Automated Lint Fixes

This tutorial demonstrates how to use Droid Exec to automatically fix ESLint violations across your codebase. The script identifies files with lint errors and intelligently fixes them while preserving functionality.

This approach works with any ESLint rule - from simple formatting issues to complex architectural patterns.

How it works

The script:

Finds violations: Runs ESLint to identify all route.ts files missing middleware
Analyzes context: Determines the appropriate middleware type based on the route path
Adds middleware: Inserts the correct handle*Middleware call as the first statement
Preserves logic: Wraps existing code in the middleware callback
Maintains types: Ensures TypeScript types are correctly preserved
Formats code: Maintains consistent code style

Get the script

View full script source

#!/bin/bash

# Droid Route Middleware Fix Script
# Automatically adds required middleware to NextJS API routes that are missing them
#
# Usage: ./droid-fix-route-middleware.sh [directory]
# Example: ./droid-fix-route-middleware.sh apps/factory-app

set -e

# Configuration
CONCURRENCY=${CONCURRENCY:-5}
DRY_RUN=${DRY_RUN:-false}
TARGET_DIR="${1:-.}"
ESLINT_RULE="factory/require-route-middleware"

# Colors for output
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
RED='\033[0;31m'
NC='\033[0m'

# Temp files for tracking
TEMP_DIR=$(mktemp -d)
VIOLATIONS_FILE="$TEMP_DIR/violations.txt"
PROCESSED_COUNT=0
FIXED_COUNT=0
FAILED_COUNT=0

# Cleanup on exit
trap "rm -rf $TEMP_DIR" EXIT

# Function to detect violations using ESLint
find_violations() {
    echo -e "${BLUE}Scanning for route middleware violations...${NC}"
    
    # Run ESLint with the specific rule and capture violations
    # Using --format json for easier parsing
    npx eslint "$TARGET_DIR" \
        --ext .ts,.tsx \
        --rule "${ESLINT_RULE}: error" \
        --format json 2>/dev/null | \
        jq -r '.[] | select(.errorCount > 0) | .filePath' > "$VIOLATIONS_FILE" || true
    
    # Alternative approach if the above doesn't work - find all route.ts files
    # and check them individually
    if [ ! -s "$VIOLATIONS_FILE" ]; then
        find "$TARGET_DIR" -type f -name "route.ts" \
            ! -path "*/node_modules/*" \
            ! -path "*/.next/*" \
            ! -path "*/dist/*" \
            ! -path "*/build/*" | while read -r file; do
            # Check if file has middleware violations
            if npx eslint "$file" \
                --rule "${ESLINT_RULE}: error" \
                --format compact 2>&1 | grep -q "require-route-middleware"; then
                echo "$file" >> "$VIOLATIONS_FILE"
            fi
        done
    fi
}

# Function to determine the appropriate middleware type based on route path
get_middleware_type() {
    local filepath="$1"
    
    # Check for specific route patterns
    if [[ "$filepath" == *"/api/cron/"* ]]; then
        echo "cron"
    elif [[ "$filepath" == *"/api/webhooks/"* ]]; then
        echo "public"
    elif [[ "$filepath" == *"/api/admin/"* ]]; then
        echo "admin"
    elif [[ "$filepath" == *"/api/auth/"* ]] && [[ "$filepath" != *"/logout"* ]]; then
        echo "public"
    elif [[ "$filepath" == *"/api/health"* ]] || [[ "$filepath" == *"/api/echo"* ]]; then
        echo "public"
    elif [[ "$filepath" == *"factory-admin"* ]]; then
        echo "admin"
    else
        echo "authenticated"
    fi
}

# Function to process a single file
process_file() {
    local filepath="$1"
    local filename=$(basename "$filepath")
    local middleware_type=$(get_middleware_type "$filepath")
    
    echo -e "${BLUE}Processing: $filepath${NC}"
    echo -e "  Detected type: $middleware_type middleware needed"
    
    # The AI prompt for adding middleware
    local prompt="Fix the middleware violations in $filepath by adding the appropriate middleware handler.

IMPORTANT CONTEXT:
This is a NextJS API route file that needs middleware added to each exported HTTP handler (GET, POST, PUT, DELETE, etc.).
The middleware must be the FIRST statement in each handler function.

Based on the route type ($middleware_type), use the appropriate middleware:

1. For 'authenticated' routes (require user login):
\`\`\`typescript
import { handleAuthenticatedMiddleware } from '@/app/api/_utils/middleware';

export async function GET(req: NextRequest) {
  return handleAuthenticatedMiddleware(req, async ({ req, user }) => {
    // Existing route logic here
    // 'user' is the authenticated UserRecord
    return NextResponse.json({ data });
  });
}
\`\`\`

2. For 'public' routes (no auth required):
\`\`\`typescript
import { handlePublicMiddleware } from '@/app/api/_utils/middleware';

export async function POST(req: NextRequest) {
  return handlePublicMiddleware(req, async (req) => {
    // Existing route logic here
    return NextResponse.json({ data });
  });
}
\`\`\`

3. For 'cron' routes (require cron secret):
\`\`\`typescript
import { handleCronMiddleware } from '@/app/api/_utils/middleware';

export async function POST(req: NextRequest) {
  return handleCronMiddleware(req, async (req) => {
    // Existing route logic here
    return NextResponse.json({ success: true });
  });
}
\`\`\`

4. For 'admin' routes (require admin role):
\`\`\`typescript
import { handleAuthenticatedMiddleware, AdminRole } from '@/app/api/_utils/middleware';

export async function GET(req: NextRequest) {
  return handleAuthenticatedMiddleware(
    req,
    async ({ req, user }) => {
      // Existing route logic here
      return NextResponse.json({ data });
    },
    { requiredRole: AdminRole.ADMIN_1 }
  );
}
\`\`\`

Additional options can be passed:
- \`context\`: String for error logging context
- \`requireCsrf\`: Boolean to enable CSRF validation
- \`requiredRole\`: AdminRole enum value for role-based access

INSTRUCTIONS:
1. Add the appropriate import for the middleware function if not present
2. Wrap the ENTIRE body of each exported HTTP handler with the middleware call
3. The middleware should return the result of the middleware function
4. Move ALL existing logic inside the middleware callback
5. Preserve all existing imports, types, and logic exactly as-is
6. If the handler already uses try-catch for error handling, you can remove it as the middleware handles errors
7. Ensure the callback parameters match the middleware type (some provide 'user', others just 'req')

Only modify the route handlers to add middleware. Return the complete fixed file."
    
    if [ "$DRY_RUN" = "true" ]; then
        echo -e "${YELLOW}  [DRY RUN] Would add $middleware_type middleware${NC}"
        return 0
    fi
    
    # Run droid to fix the middleware
    if droid exec --auto low "$prompt" 2>/dev/null; then
        # Verify the fix worked by running ESLint again
        if npx eslint "$filepath" \
            --rule "${ESLINT_RULE}: error" \
            --no-eslintrc \
            --plugin factory \
            --format compact 2>&1 | grep -q "require-route-middleware"; then
            echo -e "${RED}  ✗ Failed to fix all violations${NC}"
            ((FAILED_COUNT++))
        else
            echo -e "${GREEN}  ✓ Fixed middleware violations${NC}"
            ((FIXED_COUNT++))
        fi
        ((PROCESSED_COUNT++))
    else
        echo -e "${RED}  ✗ Failed to process${NC}"
        ((FAILED_COUNT++))
    fi
}

# Export function and variables for parallel execution
export -f process_file get_middleware_type
export DRY_RUN GREEN YELLOW BLUE RED NC ESLINT_RULE

# Main execution
echo -e "${BLUE}=== Droid Route Middleware Fix ===${NC}"
echo -e "${BLUE}Directory: $TARGET_DIR${NC}"
echo -e "${BLUE}Concurrency: $CONCURRENCY${NC}"
[ "$DRY_RUN" = "true" ] && echo -e "${YELLOW}DRY RUN MODE${NC}"
echo ""

# Find violations
find_violations

VIOLATION_COUNT=$(wc -l < "$VIOLATIONS_FILE" 2>/dev/null | tr -d ' ' || echo 0)

if [ "$VIOLATION_COUNT" -eq 0 ]; then
    echo -e "${GREEN}No middleware violations found!${NC}"
    exit 0
fi

echo -e "${YELLOW}Found $VIOLATION_COUNT files with middleware violations${NC}\n"

# Process files in parallel
cat "$VIOLATIONS_FILE" | xargs -n 1 -P "$CONCURRENCY" -I {} bash -c 'process_file "$@"' _ {}

# Show summary
echo -e "\n${BLUE}=== Summary ===${NC}"
echo -e "${GREEN}Files processed: $PROCESSED_COUNT${NC}"
if [ "$DRY_RUN" = "false" ]; then
    echo -e "${GREEN}Files fixed: $FIXED_COUNT${NC}"
    [ "$FAILED_COUNT" -gt 0 ] && echo -e "${RED}Files failed: $FAILED_COUNT${NC}"
fi

if [ "$DRY_RUN" = "false" ] && [ "$FIXED_COUNT" -gt 0 ]; then
    echo -e "\n${BLUE}Next steps:${NC}"
    echo "  npm run lint           # Verify all violations are fixed"
    echo "  npm run typecheck      # Check TypeScript compilation"
    echo "  npm run test           # Run tests"
    echo "  git diff              # Review changes"
    echo "  git add -A            # Stage changes"
    echo "  git commit -m 'fix: add required middleware to API routes'"
fi

# Exit with error if some files failed
[ "$FAILED_COUNT" -gt 0 ] && exit 1
exit 0

Critical for Success: When customizing this script for your own lint rules, always include concrete before/after examples in the prompt you give to Droid Exec. This dramatically improves accuracy.Good prompt structure:

Describe the violation to fix
Show a “before” code example with the violation
Show an “after” code example with the fix applied
List any edge cases or patterns to preserve

The more specific your examples, the better Droid will understand and implement the fix pattern.

Prerequisites

Before you begin, ensure you have completed the Droid Exec installation

Basic usage

Preview violations (dry run)

Always start with a dry run to see which files need fixing before making changes.

The dry run shows you which files violate the middleware rule and what type of middleware would be added:

# Preview what would happen (no changes made)
DRY_RUN=true ./droid-fix-route-middleware.sh apps/factory-admin/src/app/api

# Example output:
# === Droid Route Middleware Fix ===
# Directory: apps/factory-admin/src/app/api
# Concurrency: 5
# DRY RUN MODE
#
# Scanning for route middleware violations...
# Found 3 files with middleware violations
#
# Processing: apps/factory-admin/src/app/api/health/route.ts
#   Detected type: public middleware needed
#   [DRY RUN] Would add public middleware
# Processing: apps/factory-admin/src/app/api/orgs/route.ts
#   Detected type: admin middleware needed
#   [DRY RUN] Would add admin middleware
# Processing: apps/factory-admin/src/app/api/cron/batch-friction/poll-and-report/route.ts
#   Detected type: cron middleware needed
#   [DRY RUN] Would add cron middleware
#
# === Summary ===
# Files processed: 0

How dry run works:

When DRY_RUN=true: Identifies violations and shows what middleware type would be added
When DRY_RUN=false (default): Actually fixes the violations by adding middleware

This helps you:

Understand which routes are missing middleware
Verify the correct middleware type will be used
Estimate the scope of changes

Apply fixes

Once ready, run the actual fix:

# Fix all violations in a directory
./droid-fix-route-middleware.sh apps/factory-admin/src/app/api

# Example output:
# === Droid Route Middleware Fix ===
# Directory: apps/factory-admin/src/app/api
# Concurrency: 5
#
# Scanning for route middleware violations...
# Found 3 files with middleware violations
#
# Processing: apps/factory-admin/src/app/api/health/route.ts
#   Detected type: public middleware needed
# Processing: apps/factory-admin/src/app/api/cron/batch-friction/poll-and-report/route.ts
#   Detected type: cron middleware needed
# Processing: apps/factory-admin/src/app/api/orgs/route.ts
#   Detected type: admin middleware needed
# ✓ Fixed middleware violations
# ✓ Fixed middleware violations  
# ✓ Fixed middleware violations

Real-world transformations

Example 1: Simple GET Handler

Before
After

Missing middleware - no authentication check!

// apps/factory-app/src/app/api/sessions/route.ts
import { NextRequest, NextResponse } from 'next/server';
import { getFirestoreInstance } from '@factory/services/firebase/admin';

export async function GET(req: NextRequest) {
  const searchParams = req.nextUrl.searchParams;
  const userId = searchParams.get('userId');
  
  ...
  
  return NextResponse.json({
    sessions: sessions.docs.map(doc => doc.data())
  });
}

Example 2: Cron Job Handler

Before
After

Cron job without authorization - anyone could trigger it!

// apps/factory-admin/src/app/api/cron/batch-friction/poll-and-report/route.ts
export async function GET(request: NextRequest) {
  
  logInfo('[poll-report] Starting poll and report workflow');

  const results = {
    polledBatches: 0,
    processedBatches: 0,
    failedBatches: [],
    reportGenerated: false,
    reportError: null,
  };

  // ... rest of the cron job logic ...

  return NextResponse.json({
    success,
    message,
    summary: {
      processedBatches: results.processedBatches,
      failedBatches: results.failedBatches.length,
      reportGenerated: results.reportGenerated,
    },
  });
}

Best practices

Follow these best practices for safe and effective middleware addition.

Start with dry run

Preview changes before applying:

# See what would be fixed without making changes
DRY_RUN=true ./droid-fix-route-middleware.sh apps

Process by app

Fix one application at a time for easier review:

# Fix factory-app routes
./droid-fix-route-middleware.sh apps/factory-app
npm run typecheck -- --filter=factory-app
git add -A && git commit -m "fix(factory-app): add required middleware to API routes"

# Fix factory-admin routes
./droid-fix-route-middleware.sh apps/factory-admin
npm run typecheck -- --filter=factory-admin
git add -A && git commit -m "fix(factory-admin): add required middleware to API routes"

Getting Started

User Guides

Configuration

Droid Exec (Headless)

Account

How it works

Get the script

Prerequisites

Basic usage

Preview violations (dry run)

Apply fixes

Real-world transformations

Example 1: Simple GET Handler

Example 2: Cron Job Handler

Best practices

Getting Started

User Guides

Configuration

Droid Exec (Headless)

Account

​How it works

​Get the script

​Prerequisites

​Basic usage

​Preview violations (dry run)

​Apply fixes

​Real-world transformations

​Example 1: Simple GET Handler

​Example 2: Cron Job Handler

​Best practices

How it works

Get the script

Prerequisites

Basic usage

Preview violations (dry run)

Apply fixes

Real-world transformations

Example 1: Simple GET Handler

Example 2: Cron Job Handler

Best practices