Charles Proxy Extract

Required Parameters

1. <file.chlsj> - Path to the Charles Proxy session file (use exact path provided by user)
2. <pattern> - URL path pattern to match (e.g., "/today", "/logs", "/" for all)

Optional Flags

• -m, --method METHOD - Filter by HTTP method (GET, POST, PUT, PATCH, DELETE)
• -f, --first-only - Show only first matching request (for quick inspection)
• -s, --summary-only - Show statistics without response bodies
• -o, --output FILE - Save responses to JSON file
• --no-pretty - Disable JSON pretty-printing

Execution Examples

Extract all /today responses:

python3 ./extract_responses.py session.chlsj "/today"

Filter by POST method (automatically shows request bodies):

python3 ./extract_responses.py session.chlsj "/logs" --method POST

Quick peek (first result only):

python3 ./extract_responses.py session.chlsj "/users" --first-only

Summary without bodies:

python3 ./extract_responses.py session.chlsj "/" --summary-only

Export to file:

python3 ./extract_responses.py session.chlsj "/items" --output items_data.json

User Request Patterns

When users say things like:

• "Extract [endpoint] from [file]" → Use basic extraction with pattern matching
• "Show POST/PUT/PATCH to [endpoint]" → Add --method flag (request bodies auto-shown)
• "First [endpoint] response" → Add --first-only flag
• "Summarize [file]" or "What's in [file]" → Add --summary-only flag
• "Save [endpoint] to [output]" → Add --output flag
• "Compare [endpoint] with model" → Extract first response, then analyze structure

Important Notes

• Pattern matching is case-sensitive substring matching
• Method filtering is case-insensitive
• POST/PUT/PATCH methods automatically display request bodies when method filter is applied
• Use "/" as pattern to match all requests

What This Skill Does

Extracts HTTP/HTTPS request and response data from Charles Proxy session files, allowing you to:

• Filter requests by URL pattern (substring matching)
• Filter requests by HTTP method (GET, POST, PUT, PATCH, DELETE)
• View request bodies for mutation operations (POST/PUT/PATCH)
• Export extracted data to JSON files
• Generate traffic summaries with statistics
• Pretty-print JSON response bodies

Input Requirements

Required:

• Path to Charles Proxy session file (.chlsj format)
• URL pattern to match (use "/" to match all requests)

Optional:

• HTTP method filter (GET, POST, PUT, PATCH, DELETE)
• Output mode (full, first-only, summary-only)
• Output file path for JSON export
• Pretty-print toggle for JSON formatting

Output Format

Summary mode:

• Pattern match statistics
• Grouped paths with request counts
• Method and status code distribution

Full mode:

• Request details (method, path, status, timestamp)
• Request body (for POST/PUT/PATCH when method filter applied)
• Response body (JSON parsed or raw text)
• Pretty-printed JSON by default

Export mode:

• JSON file with structure:

  {
    "pattern": "/api/endpoint",
    "total_requests": 10,
    "extracted_at": "ISO8601 timestamp",
    "requests": [...]
  }
  

Common Usage Scenarios

"Extract all /today responses from session.chlsj" → Shows all requests matching /today pattern

"Show POST requests to /logs with request bodies" → Filters by POST method and displays request bodies

"Export all /items responses to items.json" → Saves filtered responses to JSON file

"Summarize requests in the Charles session" → Shows statistics without response bodies

Limitations

• Only supports Charles Proxy JSON session format (.chlsj)
• Pattern matching is case-sensitive substring matching
• Method filtering is case-insensitive
• Large response bodies may be truncated in display (not in exports)
• Requires Python 3.x with standard library only (no external dependencies)

Error Handling

The skill handles:

• Missing or inaccessible files (clear error message)
• Invalid JSON in session files (decoding error details)
• Empty result sets (informative message)
• Malformed request/response structures (graceful degradation)

Troubleshooting

"File not found" error:

• Verify the .chlsj file path is correct
• Use absolute paths or ensure the file is in the current directory

"Invalid JSON" error:

• Ensure the file is a valid Charles Proxy session export
• Re-export the session from Charles Proxy

No results found:

• Pattern matching is case-sensitive - check capitalization
• Try using "/" to match all requests first
• Verify the endpoint exists in the session file using --summary-only

Python not found:

• Ensure Python 3.x is installed and available in PATH
• Try using python instead of python3 or vice versa