Asp Net Mvc Is Restricting Request for Large Upload

I bet that most of you have faced this common problem: "How to upload large size files (in a higher place 4MB) in ASP.NET?"  As y'all know, the default maximum file size allowed in the framework is 4MB and this is to prevent service attacks like submitting large files, which can overwhelm the server resources. In this blog mail I am going to show yous how to overcome this limitation, likewise as how to validate the file size and type on the client earlier submitting it to the server.

Uploading large files in ASP.Internet – the solution:

All it takes to overcome the framework limitation is to do several modifications to the project's web.config file. To enable large file uploads yous need to modify the value of the following attributes on the system.spider web/httpRuntime configuration element:

• maxRequestLength : Specifies the limit for the input stream buffering threshold in KB and allows yous to control the immune total size of the upload. Anything bigger than that volition consequence in the default for the framework "Folio not found" fault.
• ExecutionTimeout : Specifies the maximum number of seconds for which a request is immune to be executed earlier being automatically shut down past ASP.Net – the default fourth dimension is 110 seconds. If the asking takes longer to be executed, an exception will be thrown.
• maxAllowedContentLength (IIS seven) - specifies the maximum length of content in a request supported by IIS. By default information technology restricts the content length to thirty,000,000 bytes.

For example, the web.config configuration allowing uploads of files up to 100MB and upload periods of upward to 1 hr should look like the following:

< configuration >

...

< organisation. web>

< httpRuntime maxRequestLength = "102400" executionTimeout = "3600" />

...

</ system .web>

</ configuration >

If you use IIS7 and y'all want to upload files larger than the restricted 30000000 bytes or 28.half-dozen MB, you can add the following code to your web.config file in order to prepare that value to 100 MB:

< system.webServer >

< security >

< requestFiltering >

< requestLimits maxAllowedContentLength = "104857600" />

</ requestFiltering >

</ security >

</ system.webServer >

Validating the File Type and Size

Sometimes you want to limit the file type and size which the user is allowed to upload on the server. This might exist related to the application's security or overall performance.

Here are some validation options you can cull from:

Using the ASP File Upload command

The principal disadvantage of the standard file upload control is that it does not offering client-side validation. Therefore the file needs to get-go exist uploaded to the server and so validated by some custom implementation of such functionality. Here is a simple server-side validation scenario involving the ASP File Upload control:

//markup lawmaking

< asp:FileUpload ID = "fileUpload" runat = "server" />

< asp:Push button runat = "server" ID = "btnUpload" Text = "Upload" OnClick = "btnUpload_Click" />

//code backside

protected void btnUpload_Click( object sender, EventArgs e)

{

HttpPostedFile file = fileUpload.PostedFile;

if ((file != null ) && (file.ContentLength > 0))

{

if (IsImage(file) == false )

{

// Invalid file type

return ;

}

}

int iFileSize = file.ContentLength;

if (iFileSize > 1048576) // 1MB

{

// File exceeds the file maximum size

return ;

}

// validation passed successfully

}

private bool IsImage(HttpPostedFile file)

{

//Checks for image type... yous could also do filename extension checks and other things

render ((file != nil ) && System.Text.RegularExpressions.Regex.IsMatch(file.ContentType, "prototype/\\Southward+" ) && (file.ContentLength > 0));

}

Using an HTML5 Input and File API in Modernistic Browsers

The File API comes with the new web standard HTML5 and is supported by all modernistic browsers. Its main advantages are that it offers client-side validation and additionally supports the following features:

• Multiple file upload
• Stand up-alone progress monitoring (No http module used!)
• Support for the aforementioned events as the other modules
• Upload cancellation
• Upload files via chunks, effectively walking around the ASP.Internet max files size limitation.
• File type and size validation on the client side.

The sample code below shows how powerful the File API could be in accessing the selected files on the client side and how to perform a custom validation:

< input id = "image-file" type = "file" proper noun = "file" />

<script blazon= "text/javascript" >

//this code will be executed when a new file is selected

$( '#image-file' ).bind( 'change' , function () {

//converts the file size from bytes to MB

var fileSize = this .files[0].size / 1024 / 1024;

//gets the full file name including the extension

var fileName = this .files[0].name;

//finds where the extension starts

var dotPosition = fileName.lastIndexOf( "." );

//gets only the extension

var fileExt = fileName.substring(dotPosition);

//checks whether the file is .png and less than ane MB

if (fileSize <=  1 && fileExt == ".png" ) {

//successfully validated

}

});

</script>

Custom JavaScript Code for Non-modern Browsers

So what happens when you want to validate uploaded files in browsers which don't support HTML5? The most mutual solution for validating the file type in such case is to use a custom JavaScript code and for validating the file size - to utilise the approach for server-side validation described above.  A sample scenario would await like this:

< input id = "epitome-file" type = "file" proper name = "file" />

<script type= "text/javascript" >

//this code will be executed when a new file is selected

$( '#image-file' ).bind( 'change' , function () {

//gets the full file proper noun including the extension

var fileName = this .value;

//finds where the extension starts

var dotPosition = fileName.lastIndexOf( "." );

//gets simply the extension

var fileExt = fileName.substring(dotPosition);

//checks whether the file is .png

if (fileExt == ".png" ) {

//successfully validated

}

});

</script>

Other options: using Silverlight, Flash or IFrame plugins

Of grade there are some additional options to cull from if your browser does not back up the HTML5 File API and you desire to avoid writing a custom JavaScript code. You can only use the Adobe Flash or Silverlight plugin.  They are available for download and install though your browser Add together-on managing director.

Let's explain a bit about each of the modules:

Wink & IFrame Modules

The IFrame and Flash modules upload the selected file(s) using normal http post request. The IFrame uses <input type="file" /> tag for file uploads, whereas Flash uses the Flex object in order to upload files.

It is very of import to know that the Wink module allows you lot to validate both file blazon and size on the client side.  The files are uploaded using Mail HTTP request in absolutely the same style every bit the normal <input type="file" />. Since both modules upload a file with a single request, in case of uploading a file larger than the 4MB ASP.Net default limitation, you demand to change your spider web.config file every bit shown in the outset section.

Browser support: IE9,eight,vii.

Silverlight Module

In dissimilarity, the Silverlight upload is designed in a different way so that it divides the file to exist uploaded on the customer side in many chunks, each of which is 2MB big. It then starts uploading the chunks one after another later . Information technology does support file blazon and size validation on the client.

Browser support: Firefox  < 3.6, IE9,8,vii.

There'due south an easier way to upload and validate files

If yous're using a 3rd-party command, such equally Telerik'southward Asynchronous ASP.NET upload control, all of the in a higher place modifications will be taken care of for you.

RadAsyncUpload is working with modules based on the above information in order to handle the upload process no matter of the current browser version. The module with highest priority is File API. If the browser does not support File API, the module is automatically changed to Silverlight. If in that location is no Silverlight installed on the client machine, RadAsyncUpload will apply the Flash module. If neither Flash nor Silverlight are installed – the IFrame module takes identify.

RadAsyncUpload helps you lot overcome the 4 MB file size upload limitation in ASP.Cyberspace by dividing the large files into smaller chunks and uploading them subsequently. You lot can control the size of the chunks and thus the number of requests to the server required to upload the file, which tin improve your application's performance. No demand to modify the configuration file and override different properties.

Merely prepare the ChunkSize property to the desired value and you are prepare to go!

< telerik:RadAsyncUpload runat = "server" ID = "AsyncUpload1" ChunkSize = "1048576" />

If you wonder how to monitor the modify in the number of requests to the server, when you change the size of the chunks – the Telerik web debugging tool Fiddler could quickly practise that for you:

What we have done so far:

Subsequently reading this article you lot should at present exist able to:

• Implement custom server-side validation for your uploaded files with the standard ASP.Net File Upload command in guild to prevent any service attacks submitting large files.
• Validate the selected files on the client only past using HTML five File API and a unmarried input field on the page.
• Implement a custom JavaScript code to cheque the file name on the client when working with browsers which do non back up HTML5.
• Understand different options and modules required based on the client browser in order to upload a file successfully to the server.

Please feel free to comment below if you know other or easier ways to accomplish the things described in a higher place.

CodeProject

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Source: https://www.telerik.com/blogs/upload-large-files-asp-net-radasyncupload