Could someone please explain this mod rewrite to me?

[blizzman24]

RewriteEngine on

RewriteRule ^article/([0-9]+)/([0-9]+)/(.*?).html$ /article.php?articleid=$1&categoryid=$2

I've been trying to find a site that explains what each part of this code does but I can't seem to find it. I understand some of the regular expression, but can't seem to grasp what "$1" or "$2" are for. what do those do? What does the "^" and "$" after the .html serve?

all I know is that it turns this...

http://www.yoursite.com/product.php?productid=2&categoryid=3

into this...

http://www.yoursite.com/product/13/3/2-GB-MP3-player.html.

[Syam]

^article/([0-9]+)/([0-9]+)/(.*?).html$

It means "beginning with 'article/<some number>/<again some number>/<anything>' and ends with '.html' ".

^ means starting position of the string.
$ means ending position of the string.

$1 is the "<some number>" part.
$2 is the "<again some number>" part.
$3 (not used in this regex) will be "<anything>"

http://en.wikipedia.org/wiki/Regular_expression#Syntax

[php_daemon]

all I know is that it turns this...

http://www.yoursite.com/product.php?productid=2&categoryid=3

into this...

http://www.yoursite.com/product/13/3/2-GB-MP3-player.html.

Actually it's quite the opposite. Maybe if you looked at it the other way around, you'd see how it works.

[dklynn]

zz,

Have a read of the mod_rewrite tutorial linked in my signature.

Regards,

DK

[sovanndy]

RewriteEngine on

RewriteRule ^article/([0-9]+)/([0-9]+)/(.*?).html$ /article.php?articleid=$1&categoryid=$2

I have some doubt of above code at part (.*?). cos * is quantifier or ? is also quantifier, for (.*) or (.?) is quit enough to someone need. what about (.*?)? I don't understand this part.


Could anyone explain me about this part (.*?)?

Thank in advance

[dklynn]

sovanndy,

RewriteEngine on

RewriteRule ^article/([0-9]+)/([0-9]+)/(.*?)\.html$ /article.php?articleid=$1&categoryid=$2 [L]

The above code in red MUST be &, not the HTML version of the & character! The blue code (Last flag) is necessary to terminate your mod_rewrite block statement the same way that ; is commonly used in programming languages. Also, escape the dot character in the regex.

(.*?) is the non-greedy version of (.*) but the ? is really irrelevant as you've specified EVERYTHING up to but NOT including .html at the end of the {REQUEST_URI} string. In this case, the ? is the modifier of the * metacharacter, otherwise, it would be the metacharacter for zero or one of the preceding character.

Regards,

DK

[sovanndy]

According with your saying

In this case, the ? is the modifier of the * metacharacter, otherwise, it would be the metacharacter for zero or one of the preceding character.

, (.?) is quit enouch to what...., but not (.*?)


cos ? have to modify to preceeding metacharacter like . , but not +, *

. is identified for any characters, but * is not identified for any characters, but just modifier for any characters......

Could you explain me clearly?


Thank

[dklynn]

sov,

Metacharacters:

. is ANY character

? is zero or one of the previous character

+ is one or more of the previous character

* is zero or more of the previous character

using +? or *? is the "non-greedy" form of the "greedy" metacharacter

What does that mean for regex within mod_rewrite? NOTHING! I can't see any use for the ? as a metacharacter modifier in mod_rewrite. It IS, however, very useful in parsing text strings in scripts. Have a read of Friedl's Mastering Regular Expressions, it's the definitive treatment of Regex.

Regards,

DK

According with your saying , (.?) is quit enouch to what...., but not (.*?)


cos ? have to modify to preceeding metacharacter like . , but not +, *

. is identified for any characters, but * is not identified for any characters, but just modifier for any characters......

Could you explain me clearly?


Thank