How can I properly URL encode a string in PHP?

For the URI query use urlencode/urldecode; for anything else use rawurlencode/rawurldecode.

The difference between urlencode and rawurlencode is that

• urlencode encodes according to application/x-www-form-urlencoded (space is encoded with +) while
• rawurlencode encodes according to the plain Percent-Encoding (space is encoded with %20).