FTP文件上传、下载（基于curl库 ）

在Linux中curl是一个利用URL规则在命令行下工作的文件传输工具，如下为通过curl命令上传、下载ftp文件的用法：

# curl -T upload_test.txt -u fangye:fangye ftp://192.168.10.105/   //下载ftp文件 -u 账号:密码

更多curl命令用法参考博客： https://blog.csdn.net/gubenpeiyuan/article/details/50803095

libcurl库为通信协议库，支持HTTP, HTTPS, FTP, FTPS, GOPHER, TFTP, SCP, SFTP, SMB, TELNET, DICT, LDAP, LDAPS, FILE, IMAP, SMTP, POP3, RTSP 和 RTMP等多种协议，如下为基于curl库中ftp协议实现的文件上传、下载示例：

ftp-manager.c

#include 
#include 
#include 

#include "ftp-manager.h"

int get_file_size(FILE *file) //获取文件大小
{
	int size = 0;
	fseek(file, 0L, SEEK_END);
	size = ftell(file);
	fseek(file, 0L, SEEK_SET);
	return size;
}

CURL *curl_init()          //curl初始化
{
	curl_global_init(CURL_GLOBAL_DEFAULT); 
	CURL *curl = curl_easy_init();
	if(NULL == curl)
	{
		fprintf(stderr, "Init curl failed.\n");
		exit(1);
	}
	return curl;
}

void curl_set_upload_opt(CURL *curl, const char *url, const char *user_key, FILE *file) //设置上传配置参数
{
	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_USERPWD, user_key);
	curl_easy_setopt(curl, CURLOPT_READDATA, file);	
	curl_easy_setopt(curl, CURLOPT_UPLOAD, 1);
	curl_easy_setopt(curl, CURLOPT_INFILESIZE, get_file_size(file));
	curl_easy_setopt(curl, CURLOPT_FTP_CREATE_MISSING_DIRS, 1);
//	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
}

void curl_set_download_opt(CURL *curl, const char *url, const char *user_key, FILE *file) //设置下载配置参数
{
	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_USERPWD, user_key);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, file);
//	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
}

void curl_exit(CURL *curl)  //退出curl
{
	curl_easy_cleanup(curl);
	curl_global_cleanup(); 
}

CURLcode curl_perform(CURL *curl) //执行curl
{
	CURLcode ret = curl_easy_perform(curl);
	if(ret != 0)
	{
		fprintf(stderr, "Perform curl failed.\n");
		curl_exit(curl);
		exit(1);
	}
	return ret;
}


FTP_STATE ftp_upload(const FTP_OPT ftp_option) //ftp上传文件
{
	FTP_STATE state;
	CURL *curl;;
	FILE *fp = fopen(ftp_option.file, "r");
	if(NULL == fp)
	{
		fprintf(stderr, "Open file failed at %s:%d\n", __FILE__, __LINE__);
		return FTP_UPLOAD_FAILED;
	}

	curl = curl_init();
	curl_set_upload_opt(curl, ftp_option.url, ftp_option.user_key, fp);
	if(CURLE_OK == curl_perform(curl))
		state = FTP_UPLOAD_SUCCESS;
	else
		state = FTP_UPLOAD_FAILED;

	curl_exit(curl);
	fclose(fp);
	return state;
}

FTP_STATE ftp_download(const FTP_OPT ftp_option) // ftp下载文件
{
	FTP_STATE state;
	CURL *curl;
	FILE *fp = fopen(ftp_option.file, "w");
	if(NULL == fp)
	{
		fprintf(stderr, "Open file failed at %s:%d\n", __FILE__, __LINE__);
		return FTP_UPLOAD_FAILED;
	}

	curl = curl_init();
	curl_set_download_opt(curl, ftp_option.url, ftp_option.user_key, fp);
	if(CURLE_OK == curl_perform(curl))
		state = FTP_DOWNLOAD_SUCCESS;
	else
		state = FTP_DOWNLOAD_FAILED;

	curl_exit(curl);
	fclose(fp);
	return state;
}

ftp-manager.h

#ifndef _FTP_MANAGER_H_
#define _FTP_MANAGER_H_

typedef enum FTP_STATE
{
	FTP_UPLOAD_SUCCESS,
	FTP_UPLOAD_FAILED,
	FTP_DOWNLOAD_SUCCESS,
	FTP_DOWNLOAD_FAILED 
}FTP_STATE;

typedef struct FTP_OPT
{
	char *url;		/*url of ftp*/
	char *user_key;		/*username:password*/
	char *file;		/*filepath*/
}FTP_OPT;

#ifdef __cplusplus
	extern "C" {
#endif


FTP_STATE ftp_upload(const FTP_OPT ftp_option); //上传文件


FTP_STATE ftp_download(const FTP_OPT ftp_option); //下载文件

#ifdef __cplusplus
	}
#endif

#endif

main.c  //ftp文件上传、下载调用curl示例

#include 
#include "ftp-manager.h"

#define UPLOAD
#define DOWNLOAD

int main()
{
	FTP_OPT ftp_opt;
	
#ifdef UPLOAD
	ftp_opt.url = "ftp://192.168.10.105/upload/upload_test.txt"; //传到ftp服务器路径名
	ftp_opt.user_key = "fangye:fangye"; //ftp 账号密码   格式<账号:密码>  
	ftp_opt.file = "./upload_test.txt"; //指本地文件要上传的文件
	if(FTP_UPLOAD_SUCCESS == ftp_upload(ftp_opt))
		printf("Upload success.\n");
	else
		printf("Upload failed.\n");
#endif

#ifdef DOWNLOAD
	ftp_opt.url = "ftp://192.168.10.105/download/ZeroMQ.pdf"; //ftp服务器文件
	ftp_opt.file = "zmq.pdf";	//指下载到本地文件名
	if(FTP_DOWNLOAD_SUCCESS == ftp_download(ftp_opt))
		printf("Download success.\n");
	else
		printf("Download failed.\n");
#endif

	return 0;
}