Take a screenshot of an iFrame

Question

I am looking for a simple way to take a screenshot of an iFrame in my ASP page. I just couldn't achieve it with C# and I lack of knowledge of Javascript! Does anyone out there know the simple and best way to achieve this?

What I am trying to do is, I am building a website that students can log in to e-government website in my country and prove if they are continuing student with a single click so that they can get discount from our service.

Edit: The puzzle should be solved in local.

Personally, I do not think a screenshot of an IFRAME is proof of much and would be significantly insecure as a concept of proving that a student is legitimate. I would advocate thinking up a different solution. — SpaceBison, Feb 20 '12 at 14:27

score 2 · Answer 1 · answered Mar 12 '12 at 15:23

this piece of code worked for me. I hope it does the same to the others.

private void saveURLToImage(string url) 
    { 
        if (!string.IsNullOrEmpty(url)) 
        { 
            string content = ""; 


            System.Net.WebRequest webRequest = WebRequest.Create(url); 
            System.Net.WebResponse webResponse = webRequest.GetResponse(); 
            System.IO.StreamReader sr = new StreamReader(webResponse.GetResponseStream(), System.Text.Encoding.GetEncoding("UTF-8"));

            content = sr.ReadToEnd(); 
            //save to file 
            byte[] b = Convert.FromBase64String(content); 
            System.IO.MemoryStream ms = new System.IO.MemoryStream(b); 
            System.Drawing.Image img = System.Drawing.Image.FromStream(ms); 
            img.Save(@"c:\pic.jpg", System.Drawing.Imaging.ImageFormat.Jpeg); 


            img.Dispose(); 
            ms.Close(); 
        } 
    }

Does it even answer he question? The code isn't taking a screenshot. Also, it seems to be designed to download images and save them locally, even though there are framework methods for that. If you gave it a page URL, it wouldn't render it, so there's no image to save. — Edgar, Mar 09 '16 at 13:10

score 0 · Answer 2 · answered Feb 20 '12 at 14:22

0

Unless I'm misunderstanding you, this is impossible.

You cannot instruct the user's browser to take a screenshot (this would be a security risk … and has few uses cases anyway).
You cannot load the page you want a screenshot of yourself (with server side code) because you don't have the credentials needed to access it.

answered Feb 20 '12 at 14:22

Quentin

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@Aristos — No, it isn't. Those try to render HTML to PNG. It says at the top that it isn't accurate. Also the same origin policy would prevent it from reading the data from the iframe. – Quentin Feb 20 '12 at 14:32
+1 hmm you have right, the one that ask here maybe this way is not possible. – Aristos Feb 20 '12 at 14:35
one could use a JAVA applet to take a screenshot. – Stefan Paul Noack Feb 20 '12 at 14:38

score -2 · Answer 3 · edited May 23 '17 at 12:20

-2

server side Take a screenshot of a webpage with JavaScript?

javascript http://html2canvas.hertzen.com/

edited May 23 '17 at 12:20

Community

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answered Feb 20 '12 at 14:27

Daniel B

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This won't work [due to standard security restrictions](http://en.wikipedia.org/wiki/Same_origin_policy). – Quentin Feb 20 '12 at 14:33
if you on the 2nd link and then test console button you'll see that it takes a snapshot of the given link it's true that it needs the credentials for the given url to login. – Daniel B Feb 22 '12 at 14:44
To quote that page: "There are a lot of problems of loading external pages, even with a proxy, and as such many pages will not render at all." – Quentin Feb 22 '12 at 14:49
Also, since it requires using a proxy, it wouldn't be able to fetch the page that the OP wants a screenshot off … because that requires the user's credentials. – Quentin Feb 22 '12 at 14:50

Take a screenshot of an iFrame

3 Answers3

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