How can I retrieve a saved PDF file in SQL Server, stored as binary?

Question

I have checked many questions on StackOverflow, and also searched on many different websites for possible solutions, but I don't seem to find any answer. Some don't work, others are very old and don't work either.

I have saved .pdf files in SQL Server as binary. Seems to work. But I don't know how to retrieve the data and turn the byte[] back to the .pdf file and make it available for download.

This is my model, where I save the .pdf file in byte[]:

public class Language
{
    public int Id { get; set; }
    public string Name { get; set; }
    public byte[] Certificate { get; set; }
}

This is how I upload into database:

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create(string name, IFormFile certificate)
{
    Language language = new Language()
    {
        Name = name
    };

    if(certificate.Length > 0)
    {
        using (var stream = new MemoryStream())
        {
            await certificate.CopyToAsync(stream);
            language.Certificate = stream.ToArray();
        }
    }

    _context.Add(language);
    await _context.SaveChangesAsync();

    return RedirectToAction(nameof(Index));
}

I would like it to be able to retrieve the data and then download it.

I appreciate any help.

What class are you using for the pdf file when you converted to bytes. — jdweng
– jdweng, Commented Mar 29, 2019 at 12:07
Do you mean FromFile? FromFile crates a string which wil corrupt pdf which is binary. Better to use byte[] pdf = File.ReadAllBytes("filename"); File.WriteAllBytes("filename", pdf); — jdweng
– jdweng, Commented Mar 29, 2019 at 12:54

Chris Pratt · Accepted Answer · 2019-03-29 12:35:03Z

2

You need an action to return the bytes:

public async Task<IActionResult> GetCertificate(int id)
{
    var language = await _context.Languages.FindAsync(id);
    if (language == null)
        return NotFound();

    return File(language.Certificate, "application/pdf");
}

Then, you can simply link to this action.

answered Mar 29, 2019 at 12:35

Chris Pratt

240k37 gold badges414 silver badges469 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

rpowell6 Over a year ago

Can you elaborate on "simply link to this action"? I have the same issue described by @Max. PDF files are stored in SQL Server but how to render them in an HTML element becomes the question. Are you suggesting use of an <embed> tag with a "src" attribute set to "controller/action"? Or, is there a better method?

Collectives™ on Stack Overflow

How can I retrieve a saved PDF file in SQL Server, stored as binary?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related