inspector: Add WebSocket support for Chrome DevTools Protocol integration #106

Copilot · 2025-07-18T17:02:35Z

This PR implements WebSocket support in the JSAR Inspector, enabling real-time debugging communication as the foundation for Chrome DevTools Protocol (CDP) integration.

Changes Made

Core WebSocket Implementation

Connection Upgrade: Added automatic detection and handling of HTTP to WebSocket upgrade requests
RFC 6455 Compliance: Implemented proper WebSocket handshake with SHA-1 + Base64 key generation
Frame Handling: Added WebSocket frame parsing for incoming messages and frame generation for outgoing messages
Connection Management: Added connection type tracking (HTTP vs WebSocket) with proper state transitions

Connection Limiting

Maximum Connections: Enforced limit of 5 concurrent WebSocket connections
Graceful Rejection: Additional connection attempts receive HTTP 503 Service Unavailable response
Connection Tracking: Added getWebSocketConnectionCount() method to monitor active connections

Enhanced Inspector Architecture

// New connection type tracking
enum class ConnectionType { HTTP, WEBSOCKET };

// WebSocket-specific methods
bool tryUpgradeToWebSocket();
void handleWebSocketFrame();
void sendWebSocketMessage(const std::string &message);
bool canAcceptWebSocketConnection();

Backward Compatibility

Preserved HTTP API: All existing /json/* endpoints continue to work unchanged
No Breaking Changes: HTTP functionality remains completely intact
Graceful Degradation: Invalid WebSocket upgrade requests are processed as normal HTTP requests

Usage Example

// Connect to JSAR Inspector via WebSocket
const ws = new WebSocket('ws://localhost:9423/devtools/inspector/1');

ws.onopen = () => {
    // Send CDP-style command
    ws.send(JSON.stringify({
        id: 1,
        method: 'Runtime.enable',
        params: {}
    }));
};

ws.onmessage = (event) => {
    const response = JSON.parse(event.data);
    console.log('Inspector response:', response);
};

Testing

Unit Tests: Comprehensive tests for WebSocket key generation and frame parsing
Integration Tests: Validation of HTTP endpoint compatibility and WebSocket upgrade process
Connection Limit Testing: Verification of 5-connection limit enforcement

Technical Details

WebSocket Handshake: Validates required headers (Upgrade: websocket, Connection: Upgrade, Sec-WebSocket-Key)
Frame Format: Supports text frames (opcode 0x1) and close frames (opcode 0x8)
Message Handling: Currently implements echo functionality as placeholder for CDP implementation
Error Handling: Proper connection cleanup, frame validation, and timeout handling

This implementation provides the WebSocket transport layer needed for CDP, with the next phase being the replacement of echo functionality with actual CDP message routing and domain implementations.

Fixes #105.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

registry.npmmirror.com
- Triggering command: npm install (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to my firewall allow list

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

yorkie

Remove the build files which should not be committed
Follow the clang-format style in your C/C++ files
Does the SSL necessary?
Add a sample to connect & send/recv from the inspector websocket

Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Copilot · 2025-07-18T17:33:27Z

Remove the build files which should not be committed

Follow the clang-format style in your C/C++ files

Does the SSL necessary?
...

All feedback addressed in commits a47862e and 79eaa34:

✅ Removed build files (build/cmake/*) that were incorrectly committed
✅ Applied clang-format to all C++ files for consistent formatting
✅ Replaced OpenSSL dependency with self-contained SHA-1 and Base64 implementation for WebSocket handshake (RFC 6455 compliant)
✅ Added comprehensive WebSocket examples: Node.js client, HTML test page, and documentation in /examples/

yorkie · 2025-07-18T17:54:03Z

examples/README.md

Move the inspector example to the fixtures/inspector-client

Moved inspector examples to fixtures/inspector-client/ directory as requested in commit af2033b.

yorkie · 2025-07-18T17:54:39Z

examples/inspector_websocket_test.html

Use 2 spaces

Fixed HTML indentation to use 2 spaces instead of 4 spaces in commit af2033b.

src/runtime/inspector_client.hpp

yorkie · 2025-07-18T17:58:21Z

src/runtime/inspector_server.cpp

+  for (const auto &client : clients_)
+  {
+    if (client->isWebSocket())
+    {


Suggested change

{

count++;

yorkie · 2025-07-18T17:58:57Z

src/runtime/inspector_server.hpp

 public:
  void tryAccept();
  void tick();
+  int getWebSocketConnectionCount() const;


Suggested change

int getWebSocketConnectionCount() const;

int coutWebSocketClients() const;

yorkie · 2025-07-18T18:02:51Z

src/runtime/inspector_client.cpp

+
+  for (const auto &header : headers_)
+  {
+    std::string lowerKey = header.first;


yorkie · 2025-07-18T18:02:58Z

src/runtime/inspector_client.cpp

+  for (const auto &header : headers_)
+  {
+    std::string lowerKey = header.first;
+    std::transform(lowerKey.begin(), lowerKey.end(), lowerKey.begin(), ::tolower);


yorkie · 2025-07-18T18:04:18Z

src/runtime/inspector_client.cpp

+      DEBUG(LOG_TAG_INSPECTOR, "WebSocket connection limit reached, rejecting upgrade");
+      // Send 503 Service Unavailable
+      std::stringstream response;
+      response << "HTTP/1.1 503 Service Unavailable\r\n";


You can add a method for sending 400 or 500 response, which auto calucate the content-length.

Added sendHttpErrorResponse() helper method that auto-calculates Content-Length header in commit af2033b.

yorkie · 2025-07-18T18:05:42Z

src/runtime/inspector_client.cpp

+  auto hash = sha1(combined);
+
+  // Base64 encode the hash
+  auto base64Encode = [](const std::array<uint8_t, 20> &input) -> std::string


Move the base64 encoding to the src/common/

Moved base64 encoding to src/common/utility.hpp as Base64Encode template function in commit af2033b.

yorkie · 2025-07-18T18:10:22Z

src/runtime/inspector_client.cpp

+    DEBUG(LOG_TAG_INSPECTOR, "Received WebSocket message: %s", message.c_str());
+
+    // For now, just echo the message back (placeholder for CDP implementation)
+    sendWebSocketMessage("Echo: " + message);


This should be moved to TrInspector such as a lifetime onMessage(client), and you can does this echo logic there :)

Moved echo logic to TrInspector::onMessage(client, message) method - the client now forwards WebSocket messages to the inspector for handling in commit af2033b.

…tility methods Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Copilot · 2025-07-18T18:24:36Z

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

registry.npmmirror.com
- Triggering command: npm install (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to my firewall allow list

src/runtime/inspector_client.hpp

src/runtime/inspector_server.hpp

src/runtime/inspector_client.cpp

…nlikely attribute, remove debug log Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Initial plan

3fe2934

Copilot AI assigned Copilot and yorkie Jul 18, 2025

Copilot started work on behalf of yorkie July 18, 2025 17:02 View session

Copilot AI and others added 2 commits July 18, 2025 17:12

Add WebSocket support to inspector client with connection upgrade

b3a0082

Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Add WebSocket connection limiting (max 5) and test infrastructure

929ea69

Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] inspector: supports accept connection as websocket~~ inspector: Add WebSocket support for Chrome DevTools Protocol integration Jul 18, 2025

Copilot finished work on behalf of yorkie July 18, 2025 17:19

Copilot AI requested a review from yorkie July 18, 2025 17:19

yorkie requested changes Jul 18, 2025

View reviewed changes

Copilot started work on behalf of yorkie July 18, 2025 17:25 View session

Copilot AI and others added 2 commits July 18, 2025 17:30

Remove build artifacts, apply clang-format, and add WebSocket examples

a47862e

Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Replace OpenSSL dependency with self-contained crypto implementation

79eaa34

Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Copilot finished work on behalf of yorkie July 18, 2025 17:34

Copilot AI requested a review from yorkie July 18, 2025 17:34

yorkie requested changes Jul 18, 2025

View reviewed changes

Copilot started work on behalf of yorkie July 18, 2025 18:10 View session

Address code review feedback: move examples, organize code, and add u…

af2033b

…tility methods Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Copilot AI requested a review from yorkie July 18, 2025 18:24

Copilot finished work on behalf of yorkie July 18, 2025 18:24

yorkie requested changes Jul 18, 2025

View reviewed changes

Copilot started work on behalf of yorkie July 18, 2025 18:39 View session

Address PR feedback: use std::string signatures, rename method, add u…

c2a8fdb

…nlikely attribute, remove debug log Co-authored-by: yorkie <1935767+yorkie@users.noreply.github.com>

Copilot finished work on behalf of yorkie July 18, 2025 18:55

Copilot AI requested a review from yorkie July 18, 2025 18:55

update

6eb9c61

yorkie approved these changes Jul 18, 2025

View reviewed changes

yorkie marked this pull request as ready for review July 18, 2025 19:33

yorkie merged commit f17a093 into main Jul 18, 2025
2 checks passed

yorkie deleted the copilot/fix-105 branch July 18, 2025 19:35

Copilot AI mentioned this pull request Aug 4, 2025

Release 0.9.0: Core technical improvements and feature additions #188

Merged

	int getWebSocketConnectionCount() const;
	int coutWebSocketClients() const;

inspector: Add WebSocket support for Chrome DevTools Protocol integration #106

inspector: Add WebSocket support for Chrome DevTools Protocol integration #106

Uh oh!

Conversation

Copilot AI commented Jul 18, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Changes Made

Core WebSocket Implementation

Connection Limiting

Enhanced Inspector Architecture

Backward Compatibility

Usage Example

Testing

Technical Details

I tried to connect to the following addresses, but was blocked by firewall rules:

Uh oh!

yorkie left a comment

Choose a reason for hiding this comment

Uh oh!

Copilot AI commented Jul 18, 2025

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Copilot AI Jul 18, 2025

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Copilot AI Jul 18, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Copilot AI Jul 18, 2025

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Copilot AI Jul 18, 2025

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Copilot AI Jul 18, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI commented Jul 18, 2025

I tried to connect to the following addresses, but was blocked by firewall rules:

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Copilot AI commented Jul 18, 2025 •

edited

Loading