Displaying image from WebRequest

Question

I'm obtaining an image from Google Charts by making a WebRequest via POST.

The problem I'm having is displaying the image returned by Google.

I can see in Fiddler that the request for the image is made, and the image returned in the response when I do:

var response = request.GetResponse();

However from here I don't seem to be able to output the image from my controller.

Here's what I'm doing right now:

using (var dataStream = response.GetResponseStream()) { if (dataStream == null) return; using (var reader = new StreamReader(dataStream)) { byte[] dataBytes = Encoding.UTF8.GetBytes(reader.ReadToEnd()); Response.ContentType = "image/png"; Response.BinaryWrite(dataBytes); } }

The error message displayed in my browser window is:

The image “[path to image]” cannot be displayed, because it contains errors.

Darin Dimitrov · Accepted Answer · 2011-08-25 16:38:49Z

Try using a WebClient, it will simplify your code:

public ActionResult MyChart() { using (var client = new WebClient()) { var data = client.DownloadData("http://......"); // TODO: the MIME type might need adjustment return File(data, "image/png", "chart.png"); } }

or if you need to use a POST request and send some values use the UploadValues method:

public ActionResult MyChart() { using (var client = new WebClient()) { var request = new NameValueCollection { { "foo", "foo value" }, { "bar", "bar value" }, }; var data = client.UploadValues("http://......", request); // TODO: the MIME type might need adjustment return File(data, "image/png", "chart.png"); } }

and then in the view:

<img src="@Url.Action("MyChart", "SomeController")" alt="chart" />

or if the url is static and could be reached with a GET request you could directly include it in your view (you don't need a controller action in this case):

<img src="http://......" alt="chart" />

Thanks Darin. I should have mentioned that I'm doing this as a POST request because of a large amount of data being passed to Google. Does DownloadData work over Http Post?
@Jamie Dixon, please see my update and the usage of the UploadValues method.

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