separating values in a URL, not with an &

Question

Each parameter in a URL can have multiple values. How can I separate them? Here's an example:

http://www.example.com/search?queries=cars,phones

So I want to search for 2 different things: cars and phones (this is just a contrived example). The problem is the separator, a comma. A user could enter a comma in the search form as part of their query and then this would get screwed up. I could have 2 separate URL parameters:

http://www.example.com/login?name1=harry&name2=bob

There's no real problem there, in fact I think this is how URLs were designed to handle this situation. But I can't use it in my particular situation. Requires a separate long post to say why... I need to simply separate the values.

My question is basically, is there a URL encodable character or value that can't possibly be entered in a form (textarea or input) which I can use as a separator? Like a null character? Or a non-visible character?

UPDATE: thank you all for your very quick responses. I should've listed the same parameter name example too, but order matters in my case so that wasn't an option either. We solved this by using a %00 URL encoded character (UTF-8 \u0000) as a value separator.

Answer 1

The standard approach to this is to use the same key name twice.

http://www.example.com/search?queries=cars&queries=phones

Most form libraries will allow you to access it as an array automatically. (If you are using PHP (and making use of $_POST/GET and not reinventing the wheel) you will need to change the name to queries[].)

Answer 2

Come up with your own separator that is unlikely to get entered in a query. Two underscores '__' for example.

Answer 3

easiest thing to do would be to use a custom separator like [!!ValSep!!].

Answer 4

You can give them each the same parameter name.

http://www.example.com/search?query=cars&query=phones

The average server side HTTP API is able to obtain them as an array. As per your question history, you're using JSP/Servlet, so you can use HttpServletRequest#getParameterValues() for this.

String[] queries = request.getParameterValues("query");

Answer 5

Why not just do something like "||"? Anyone who types that into a search area probably fell asleep on their keyboard :} Then just explode it on the backend.

Answer 6

Just URL-encode the user input so that their commas become %2C.