Asp.Net URL Encoding Broken

Question

I'm encrypting values and adding them to the URL. My problem though is that after I run it through HttpUtility.URLEncode I sometimes come up with bad URLs. I get stuff like

www.mysite.com/page.aspx?id=+jdghogjhior==

I think the it's the leading plus that's giving me trouble. Any ideas? What do you guys do?

Similar problems to what this guy talks about: Server.UrlEncode vs. HttpUtility.UrlEncode

Please post your code, what the input to `Encode` is and what you expect as result. — Oded, Oct 27 '11 at 15:29

score 1 · Answer 1 · answered Oct 27 '11 at 15:55

You can try to take an encrypted string, convert it to base64 string and send it via url. When you receive it, decode from base64 and decrypt it.

Encoding:

byte[] bt = Encoding.Unicode.GetBytes("5dnjnbf&&#jnb3=+");
string str = Convert.ToBase64String(bt);

Decode:

byte[] bt = Convert.FromBase64String(str);
string s = Encoding.Unicode.GetString(bt);

score 0 · Answer 2 · answered Oct 27 '11 at 15:34

0

I think the + is the only problem, so habitualy I replace it with something else that I know won't be in the query like space (%20)

But in somme case you need spaces

so have you try : Uri.EscapeDataString

Like the link you have posted ?

answered Oct 27 '11 at 15:34

GregM

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score 0 · Answer 3 · answered Oct 27 '11 at 15:46

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I tried this and it brought the id across correctly:

<a href='Page.aspx?ID=
    <%=server.urlencode(server.htmlencode("+jdghogjhior==")) %>'>Click here</a>

answered Oct 27 '11 at 15:46

Steve

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So, really, htmlEncoding it, then urlEncoding it did the trick. – Steve Oct 28 '11 at 17:33

score 0 · Accepted Answer · edited May 23 '17 at 12:03

0

Is the thing you're encoding by chance already base64 encoded?

If so you'll need to use a "modified" base64 which is compatible with URLs:

... a modified Base64 for URL variant exists, where no padding '=' will be used, and the '+' and '/' characters of standard Base64 are respectively replaced by '-' and '_'

See Code for decoding/encoding a modified base64 URL for example.

edited May 23 '17 at 12:03

Community

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answered Oct 27 '11 at 15:58

Craig

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yup, that was it. I was double encoding / decoding – John Jul 06 '12 at 15:28

Asp.Net URL Encoding Broken

4 Answers4