Regular Expressions best way to repace strings

[DeveloperX 0]

Hello! I as all of You use this greatful FORUM. But I want to know how engine of forum replaces post like

[color=red]TEXT[/color]

to

<font color=red>TEXT</font>

But I think that some Bbcodes like

[b][/b]

maybe replaced by this method:

$str="[b]TEXT[/b]";$str=str_replace("[b]","<b>",$str);$str=str_replace("[/b]","</b>",$str);echo $str;

Please help me with URL, Email, Img, Color bbcodes!
Edited March 12, 2006 by DeveloperX (see edit history)

[Spectre 0]

Regular expressions are used, but it's a little more complex than that. If you have a look through the source code of IPB (or any other forum software that supports bbCode tags), you'll be able to get a much better example than anything I can provide.

Anyway, here's a quick example of how formatting could work (in theory, anyway):

<?php$post = preg_replace('/\[(\/)?(b|u|i)\]/ie', '"<$1" . strtoupper("$2") . ">"', $post);?>

[b]This[/b] is my [i]post[/i] and it [b][u]rocks[/u][/b].Becomes:<B>This</B> is my <I>post</I> and it <B><U>rocks</U></B>.

[DeveloperX 0]

Regular expressions are used, but it's a little more complex than that. If you have a look through the source code of IPB (or any other forum software that supports bbCode tags), you'll be able to get a much better example than anything I can provide.

 

Anyway, here's a quick example of how formatting could work (in theory, anyway):

Thanks!

And how about bbcodes???

Help...

Edited December 17, 2016 by OpaQue (see edit history)

[truefusion 3]

Correct me if i'm wrong, but Spectre's way wont work all that well. Cause it'll replace the tags whether or not they've ended or began the tags.

Bold:

$var = preg_replace('/\\[(b|i|u)[^\\]]*\\](.*?)\\[\/\\1\\]/', '<\\1>\\2</\\1>', $var);

Italic:

$var = preg_replace('/\\[(b|i|u)[^\\]]*\\](.*?)\\[\/\\1\\]/', '<\\1>\\2</\\1>', $var);

Underline:

$var = preg_replace('/\\[(b|i|u)[^\\]]*\\](.*?)\\[\/\\1\\]/', '<\\1>\\2</\\1>', $var);

Color:

$var = eregi_replace('\\[color="([^"]*)"\\]([^\\[]*)\\[/color\\]', '<font color="\\1">\\2</font>', $var);

Url:

$var = eregi_replace('\\[url="([^"]*)"\\]([^\\[]*)\\[/url\\]', '<a href="\\1" target="_blank">\\2</a>', $var);

Email:

$var = eregi_replace('\\[mail="([^"]*)"\\]([^\\[]*)\\[/mail\\]', '<a href="mailto:\\1">\\2</a>', $var);

Img:

$var = eregi_replace('\\[img\\]([^\\[]*)\\[/img\\]', '<img src="\\1" />', $var);

These should all work properly.

[edit]Yes, i noticed that too, Spectre, but i modified it now so it'll work if it were to be like that. The 3 multiples are required for the script to work, don't ask me why...[/edit]
Edited March 13, 2006 by truefusion (see edit history)

[Spectre 0]

Well, I don't know exactly how IPB does it (as I don't have the source code on hand), but something like this should do the trick:

$post = preg_replace('/\[url=http:\/\/(.[^\]]*)\](.[^\[]*)\[\/url\]/ie', '\'<a href="http://$1" target="_blank" title="\'.htmlentities(\'$2\').\'">\'.htmlentities(\'$2\').\'</a>\'', $post);

[Spectre 0]

truefusion, although you are right on it picking up unclosed (or unopened) tags, I don't think your way would work all that well either. Your method would skip over text which contains a [ character - for example, in the sample text I provided above, '[ b ][ u ]rocks[ / u ][ / b ]' would not be set as bold and italic, but only as italic.

Edited March 13, 2006 by Spectre (see edit history)

[DeveloperX 0]

@truefusion

Color:
$var = eregi_replace('\\*)"\\]([^\\[]*)\\[/color\\]', '<font color="\\1">\\2</font>', $var);

Url:
$var = eregi_replace('\\*)"\\]([^\\[]*)\\[/url\\]', '<a href="\\1" target="_blank">\\2</a>', $var);

Email:
$var = eregi_replace('\\[mail=([^]*)"\\]([^\\[]*)\\[/mail\\]', '<a href="mailto:\\1">\\2</a>', $var);

I'm sorry, but these scripts not works!

@Spectre

$post = preg_replace('/\]*)\](.[^\[]*)\[\/url\]/ie', '\'<a href="$1; target="_blank" title="\'.htmlentities(\'$2\').\'">\'.htmlentities(\'$2\').\'</a>\'', $post);

Thanks! Very nice script and works!
Please write me scripts for COLOR, EMAIL and IMG bbcodes!

[truefusion 3]

Email:

$var = preg_replace('/\\[mail\\]([\\w\\._-]+@[\\w\\-_]+\\.[a-zA-Z]{2,4})\\[\/mail\\]/', '<a href="mailto:\\1">email</a>', $var);

Color:

$var = ereg_replace('\\[color="([\\w#]*)"\\]([^\\[]*)\\[/color\\]', '<font color="\\1">\\2</font>', $var);

Image:

$var = preg_replace('/\\[img\\](https?:\/\/[a-z.]{4,}\\w*\\.[a-z]{2,4}(?::\\\\d+)?\/[\\w\\-_\\d\/]*\\.(?:jpg|jpeg|png|gif))\\[\/img\\]/', '<img src="\\1" />', $var);

Edited March 15, 2006 by truefusion (see edit history)

[DeveloperX 0]

@truefusion

$var = ereg_replace('\\*)"\\]([^\\[]*)\\[/color\\]', '<font color="\\1">\\2</font>', $var);

 

I'm sorry, but it not works...

I use such colors as RED, #ff00ff, BLUE...

Please check it.

[truefusion 3]

If ereg_replace() fails to work, switch to preg_replace(), and then modify the pattern for it to work with preg_replace():

$var = preg_replace('/\\[color="([\\w#]*)"\\]([^\\[]*)\\[\/color\\]/', '<font color="\\1">\\2</font>', $var);

[DeveloperX 0]

If ereg_replace() fails to work, switch to preg_replace(), and then modify the pattern for it to work with preg_replace():

$var = preg_replace('/\\[color="([\\w#]*)"\\]([^\\[]*)\\[\/color\\]/', '<font color="\\1">\\2</font>', $var);

I'm sorry, but your code not works again!
Maybe something wrong?
Please give me a workable code...