【C++】基于libcurl的HTTP请求客户端。
- C++版本:
c++11 - 支持
Windows和Linux - 引入方法:
#include "iclient/iclient.h"
- HTTP、POST、PUT、DELETE、HEAD请求
- 是否重定向,及重定向最大次数
- 超时(毫秒)
- SSL证书和密钥
- 验证HTTPS请求对象的合法性
- HTTP(s)代理
- 接受的内容编码方式 (Accept-Encoding)
- Cookie
- Post请求数据(可设置MIME类型)
- 自定义传输进度处理(例如下载进度条)
- 文件下载(普通下载、断点续传、分片下载)
- 限制下载/上传速度
- namespace
ic:- namespace
client:- namespace
http- enum
Method: GET/POST/HEAD/... - enum
StatusCode: HTTP状态码 - enum
Version: V1_0/V1_1/V2_0/...
- enum
- namespace
util - enum
Status: Request请求的状态码(如超时、DNS错误等) - struct
ProxyData: 描述一个HTTP(s)代理的相关信息 - class
Request - class
Response - class
Executor: 真正执行Request请求 - class
Url: 封装URL对象,便于添加、合并参数
- namespace
- namespace
如果机器上没有安装libcurl,可以在 Release页面 下载。
下载后,将静态库文件放在lib目录下,目录结构如下:
lib ├── linux │ └── libcurl.a └── windows ├── Win32 │ ├── Debug │ │ └── libcurl.lib │ └── Release │ └── libcurl.lib └── x64 ├── Debug │ └── libcurl.lib └── Release └── libcurl.lib
linux平台:
# 使用makefile make iclient # 编译静态库文件 (lib/linux/x86_64/libiclient.a) make example.out # 编译示例代码 (bin/example.out) # 也可以使用xmake构建 xmake f -m release xmake b iclient xmake b example.out
windows平台:
使用Visual Studio 2019打开win-build/iclient.sln解决方案。
编译iclient项目生成静态库文件 (lib/windows/x64/Release/iclient.lib)
编译example项目生成示例程序 (bin/example.exe)
可以参考 example/目录下的文件
$ tree example example ├── main.cpp ├── test_download.cpp ├── test_download_range.cpp ├── test_download_resume.cpp ├── test_download_speed_limit.cpp ├── test_http_get.cpp ├── test_http_post.cpp ├── test_http_put.cpp └── test_url.cpp
例如需要构造一个URL,https://api.icrystal.top/util/random?min=1&max=100&count=20,该链接含有3个参数。
ic::client::Url url("https://api.icrystal.top/util/random"); url.SetParam("min", 1); url.SetParam("max", 100); url.SetParam("count", 20) // 获取合并的参数串 // "min=1&max=100&count=20" url.GetParamsString(); // 获取整个URL字符串 // "https://api.icrystal.top/random?min=1&max=100&count=20" url.ToString();
注意 !
- AddParam: 添加参数,保留同名的其他参数,如:
AddParam("name", "Tom"); "name=Tom" AddParam("name", "Jack"); "name=Tom&name=Jack"
- setParam: 唯一参数,覆盖同名的参数值。
SetParam("name", "Tom"); "name=Tom" SetParam("name", "Jack"); "name=Jack"
GET请求
ic::client::Request request("http://httpbin.org/ip"); //request.set_http_method(ic::client::http::Method::HTTP_GET); // 默认为GET请求 ic::client::Response res = request.Perform(); if (res.status() == ic::client::Status::SUCCESS && res.http_status_code() == ic::client::http::StatusCode::HTTP_200_OK) // 等价于 if (res.ok()) { ... } { std::cout << res.data() << std::endl; }
POST请求
ic::client::Request request("http://httpbin.org/ip"); request.set_http_method(ic::client::http::Method::HTTP_POST);
Header名称不区分大小写!
// 设置Request的header request.set_header("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) Ap..."); request.set_header("referer", "https://www.biaud.com"); auto res = request.Perform(); // 获取Response的header // std::map<std::string, std::string> auto& headers = res.headers(); for (auto& header : headers) { std::cout << header.first << ": " << header.second << std::endl; } res.HasHeader("Content-Length"); // true res.GetHeader("Content-Length"); // 10134
struct ProxyData { ProxyType type = ProxyType::HTTP; uint32_t port; HttpAuthType auth_type = HttpAuthType::ANY; std::string host; std::string username; std::string password; }; ProxyData proxy_data; proxy_data.host = "11.12.13.14"; proxy.data.port = 3011; proxy.type = ic::client::ProxyType::HTTP; request.set_proxy(proxy_data); // 或者 request.set_proxy("11.12.13.14", 3011, ic::client::ProxyType::HTTP);
request.set_cookie("name=Tom&age=18"); request.set_cookie_file("/etc/xxx/cookie/12345.cookie");
request.set_data("{\"name\":\"Tom\"}");request.set_max_redirects(3); // 最多重定向3次 request.set_max_redirects(0); // 设为0,表示禁止重定向 request.set_max_redirects(-1); // 设为-1,表示不限制重定向次数(默认)
request.set_verify_ssl_host(false); request.set_verify_ssl_peer(false); request.set_verify_ssl_status(false); request.set_verify_ssl(false); // 等价于上面三条语句
// @downloadFile: 下载的本地文件名 // @resume(bool): 是否启用断点续传,默认不启用 request.set_download_file("output.jpg"/*, false*/); // @range: 单位bytes // 包括0和4095 request.set_download_range(0, 4095);
request.set_transfer_progress_handler(url_xfer_info_callback);
其中,url_xfer_info_callback 函数签名如下
bool s_curl_xfer_info( const ic::client::Request& request, curl_off_t download_total_bytes, /* 总共需要下载的字节数 */ curl_off_t download_now_bytes, /* 已经下载的字节数 */ curl_off_t upload_total_bytes, /* 总共需要上传的字节数 */ curl_off_t upload_now_bytes); /* 已经上传的字节数 */
可查看 include/iclient/request.h
No.5 断点续传
No.6 分片下载(可以放到不同的线程中同时下载,即多线程下载)
如果使用libcurl和openssl的静态链接库,在多线程环境下发送HTTPS请求,需要在每个线程结束前调用OPENSSL_thread_stop()函数执行清理工作,否则可能产生内存泄露。
#include <openssl/crypto.h> int main() { std::thread t([]{ // send https request OPENSSL_thread_stop(); // call before thread exit }); t.join(); return 0; }
ref: https://curl.se/libcurl/c/threadsafe.html
All current TLS libraries libcurl supports are thread-safe.
OpenSSL 1.1.0+ can be safely used in multi-threaded applications provided that support for the underlying OS threading API is built-in. For older versions of OpenSSL, the user must set mutex callbacks.
libcurl may not be able to fully clean up after multi-threaded OpenSSL depending on how OpenSSL was built and loaded as a library. It is possible in some rare circumstances a memory leak could occur unless you implement your own OpenSSL thread cleanup.
For example, on Windows if both libcurl and OpenSSL are linked statically to a DLL or application then OpenSSL may leak memory unless the DLL or application calls OPENSSL_thread_stop() before each thread terminates. If OpenSSL is built as a DLL then it does this cleanup automatically and there is no leak. If libcurl is built as a DLL and OpenSSL is linked statically to it then libcurl does this cleanup automatically and there is no leak (added in libcurl 8.8.0).