be33b31ae2
Most of the time, implementing an http handler consist of a small amount of logic. Function handlers are a simplified way of adding such a logic, they accept a lambda expression of various types and eliminate the need to create a type for the handlers. The prefered way of creating a handler is by using the json_request_function, it would use auto-boxing to return a json object. Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>
87 lines
2.6 KiB
C++
87 lines
2.6 KiB
C++
/*
|
|
* This file is open source software, licensed to you under the terms
|
|
* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
|
|
* distributed with this work for additional information regarding copyright
|
|
* ownership. You may not use this file except in compliance with the License.
|
|
*
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing,
|
|
* software distributed under the License is distributed on an
|
|
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
|
* KIND, either express or implied. See the License for the
|
|
* specific language governing permissions and limitations
|
|
* under the License.
|
|
*/
|
|
/*
|
|
* Copyright 2015 Cloudius Systems
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include "handlers.hh"
|
|
#include <functional>
|
|
#include "json/json_elements.hh"
|
|
|
|
namespace httpd {
|
|
|
|
/**
|
|
* A request function is a lambda expression that gets only the request
|
|
* as its parameter
|
|
*/
|
|
typedef std::function<sstring(const_req req)> request_function;
|
|
|
|
/**
|
|
* A handle function is a lambda expression that gets request and reply
|
|
*/
|
|
typedef std::function<sstring(const_req req, reply&)> handle_function;
|
|
|
|
/**
|
|
* A json request function is a lambda expression that gets only the request
|
|
* as its parameter and return a json response.
|
|
* Using the json response is done implicitly.
|
|
*/
|
|
typedef std::function<json::json_return_type(const_req req)> json_request_function;
|
|
|
|
/**
|
|
* The function handler get a lambda expression in the constructor.
|
|
* it will call that expression to get the result
|
|
* This is suited for very simple handlers
|
|
*
|
|
*/
|
|
class function_handler : public handler_base {
|
|
public:
|
|
|
|
function_handler(const handle_function & f_handle, const sstring& type)
|
|
: _f_handle(f_handle), _type(type) {
|
|
}
|
|
|
|
function_handler(const request_function & _handle, const sstring& type)
|
|
: _f_handle([_handle](const_req req, reply& rep) {
|
|
return _handle(req);
|
|
}), _type(type) {
|
|
}
|
|
|
|
function_handler(const json_request_function& _handle)
|
|
: _f_handle([_handle](const_req req, reply& rep) {
|
|
json::json_return_type res = _handle(req);
|
|
return res._res;
|
|
}), _type("json") {
|
|
|
|
}
|
|
future<std::unique_ptr<reply>> handle(const sstring& path,
|
|
std::unique_ptr<request> req, std::unique_ptr<reply> rep) override {
|
|
rep->_content += _f_handle(*req.get(), *rep.get());
|
|
rep->done(_type);
|
|
return make_ready_future<std::unique_ptr<reply>>(std::move(rep));
|
|
}
|
|
|
|
protected:
|
|
handle_function _f_handle;
|
|
sstring _type;
|
|
};
|
|
|
|
}
|