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// Copyright (C) 2016-2020 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef HTTP_RESPONSE_CREATOR_H
#define HTTP_RESPONSE_CREATOR_H
#include <http/request.h>
#include <http/response.h>
#include <boost/shared_ptr.hpp>
namespace isc {
namespace http {
class HttpResponseCreator;
/// @brief Pointer to the @ref HttpResponseCreator object.
typedef boost::shared_ptr<HttpResponseCreator> HttpResponseCreatorPtr;
/// @brief Specifies an interface for classes creating HTTP responses
/// from HTTP requests.
///
/// HTTP is designed to carry various content types. Most commonly
/// this is text/html. In Kea, the application/json content type is used
/// to carry control commands in JSON format. The libkea-http library is
/// meant to be generic and provide means for transferring different types
/// of content, depending on the use case.
///
/// This abstract class specifies a common interface for generating HTTP
/// responses from HTTP requests using specific content type and being
/// used in some specific context. Kea modules providing HTTP services need to
/// implement their specific derivations of the @ref HttpResponseCreator
/// class. These derivations use classes derived from @ref HttpRequest as
/// an input and classes derived from @ref HttpResponse as an output of
/// @c createHttpResponse method.
class HttpResponseCreator {
public:
/// @brief Destructor.
///
/// Classes with virtual functions need virtual destructors.
virtual ~HttpResponseCreator() { };
/// @brief Create HTTP response from HTTP request received.
///
/// This class implements a generic logic for creating a HTTP response.
/// Derived classes do not override this method. They merely implement
/// the methods it calls.
///
/// The request processing may generally fail at one of the two stages:
/// parsing or interpretation of the parsed request. During the former
/// stage the request's syntax is checked, i.e. HTTP version, URI,
/// headers etc. During the latter stage the HTTP server checks if the
/// request is valid within the specific context, e.g. valid HTTP version
/// used, expected content type etc.
///
/// In the @ref HttpRequest terms, the request has gone through the
/// first stage if it is "finalized" (see @ref HttpRequest::finalize).
/// This method accepts instances of both finalized and not finalized
/// requests. If the request isn't finalized it indicates that
/// the request parsing has failed. In such case, this method calls
/// @c createStockBadRequest to generate a response with HTTP 400 status
/// code. If the request is finalized, this method calls
/// @c createDynamicHttpResponse to generate implementation specific
/// response to the received request.
///
/// This method is marked virtual final to prevent derived classes from
/// overriding this method. Instead, the derived classes must implement
/// protected methods which this method calls.
///
/// @param request Pointer to an object representing HTTP request.
/// @return Pointer to the object encapsulating generated HTTP response.
/// @throw HttpResponseError if request is a NULL pointer.
virtual HttpResponsePtr
createHttpResponse(HttpRequestPtr request) final;
/// @brief Create a new request.
///
/// This method creates an instance of the @ref HttpRequest or derived
/// class. The type of the object is compatible with the instance of
/// the @ref HttpResponseCreator implementation which creates it, i.e.
/// can be used as an argument in the call to @ref createHttpResponse.
///
/// @return Pointer to the new instance of the @ref HttpRequest.
virtual HttpRequestPtr
createNewHttpRequest() const = 0;
/// @brief Creates implementation specific HTTP response.
///
/// @param request Pointer to an object representing HTTP request.
/// @param status_code Status code of the response.
/// @return Pointer to an object representing HTTP response.
virtual HttpResponsePtr
createStockHttpResponse(const HttpRequestPtr& request,
const HttpStatusCode& status_code) const = 0;
protected:
/// @brief Creates implementation specific HTTP response.
///
/// @param request Pointer to an object representing HTTP request.
/// @return Pointer to an object representing HTTP response.
virtual HttpResponsePtr
createDynamicHttpResponse(HttpRequestPtr request) = 0;
};
} // namespace http
} // namespace isc
#endif
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