背景
结合上一篇CLion之C++框架篇-优化框架，引入boost（三），继续进行框架优化！在项目中，我们经常会通过get方式拉取第三方资源，这一版优化引入类库curl，用来拉取第三方资源库。
开源框架代码：https://github.com/rtxbc/cplus/tree/master/work
配置使用
cmake_minimum_required(VERSION 3.11.2) project(work) message(STATUS "start load boost ========================================")
# BOOST
## 设置个变量控制
SET(BOOST_MIN_VERSION "1.67.0")
## 动态查找
FIND_PACKAGE(Boost ${BOOST_MIN_VERSION} REQUIRED)
if(NOT Boost_FOUND)
message(FATAL_ERROR "Fatal error:Boost (version >=${BOOST_MIN_VERSION}) required.\n")
endif()
message(STATUS "Boost_INCLUDE_DIRS: ${Boost_INCLUDE_DIRS}")
message(STATUS "Boost_LIBRARIES: ${BOOST_LIBRARY_DIRS}")
message(STATUS "Boost_VERSION: ${Boost_VERSION}")
## 头文件
INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
LINK_DIRECTORIES(${Boost_LIBRARY_DIRS})
# .BOOST
message(STATUS "end load boost ========================================") # 编译google test，会在当前目录生成libtest.a静态库
add_subdirectory(lib/ext/googletest) #头文件
INCLUDE_DIRECTORIES(${PROJECT_SOURCE_DIR}/src/include ${PROJECT_SOURCE_DIR}lib/ext/googletest/include) #库文件 : libtest.a 添加到链接路径中
link_directories(${PROJECT_SOURCE_DIR}/lib ${PROJECT_SOURCE_DIR}/lib/ext/googletest /usr/local/opt/curl/lib/) #编译器相关设置
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/output/bin")
set(LIBRARIES pthread)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_COMPILER "clang++" ) # 显示指定使用的C++编译器
set(CMAKE_CXX_FLAGS "-g") # 调试信息
set(CMAKE_CXX_FLAGS "-Wall") # 开启所有警告
set(CMAKE_CXX_FLAGS "-lboost_date_time-mt-d") # boost #源码目录
FILE(GLOB_RECURSE SOURCEFILES ${PROJECT_SOURCE_DIR}/src/utility/*.cpp)
FILE(GLOB_RECURSE TEST_SOURCEFILES ${PROJECT_SOURCE_DIR}/src/test/*.cpp) add_custom_target(cmake-build-debug)
add_executable(${PROJECT_NAME} ${PROJECT_SOURCE_DIR}/src/main/main.cpp ${SOURCEFILES})
add_executable(work_test ${TEST_SOURCEFILES} ${SOURCEFILES}) target_link_libraries(${PROJECT_NAME} gtest ${Boost_LIBRARIES} curl)
target_link_libraries(work_test gtest ${Boost_LIBRARIES} curl)
使用
设定头部文件:
//
// Created by Zhou,Baochuan on 18/6/5.
// #ifndef WORK_HTTP_H
#define WORK_HTTP_H #include "common.h"
#include <curl/curl.h> namespace work {
class Http {
public:
Http();
~Http();
static string get(string url, unsigned retries = 3);
};
} #endif //WORK_HTTP_H
注意：get方法中增加了retries重试机制。在实现中看一下细节！
//
// Created by Zhou,Baochuan on 18/6/5.
// #include "http.h" using namespace work; Http::Http()
{
curl_global_init(CURL_GLOBAL_NOTHING);
} Http::~Http()
{
curl_global_cleanup();
} size_t req_reply(void* ptr, size_t size, size_t nmemb, void* stream) {
//cout << "----->reply" << endl;
std::string* str = (std::string*)stream;
//cout << *str << endl;
(*str).append((char*)ptr, size * nmemb);
return size * nmemb;
}
string Http::get(string url, unsigned int retries)
{
string response;
CURL *curl;
struct curl_slist *headers = NULL;
//headers = curl_slist_append(headers, "Accept: Agent-007"); curl = curl_easy_init() ;
if (curl) {
//curl_easy_setopt(curl, CURLOPT_PROXY, "10.99.60.201:8080");// 代理
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, req_reply);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*) &response);
//curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
curl_easy_setopt(curl, CURLOPT_TIMEOUT, 0); // 传输超时
curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 0); // 连接超时
curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1L);
curl_easy_setopt(curl, CURLOPT_FORBID_REUSE, 1);
CURLcode res = curl_easy_perform(curl); // 执行 // 重试
while (res != CURLE_OK && --retries > 0) {
res = curl_easy_perform(curl); // 执行
} curl_easy_cleanup(curl);
}
curl_slist_free_all(headers);
return response;
}
测试代码：
#include "common.h"
#include "http.h"
#include <gtest/gtest.h> using namespace work; // curl版本要求
TEST(curl, all)
{
EXPECT_EQ(3, CURLVERSION_NOW);
Http http;
string url = "http://47.95.220.249/";
ASSERT_FALSE(http.get(url).empty());
}
CURL 注意事项
1、解决线程安全及避免core错误问题方式
1） curl_global_init（）在多线程环境下，是线程不安全的。所以在多线程环境下，要在主线程中调用这个方法。配套的，在主线程中调用curl_global_cleanup()方法。
2）curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1L); 控制域名解析的超时，其需要一个sigjmp_buf型的全局变量，多线程时会修改它。
3) curl_easy_setopt(curl, CURLOPT_FORBID_REUSE, 1);默认情况下libcurl完成一个任务以后，出于重用连接的考虑不会马上关闭。如果没有新的TCP请求来重用这个连接，那么只能等到CLOSE_WAIT超时，这个时间默认在7200秒甚至更高，太多的CLOSE_WAIT连接会导致性能问题
2、要想让curl_easy_perform()，能够执行，必须得有个配套方法curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, req_reply);
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