ASP.Net MVC - Read File from HttpPostedFileBase without save

Question

I am uploading the file by using file upload option. And i am directly send this file from View to Controller in POST method like,

    [HttpPost]
    public ActionResult Page2(FormCollection objCollection)
    {
        HttpPostedFileBase file = Request.Files[0];
    }

Assume, i am uploading a notepad file. How do i read this file & append this text to string builder,, without save that file....

I'm aware about after SaveAs this file, we can read this file. But How do i read this file from HttpPostedFileBase without save?

Defence

Answer 1

This can be done using httpPostedFileBase class returns the HttpInputStreamObject as per specified here

You should convert the stream into byte array and then you can read file content

Please refer following link

http://msdn.microsoft.com/en-us/library/system.web.httprequest.inputstream.aspx]

Hope this helps

UPDATE :

The stream that you get from your HTTP call is read-only sequential (non-seekable) and the FileStream is read/write seekable. You will need first to read the entire stream from the HTTP call into a byte array, then create the FileStream from that array.

Taken from here

// Read bytes from http input stream
BinaryReader b = new BinaryReader(file.InputStream);
byte[] binData = b.ReadBytes(file.ContentLength);

string result = System.Text.Encoding.UTF8.GetString(binData);

Malleus

meta.stackexchange.com/questions/8231/… – Repugnant

P.S. b.ReadBytes() wants an int but file.InputStream.Length is a long – Trantham

but file.InputStream.ContentLength is an int – Trantham

Tiny modification, ContentLength is on file.ContentLength, not file.InputStream.ContentLength – Pickford

Answer 2

An alternative is to use StreamReader.

public void FunctionName(HttpPostedFileBase file)
{
    string result = new StreamReader(file.InputStream).ReadToEnd();
}

Cheese

this will empty out the stream making file.Length = 0 – Westmorland

agreed, but in a lot of cases this is OK. – Cheese

Althought +1, You aren't disposing of an IDisposable. – Barquentine

Answer 3

A slight change to Thangamani Palanisamy answer, which allows the Binary reader to be disposed and corrects the input length issue in his comments.

string result = string.Empty;

using (BinaryReader b = new BinaryReader(file.InputStream))
{
  byte[] binData = b.ReadBytes(file.ContentLength);
  result = System.Text.Encoding.UTF8.GetString(binData);
}

Vesture

Answer 4

byte[] data; using(Stream inputStream=file.InputStream) { MemoryStream memoryStream = inputStream as MemoryStream; if (memoryStream == null) { memoryStream = new MemoryStream(); inputStream.CopyTo(memoryStream); } data = memoryStream.ToArray(); }

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