解决webserver在IE下载文件，文件名为乱码问题

通常使用以下代码就能导出为流的文件，而不是打开文件

	websWrite(wp, T("HTTP/1.1 200 OK\n"));
	websWrite(wp, T("Pragma: no-cache\n"));
	websWrite(wp, T("Cache-control: no-cache\n"));
	websWrite(wp, T("Content-Length: %ld\n"),sbufs.st_size);
	websWrite(wp, T("Content-Type: application/force-download\n"));
	websWrite(wp, T("Content-Type: application/vnd.ms-excel; charset=utf-8\n"));
//	websWrite(wp, T("Content-type: application/octet-stream\n"));
	websWrite(wp, T("Content-Transfer-Encoding: binary\r\n"));
	websWrite(wp, T("Content-Disposition: attachment; filename=\"%s\"\n\n"),pname);

webserver支持下载的函数：

/** 
* @brief URLEncode 对字符串URL编码 
* 
* @param str 原字符串 
* @param strSize 原字符串长度(不包括最后的\0) 
* @param result 结果缓冲区的地址 
* @param resultSize 结果缓冲区的大小(包括最后的\0) 
* 
* @return: >0:resultstring 里实际有效的长度 
*            0: 解码失败. 
*/  
int URLEncode(const char* str, const int strSize, char* result, const int resultSize)  
{  
    int i;  
    int j = 0;//for result index  
    char ch;  
  
    if ((str==NULL) || (result==NULL) || (strSize<=0) || (resultSize<=0)) {  
        return 0;  
    }  
  
    for ( i=0; (i<strSize)&&(j<resultSize); ++i) {  
        ch = str[i];  
        if (((ch>='A') && (ch<'Z')) ||  
            ((ch>='a') && (ch<'z')) ||  
            ((ch>='0') && (ch<'9'))) {  
            result[j++] = ch;  
        } else if (ch == ' ') {  
            result[j++] = '+';  
        } else if (ch == '.' || ch == '-' || ch == '_' || ch == '*') {  
            result[j++] = ch;  
        } else {  
            if (j+3 < resultSize) {  
                sprintf(result+j, "%%%02X", (unsigned char)ch);  
                j += 3;  
            } else {  
                return 0;  
            }  
        }  
    }  
  
    result[j] = '\0';  
    return j;  
}  
#define BUFFER_SIZE 2048
static void downloadFiles(webs_t wp, char_t *path, char_t *query) 
{
	char _filePath[1024]={0},encodFilename[1024]={0};
	char *fileName,*file_path,*browser,*pname;
	unsigned char data[BUFFER_SIZE]={0};
	char err_msg[256];
	long  count;
	struct stat sbufs;
	FILE  *src;
	
	fileName = websGetVar(wp, T("downFileName"), T(""));
	file_path = websGetVar(wp, T("download_path"), T(""));
	browser = websGetVar(wp, T("browserType"), T("")); //浏览器类型
	sprintf(_filePath,"/media%s",file_path);
	memset(&sbufs,0,sizeof(sbufs));
	
	
	src = fopen(_filePath, "r");
	if (!src) {
		websWrite(wp, T("HTTP/1.1 200 OK\nContent-type: text/plain\nPragma: no-cache\nCache-Control: no-cache\n\n"));
		sprintf (err_msg, "Can't fopen %s: %s\n", _filePath, strerror(errno));
		websWrite(wp,T("%s"),err_msg); 
		websDone(wp, 200);
		goto error;
	}
	if(!strcmp(browser,"IE")){
		URLEncode(fileName, strlen(fileName), encodFilename, sizeof(encodFilename));
		pname=encodFilename;
	}else{
		pname=fileName;
	}
	
	stat(_filePath, &sbufs);
	websWrite(wp, T("HTTP/1.1 200 OK\n"));
	websWrite(wp, T("Pragma: no-cache\n"));
	websWrite(wp, T("Cache-control: no-cache\n"));
	websWrite(wp, T("Content-Length: %ld\n"),sbufs.st_size);
	websWrite(wp, T("Content-Type: application/force-download\n"));
	websWrite(wp, T("Content-Type: application/vnd.ms-excel; charset=utf-8\n"));
//	websWrite(wp, T("Content-type: application/octet-stream\n"));
	websWrite(wp, T("Content-Transfer-Encoding: binary\r\n"));
	websWrite(wp, T("Content-Disposition: attachment; filename=\"%s\"\n\n"),pname);
		
	while ((count = fread(data, 1, BUFFER_SIZE, src)) > 0) {
		websWriteBlock(wp, data, count);
	}
	fclose(src);

error:
	return;
	//websDone(wp, 200);
}

但是，如果fileName是UTF-8编码的，比如文件名为测试.html;
ie这时就搞些小情绪，文件名变成了乱码了

在RFC2231的定义里面， 多语言编码的Content-Disposition应该这么定义：
Content-Disposition: attachment; filename*="utf8''%E6%B5%8B%E8%AF%95.html"
即：
filename后面的等号之前要加 *
filename的值用单引号分成三段，分别是字符集(utf8)、语言(空)和urlencode过的文件名。
所以这时应该对文件名进行url编码转换 ，使用urlencode很轻松就搞定了

因此，以上代码应该加上url编码转换