国外做各种趣味实验的网站/做公司网站
服务端处理商品文档的图片元素(提供了描述,图片URL信息)时,采用HTTP把文件下载到本地服务器,并把图片信息保存在tb_gdsn_goods_pic表中.
开发时注意:
.从SVN上下载vendor\curl-7.31.0到本地环境
.vs2005环境设置(或者工程属性):
include路径: v:\curl-7.31.0\include
lib路径v:\curl-7.31.0\vs\vc8\lib\Debug
.修改CExtFile,支持在下载前确定文件名
.图片下载参考下面的demo代码
1.CExtFile修改
CExtFile的实现在lssdk工程中,增加了NewFileName方法,用于获取具有唯一性的将要保存在本地的图片文件的名称。
可以从trunk下复制到分支.
增加NewFileName定义.
class LS_API CExtFile {
public:int NewFileName(char *file_name,const char *suffix); ///< 生成唯一文件名
};ExtFile.cpp
int CExtFile::NewFileName(char *file_name,const char *suffix) {if (this->GetTempFile(fn))return -1;if (suffix)ACE_OS::sprintf(file_name,"%s\\%s.%s",root_path_,fn,suffix);elseACE_OS::sprintf(file_name,"%s\\%s",root_path_,fn);return 0;
}2.demo代码
#include <curl/curl.h>
#include <curl/easy.h>#pragma comment(lib,"libcurl.lib")
#pragma comment(lib,"wldap32.lib")size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {size_t written = fwrite(ptr, size, nmemb, stream);return written;
}int http_download_pic(const char *url,const char *outfilename) {CURL *curl;FILE *fp;CURLcode res;curl = curl_easy_init(); ///< @todo 在插件初始化(Initialize)时执行(应该是只需要执行一次)if (curl) {fp = fopen(outfilename,"wb");curl_easy_setopt(curl, CURLOPT_URL, url);curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);res = curl_easy_perform(curl);curl_easy_cleanup(curl); ///< @todo 插件释放(Release)时执行fclose(fp);if (res!=CURLE_OK)return -1;}return 0;
}int handle_pic_element() {///< @todo 解析ULR后缀(如jpg)char file_ext[MAX_PATH];///< 确定文件名char pic_file_name[MAX_PATH];CExtFileControl pic_file_control_;pic_file_control_.NewFileName(pic_file_name,file_ext); ///< 保存的文件和原文件有相同的扩展名if (http_download_pic(url,pic_file_name))return -1;///< @todo 把商品图片的文件名称信息写入tb_gdsn_goods_pic表中return 0;
}3.资料
Download file using libcurl in C/C++
http://stackoverflow.com/questions/1636333/download-file-using-libcurl-in-c-c
demo工程在连接libcurl.lib时报以下错误:
error LNK2019: unresolved external symbol __imp__curl_easy_init referenced i
解决方法:
Project properties -> all releases -> configuration properties -> linker -> input -> and set
additional dependencies to = libcurl.lib ws2_32.lib winmm.lib wldap32.libAdd new macros at the preprocessors = ;BUILDING_LIBCURL;HTTP_ONLYhttp://social.msdn.microsoft.com/Forums/vstudio/en-US/1bd29762-2469-4ab7-812a-cb042a4de83c/what-can-i-solve-the-problem-error-lnk2019-unresolved-external-symbol