ASP.NET中如何检测一个图片是否是真实图片防范病毒上传

程序员文章站 2023-02-28 15:28:18

主要是用来判断客户端上传的图片是否为真实的图片，以防病毒侵入，保证上传的文件的安全。主要代码如下：需要引用 [csharp] using system.io; usi...

主要是用来判断客户端上传的图片是否为真实的图片，以防病毒侵入，保证上传的文件的安全。

主要代码如下：

需要引用

[csharp]
using system.io;

using system.io;

[csharp]
public void uploadfile()
{
try
            {
                httppostedfile postfile = request.files["file"];
                string savepath = server.mappath("image/" + postfile.filename);
                postfile.saveas(savepath);
                filestream fs = new filestream(savepath, filemode.open, fileaccess.read);
                binaryreader reader = new binaryreader(fs);
                string fileclass;
                byte buffer;
                byte[] b = new byte[2];
                buffer = reader.readbyte();
                b[0] = buffer;
                fileclass = buffer.tostring();
                buffer = reader.readbyte();
                b[1] = buffer;
                fileclass += buffer.tostring();
                reader.close();
                fs.close();

                if (fileclass == "255216" || fileclass == "7173" || fileclass == "6677" || fileclass == "13780")
                {
                    //255216是jpg;7173是gif;6677是bmp,13780是png;7790是exe,8297是rar
                    //response.write("图片可用");
                    //保存到中
                }
                else
                {
                    //response.write("图片非法");
                    file.delete(savepath); //删除文件
                    return;
                }
            }
            catch (exception)
            { //response.write("图片非法！");
                return;
                throw;
            }
}

public void uploadfile()
{
try
            {
                httppostedfile postfile = request.files["file"];
                string savepath = server.mappath("image/" + postfile.filename);
                postfile.saveas(savepath);
                filestream fs = new filestream(savepath, filemode.open, fileaccess.read);
                binaryreader reader = new binaryreader(fs);
                string fileclass;
                byte buffer;
                byte[] b = new byte[2];
                buffer = reader.readbyte();
                b[0] = buffer;
                fileclass = buffer.tostring();
                buffer = reader.readbyte();
                b[1] = buffer;
                fileclass += buffer.tostring();
                reader.close();
                fs.close();

                if (fileclass == "255216" || fileclass == "7173" || fileclass == "6677" || fileclass == "13780")
                {
                    //255216是jpg;7173是gif;6677是bmp,13780是png;7790是exe,8297是rar
                    //response.write("图片可用");
                    //保存到数据库中
                }
                else
                {
                    //response.write("图片非法");
                    file.delete(savepath); //删除文件
                    return;
                }
            }
            catch (exception)
            { //response.write("图片非法！");
                return;
                throw;
            }
}
mvc 中的代码如下，在这里我返回的json格式，当然可以返回content或其他：

[csharp]
/// <summary>
        /// 上传头像
        /// </summary>
        /// <param name="userid">用户编号</param>
        /// <returns>json(-1表示异常，-2表示文件不合法)</returns>
        [httppost]
        public jsonresult uploadavatar(string userid)
        {
            //上传头像
            string folderpath = "/upload/avatar/";
            //判断路径是否存在
            if (!directory.exists(folderpath))
                directory.createdirectory(folderpath);//创建文件路径
            httppostedfilebase uploadfile = request.files["avatars"];
            if (uploadfile != null)
            {
                string orifilename = uploadfile.filename;//原始文件名
                string filename = userid + "_" + orifilename;
                uploadfile.saveas(server.mappath(folderpath + filename));
                filestream fs = new filestream(server.mappath(folderpath + filename), filemode.open, fileaccess.read);
                binaryreader reader = new binaryreader(fs);
                string fileclass;
                byte buffer;
                byte[] b = new byte[2];
                buffer = reader.readbyte();
                b[0] = buffer;
                fileclass = buffer.tostring();
                buffer = reader.readbyte();
                b[1] = buffer;
                fileclass += buffer.tostring();
                reader.close();
                fs.close();
                if (fileclass == "255216" || fileclass == "7173" || fileclass == "6677" || fileclass == "13780")
                {
                    //255216是jpg;7173是gif;6677是bmp,13780是png;7790是exe,8297是rar
                    //response.write("图片可用");
                    //保存到数据库中
                }
                else
                {

                    //response.write("图片非法");
                    fileinfo f = new fileinfo(server.mappath(folderpath + filename));
                    f.delete(); //删除文件
                    return json(-2, jsonrequestbehavior.allowget);
                }
                return json(server.htmlencode(folderpath + filename), jsonrequestbehavior.allowget);
            }
            return json(-1, jsonrequestbehavior.allowget);

        }

/// <summary>
        /// 上传头像
        /// </summary>
        /// <param name="userid">用户编号</param>
        /// <returns>json(-1表示系统异常，-2表示文件不合法)</returns>
        [httppost]
        public jsonresult uploadavatar(string userid)
        {
            //上传头像
            string folderpath = "/upload/avatar/";
            //判断路径是否存在
            if (!directory.exists(folderpath))
                directory.createdirectory(folderpath);//创建文件路径
            httppostedfilebase uploadfile = request.files["avatars"];
            if (uploadfile != null)
            {
                string orifilename = uploadfile.filename;//原始文件名
                string filename = userid + "_" + orifilename;
                uploadfile.saveas(server.mappath(folderpath + filename));
                filestream fs = new filestream(server.mappath(folderpath + filename), filemode.open, fileaccess.read);
                binaryreader reader = new binaryreader(fs);
                string fileclass;
                byte buffer;
                byte[] b = new byte[2];
                buffer = reader.readbyte();
                b[0] = buffer;
                fileclass = buffer.tostring();
                buffer = reader.readbyte();
                b[1] = buffer;
                fileclass += buffer.tostring();
                reader.close();
                fs.close();
                if (fileclass == "255216" || fileclass == "7173" || fileclass == "6677" || fileclass == "13780")
                {
                    //255216是jpg;7173是gif;6677是bmp,13780是png;7790是exe,8297是rar
                    //response.write("图片可用");
                    //保存到数据库中
                }
                else
                {

                    //response.write("图片非法");
                    fileinfo f = new fileinfo(server.mappath(folderpath + filename));
                    f.delete(); //删除文件
                    return json(-2, jsonrequestbehavior.allowget);
                }
                return json(server.htmlencode(folderpath + filename), jsonrequestbehavior.allowget);
            }
            return json(-1, jsonrequestbehavior.allowget);

}

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ASP.NET中如何检测一个图片是否是真实图片防范病毒上传