How to convert a file into byte array in memory?
C#asp.net CoreC# Problem Overview
Here is my code:
public async Task<IActionResult> Index(ICollection<IFormFile> files)
{
foreach (var file in files)
uploaddb(file);
var uploads = Path.Combine(_environment.WebRootPath, "uploads");
foreach (var file in files)
{
if (file.Length > 0)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
await file.SaveAsAsync(Path.Combine(uploads, fileName));
}
}
}
Now I am converting this file into byte array using this code:
var filepath = Path.Combine(_environment.WebRootPath, "uploads/Book1.xlsx");
byte[] fileBytes = System.IO.File.ReadAllBytes(filepath);
string s = Convert.ToBase64String(fileBytes);
And then I am uploading this code into my nosql database.This is all working fine but the problem is i don't want to save the file. Instead of that i want to directly upload the file into my database. And it can be possible if i can just convert the file into byte array directly without saving it.
public async Task<IActionResult> Index(ICollection<IFormFile> files)
{
foreach (var file in files)
uploaddb(file);
var uploads = Path.Combine(_environment.WebRootPath, "uploads");
foreach (var file in files)
{
if (file.Length > 0)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
///Code to Convert the file into byte array
}
C# Solutions
Solution 1 - C#
As opposed to saving the data as a string (which allocates more memory than needed and might not work if the binary data has null bytes in it), I would recommend an approach more like
foreach (var file in files)
{
if (file.Length > 0)
{
using (var ms = new MemoryStream())
{
file.CopyTo(ms);
var fileBytes = ms.ToArray();
string s = Convert.ToBase64String(fileBytes);
// act on the Base64 data
}
}
}
Also, for the benefit of others, the source code for IFormFile
can be found on GitHub
Solution 2 - C#
You can just write a simple extension:
public static class FormFileExtensions
{
public static async Task<byte[]> GetBytes(this IFormFile formFile)
{
await using var memoryStream = new MemoryStream();
await formFile.CopyToAsync(memoryStream);
return memoryStream.ToArray();
}
}
Usage
var bytes = await formFile.GetBytes();
var hexString = Convert.ToBase64String(bytes);
Solution 3 - C#
You can use the following code to convert it to a byte array:
foreach (var file in files)
{
if (file.Length > 0)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
using (var reader = new StreamReader(file.OpenReadStream()))
{
string contentAsString = reader.ReadToEnd();
byte[] bytes = new byte[contentAsString.Length * sizeof(char)];
System.Buffer.BlockCopy(contentAsString.ToCharArray(), 0, bytes, 0, bytes.Length);
}
}
}