Make URL encode of variables explict per instance

[mattporritt]

Current all HTTP Post variables are URL encoded, this is not always helpful. Sometimes we don't want to URL encode values, and sometimes we only want to encode some values.

I suggest making a prefix on a value to indicate if it should be url encoded. So: {urlencode:username} will be encoded but {username} won't be

[agwells]

The code that does the {placeholder} replacement stuff is in classes/helper/datafield_manager.php

Right now it finds placeholders by searching for the regex /\{([-_A-Za-z0-9]+)\}/u. You'll need to add : to that, and maybe also capture the "function" part before the : separately. So something like something like /\{(?:(?P<func>[_A-Za-z0-9]+):)?(?P<datafield>[-_A-Za-z0-9]+)\}/u.

[agwells]

As discussed on chat, it might also be a good idea to change the syntax from {placeholder} to %placeholder% or #placeholder#, in order to reduce the conflict with JSON syntax. Particularly if we're going to be adding colons inside the {}. Although I suppose we could use something else instead, like | or even just a space: {urlencode user_username}.