Keith Devens .com

Tuesday, November 22, 2005

uriescape

I've been meaning to write a replacement for PHP's built-in urlencode so that characters that don't have to be escaped in the path part of a URI won't be. Here 'tis:


<?php
function uriescape($uri){
    static $invalid_chars = '/([^-A-Za-z0-9_.!~*\'():@&=$, ])/e';
    return str_replace(' ', '+', preg_replace($invalid_chars, '\'%\'.dechex(ord(\'$1\'))', $uri));
}

$uri = ' -_.!~*\'():@&=+$,';
var_dump(urlencode($uri));
var_dump(uriescape($uri));
?>

Gives:

string(43) "+-_.%21%7E%2A%27%28%29%3A%40%26%3D%2B%24%2C"
string(17) "+-_.!~*'():@&=%2b$,"

Note that this is only valid for the path component of the URI. In particular, it's not valid for a query string since the extra characters ":", "@", "&", "+", ",", and "$" are reserved there. Though "+" is interpreted as a space anyway, so I don't know what it means to say that it's reserved in the query and not a path segment. And I don't know why characters like "/" and "?" are reserved in the query as well.

Update: Fixed so that the '+' would still be escaped, as it needs to be, despite what the spec says, to not be interpreted as a space. Where did that convention of using a '+' to represent a space come from anyway? I didn't notice that specified anywhere in the URI spec.

Permalink | 3 Comments | Tags: Programming, This website | id 7617

02:24 (utc-5)
edited: 18:18 (utc-5)

Comments

The HTML spec mentions turning spaces to +, and then escaping per the URI RFC. As far as I can tell it's a more or less arbitary decision made back in the HTML 2 days, but I haven't found anything more specific yet.

∴ Adam V. | 22-Nov-2005 8:31pm est | http://adamv.com | #8724

Jim wrote:

Thank you very much, Keith, for sharing your code examples! I certainly appreciate them.

∴ Jim | 22-Nov-2005 10:44pm est | #8725

...arbitary decision made back in the HTML 2 days...

A lot of this seems like I can do whatever I want and nothing along the way will care, as long as I simply comply with what browsers and PHP expect.

∴ Keith | 23-Nov-2005 12:17am est | http://keithdevens.com/ | #8727

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Tuesday, November 22, 2005

uriescape

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