontend

Dockerfile

@@ -1,13 +1,28 @@
 # Dockerfile
 FROM python:3.9-slim
 WORKDIR /app
-# Install git and gosu for user switching
-RUN apt-get update && apt-get install -y git gosu && rm -rf /var/lib/apt/lists/*
+# Install git, gosu, and PowerShell Core
+RUN apt-get update && apt-get install -y \
+    git \
+    gosu \
+    wget \
+    ca-certificates \
+    libicu-dev \
+    && wget -O /tmp/powershell.tar.gz https://github.com/PowerShell/PowerShell/releases/download/v7.4.0/powershell-7.4.0-linux-x64.tar.gz \
+    && mkdir -p /opt/microsoft/powershell/7 \
+    && tar zxf /tmp/powershell.tar.gz -C /opt/microsoft/powershell/7 \
+    && chmod +x /opt/microsoft/powershell/7/pwsh \
+    && ln -s /opt/microsoft/powershell/7/pwsh /usr/bin/pwsh \
+    && rm /tmp/powershell.tar.gz \
+    && rm -rf /var/lib/apt/lists/*
 # Copy pre-built files from dist directory
 COPY dist/backend/app ./app
+COPY dist/backend/scripts ./app/scripts
 COPY dist/static ./app/static
 COPY dist/requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
+# Ensure scripts are executable
+RUN chmod +x /app/scripts/*.ps1 || true
 # Copy and setup entrypoint script
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh

backend/Dockerfile

@@ -1,7 +1,21 @@
 FROM python:3.9
 WORKDIR /app
+# Install PowerShell Core
+RUN apt-get update && apt-get install -y \
+    wget \
+    ca-certificates \
+    libicu-dev \
+    && wget -O /tmp/powershell.tar.gz https://github.com/PowerShell/PowerShell/releases/download/v7.4.0/powershell-7.4.0-linux-x64.tar.gz \
+    && mkdir -p /opt/microsoft/powershell/7 \
+    && tar zxf /tmp/powershell.tar.gz -C /opt/microsoft/powershell/7 \
+    && chmod +x /opt/microsoft/powershell/7/pwsh \
+    && ln -s /opt/microsoft/powershell/7/pwsh /usr/bin/pwsh \
+    && rm /tmp/powershell.tar.gz \
+    && rm -rf /var/lib/apt/lists/*
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 COPY . .
+# Ensure scripts are executable
+RUN chmod +x /app/scripts/*.ps1 || true
 # Use gunicorn with 10-minute timeout
 CMD ["python", "-m", "app.main"]

backend/app/data/__init__.py

@@ -226,6 +226,32 @@ def handle_item(category, name):
         return jsonify({"error": "An unexpected error occurred"}), 500
 
 
+@bp.route('/regex/verify', methods=['POST'])
+def verify_regex():
+    """Verify a regex pattern using .NET regex engine via PowerShell"""
+    try:
+        data = request.get_json()
+        if not data:
+            return jsonify({"error": "No JSON data provided"}), 400
+        
+        pattern = data.get('pattern')
+        if not pattern:
+            return jsonify({"error": "Pattern is required"}), 400
+        
+        from .utils import verify_dotnet_regex
+        
+        success, message = verify_dotnet_regex(pattern)
+        
+        if success:
+            return jsonify({"valid": True, "message": "Pattern is valid"}), 200
+        else:
+            return jsonify({"valid": False, "error": message}), 200
+    
+    except Exception as e:
+        logger.exception("Error verifying regex pattern")
+        return jsonify({"valid": False, "error": str(e)}), 500
+
+
 @bp.route('/<string:category>/test', methods=['POST'])
 def run_tests(category):
     logger.info(f"Received test request for category: {category}")

backend/app/data/utils.py

@@ -7,6 +7,8 @@ from typing import Dict, List, Any, Tuple, Union
 import git
 import regex
 import logging
+import subprocess
+import json
 from ..db.queries.arr import update_arr_config_on_rename, update_arr_config_on_delete
 
 logger = logging.getLogger(__name__)
@@ -360,6 +362,68 @@ def check_delete_constraints(category: str, name: str) -> Tuple[bool, str]:
         return False, f"Error checking references: {str(e)}"
 
 
+def verify_dotnet_regex(pattern: str) -> Tuple[bool, str]:
+    """
+    Verify a regex pattern using .NET regex engine via PowerShell.
+    Returns (success, message) tuple.
+    """
+    try:
+        # Get the path to the validate.ps1 script
+        # In Docker, the structure is /app/app/data/utils.py and script is at /app/scripts/validate.ps1
+        script_path = os.path.join('/app', 'scripts', 'validate.ps1')
+        if not os.path.exists(script_path):
+            # Fallback for local development
+            script_path = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'scripts', 'validate.ps1')
+        
+        # Run PowerShell script, passing pattern via stdin to avoid shell escaping issues
+        result = subprocess.run(
+            ['pwsh', '-File', script_path],
+            input=pattern,
+            capture_output=True,
+            text=True,
+            timeout=5
+        )
+        
+        if result.returncode != 0 and not result.stdout:
+            logger.error(f"PowerShell script failed: {result.stderr}")
+            return False, "Failed to validate pattern"
+        
+        # Log the raw output for debugging
+        logger.debug(f"PowerShell output: {result.stdout}")
+        
+        # Parse JSON output
+        try:
+            output = json.loads(result.stdout.strip())
+        except json.JSONDecodeError:
+            # Try to find JSON in the output
+            lines = result.stdout.strip().split('\n')
+            for line in reversed(lines):
+                if line.strip():
+                    try:
+                        output = json.loads(line)
+                        break
+                    except json.JSONDecodeError:
+                        continue
+            else:
+                logger.error(f"No valid JSON found in output: {result.stdout}")
+                return False, "Failed to parse validation result"
+        
+        if output.get('valid'):
+            return True, output.get('message', 'Pattern is valid')
+        else:
+            return False, output.get('error', 'Invalid pattern')
+            
+    except subprocess.TimeoutExpired:
+        logger.error("Pattern validation timed out")
+        return False, "Pattern validation timed out"
+    except FileNotFoundError:
+        logger.error("PowerShell (pwsh) not found")
+        return False, "PowerShell is not available"
+    except Exception as e:
+        logger.error(f"Error validating pattern: {e}")
+        return False, f"Validation error: {str(e)}"
+
+
 def update_references(category: str, old_name: str,
                       new_name: str) -> List[str]:
     """

backend/scripts/validate.ps1

@@ -0,0 +1,73 @@
+#!/usr/bin/env pwsh
+# Validate a .NET regex pattern
+
+param(
+    [Parameter(Mandatory=$false)]
+    [string]$Pattern
+)
+
+# Set output encoding to UTF-8
+[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+$ErrorActionPreference = "Stop"
+
+# Read pattern from stdin if not provided as parameter
+if (-not $Pattern) {
+    $Pattern = [System.Console]::In.ReadToEnd()
+}
+
+# Ensure we have a pattern
+if ([string]::IsNullOrWhiteSpace($Pattern)) {
+    $result = @{
+        valid = $false
+        error = "No pattern provided"
+    }
+    Write-Output (ConvertTo-Json $result -Compress)
+    exit 0
+}
+
+try {
+    # Attempt to create a .NET Regex object with the pattern
+    # Using IgnoreCase option as per requirement
+    $regex = [System.Text.RegularExpressions.Regex]::new($Pattern, [System.Text.RegularExpressions.RegexOptions]::IgnoreCase)
+    
+    # If we get here, the pattern is valid
+    $result = @{
+        valid = $true
+        message = "Pattern is valid .NET regex"
+    }
+    
+    Write-Output (ConvertTo-Json $result -Compress)
+    exit 0
+}
+catch {
+    # Pattern is invalid, extract the meaningful part of the error message
+    $errorMessage = $_.Exception.Message
+    
+    # Try to extract just the useful part of .NET regex errors
+    if ($errorMessage -match "Invalid pattern '.*?' at offset (\d+)\. (.+)") {
+        $errorMessage = "At position $($matches[1]): $($matches[2])"
+    }
+    elseif ($errorMessage -match 'parsing ".*?" - (.+)') {
+        $errorMessage = $matches[1]
+    }
+    elseif ($errorMessage -match 'Exception calling .* with .* argument\(s\): "(.+)"') {
+        $innerError = $matches[1]
+        if ($innerError -match "Invalid pattern '.*?' at offset (\d+)\. (.+)") {
+            $errorMessage = "At position $($matches[1]): $($matches[2])"
+        }
+        else {
+            $errorMessage = $innerError
+        }
+    }
+    
+    # Remove any trailing quotes or periods followed by quotes
+    $errorMessage = $errorMessage -replace '\."$', '.' -replace '"$', ''
+    
+    $result = @{
+        valid = $false
+        error = $errorMessage
+    }
+    
+    Write-Output (ConvertTo-Json $result -Compress)
+    exit 0
+}

frontend/src/api/data.js

@@ -301,5 +301,15 @@ export const RegexPatterns = {
     update: (name, data, newName) =>
         updateItem('regex_pattern', name, data, newName),
     delete: name => deleteItem('regex_pattern', name),
-    runTests: createSpecialEndpoint('regex_pattern', 'test')
+    runTests: createSpecialEndpoint('regex_pattern', 'test'),
+    verify: async pattern => {
+        try {
+            const response = await axios.post(`${BASE_URL}/regex/verify`, {
+                pattern
+            });
+            return response.data;
+        } catch (error) {
+            throw handleError(error, 'verify regex pattern');
+        }
+    }
 };

frontend/src/components/regex/RegexGeneralTab.jsx

@@ -2,7 +2,9 @@ import React, {useState} from 'react';
 import PropTypes from 'prop-types';
 import MarkdownEditor from '@ui/MarkdownEditor';
 import AddButton from '@ui/DataBar/AddButton';
-import {InfoIcon} from 'lucide-react';
+import {Regex, Loader} from 'lucide-react';
+import {RegexPatterns} from '@api/data';
+import Alert from '@ui/Alert';
 
 const RegexGeneralTab = ({
     name,
@@ -18,6 +20,7 @@ const RegexGeneralTab = ({
     patternError
 }) => {
     const [newTag, setNewTag] = useState('');
+    const [validating, setValidating] = useState(false);
 
     const handleAddTag = () => {
         if (newTag.trim() && !tags.includes(newTag.trim())) {
@@ -33,6 +36,30 @@ const RegexGeneralTab = ({
         }
     };
 
+    const handleValidatePattern = async () => {
+        if (!pattern?.trim()) {
+            Alert.warning('Please enter a pattern to validate');
+            return;
+        }
+
+        setValidating(true);
+        
+        try {
+            const result = await RegexPatterns.verify(pattern);
+            
+            if (result.valid) {
+                Alert.success('Pattern is valid .NET regex');
+            } else {
+                Alert.error(result.error || 'Invalid pattern');
+            }
+        } catch (error) {
+            console.error('Validation error:', error);
+            Alert.error('Failed to validate pattern');
+        } finally {
+            setValidating(false);
+        }
+    };
+
     return (
         <div className='w-full'>
             {error && (
@@ -89,17 +116,28 @@ const RegexGeneralTab = ({
                 <div className='space-y-2'>
                     <div className='space-y-1'>
                         <div className='flex items-center justify-between'>
-                            <label className='text-sm font-medium text-gray-700 dark:text-gray-300'>
-                                Pattern
-                            </label>
-                            <div className='flex items-center gap-2 text-xs text-blue-600 dark:text-blue-400'>
-                                <InfoIcon className='h-4 w-4' />
-                                <span>Case insensitive PCRE2</span>
+                            <div>
+                                <label className='text-sm font-medium text-gray-700 dark:text-gray-300'>
+                                    Pattern
+                                </label>
+                                <p className='text-xs text-gray-500 dark:text-gray-400'>
+                                    Enter your regular expression pattern (case-insensitive .NET)
+                                </p>
                             </div>
+                            <button
+                                onClick={handleValidatePattern}
+                                disabled={validating || !pattern?.trim()}
+                                className='inline-flex items-center px-3 py-1.5 text-sm font-medium rounded-md 
+                                bg-blue-600 hover:bg-blue-700 disabled:bg-blue-600/50 text-white
+                                transition-colors duration-200'>
+                                {validating ? (
+                                    <Loader className='w-4 h-4 mr-2 animate-spin' />
+                                ) : (
+                                    <Regex className='w-4 h-4 mr-2' />
+                                )}
+                                Validate
+                            </button>
                         </div>
-                        <p className='text-xs text-gray-500 dark:text-gray-400'>
-                            Enter your regular expression pattern
-                        </p>
                     </div>
                     {patternError && (
                         <p className='text-sm text-red-600 dark:text-red-400'>

frontend/src/hooks/useRegexModal.js

@@ -65,6 +65,19 @@ export const useRegexModal = (initialPattern, onSave) => {
             return;
         }
 
+        // Validate pattern with .NET regex engine
+        try {
+            const validationResult = await RegexPatterns.verify(patternValue);
+            if (!validationResult.valid) {
+                Alert.error(`Invalid regex pattern: ${validationResult.error || 'Pattern validation failed'}`);
+                return;
+            }
+        } catch (error) {
+            console.error('Pattern validation error:', error);
+            Alert.error('Failed to validate pattern. Please check the pattern and try again.');
+            return;
+        }
+
         try {
             const data = {
                 name,