确定是否上传的文件图像(任何格式)的MVC [英] Determine if uploaded file is image (any format) on MVC
本文介绍了确定是否上传的文件图像(任何格式)的MVC的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
所以我用这个code的观点:
So I'm using this code for view:
<form action="" method="post" enctype="multipart/form-data">
<label for="file">Filename:</label>
<input type="file" name="file" id="file" />
<input type="submit" />
</form>
这对模型:
[HttpPost]
public ActionResult Index(HttpPostedFileBase file) {
if (file.ContentLength > 0) {
var fileName = Path.GetFileName(file.FileName);
var path = Path.Combine(Server.MapPath("~/App_Data/uploads"), fileName);
file.SaveAs(path);
}
return RedirectToAction("Index");
}
除非用户添加一个文件,该文件不是图像的伟大工程。如何我可以保证上传的文件是一个图像。谢谢
Works great unless the user add a file which isn't an image. How can I assure the file uploaded is an image. Thanks
推荐答案
在情况下,它可以帮助任何人,这里是HttpPostedFileBase来检查,如果给定上传的文件图像的静态方法:
In case it can helps anyone, Here is a static method for HttpPostedFileBase that checks if a given uploaded file is an image:
public static class HttpPostedFileBaseExtensions
{
public const int ImageMinimumBytes = 512;
public static bool IsImage(this HttpPostedFileBase postedFile)
{
//-------------------------------------------
// Check the image mime types
//-------------------------------------------
if (postedFile.ContentType.ToLower() != "image/jpg" &&
postedFile.ContentType.ToLower() != "image/jpeg" &&
postedFile.ContentType.ToLower() != "image/pjpeg" &&
postedFile.ContentType.ToLower() != "image/gif" &&
postedFile.ContentType.ToLower() != "image/x-png" &&
postedFile.ContentType.ToLower() != "image/png")
{
return false;
}
//-------------------------------------------
// Check the image extension
//-------------------------------------------
if (Path.GetExtension(postedFile.FileName).ToLower() != ".jpg"
&& Path.GetExtension(postedFile.FileName).ToLower() != ".png"
&& Path.GetExtension(postedFile.FileName).ToLower() != ".gif"
&& Path.GetExtension(postedFile.FileName).ToLower() != ".jpeg")
{
return false;
}
//-------------------------------------------
// Attempt to read the file and check the first bytes
//-------------------------------------------
try
{
if (!postedFile.InputStream.CanRead)
{
return false;
}
if (postedFile.ContentLength < ImageMinimumBytes)
{
return false;
}
byte[] buffer = new byte[512];
postedFile.InputStream.Read(buffer, 0, 512);
string content = System.Text.Encoding.UTF8.GetString(buffer);
if (Regex.IsMatch(content, @"<script|<html|<head|<title|<body|<pre|<table|<a\s+href|<img|<plaintext|<cross\-domain\-policy",
RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Multiline))
{
return false;
}
}
catch (Exception)
{
return false;
}
//-------------------------------------------
// Try to instantiate new Bitmap, if .NET will throw exception
// we can assume that it's not a valid image
//-------------------------------------------
try
{
using (var bitmap = new System.Drawing.Bitmap(postedFile.InputStream))
{
}
}
catch (Exception)
{
return false;
}
return true;
}
}
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