Support persistent connection for server.

webcc/CMakeLists.txt

@@ -19,6 +19,7 @@ set(HEADERS
     http_client_pool.h
     http_client_session.h
     http_connection.h
+    http_connection_pool.h
     http_message.h
     http_parser.h
     http_request.h
@@ -46,6 +47,7 @@ set(SOURCES
     http_client_pool.cc
     http_client_session.cc
     http_connection.cc
+    http_connection_pool.cc
     http_message.cc
     http_parser.cc
     http_request.cc

webcc/http_client.cc

@@ -22,8 +22,8 @@ HttpClient::HttpClient()
 bool HttpClient::Request(HttpRequestPtr request, bool connect) {
   io_context_.restart();
 
-  response_.reset(new HttpResponse());
-  response_parser_.reset(new HttpResponseParser(response_.get()));
+  response_.reset(new HttpResponse{});
+  response_parser_.Init(response_.get());
 
   closed_ = false;
   timer_canceled_ = false;
@@ -166,7 +166,7 @@ void HttpClient::DoReadResponse(Error* error) {
 
     LOG_VERB("Socket async read handler.");
 
-    // Stop the deadline timer once the read has started.
+    // Stop the deadline timer once the read has started (or failed).
     CancelTimer();
 
     if (ec || length == 0) {
@@ -179,20 +179,17 @@ void HttpClient::DoReadResponse(Error* error) {
     LOG_INFO("Read data, length: %u.", length);
 
     // Parse the response piece just read.
-    if (!response_parser_->Parse(buffer_.data(), length)) {
-      //CancelTimer();
+    if (!response_parser_.Parse(buffer_.data(), length)) {
       Close();
       *error = kHttpError;
       LOG_ERRO("Failed to parse HTTP response.");
       return;
     }
 
-    if (response_parser_->finished()) {
+    if (response_parser_.finished()) {
       // Stop trying to read once all content has been received, because
       // some servers will block extra call to read_some().
 
-      //CancelTimer();
-
       if (response_->IsConnectionKeepAlive()) {
         // Close the timer but keep the socket connection.
         LOG_INFO("Keep the socket connection alive.");
@@ -220,22 +217,24 @@ void HttpClient::DoReadResponse(Error* error) {
 }
 
 void HttpClient::DoWaitTimer() {
+  LOG_VERB("Wait timer asynchronously.");
   timer_.async_wait(
       std::bind(&HttpClient::OnTimer, this, std::placeholders::_1));
 }
 
 void HttpClient::OnTimer(boost::system::error_code ec) {
-  if (closed_) {
+  LOG_VERB("On deadline timer.");
+
+  // timer_.cancel() was called.
+  if (ec == boost::asio::error::operation_aborted) {
+    LOG_VERB("Deadline timer canceled.");
     return;
   }
 
-  LOG_VERB("On deadline timer.");
-
-  // NOTE: Can't check this:
-  //   if (ec == boost::asio::error::operation_aborted) {
-  //     LOG_VERB("Deadline timer canceled.");
-  //     return;
-  //   }
+  if (closed_) {
+    LOG_VERB("Socket has been closed.");
+    return;
+  }
 
   if (timer_.expires_at() <= boost::asio::deadline_timer::traits_type::now()) {
     // The deadline has passed.

webcc/http_client.h

@@ -83,7 +83,7 @@ private:
   std::unique_ptr<HttpSocketBase> socket_;
 
   HttpResponsePtr response_;
-  std::unique_ptr<HttpResponseParser> response_parser_;
+  HttpResponseParser response_parser_;
 
   // Timer for the timeout control.
   boost::asio::deadline_timer timer_;

webcc/http_client_session.h

@@ -1,12 +1,9 @@
 #ifndef WEBCC_HTTP_CLIENT_SESSION_H_
 #define WEBCC_HTTP_CLIENT_SESSION_H_
 
-#include <memory>
 #include <string>
 #include <vector>
 
-#include "boost/optional.hpp"
-
 #include "webcc/http_client_pool.h"
 #include "webcc/http_request_builder.h"
 #include "webcc/http_response.h"

webcc/http_connection.cc

@@ -4,6 +4,7 @@
 
 #include "boost/asio/write.hpp"
 
+#include "webcc/http_connection_pool.h"
 #include "webcc/http_request_handler.h"
 #include "webcc/logger.h"
 
@@ -11,14 +12,17 @@ using boost::asio::ip::tcp;
 
 namespace webcc {
 
-HttpConnection::HttpConnection(tcp::socket socket, HttpRequestHandler* handler)
+HttpConnection::HttpConnection(tcp::socket socket, HttpConnectionPool* pool,
+                               HttpRequestHandler* handler)
     : socket_(std::move(socket)),
+      pool_(pool),
       buffer_(kBufferSize),
-      request_handler_(handler),
-      request_parser_(&request_) {
+      request_handler_(handler) {
 }
 
 void HttpConnection::Start() {
+  request_.reset(new HttpRequest{});
+  request_parser_.Init(request_.get());
   DoRead();
 }
 
@@ -37,8 +41,11 @@ void HttpConnection::SendResponse(HttpResponsePtr response) {
 
   response_ = response;
 
-  // TODO: Support keep-alive.
-  response_->SetHeader(http::headers::kConnection, "Close");
+  if (request_->IsConnectionKeepAlive()) {
+    response_->SetHeader(http::headers::kConnection, "Keep-Alive");
+  } else {
+    response_->SetHeader(http::headers::kConnection, "Close");
+  }
 
   response_->Prepare();
 
@@ -60,7 +67,7 @@ void HttpConnection::OnRead(boost::system::error_code ec, std::size_t length) {
   if (ec) {
     LOG_ERRO("Socket read error (%s).", ec.message().c_str());
     if (ec != boost::asio::error::operation_aborted) {
-      Close();
+      pool_->Close(shared_from_this());
     }
     return;
   }
@@ -79,7 +86,7 @@ void HttpConnection::OnRead(boost::system::error_code ec, std::size_t length) {
     return;
   }
 
-  LOG_VERB("HTTP request:\n%s", request_.Dump(4, "> ").c_str());
+  LOG_VERB("HTTP request:\n%s", request_->Dump(4, "> ").c_str());
 
   // Enqueue this connection.
   // Some worker thread will handle it later.
@@ -104,13 +111,19 @@ void HttpConnection::OnWrite(boost::system::error_code ec, std::size_t length) {
     LOG_ERRO("Socket write error (%s).", ec.message().c_str());
 
     if (ec != boost::asio::error::operation_aborted) {
-      Close();
+      pool_->Close(shared_from_this());
     }
   } else {
     LOG_INFO("Response has been sent back, length: %u.", length);
 
-    Shutdown();
-    Close();  // Necessary even after shutdown!
+    if (request_->IsConnectionKeepAlive()) {
+      LOG_INFO("The client asked for keep-alive connection.");
+      LOG_INFO("Continue to read next request...");
+      Start();
+    } else {
+      Shutdown();
+      pool_->Close(shared_from_this());
+    }
   }
 }
 

webcc/http_connection.h

@@ -15,13 +15,14 @@
 namespace webcc {
 
 class HttpConnection;
+class HttpConnectionPool;
 class HttpRequestHandler;
 
 typedef std::shared_ptr<HttpConnection> HttpConnectionPtr;
 
 class HttpConnection : public std::enable_shared_from_this<HttpConnection> {
 public:
-  HttpConnection(boost::asio::ip::tcp::socket socket,
+  HttpConnection(boost::asio::ip::tcp::socket socket, HttpConnectionPool* pool,
                  HttpRequestHandler* handler);
 
   ~HttpConnection() = default;
@@ -29,7 +30,7 @@ public:
   HttpConnection(const HttpConnection&) = delete;
   HttpConnection& operator=(const HttpConnection&) = delete;
 
-  const HttpRequest& request() const {
+  HttpRequestPtr request() const {
     return request_;
   }
 
@@ -57,6 +58,9 @@ private:
   // Socket for the connection.
   boost::asio::ip::tcp::socket socket_;
 
+  // The pool for this connection.
+  HttpConnectionPool* pool_;
+
   // Buffer for incoming data.
   std::vector<char> buffer_;
 
@@ -64,7 +68,7 @@ private:
   HttpRequestHandler* request_handler_;
 
   // The incoming request.
-  HttpRequest request_;
+  HttpRequestPtr request_;
 
   // The parser for the incoming request.
   HttpRequestParser request_parser_;

webcc/http_connection_pool.cc

@@ -0,0 +1,30 @@
+#include "webcc/http_connection_pool.h"
+
+#include "webcc/logger.h"
+
+namespace webcc {
+
+HttpConnectionPool::HttpConnectionPool() {
+}
+
+void HttpConnectionPool::Start(HttpConnectionPtr c) {
+  LOG_VERB("Starting connection...");
+  connections_.insert(c);
+  c->Start();
+}
+
+void HttpConnectionPool::Close(HttpConnectionPtr c) {
+  LOG_VERB("Closing connection...");
+  connections_.erase(c);
+  c->Close();
+}
+
+void HttpConnectionPool::CloseAll() {
+  LOG_VERB("Closing all (%u) connections...", connections_.size());
+  for (auto& c : connections_) {
+    c->Close();
+  }
+  connections_.clear();
+}
+
+}  // namespace webcc

webcc/http_connection_pool.h

@@ -0,0 +1,33 @@
+#ifndef WEBCC_HTTP_CONNECTION_POOL_H_
+#define WEBCC_HTTP_CONNECTION_POOL_H_
+
+#include <set>
+
+#include "webcc/http_connection.h"
+
+namespace webcc {
+
+class HttpConnectionPool {
+public:
+  HttpConnectionPool(const HttpConnectionPool&) = delete;
+  HttpConnectionPool& operator=(const HttpConnectionPool&) = delete;
+
+  HttpConnectionPool();
+
+  // Add a connection to the pool and start it.
+  void Start(HttpConnectionPtr c);
+
+  // Close a connection.
+  void Close(HttpConnectionPtr c);
+
+  // Close all connections.
+  void CloseAll();
+
+private:
+  /// The managed connections.
+  std::set<HttpConnectionPtr> connections_;
+};
+
+}  // namespace webcc
+
+#endif  // WEBCC_HTTP_CONNECTION_POOL_H_

webcc/http_message.h

@@ -48,6 +48,10 @@ public:
   // optional |existed| parameter will be set to false.
   const std::string& Get(const std::string& key, bool* existed = nullptr) const;
 
+  void Clear() {
+    headers_.clear();
+  }
+
 private:
   std::vector<HttpHeader>::iterator Find(const std::string& key);
 

webcc/http_parser.cc

@@ -33,6 +33,11 @@ HttpParser::HttpParser(HttpMessage* message)
       finished_(false) {
 }
 
+void HttpParser::Init(HttpMessage* message) {
+  Reset();
+  message_ = message;
+}
+
 bool HttpParser::Parse(const char* data, std::size_t length) {
   // Append the new data to the pending data.
   pending_data_.append(data, length);
@@ -63,6 +68,19 @@ bool HttpParser::Parse(const char* data, std::size_t length) {
   }
 }
 
+void HttpParser::Reset() {
+  pending_data_.clear();
+  content_.clear();
+
+  content_length_ = kInvalidLength;
+  start_line_parsed_ = false;
+  content_length_parsed_ = false;
+  header_ended_ = false;
+  chunked_ = false;
+  chunk_size_ = kInvalidLength;
+  finished_ = false;
+}
+
 bool HttpParser::ParseHeaders() {
   std::size_t off = 0;
 

webcc/http_parser.h

@@ -19,6 +19,8 @@ public:
   HttpParser(const HttpParser&) = delete;
   HttpParser& operator=(const HttpParser&) = delete;
 
+  void Init(HttpMessage* message);
+
   bool finished() const { return finished_; }
 
   std::size_t content_length() const { return content_length_; }
@@ -26,6 +28,9 @@ public:
   bool Parse(const char* data, std::size_t length);
 
 protected:
+  // Reset for next parse.
+  void Reset();
+
   // Parse headers from pending data.
   // Return false only on syntax errors.
   bool ParseHeaders();

webcc/http_request.h

@@ -64,10 +64,12 @@ public:
     return port().empty() ? default_port : port();
   }
 
+  // TODO: Remove
   std::size_t buffer_size() const {
     return buffer_size_;
   }
 
+  // TODO: Remove
   bool ssl_verify() const {
     return ssl_verify_;
   }

webcc/http_request_handler.cc

@@ -24,11 +24,10 @@ void HttpRequestHandler::Start(std::size_t count) {
 void HttpRequestHandler::Stop() {
   LOG_INFO("Stopping workers...");
 
-  // Close pending connections.
-  for (HttpConnectionPtr s = queue_.Pop(); s; s = queue_.Pop()) {
-    LOG_INFO("Closing pending connection...");
-    s->Close();
-  }
+  // Clear pending connections.
+  // The connections will be closed later (see HttpServer::DoAwaitStop).
+  LOG_INFO("Clear pending connections...");
+  queue_.Clear();
 
   // Enqueue a null connection to trigger the first worker to stop.
   queue_.Push(HttpConnectionPtr());

webcc/http_request_handler.h

@@ -29,7 +29,7 @@ public:
   // Start worker threads.
   void Start(std::size_t count);
 
-  // Close pending connections and stop worker threads.
+  // Clear pending connections from the queue and stop worker threads.
   void Stop();
 
 private:

webcc/http_request_parser.cc

@@ -11,6 +11,11 @@ HttpRequestParser::HttpRequestParser(HttpRequest* request)
     : HttpParser(request), request_(request) {
 }
 
+void HttpRequestParser::Init(HttpRequest* request) {
+  HttpParser::Init(request);
+  request_ = request;
+}
+
 bool HttpRequestParser::ParseStartLine(const std::string& line) {
   std::vector<std::string> strs;
   boost::split(strs, line, boost::is_any_of(" "), boost::token_compress_on);

webcc/http_request_parser.h

@@ -11,12 +11,14 @@ class HttpRequest;
 
 class HttpRequestParser : public HttpParser {
 public:
-  explicit HttpRequestParser(HttpRequest* request);
+  explicit HttpRequestParser(HttpRequest* request = nullptr);
 
   ~HttpRequestParser() override = default;
 
+  void Init(HttpRequest* request);
+
 private:
-  bool ParseStartLine(const std::string& line) override;
+  bool ParseStartLine(const std::string& line) final;
 
   HttpRequest* request_;
 };

webcc/http_response_parser.cc

@@ -2,8 +2,8 @@
 
 #include "boost/algorithm/string.hpp"
 
-#include "webcc/logger.h"
 #include "webcc/http_response.h"
+#include "webcc/logger.h"
 
 namespace webcc {
 
@@ -11,6 +11,11 @@ HttpResponseParser::HttpResponseParser(HttpResponse* response)
     : HttpParser(response), response_(response) {
 }
 
+void HttpResponseParser::Init(HttpResponse* response) {
+  HttpParser::Init(response);
+  response_ = response;
+}
+
 bool HttpResponseParser::ParseStartLine(const std::string& line) {
   std::vector<std::string> parts;
   boost::split(parts, line, boost::is_any_of(" "), boost::token_compress_on);

webcc/http_response_parser.h

@@ -11,13 +11,15 @@ class HttpResponse;
 
 class HttpResponseParser : public HttpParser {
 public:
-  explicit HttpResponseParser(HttpResponse* response);
+  explicit HttpResponseParser(HttpResponse* response = nullptr);
 
   ~HttpResponseParser() override = default;
 
+  void Init(HttpResponse* response);
+
 private:
   // Parse HTTP start line; E.g., "HTTP/1.1 200 OK".
-  bool ParseStartLine(const std::string& line) override;
+  bool ParseStartLine(const std::string& line) final;
 
   // The result response message.
   HttpResponse* response_;

webcc/http_server.cc

@@ -96,8 +96,10 @@ void HttpServer::DoAccept() {
         if (!ec) {
           LOG_INFO("Accepted a connection.");
 
-          std::make_shared<HttpConnection>(std::move(socket),
-                                           GetRequestHandler())->Start();
+          auto connection = std::make_shared<HttpConnection>(
+              std::move(socket), &pool_, GetRequestHandler());
+
+          pool_.Start(connection);
         }
 
         DoAccept();
@@ -111,8 +113,14 @@ void HttpServer::DoAwaitStop() {
         // operations. Once all operations have finished the io_context::run()
         // call will exit.
         LOG_INFO("On signal %d, stopping the server...", signo);
+
         acceptor_.close();
+
+        // Stop worker threads.
         GetRequestHandler()->Stop();
+
+        // Close all connections.
+        pool_.CloseAll();
       });
 }
 

webcc/http_server.h

@@ -9,6 +9,7 @@
 
 #include "webcc/globals.h"
 #include "webcc/http_connection.h"
+#include "webcc/http_connection_pool.h"
 
 namespace webcc {
 
@@ -47,6 +48,9 @@ private:
   // Acceptor used to listen for incoming connections.
   boost::asio::ip::tcp::acceptor acceptor_;
 
+  // The connection pool which owns all live connections.
+  HttpConnectionPool pool_;
+
   // The signal_set is used to register for process termination notifications.
   boost::asio::signal_set signals_;
 

webcc/queue.h

@@ -41,6 +41,11 @@ public:
     return message;
   }
 
+  void Clear() {
+    std::lock_guard<std::mutex> lock(mutex_);
+    message_list_.clear();
+  }
+
   void Push(const T& message) {
     {
       std::lock_guard<std::mutex> lock(mutex_);

webcc/rest_request_handler.cc

@@ -15,12 +15,13 @@ bool RestRequestHandler::Bind(RestServicePtr service, const std::string& url,
 }
 
 void RestRequestHandler::HandleConnection(HttpConnectionPtr connection) {
-  const HttpRequest& http_request = connection->request();
+  HttpRequestPtr http_request = connection->request();
+  assert(http_request);
 
-  const Url& url = http_request.url();
+  const Url& url = http_request->url();
 
   RestRequest rest_request{
-    http_request.method(), http_request.content(), url.query()
+    http_request->method(), http_request->content(), url.query()
   };
 
   // Get service by URL path.
@@ -46,7 +47,7 @@ void RestRequestHandler::HandleConnection(HttpConnectionPtr connection) {
 
     // Only support gzip for response compression.
     if (rest_response.content.size() > kGzipThreshold &&
-        http_request.AcceptEncodingGzip()) {
+        http_request->AcceptEncodingGzip()) {
       std::string compressed;
       if (Compress(rest_response.content, &compressed)) {
         http_response->SetHeader(http::headers::kContentEncoding, "gzip");

webcc/soap_request_handler.cc

@@ -16,12 +16,15 @@ bool SoapRequestHandler::Bind(SoapServicePtr service, const std::string& url) {
 }
 
 void SoapRequestHandler::HandleConnection(HttpConnectionPtr connection) {
+  HttpRequestPtr http_request = connection->request();
+  assert(http_request);
+
   auto http_response = std::make_shared<HttpResponse>();
 
   // TODO: Support keep-alive.
   http_response->SetHeader(http::headers::kConnection, "Close");
 
-  std::string path = "/" + connection->request().url().path();
+  std::string path = "/" + http_request->url().path();
   SoapServicePtr service = GetServiceByUrl(path);
   if (!service) {
     http_response->set_status(http::Status::kBadRequest);
@@ -31,7 +34,7 @@ void SoapRequestHandler::HandleConnection(HttpConnectionPtr connection) {
 
   // Parse the SOAP request XML.
   SoapRequest soap_request;
-  if (!soap_request.FromXml(connection->request().content())) {
+  if (!soap_request.FromXml(http_request->content())) {
     http_response->set_status(http::Status::kBadRequest);
     connection->SendResponse(http_response);
     return;

webcc/utility.h

@@ -3,7 +3,6 @@
 
 #include <iosfwd>
 #include <string>
-#include <vector>
 
 #include "boost/asio/ip/tcp.hpp"
 
@@ -23,25 +22,6 @@ std::string EndpointToString(const TcpEndpoint& endpoint);
 // See: https://tools.ietf.org/html/rfc7231#section-7.1.1.2
 std::string GetHttpDateTimestamp();
 
-// Resize a buffer in ctor and restore its original size in dtor.
-struct BufferResizer {
-  BufferResizer(std::vector<char>* buffer, std::size_t new_size)
-    : buffer_(buffer), old_size_(buffer->size()) {
-    if (new_size != 0 && new_size != old_size_) {
-      buffer_->resize(new_size);
-    }
-  }
-
-  ~BufferResizer() {
-    if (buffer_->size() != old_size_) {
-      buffer_->resize(old_size_);
-    }
-  }
-
-  std::vector<char>* buffer_;
-  std::size_t old_size_;
-};
-
 }  // namespace webcc
 
 #endif  // WEBCC_UTILITY_H_