PHP URL encoding retaining invalid url characters

I need to replace url invalid characters with something url valid then convert it back again.

This is for a search page with a url like http://my.site/search/this-is-a-search, the search form POSTS then the user redirected to the new url.

Php has functions urlencode and urldecode however these do not work at all, and leave invalid characters 开发者_如何学Cin my url.

Surely I don't need to reinvent the wheel here.

For stuff like http://my.site/search/this-is-a-search (i.e., outside the query string), you should use rawurlencode and rawurldecode. These are guaranteed to be URL-safe.

However, urlencode will never generate an unsafe URL path either, since the only difference is how spaces are encoded and urlencode encodes spaces to +, which is permitted in the URL path.

From RFC 1738:

httpurl        = "http://" hostport [ "/" hpath [ "?" search ]]
hpath          = hsegment *[ "/" hsegment ]
hsegment       = *[ uchar | ";" | ":" | "@" | "&" | "=" ]
uchar          = unreserved | escape
unreserved     = alpha | digit | safe | extra
safe           = "$" | "-" | "_" | "." | "+"

What about rawurlencode().

http://www.php.net/manual/en/function.rawurlencode.php

echo rawurlencode('http://my.site/search/this-is-a-search');
// http%3A%2F%2Fmy.site%2Fsearch%2Fthis-is-a-search