The server now returns an HTTP Bad Request when parsing fails and returns a...

The server now returns an HTTP Bad Request when parsing fails and returns a 500 when an exception is thrown

src/http.cc

@@ -106,8 +106,8 @@ namespace Private {
     }
 
     void
-    Parser::Step::raise(const char* msg) {
-        throw ParsingError(msg);
+    Parser::Step::raise(const char* msg, Code code /* = Code::Bad_Request */) {
+        throw HttpError(code, msg);
     }
 
     Parser::State
@@ -143,10 +143,13 @@ namespace Private {
         else if (tryMatch("DELETE")) {
             request->method = Method::Delete;
         }
+        else {
+            raise("Unknown HTTP request method");
+        }
 
         auto n = cursor.next();
         if (n == Cursor::Eof) return State::Again;
-        else if (n != ' ') raise("Malformed HTTP Request");
+        else if (n != ' ') raise("Malformed HTTP request after Method, expected SP");
 
         if (!cursor.advance(2)) return State::Again;
 
@@ -376,9 +379,19 @@ const char* codeString(Code code)
 #undef CODE
     }
 
-    unreachable();
+    return "";
 }
 
+HttpError::HttpError(Code code, std::string reason)
+    : code_(static_cast<int>(code))
+    , reason_(std::move(reason))
+{ }
+
+HttpError::HttpError(int code, std::string reason)
+    : code_(code)
+    , reason_(std::move(reason))
+{ }
+
 Message::Message()
     : version(Version::Http11)
 { }
@@ -448,8 +461,13 @@ Handler::onInput(const char* buffer, size_t len, Tcp::Peer& peer) {
                 onRequest(parser.request, peer);
                 parser.reset();
             }
-        } catch (const Private::ParsingError &err) {
-            cerr << "Error when parsing HTTP request: " << err.what() << endl;
+        } catch (const HttpError &err) {
+            Response response(err.code(), err.reason());
+            response.writeTo(peer);
+        }
+        catch (const std::exception& e) {
+            Response response(Code::Internal_Server_Error, e.what());
+            response.writeTo(peer);
         }
     }
 }

src/http.h

@@ -90,6 +90,22 @@ enum class Version {
 const char* methodString(Method method);
 const char* codeString(Code code);
 
+struct HttpError : public std::exception {
+    HttpError(Code code, std::string reason);
+    HttpError(int code, std::string reason);
+
+    ~HttpError() noexcept { }
+
+    const char* what() const noexcept { return reason_.c_str(); }
+
+    int code() const { return code_; }
+    std::string reason() const { return reason_; }
+
+private:
+    int code_;
+    std::string reason_;
+};
+
 // 4. HTTP Message
 class Message {
 public:
@@ -124,10 +140,6 @@ private:
 
 namespace Private {
 
-    struct ParsingError : public std::runtime_error {
-        ParsingError(const char* msg) : std::runtime_error(msg) { }
-    };
-
     struct Parser {
 
         struct Buffer {
@@ -204,7 +216,7 @@ namespace Private {
 
             virtual State apply(Cursor& cursor) = 0;
 
-            void raise(const char* msg);
+            void raise(const char* msg, Code code = Code::Bad_Request);
 
             Request *request;
         };
@@ -336,7 +348,6 @@ public:
 
 private:
     Private::Parser& getParser(Tcp::Peer& peer);
-
 };
 
 class Endpoint {