File upload and download asp.net

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Privacy policy. By Steve Smith and Rutger Storm. NET Core supports uploading one or more files using buffered model binding for smaller files and unbuffered streaming for larger files. View or download sample code how to download. Use caution when providing users with the ability to upload files to a server. Attackers may attempt to:. For information on reducing the attack surface area when accepting files from users, see the following resources:.

For more information on implementing security measures, including examples from the sample app, see the Validation section.

Cloud data storage service, for example, Azure Blob Storage. For more information, see Quickstart: Use. NET to create a blob in object storage. The entire file is read into an IFormFile , which is a C representation of the file used to process or save the file. 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. In my opinion should you save file in eg. Azure Blobs or simply in wwwroot in application. If you are passing the file back to your controller using HttpPostedFileBase , you can adapt the following code to suit your needs. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?

Collectives on Stack Overflow. Learn more. File Upload and Download Asp. Asked 1 year, 8 months ago. Active 7 months ago. Viewed 11k times. Generic; using System. Improve this question. Shaker Kamal. Shaker Kamal Shaker Kamal 77 1 1 gold badge 1 1 silver badge 9 9 bronze badges.

It's kinda unclear as to what you are asking here. Are you asking whether you need a ViewModel to store outside of the Project Directory? Or just how to store file outside of the project directory? How to store the file outside the directory? What type of object is used to pass the file back to the Controller? Are you using something like HttpPostedFileBase?

By this, I mean the actual file, not the metadata — GipsyD. Related : stackoverflow. Add a comment. Active Oldest Votes. Next Recommended Reading. Net Core 6. Create A. Understanding Thread Starvation in. NET Core Applications. Exploring Numeric Streams In Java. What Is The Metaverse. Microservice Circuit Breaker Pattern.