ASP.NET MVC5: Limit Upload File Size
File size of an upload file is important factor for storage capacity. We cannot allow infinite amount of file size to end-user because this will cause only one user to fill the server storage capacity in worst case scenario, which could add a lot of issues at back-end sever. So, Restricting or limiting upload file size is one of the key business requirement of the web application. Sometimes only image files are accepted by the web application, sometimes only documents and sometimes the combination of image, documents and compress file types are accepted by the web system.
Today, I shall be demonstrating limiting/restricting of upload file size via implementing custom data annotation/attribute component on ASP.NET MVC5 platform. This article is not specific to image file only, you can use the provided solution with any type of file format as well.
Following are some prerequisites before you proceed any further in this tutorial:
- Knowledge of ASP.NET MVC5.
- Knowledge of HTML.
- Knowledge of Bootstrap.
- Knowledge of C# Programming.
You can download the complete source code for this tutorial or you can follow the step by step discussion below. The sample code is being developed in Microsoft Visual Studio 2015 Enterprise.
Let's begin now.
1) Create a new MVC web project and name it "ImgFileSizeLimit".
2) You need to add/update "executionTimeout", "maxRequestLength" & "maxAllowedContentLength" properties values if not already added in the "Web.config" file as shown below i.e.
executionTimeout -> The amount of time require to process your request on the web server. The value is provided in seconds.
maxRequestLength -> The maximum size which your request can capture and send to the web server. The value is provided in bytes.
maxAllowedContentLength -> The maximum allowed size of your content (e.g. file, text data etc) which is sent to the web server. The value is provided in bytes.
3) Open the "Views->Shared->_Layout.cshtml" file and replace following code in it i.e.
In the above code, I have simply created a basic default layout page and linked the require libraries into it.
4) Create a new "Helper_Code\Common\AllowFileSizeAttribute.cs" file and replace the following code in it i.e.
In asp.net mvc5 creating customize data annotations/attributes is one of the cool feature. In the above code, I have created a new class "AllowFileSizeAttribute" (by following naming convention of custom attribute class) and inherit ValidationAttribute class. Then, I have created a public property "FileSize" and set the default value as 1 GB in bytes which means that my custom attribute will accept only upload files with maximum file size less than or equal to 1 GB. So, in order to allow require file size, this property will be updated at the time of my custom attribute utilization accordingly. Finally, I have overridden the "IsValid(....)" method which will receive my upload file as "HttpPostedFileBase" data type and from this I will extract the file size of the upload file and then validates that whether it is less than or equal to default file size restriction or according to my provided file size.
5) Now, create a new "Models\ImgViewModel.cs" file and replace the following code in it i.e.
In the above code, I have created my view model which I will attach with my view. Here, I have created HttpPostedFileBase type file attachment property which will capture uploaded image/file data from the end-user, then I have also applied my custom "AllowFileSize" attribute to the FileAttach property and provide default file size as 5 MB that I have allowed my system to accept. Then, I have created two more properties i.e. Message of data type string and isValid of data type Boolean for processing purpose.
6) Create a new "Controllers\ImgController.cs" file and replace the following code in it i.e.
In the above code, I have created GET "Index(...)" method which will initialize the view model with default values and send it to the view page. Finally, I have created POST "Index(...)" method which will receive input file from the end-user, then validate the view model for allowed file size and then send the response message accordingly.
7) Now, create a view "Views\Img\Index.cshtml" file and replace the following code in it i.e.
In the above code, I have created a simple view for uploading file to the server which will validate the allowed file size at server side.
8) Now, execute the project and you will be able to see the following in action i.e.
In this article, you will learn about uploading of file by limiting/restricting the desire upload file size via implementing custom data annotation/attribute component on ASP.NET MVC5 platform.You will also learn to create a custom data annotation/attribute class and then utilize the custom attribute in your view model property of type HttpPostedFileBase.