Libcurl上传图片

超、凢脫俗 2022-08-12 12:00 142阅读 0赞

最近使用C++做一些编程，JAVA中采用HTTP协议通信很简单，我们熟知的HTTPClient就可以完成通信。在C++中BOOST库仅仅将TCP/UDP协议进行了很好的封装，但是HTTP需要我们自己在编写一部分代码才能很好的同步HTTP来完成客户端与服务器端的信息交互。libcurl对HTTP等协议进行了很好的封装，于是采用libcurl来完成图片上传的功能。

1.libcurl简单认识

libcurl支持用不同的协议连接和沟通不同的服务器，其支持http, https, ftp, gopher, telnet, dict, file, 和ldap 协议。libcurl是C++中比较好的网络交互的库。

libcurl下载地址为：[http://curl.haxx.se/download.html][http_curl.haxx.se_download.html]

libcurl 在线API地址为：[http://curl.haxx.se/libcurl/c/][http_curl.haxx.se_libcurl_c]

libcurl 接口介绍（中文）为：[http://blog.csdn.net/fengshuiyue/article/details/39530093][http_blog.csdn.net_fengshuiyue_article_details_39530093]

2.libcurl图片上传源码

InnoVSSImgSendStateType InnoVSSImgNetStorage::NetStorageImg(PicStorageModel& picStorageModel)
    	{
    		curl = curl_easy_init();
    		multi_handle = curl_multi_init();
    
    		int still_running;
    
    		struct curl_httppost *formpost=NULL;
    		struct curl_httppost *lastptr=NULL;
    		struct curl_slist *headerlist=NULL;
    		static const char buf[] = "Expect:";
    
    		curl_formadd(&formpost,
    					&lastptr,
    					CURLFORM_COPYNAME, "sendfile",
    					CURLFORM_FILE, picStorageModel.picInfo.localPath.c_str(),
    					CURLFORM_END);
    		curl_formadd(&formpost,
    					&lastptr,
    					CURLFORM_COPYNAME, "filename",
    					CURLFORM_COPYCONTENTS, picStorageModel.picInfo.fullView.c_str(),
    					CURLFORM_END);
    
    		std::string imageInfo;
    		picStorageModel.postInfo.getImageInfoXml(imageInfo); 
    		imageInfo = StringEncode::GBKToUTF8(imageInfo);
    
    		curl_formadd(&formpost,
    			&lastptr,
    			CURLFORM_COPYNAME, "imageInfo",
    			CURLFORM_COPYCONTENTS, imageInfo.c_str(),
    			CURLFORM_END);
    
    		std::string urlPath = picStorageModel.urlRequestPath;
    		//headerlist = curl_slist_append(headerlist, "Accept-Encoding:UTF-8");
    		//headerlist = curl_slist_append(headerlist, "Content-type: application/form-data;charset:UTF-8");
    		headerlist = curl_slist_append(headerlist, buf);
    		
    
    		if(curl && multi_handle) {
    			curl_easy_setopt(curl, CURLOPT_URL, urlPath.c_str());
    			curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    
    			curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);
    			curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);
    
    			curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writer);
    			//curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION,headerfunction);
    
    			ImgNetStorageResultModel resultModel;
    			resultModel.picStorageModel = picStorageModel;
    			resultModel.imgNetStorage = this;
    			curl_easy_setopt(curl, CURLOPT_WRITEDATA, &resultModel);
    
    			curl_multi_add_handle(multi_handle, curl);
    
    			CURLMcode curlm_code = CURLM_CALL_MULTI_PERFORM;
    			curlm_code = curl_multi_perform(multi_handle, &still_running);
    
    			int count = 0;
    			int responseCode = 0;
    			do {
    				struct timeval timeout;
    				int rc; 
    
    				fd_set fdread;
    				fd_set fdwrite;
    				fd_set fdexcep;
    				int maxfd = -1;
    
    				long curl_timeo = -1;
    
    				FD_ZERO(&fdread);
    				FD_ZERO(&fdwrite);
    				FD_ZERO(&fdexcep);
    
    				timeout.tv_sec = 1;
    				timeout.tv_usec = 0;
    
    				curl_multi_timeout(multi_handle, &curl_timeo);
    				if(curl_timeo >= 0) {
    				timeout.tv_sec = curl_timeo / 1000;
    				if(timeout.tv_sec > 1)
    					timeout.tv_sec = 1;
    				else
    					timeout.tv_usec = (curl_timeo % 1000) * 1000;
    				}
    
    				curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
    
    				rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
    
    				switch(rc) {
    				case -1:
    					count++;
    					break;
    				case 0:
    				default:
    					LOGD << "正在上传图片....." << zhxy_log::endl;
    					curlm_code = curl_multi_perform(multi_handle, &still_running);
    					if (curlm_code ==  CURLM_OK){
    						CURLcode res = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &responseCode);
    					}
    						
    					break;
    				}
    				
    			} while(still_running&&count < _adapterConfig.timeOutCount);
    
    			//if (curlm_code == CURLM_OK) {
    			//	long code;
    			//	CURLcode res = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
    			//	long connectCode;
    			//	res = curl_easy_getinfo(curl, CURLINFO_HTTP_CONNECTCODE, &connectCode);
    			//	LOGD << "connectCode:" << connectCode << zhxy_log::endl;
    			//}
    			curl_formfree(formpost);
    			curl_slist_free_all (headerlist);
    			curl_multi_cleanup(multi_handle);
    			curl_easy_cleanup(curl);
    			multi_handle = NULL;
    			curl = NULL;
    			if (curlm_code != CURLM_OK) {
    				LOGD << "curlm_code:" <<  curlm_code << "\n" <<curl_multi_strerror(curlm_code);
    				return InnoVSSImgSendStateTypes::Failed;
    			}
    			if (responseCode != 200)
    			{
    				return InnoVSSImgSendStateTypes::Failed;
    			}
    			if (count>=_adapterConfig.timeOutCount)
    			{
    				return InnoVSSImgSendStateTypes::Failed;
    			}else{
    				return InnoVSSImgSendStateType::Success;
    			}
    		}
    	}

3.上传代码部分说明

1）在调试中发现不管图片服务器是否开启，curl\_multi\_perform(multi\_handle, &still\_running);返回值一直是成功，通过返回值无法捕获到上传是否成功。

2）代码中可以通过curl\_easy\_getinfo(curl, CURLINFO\_RESPONSE\_CODE, &responseCode);获取http相应值，在退出循环后判断responseCode是否为200，是则上传成功，否则上传失败

[http_curl.haxx.se_download.html]: http://curl.haxx.se/download.html
[http_curl.haxx.se_libcurl_c]: http://curl.haxx.se/libcurl/c/
[http_blog.csdn.net_fengshuiyue_article_details_39530093]: http://blog.csdn.net/fengshuiyue/article/details/39530093