Returning an image using Web API

Question

I have a web service method, which looks like this:

[HttpGet("{id}")]
public ActionResult<byte[]> Get(Guid id)
{
    var files = Directory.GetFiles(@"Pictures\");
    foreach (var file in files)
    {
        if (file.Contains(id.ToString()))
        {
            return System.IO.File.ReadAllBytes(file);
        }
    }
    return null;
}

Here is the client code, which is definitely working i.e. it is calling the web service and the web service is returning the image:

var response2 = await client.GetAsync("http://localhost:59999/api/Images/5c60f693-bef5-e011-a485-80ee7300c692");
byte[] image2 = await response2.Content.ReadAsByteArrayAsync(); //https://stackoverflow.com/questions/39190018/how-to-get-object-using-httpclient-with-response-ok-in-web-api
System.IO.File.WriteAllBytes("image.jpg", image2);

When I try to open image.jpg in Paint; it says it is an invalid file. What is the problem?

The image picked up by the webervice, are you sure this is a jpg? — D.J.
– D.J., Commented Mar 16, 2019 at 16:04
ok, can you check if the bytearray received by the client is as long as the one send from the webservice ? maybe the image is not fully sent to the client — D.J.
– D.J., Commented Mar 16, 2019 at 16:08
@D.J, the sizes of the byte arrays are different. There is something wrong. How do I get the image from the response? I cannot believe how difficult this is. — w0051977
– w0051977, Commented Mar 16, 2019 at 16:10
my first guess would be that the client doesn't receive the image but an error or info page, can you open url that is requested by the client in a browser ? — D.J.
– D.J., Commented Mar 16, 2019 at 16:13

Oleksandr · Accepted Answer · 2019-03-16 16:29:15Z

5

If you want to return file do not return byte[] from action because it gets base64 encoded. You can decode base64 string on client or better would be using File method in action

[HttpGet("{id}")]
public ActionResult Get(Guid id)
{
    var files = Directory.GetFiles(@"Pictures\");
    foreach (var file in files)
    {
        if (file.Contains(id.ToString()))
        {
            return File(System.IO.File.ReadAllBytes(file), "image/jpeg");
        }
    }
    return null;
}

edited Mar 16, 2019 at 16:29

answered Mar 16, 2019 at 16:13

Oleksandr

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2 Comments

Oleksandr Over a year ago

@w0051977 with this answer client should be unchanged. Try it out

w0051977 Over a year ago

Are you saying use the client code in my original post? Thanks.

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