linux 下 libcurl 库的使用

libcurl 库的使用

libcurl主要功能就是用不同的协议连接和沟通不同的服务器。

libcurl当前支持http, https, ftp, gopher, telnet, dict, file, 和ldap 协议。

libcurl同样支持HTTPS证书授权，HTTP POST, HTTP PUT, FTP 上传, HTTP基本表单上传，代理，cookies,和用户认证。

1 、 源码下载

https://github.com/curl/curl

2、编译安装

#./configure –enable-shared –enable-static –prefix=/usr/local/

#make

#make install

3、查看

# curl -V

curl 7.50.2 (x86_64-pc-linux-gnu) libcurl/7.50.2 OpenSSL/1.0.1e zlib/1.2.3 libidn/1.18

Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtsp smb smbs smtp smtps telnet tftp

Features: IDN IPv6 Largefile NTLM NTLM_WB SSL libz UnixSockets

4、代码测试

main.hpp

#ifndef main_hpp
#define main_hpp

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>

#define ERROR_LOG(fmt,args...) {printf("\n[%s(line:%d)]:" fmt,__FILE__, __LINE__,##args);fflush(stdout);}
#define DEBUG_LOG(fmt,args...)  {printf("\n[%s(line:%d)%ld]:" fmt,__FILE__, __LINE__,time(NULL),##args);fflush(stdout);}
#define WARNING_LOG(fmt,args...)  {printf("\n[%s(line:%d)]:" fmt,__FILE__, __LINE__,##args);fflush(stdout);}
#define TRACE_LOG(fmt,args...)  {printf("\n[%s(line:%d)]:" fmt,__FILE__, __LINE__,##args);fflush(stdout);}
#define INFO_LOG(fmt,args...)  {printf("\n[%s(line:%d)]:" fmt,__FILE__, __LINE__,##args);fflush(stdout);}

#endif

main.cpp

#include"main.hpp"
#include"curlDownload.hpp"

int main(int argc, char **argv)
{
if (argc != 3)
{
ERROR_LOG("input command param error");
return -1;
}
curlDownload mydownload;
mydownload.download(argv[1],0,argv[2]);
return 0;
}

curlDownload.hpp

//
//  curlDownload.hpp
//
//
//  Created by jianjian Qi on 9/9/16.
//  Copyright © 2016 tgbtgb. All rights reserved.
//

#ifndef curlDownload_hpp
#define curlDownload_hpp

#include <stdio.h>
#include <curl/curl.h>
#include "main.hpp"

static size_t write_callback(char *ptr, size_t size, size_t nmemb, void *userdata);

class curlDownload
{

friend size_t write_callback(char *ptr, size_t size, size_t nmemb, void *userdata);

public:

int download(char * sourceUrl, long long totalSize, char * saveFile);

private:

char szSourceUrl[1024];
char szSaveFile[1024];

FILE * fp;
long long llCurrentSize;
long long llTotoalSize;
CURL *curl;
};

#endif /* curlDownload_hpp */

curlDownload.cpp

//
//  curlDownload.cpp
//
//
//  Created by jianjian Qi on 9/9/16.
//  Copyright © 2016 tgbtgb. All rights reserved.
//

#include "curlDownload.hpp"

size_t write_callback(char *ptr, size_t size, size_t nmemb, void *userdata)
{
if (userdata == NULL)
{
ERROR_LOG("write_callback userdata error");
return -1;
}

curlDownload * download = (curlDownload *)userdata;
size_t res = fwrite(ptr, size, nmemb, download->fp);
if (res <= 0)
{
ERROR_LOG("[%s] write(%lld) faild@%s",download->szSourceUrl,download->llCurrentSize,strerror(errno));
return -1;
}

download->llCurrentSize += res;
return res;
}

int curlDownload::download(char * sourceUrl, long long totalSize, char * saveFile)
{

CURLcode res;
int ret = -1;
fp      = NULL;
llCurrentSize = 0;
llTotoalSize  = totalSize;

memset(szSourceUrl,0,sizeof(szSourceUrl));
memset(szSaveFile,0,sizeof(szSaveFile));

memcpy(szSourceUrl, sourceUrl, strlen(sourceUrl));
memcpy(szSaveFile, saveFile, strlen(saveFile));

do
{
fp = fopen(szSaveFile,"wb");

if (fp == NULL)
{
ERROR_LOG("[%s] open %s faild@%s",szSourceUrl, szSaveFile, strerror(errno));
break;
}

/* get a curl handle */
curl = curl_easy_init();

if (!curl)
{
ERROR_LOG("[%s] curl_easy_init error@%s",szSourceUrl,curl_easy_strerror(res));
break;
}

res = curl_easy_setopt(curl, CURLOPT_URL, szSourceUrl);

if (CURLE_OK != res)
{
ERROR_LOG("[%s] CURLOPT_URL error@%s",szSourceUrl,curl_easy_strerror(res));
break;
}

res = curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);

if (CURLE_OK != res)
{
ERROR_LOG("[%s] CURLOPT_WRITEFUNCTION error@%s",szSourceUrl,curl_easy_strerror(res));
break;
}

res = curl_easy_setopt(curl, CURLOPT_WRITEDATA, this);

if (CURLE_OK != res)
{
ERROR_LOG("[%s] CURLOPT_WRITEDATA error@%s",szSourceUrl,curl_easy_strerror(res));
break;
}

res = curl_easy_perform(curl);

if (CURLE_OK != res)
{
ERROR_LOG("[%s] curl_easy_perform error@%s",szSourceUrl,curl_easy_strerror(res));
break;
}

/* download succ */
INFO_LOG("[%s] download succ and save as %s", szSourceUrl, szSaveFile);
ret = 0;

} while(0);

if (fp == NULL)
{
return ret;
}

fclose(fp);
fp = NULL;

if (curl)
{
curl_easy_cleanup(curl);
curl = NULL;
}

return ret;

}

5、编译

#g++ main.cpp curlDownload.cpp -lcurl

6、测试

#./a.out https://github.com/curl/curl/archive/master.zip master.zip

参考网址：https://curl.haxx.se/libcurl/c/