Asp.net file upload download module demo

The resources disk, memory used by file uploads depend on the number and size of concurrent file uploads. If an app attempts to buffer too many uploads, the site crashes when it runs out of memory or disk space. If the size or frequency of file uploads is exhausting app resources, use streaming. The file is received from a multipart request and directly processed or saved by the app. Streaming doesn't improve performance significantly. Streaming reduces the demands for memory or disk space when uploading files.

Streaming large files is covered in the Upload large files with streaming section. Use a Fetch Polyfill for example, window. The sample app demonstrates multiple buffered file uploads for database and physical storage scenarios. When displaying or logging, HTML encode the file name. An attacker can provide a malicious filename, including full paths or relative paths.

Applications should:. The examples provided thus far don't take into account security considerations. Additional information is provided by the following sections and the sample app :. When uploading files using model binding and IFormFile , the action method can accept:. Binding matches form files by name. Use Path. GetRandomFileName to generate a file name without a path. In the following example, the path is obtained from configuration:. The path passed to the FileStream must include the file name.

If the file name isn't provided, an UnauthorizedAccessException is thrown at runtime. Files uploaded using the IFormFile technique are buffered in memory or on disk on the server before processing. Inside the action method, the IFormFile contents are accessible as a Stream. In addition to the local file system, files can be saved to a network share or to a file storage service, such as Azure Blob storage. GetTempFileName throws an IOException if more than 65, files are created without deleting previous temporary files.

The limit of 65, files is a per-server limit. For more information on this limit on Windows OS, see the remarks in the following topics:. To store binary file data in a database using Entity Framework , define a Byte array property on the entity:. Specify a page model property for the class that includes an IFormFile :. IFormFile can be used directly as an action method parameter or as a bound model property.

The prior example uses a bound model property. Use caution when storing binary data in relational databases, as it can adversely impact performance.

The examples provided don't take into account security considerations. The 3. The file's antiforgery token is generated using a custom filter attribute and passed to the client HTTP headers instead of in the request body. Because the action method processes the uploaded data directly, form model binding is disabled by another custom filter.

Within the action, the form's contents are read using a MultipartReader , which reads each individual MultipartSection , processing the file or storing the contents as appropriate. After the multipart sections are read, the action performs its own model binding. The initial page response loads the form and saves an antiforgery token in a cookie via the GenerateAntiforgeryTokenCookieAttribute attribute. The attribute uses ASP. NET Core's built-in antiforgery support to set a cookie with a request token:.

ConfigureServices using Razor Pages conventions :. Since model binding doesn't read the form, parameters that are bound from the form don't bind query, route, and header continue to work. The action method works directly with the Request property. A MultipartReader is used to read each section. After the multipart sections are read, the contents of the KeyValueAccumulator are used to bind the form data to a model type.

The complete StreamingController. UploadDatabase method for streaming to a database with EF Core:. UploadPhysical method for streaming to a physical location:. In the sample app, validation checks are handled by FileHelpers. The sample app's FileHelpers class demonstrates a several checks for buffered IFormFile and streamed file uploads.

AddWithValue " refno", rid ; cmd3. Value ; cmd3. Text ; if fileUpload1. GetFileName fileUpload1. FileName ; fileUpload1. SaveAs Server. AddWithValue " Name1", filename ; cmd3. AddWithValue " Name1", "" ; cmd3. ExecuteNonQuery ; Response. ToString ; HyperLink1. ToString ; con. AppSettings["Connection"]; con2. AppSettings["Connection"]; if! Open ; con2. ExecuteReader ; while dr. Fill ds ; GridView1. Description: HTTP The resource you are looking for or one of its dependencies could have been removed, had its name changed, or is temporarily unavailable.

Please review the following URL and make sure that it is spelled correctly. ToString System. Here we see a method to download a file in ASP. Here is perhaps the simplest, shortest way to download a file in an ASP. Net application: Response. TransmitFile Server. End ; The first step is to set the content type. In the example above, we're downloading a. Here are some of the most common content types:.

TransmitFile retrieves a file and writes it to the Response. In some cases, we can't call TransmitFile because we can't map a path to the file.