How to encode the plus (+) symbol in a URL

90
votes

The URL link below will open a new Google mail window. The problem I have is that Google replaces all the plus (+) signs in the email body with blank space. It looks like it only happens with the + sign. How can I remedy this? (I am working on a ASP.NET web page.)

https://mail.google.com/mail?view=cm&tf=0&[email protected]&su=some subject&body=Hi there+Hello there

(In the body email, "Hi there+Hello there" will show up as "Hi there Hello there")

5
asp.netc#-4.0gmailurlencodehtml-encode

5 Answers

135
votes

The + character has a special meaning in a URL => it means whitespace - . If you want to use the literal + sign, you need to URL encode it to %2b:

body=Hi+there%2bHello+there

Here's an example of how you could properly generate URLs in .NET:

var uriBuilder = new UriBuilder("https://mail.google.com/mail");

var values = HttpUtility.ParseQueryString(string.Empty);
values["view"] = "cm";
values["tf"] = "0";
values["to"] = "[email protected]";
values["su"] = "some subject";
values["body"] = "Hi there+Hello there";

uriBuilder.Query = values.ToString();

Console.WriteLine(uriBuilder.ToString());

The result

https://mail.google.com:443/mail?view=cm&tf=0&to=someemail%40somedomain.com&su=some+subject&body=Hi+there%2bHello+there

24
votes

Is you want a plus (+) symbol in the body you have to encode it as 2B.

For example: Try this

9
votes

In order to encode + value using JavaScript, you can use encodeURIComponent function.

Example: 

var url = "+11";
var encoded_url = encodeURIComponent(url);
console.log(encoded_url)
3
votes

It's safer to always percent-encode all characters except those defined as "unreserved" in RFC-3986.

unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"

So, percent-encode the plus character and other special characters.

The problem that you are having with pluses is because, according to RFC-1866 (HTML 2.0 specification), paragraph 8.2.1. subparagraph 1., "The form field names and values are escaped: space characters are replaced by `+', and then reserved characters are escaped"). This way of encoding form data is also given in later HTML specifications, look for relevant paragraphs about application/x-www-form-urlencoded.

1
votes

Just to add this to the list:

Uri.EscapeUriString("Hi there+Hello there") // Hi%20there+Hello%20there
Uri.EscapeDataString("Hi there+Hello there") // Hi%20there%2BHello%20there

See https://stackoverflow.com/a/34189188/98491

Usually you want to use EscapeDataString which does it right.