How to stop HttpUtility.UrlEncode() from changing + to space?

Question

I am using HttpUtility.UrlEncode() on a string token the original token is t+Bj/YpH6zE= when i HttpUtility.UrlDecode() it becomes t Bj/YpH6zE= which breaks the algorithm. is a way to stop changing + to a space in c#.

I am currently using replace method to achieve that var token_decrypt = HttpUtility.UrlDecode(token).Replace(" ", "+");

public HttpResponseMessage RegisterUser(User user, string token)
        {
            int accID;

            if(string.IsNullOrWhiteSpace(token))
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest);
            }
            else
            {
                try
                {
                     // token now = t Bj/YpH6zE= which will fail 
                     var token_decrypt = HttpUtility.UrlDecode(token);
                      token now = t Bj/YpH6zE= still the same 
                     accID = int.Parse(Crypto.Decrypt(token_decrypt, passPhrase));
                }
                catch
                {
                    return Request.CreateResponse(HttpStatusCode.BadRequest, "Invalid account ");
                }

her i encode the token

  string encoded_token = HttpUtility.UrlEncode(token);

            System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();
            SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
            msg.To.Add(mail);
            msg.From = new System.Net.Mail.MailAddress(from);

her is the call of RegisterUser from angular js

 RegistrationFactory.registerUser = function(user, token){
    return $http({method : "post", url:ConfigService.baseUrl+"User/RegisterUser?token="+token, data : user});
};

Bunch of alternatives here: http://stackoverflow.com/questions/3840762/how-do-you-urlencode-without-using-system-web — User 12345678, Aug 04 '14 at 12:14
it is a function in a controller i will add the code of java script — MohamedAbbas, Aug 04 '14 at 13:06
Now works fine you saved my day thank you and also for @DavidG it works with encodeURIComponent(token) — MohamedAbbas, Aug 04 '14 at 13:19

score 7 · Answer 1 · answered Aug 04 '14 at 12:13

7

No need to stop changing + to . If you use UrlEncode and UrlDecode correctly. Below code works as expected

var newtoken = HttpUtility.UrlEncode("t+Bj/YpH6zE=");
//newtoken is t%2bBj%2fYpH6zE%3d now
var orgtoken = HttpUtility.UrlDecode(newtoken);
//orgtoken: t+Bj/YpH6zE=

and for bonus

byte[] buf = Convert.FromBase64String(orgtoken);

answered Aug 04 '14 at 12:13

L.B

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orgtoken is = to t Bj/YpH6zE= which breaks my decoding algorithm i need it to still have + – MohamedAbbas Aug 04 '14 at 12:16
@user2918388 No, Just copy above code and try it... Don't pass your original token to `UrlDecode`, give it the encoded one. – L.B Aug 04 '14 at 12:16
that's what i do i will check again to make sure. – MohamedAbbas Aug 04 '14 at 12:18
I have tested it agien and what i get first token is t+Bj/YpH6zE= then t%2BBj%2FYpH6zE%3D i decode ot it become t Bj/YpH6zE= – MohamedAbbas Aug 04 '14 at 12:28
1

@user2918388 I don't see your code but what you say is imposible. You must be doing double-decode somewhere. See above code. I tested it and it works. Even the base64 conversion. Or better, post a [sscce](http://sscce.org/) so that we can talk on it. – L.B Aug 04 '14 at 12:32
@user2918388 You are doing something horribly wrong if this isn't working for you. Please show us the EXACT code you have to achieve this. – DavidG Aug 04 '14 at 12:42
Wrong Input. Invalid length for a Base-64 char array or string. That what i get when using var token_decrypt = HttpUtility.UrlDecode(token) – MohamedAbbas Aug 04 '14 at 12:46
HttpUtility.UrlDecode(token).Replace(" ", "+") that one works ! – MohamedAbbas Aug 04 '14 at 12:47
@user2918388 Have you read my comment about [sscce](http://sscce.org/) ? How hard can it be to prepare a short, compilable example. – L.B Aug 04 '14 at 12:48
@user2918388 How do you think I can reproduce your case. By writing a complete web application? Prepare a small Console application. You can even use Linqpad... – L.B Aug 04 '14 at 13:06
1

If I have to guess a MVC controller is used, which will already decode the querystring parameter – Yeronimo Sep 11 '18 at 13:44
@L.B - I have a similar problem. Look at this string `A+A`. If you use `HttpUtility.UrlDecode("A+A")` it will produce `A A`. I do not have control over this. It passes to me from a 3rd party WebServer. I complained to their support, but they said we should use the standard Url Decode function. If you use https://www.urldecoder.org/ you will see that `A+A` will be decoded to `A+A`. The question is, how to make HttpUtility.UrlDecode to behave like a standard decoder? – Sam Oct 14 '22 at 11:36

score 5 · Answer 2 · answered Aug 04 '14 at 12:14

You can use the UrlPathEncode method, the documentation of UrlEncode method mentions the following

You can encode a URL using with the UrlEncode method or the UrlPathEncode method. However, the methods return different results. The UrlEncode method converts each space character to a plus character (+). The UrlPathEncode method converts each space character into the string "%20", which represents a space in hexadecimal notation. Use the UrlPathEncode method when you encode the path portion of a URL in order to guarantee a consistent decoded URL, regardless of which platform or browser performs the decoding.

More details are available at http://msdn.microsoft.com/en-us/library/4fkewx0t(v=vs.110).aspx

Can you post your entire code where you are doing the encoding and decoding ? — codelion, Aug 04 '14 at 12:56

How to stop HttpUtility.UrlEncode() from changing + to space?

2 Answers2