LQWiki - User contributions [en]

Php tips

2004-03-11T11:13:34Z

Cubal: fixed url

==PHP TIPS==
[[PHP]] Hypertext Preprocessor is a great tool for making dynamic websites. Outside this Wiki, countless tips can be found in the comments section of the [http://www.php.net/manual/en/ official php manual] in the reference pages for each function. Here's a few little PHP tips and tricks.

=== Making your first cut'n paste script work ===
The first thing people usually do when the experiment with php, is that they get a piece of php script from the web and try to use it. So here's how to make that first piece of code to work: 

* Change the [[file permissions]] so that your [[webserver]] can use it.
* Make sure that the php-code starts with ''<?php'', because sometimes just the basic ''<?'' doesn't work (or at least in my configuration)
* Make sure that the file extension is .php, not .php3, .php4 or .phtml. A lot of these old filenames won't work with modern [[apache]] web servers.

=== Creating larger pages with $variables ===
The first few pages work well by just by putting the code where you needed in the HTML-page. However,when your scripts grow bigger, it gets messy when you mix php and html.
I my opinion, the easiest way is to put the PHP-code code at the beginning of the file and the HTML in the end.

The data that your great script has generated should be placed in string-type variables. For example: ''$pagetop'', ''$list'', ''$pageend'' and ''$menu''.
So now you can put all the generated data to those variables and use them in the HTML-part of you file by just putting ''<?php echo $pagetop; ?>'' in the according place.

By doing this you can easily edit the PHP-scipt and the HTML part of your page without mixing the two so badly that you don't understand anything the next week .

===FANCY TABLES===
It is easy -- and it also looks really cool 8) -- to generate a table with alternating coloured rows from PHP. What you have to do is
#Declare a CSS style class for each background colour.
#Create an array with the background colours in the order you want them to appear in the table.
#Place some code in the loop which generates the table, to set a background colour for each row while recirculating the array.
The following code snippets should make it clear.
====Defining CSS Classes (outside <? ?>)====
:<tt>.DARKBG {background-color: #bbbbbb}</tt>
:<tt>.MIDDLEBG {background-color: #cccccc}</tt>
:<tt>.LIGHTBG {background-color: #dddddd}</tt>
====Initialising the array (inside <? ?>)====
:<tt>$backgrounds = array("LIGHTBG", "MIDDLEBG", "DARKBG", "MIDDLEBG");</tt>
====Building up the table (inside <? ?>)====
:<tt>foreach ($foo as $i => $j) {</tt>
::<tt>array_push($backgrounds, ($bg = array_shift($backgrounds));</tt>
::<tt>echo "<TR CLASS=\"$bg\">";</tt>
::<tt>echo "<TD>$i</TD><TD>$j</TD>";</tt>
::<tt>echo "</TR>\n";</tt>
:<tt>};</tt>
====Explanation====
Each time around the loop (here I've used a <tt>foreach</tt> but it could be any kind of loop), the <tt>array_shift</tt> (in the innermost brackets, so it gets evaluated first) causes a variable $bg to be set to the first element in $backgrounds and the others to be shifted down a place. Then, this is pushed onto the tail end of the shortened array by the <tt>array_push</tt>. So the whole array just gets recirculated, each time a value is read from the beginning it is moved to the end. As the <tt>array_push</tt> and <tt>array_shift</tt> functions do not care about the length of the array, you could go through a whole rainbow of colours, or you could just alternate white and coloured rows.

Note that if you want to use more than one table in your page, and you want them all to start on the same colour, you will have to re-create the array between finishing one table and starting the next. This is because the array actually gets altered each time we go around the loop.

===Configuration Tricks and Traps===

Here are some common pitfalls or trickies. Also, go take a look at [http://wact.sourceforge.net/index.php/PhpApplicationSecurity this] for a more comprehensive look at security issues in PHP.

====The <tt>register_globals</tt> flag (a php.ini config option)====

If set to true, all GET, POST, FILE, and COOKIE variables will be registered as global variables. That is, if you called the url <tt>index.php?page=home</tt> the script would have the variable <tt>$page</tt> available, with the value 'home'. However, with register_globals off (the way it should really be, for security) <tt>$page</tt> would not be available. Instead, you would use <tt>$_GET['page']</tt> or <tt>$HTTP_GET_VARS['page']</tt> (the first for any version of php beyond about 4.1; the second for older versions).

====The <tt>allow_short_open_tags</tt> option====

If set to true, <tt><?</tt> is a legitimate way of starting a php block. This also means that you can use the short echo syntax: <tt><?=$var ?></tt> will output the value of $var.

Unfortunately, the shorts tags are a bad idea if:
* You are mixing scripting languages. Different languages use different tags, but often use the <? prefix.
* You have xml content. PHP will choke on the <?xml declaration if you are allowing the short tags; it reads it as a php command "xml", which of course doesn't work, so spews a parse error.

Php tips

2004-03-11T11:08:01Z

Cubal: Added link to wact php security page

==PHP TIPS==
[[PHP]] Hypertext Preprocessor is a great tool for making dynamic websites. Outside this Wiki, countless tips can be found in the comments section of the [http://www.php.net/manual/en/ official php manual] in the reference pages for each function. Here's a few little PHP tips and tricks.

=== Making your first cut'n paste script work ===
The first thing people usually do when the experiment with php, is that they get a piece of php script from the web and try to use it. So here's how to make that first piece of code to work: 

* Change the [[file permissions]] so that your [[webserver]] can use it.
* Make sure that the php-code starts with ''<?php'', because sometimes just the basic ''<?'' doesn't work (or at least in my configuration)
* Make sure that the file extension is .php, not .php3, .php4 or .phtml. A lot of these old filenames won't work with modern [[apache]] web servers.

=== Creating larger pages with $variables ===
The first few pages work well by just by putting the code where you needed in the HTML-page. However,when your scripts grow bigger, it gets messy when you mix php and html.
I my opinion, the easiest way is to put the PHP-code code at the beginning of the file and the HTML in the end.

The data that your great script has generated should be placed in string-type variables. For example: ''$pagetop'', ''$list'', ''$pageend'' and ''$menu''.
So now you can put all the generated data to those variables and use them in the HTML-part of you file by just putting ''<?php echo $pagetop; ?>'' in the according place.

By doing this you can easily edit the PHP-scipt and the HTML part of your page without mixing the two so badly that you don't understand anything the next week .

===FANCY TABLES===
It is easy -- and it also looks really cool 8) -- to generate a table with alternating coloured rows from PHP. What you have to do is
#Declare a CSS style class for each background colour.
#Create an array with the background colours in the order you want them to appear in the table.
#Place some code in the loop which generates the table, to set a background colour for each row while recirculating the array.
The following code snippets should make it clear.
====Defining CSS Classes (outside <? ?>)====
:<tt>.DARKBG {background-color: #bbbbbb}</tt>
:<tt>.MIDDLEBG {background-color: #cccccc}</tt>
:<tt>.LIGHTBG {background-color: #dddddd}</tt>
====Initialising the array (inside <? ?>)====
:<tt>$backgrounds = array("LIGHTBG", "MIDDLEBG", "DARKBG", "MIDDLEBG");</tt>
====Building up the table (inside <? ?>)====
:<tt>foreach ($foo as $i => $j) {</tt>
::<tt>array_push($backgrounds, ($bg = array_shift($backgrounds));</tt>
::<tt>echo "<TR CLASS=\"$bg\">";</tt>
::<tt>echo "<TD>$i</TD><TD>$j</TD>";</tt>
::<tt>echo "</TR>\n";</tt>
:<tt>};</tt>
====Explanation====
Each time around the loop (here I've used a <tt>foreach</tt> but it could be any kind of loop), the <tt>array_shift</tt> (in the innermost brackets, so it gets evaluated first) causes a variable $bg to be set to the first element in $backgrounds and the others to be shifted down a place. Then, this is pushed onto the tail end of the shortened array by the <tt>array_push</tt>. So the whole array just gets recirculated, each time a value is read from the beginning it is moved to the end. As the <tt>array_push</tt> and <tt>array_shift</tt> functions do not care about the length of the array, you could go through a whole rainbow of colours, or you could just alternate white and coloured rows.

Note that if you want to use more than one table in your page, and you want them all to start on the same colour, you will have to re-create the array between finishing one table and starting the next. This is because the array actually gets altered each time we go around the loop.

===Configuration Tricks and Traps===

Here are some common pitfalls or trickies. Also, go take a look at http://wact.sourceforge.net/index.php/PhpApplicationSecurity for a more comprehensive look at security issues in PHP.

====The <tt>register_globals</tt> flag (a php.ini config option)====

If set to true, all GET, POST, FILE, and COOKIE variables will be registered as global variables. That is, if you called the url <tt>index.php?page=home</tt> the script would have the variable <tt>$page</tt> available, with the value 'home'. However, with register_globals off (the way it should really be, for security) <tt>$page</tt> would not be available. Instead, you would use <tt>$_GET['page']</tt> or <tt>$HTTP_GET_VARS['page']</tt> (the first for any version of php beyond about 4.1; the second for older versions).

====The <tt>allow_short_open_tags</tt> option====

If set to true, <tt><?</tt> is a legitimate way of starting a php block. This also means that you can use the short echo syntax: <tt><?=$var ?></tt> will output the value of $var.

Unfortunately, the shorts tags are a bad idea if:
* You are mixing scripting languages. Different languages use different tags, but often use the <? prefix.
* You have xml content. PHP will choke on the <?xml declaration if you are allowing the short tags; it reads it as a php command "xml", which of course doesn't work, so spews a parse error.

User:Cubal

2004-03-06T04:29:48Z

Cubal:

Howdy all!

Distros:
* [[Red_Hat]]. I run Red Hat; for sheer ease-of-use it takes a lot of beating, but it still lets you do a decent amount of config, and runs nice on my Celeron 400.
* [[Linux_From_Scratch]] (LFS). I built my own Linux From Scratch system when I was gonna put an mp3-playing computer in my car (car stereo prices dropped - it wasn't worth the time). It was fun - you compile everything from scratch, write your own config files, and if you get it right it works :). I wouldn't recommend it for anything beyond seriously custom boxes or an educational opportunity.
* [[Debian]]. Very limited experience; I tried installing it on a server at work. I needed [[Subversion]] running for version control; and unfortunately Debian doesn't mix very well. That is, I had Debian Stable, Subversion was in unstable, and you would not believe the hassle it took. I blitzed it and installed Red Hat - not quite as rock-solid, but at least I could compile the software I needed.

:(Ok, that's kinda harsh on Debian; it can be a brilliant system. If you need rock-solid stability with easy maintenance, and don't really need any custom software, it's excellent.)

*[[Knoppix]]. Live CDs rock! Just drop it in and boot up. [[Gentoo]] also does a Live CD distro, but Knoppix seems easier to use - mainly as it comes with a full [[KDE]] gui, rather than Gentoo's OpenBox.

And...
* Mac OS X. Yeah, I know. It's not Linux. But my main machine is a Powerbook, and it takes some beating. Having said that though, some days I just feel like using my linux box. There's something to be said for the almost infinite level of customisation possible in GNU/Linux.

Source distributions

2004-03-06T04:23:53Z

Cubal: added lfs, slackware

----

'''Description:'''

Source based distributions enable the more experienced user to have a considerable degree of control over their system. Compiling and optimizing software for your particular hardware can bring noticeable performance improvements - however, compiling software can be a lengthy process.

For more information on the various Source based distributions, click on the links below.

''This article is a [[LinuxQuestions.org_Wiki:stub_articles|stub]] and needs to be finished. [[LinuxQuestions.org_Wiki:plunging_forward|Plunge forward]] and [[LinuxQuestions.org_Wiki:How_to_edit_a_page|help it grow]] !''
 
----

'''Links:'''

*[[Gentoo]]
*[[Source_Mage]]
*[[Linux_From_Scratch]]
*[[Slackware]]

User:Cubal

2004-03-06T04:22:14Z

Cubal: my user page :) info on my used distros

Howdy all!

Distros:
* [[Red_Hat]]. I run Red Hat; for sheer ease-of-use it takes a lot of beating, but it still lets you do a decent amount of config, and runs nice on my Celeron 400.
* [[Linux_From_Scratch]] (LFS). I built my own Linux From Scratch system when I was gonna put an mp3-playing computer in my car (car stereo prices dropped - it wasn't worth the time). It was fun - you compile everything from scratch, write your own config files, and if you get it right it works :). I wouldn't recommend it for anything beyond seriously custom boxes or an educational opportunity.
* [[Debian]]. Very limited experience; I tried installing it on a server at work. I needed [[Subversion]] running for version control; and unfortunately Debian doesn't mix very well. That is, I had Debian Stable, Subversion was in unstable, and you would not believe the hassle it took. I blitzed it and installed Red Hat - not quite as rock-solid, but at least I could compile the software I needed.

(Ok, that's kinda harsh on Debian; it can be a brilliant system. If you need rock-solid stability with easy maintenance, and don't really need any custom software, it's excellent.)

And...
* Mac OS X. Yeah, I know. It's not Linux. But my main machine is a Powerbook, and it takes some beating. Having said that though, some days I just feel like using my linux box. There's something to be said for the almost infinite level of customisation possible in GNU/Linux.

Php tips

2004-03-06T04:07:30Z

Cubal: added "config tips and tricks"

==PHP TIPS==
[[PHP]] Hypertext Preprocessor is a great tool for making dynamic websites. Outside this Wiki, countless tips can be found in the comments section of the [http://www.php.net/manual/en/ official php manual] in the reference pages for each function. Here's a few little PHP tips and tricks.

=== Making your first cut'n paste script work ===
The first thing people usually do when the experiment with php, is that they get a piece of php script from the web and try to use it. So here's how to make that first piece of code to work: 

* Change the [[file permissions]] so that your [[webserver]] can use it.
* Make sure that the php-code starts with ''<?php'', because sometimes just the basic ''<?'' doesn't work (or at least in my configuration)

=== Creating larger pages with $variables ===
The first few pages work well by just by putting the code where you needed in the HTML-page, but when your scrips grow bigger, it gets messy when you have some php here and html there.
I my opinion, the easiest way is to put the PHP-code code at the beginning of the file and the HTML in the end.

The data that your great script has generated should be placed in string-type variables. For example: ''$pagetop'', ''$list'', ''$pageend'' and ''$menu''.
So now you can put all the generated data to those variables and use them in the HTML-part of you file by just putting ''<?php echo $pagetop; ?>'' in the according place.

By doing this you can easily edit the PHP-scipt and the HTML part of your page without mixing the two so badly that you don't understand anything the next week .

===FANCY TABLES===
It is easy -- and it also looks really cool 8) -- to generate a table with alternating coloured rows from PHP. What you have to do is
#Declare a CSS style class for each background colour.
#Create an array with the background colours in the order you want them to appear in the table.
#Place some code in the loop which generates the table, to set a background colour for each row while recirculating the array.
The following code snippets should make it clear.
====Defining CSS Classes (outside <? ?>)====
:<tt>.DARKBG {background-color: #bbbbbb}</tt>
:<tt>.MIDDLEBG {background-color: #cccccc}</tt>
:<tt>.LIGHTBG {background-color: #dddddd}</tt>
====Initialising the array (inside <? ?>)====
:<tt>$backgrounds = array("LIGHTBG", "MIDDLEBG", "DARKBG", "MIDDLEBG");</tt>
====Building up the table (inside <? ?>)====
:<tt>foreach ($foo as $i => $j) {</tt>
::<tt>array_push($backgrounds, ($bg = array_shift($backgrounds));</tt>
::<tt>echo "<TR CLASS=\"$bg\">";</tt>
::<tt>echo "<TD>$i</TD><TD>$j</TD>";</tt>
::<tt>echo "</TR>\n";</tt>
:<tt>};</tt>
====Explanation====
Each time around the loop (here I've used a <tt>foreach</tt> but it could be any kind of loop), the <tt>array_shift</tt> (in the innermost brackets, so it gets evaluated first) causes a variable $bg to be set to the first element in $backgrounds and the others to be shifted down a place. Then, this is pushed onto the tail end of the shortened array by the <tt>array_push</tt>. So the whole array just gets recirculated, each time a value is read from the beginning it is moved to the end. As the <tt>array_push</tt> and <tt>array_shift</tt> functions do not care about the length of the array, you could go through a whole rainbow of colours, or you could just alternate white and coloured rows.

Note that if you want to use more than one table in your page, and you want them all to start on the same colour, you will have to re-create the array between finishing one table and starting the next. This is because the array actually gets altered each time we go around the loop.

===Configuration Tricks and Traps===

Here are some common pitfalls or trickies.

====The <tt>register_globals</tt> flag (a php.ini config option)====

If set to true, all GET, POST, FILE, and COOKIE variables will be registered as global variables. That is, if you called the url <tt>index.php?page=home</tt> the script would have the variable <tt>$page</tt> available, with the value 'home'. However, with register_globals off (the way it should really be, for security) <tt>$home</tt> would not be available. Instead, you would use <tt>$_GET['home']</tt> or <tt>$HTTP_GET_VARS['home']</tt> (the first for any version of php beyond about 4.1; the second for older versions).

====The <tt>allow_short_open_tags</tt> option====

If set to true, <tt><?</tt> is a legitimate way of starting a php block. This also means that you can use the short echo syntax: <tt><?=$var ?></tt> will output the value of $var.

Unfortunately, the shorts tags are a bad idea if:
* You are mixing scripting languages. Different languages use different tags, but often use the <? prefix.
* You have xml content. PHP will choke on the <?xml declaration if you are allowing the short tags; it reads it as a php command "xml", which of course doesn't work, so spews a parse error.

Php tips

2004-03-06T04:00:10Z

Cubal:

==PHP TIPS==
[[PHP]] Hypertext Preprocessor is a great tool for making dynamic websites. Outside this Wiki, countless tips can be found in the comments section of the [http://www.php.net/manual/en/ official php manual] in the reference pages for each function. Here's a few little PHP tips and tricks.

=== Making your first cut'n paste script work ===
The first thing people usually do when the experiment with php, is that they get a piece of php script from the web and try to use it. So here's how to make that first piece of code to work: 

* Change the [[file permissions]] so that your [[webserver]] can use it.
* Make sure that the php-code starts with ''<?php'', because sometimes just the basic ''<?'' doesn't work (or at least in my configuration)

=== Creating larger pages with $variables ===
The first few pages work well by just by putting the code where you needed in the HTML-page, but when your scrips grow bigger, it gets messy when you have some php here and html there.
I my opinion, the easiest way is to put the PHP-code code at the beginning of the file and the HTML in the end.

The data that your great script has generated should be placed in string-type variables. For example: ''$pagetop'', ''$list'', ''$pageend'' and ''$menu''.
So now you can put all the generated data to those variables and use them in the HTML-part of you file by just putting ''<?php echo $pagetop; ?>'' in the according place.

By doing this you can easily edit the PHP-scipt and the HTML part of your page without mixing the two so badly that you don't understand anything the next week .

===FANCY TABLES===
It is easy -- and it also looks really cool 8) -- to generate a table with alternating coloured rows from PHP. What you have to do is
#Declare a CSS style class for each background colour.
#Create an array with the background colours in the order you want them to appear in the table.
#Place some code in the loop which generates the table, to set a background colour for each row while recirculating the array.
The following code snippets should make it clear.
====Defining CSS Classes (outside <? ?>)====
:<tt>.DARKBG {background-color: #bbbbbb}</tt>
:<tt>.MIDDLEBG {background-color: #cccccc}</tt>
:<tt>.LIGHTBG {background-color: #dddddd}</tt>
====Initialising the array (inside <? ?>)====
:<tt>$backgrounds = array("LIGHTBG", "MIDDLEBG", "DARKBG", "MIDDLEBG");</tt>
====Building up the table (inside <? ?>)====
:<tt>foreach ($foo as $i => $j) {</tt>
::<tt>array_push($backgrounds, ($bg = array_shift($backgrounds));</tt>
::<tt>echo "<TR CLASS=\"$bg\">";</tt>
::<tt>echo "<TD>$i</TD><TD>$j</TD>";</tt>
::<tt>echo "</TR>\n";</tt>
:<tt>};</tt>
====Explanation====
Each time around the loop (here I've used a <tt>foreach</tt> but it could be any kind of loop), the <tt>array_shift</tt> (in the innermost brackets, so it gets evaluated first) causes a variable $bg to be set to the first element in $backgrounds and the others to be shifted down a place. Then, this is pushed onto the tail end of the shortened array by the <tt>array_push</tt>. So the whole array just gets recirculated, each time a value is read from the beginning it is moved to the end. As the <tt>array_push</tt> and <tt>array_shift</tt> functions do not care about the length of the array, you could go through a whole rainbow of colours, or you could just alternate white and coloured rows.

Note that if you want to use more than one table in your page, and you want them all to start on the same colour, you will have to re-create the array between finishing one table and starting the next. This is because the array actually gets altered each time we go around the loop.

Php tips

2004-03-06T03:59:24Z

Cubal:

===Configuration Tricks and Traps===

==PHP TIPS==
[[PHP]] Hypertext Preprocessor is a great tool for making dynamic websites. Outside this Wiki, countless tips can be found in the comments section of the [http://www.php.net/manual/en/ official php manual] in the reference pages for each function. Here's a few little PHP tips and tricks.

=== Making your first cut'n paste script work ===
The first thing people usually do when the experiment with php, is that they get a piece of php script from the web and try to use it. So here's how to make that first piece of code to work: 

* Change the [[file permissions]] so that your [[webserver]] can use it.
* Make sure that the php-code starts with ''<?php'', because sometimes just the basic ''<?'' doesn't work (or at least in my configuration)

=== Creating larger pages with $variables ===
The first few pages work well by just by putting the code where you needed in the HTML-page, but when your scrips grow bigger, it gets messy when you have some php here and html there.
I my opinion, the easiest way is to put the PHP-code code at the beginning of the file and the HTML in the end.

The data that your great script has generated should be placed in string-type variables. For example: ''$pagetop'', ''$list'', ''$pageend'' and ''$menu''.
So now you can put all the generated data to those variables and use them in the HTML-part of you file by just putting ''<?php echo $pagetop; ?>'' in the according place.

By doing this you can easily edit the PHP-scipt and the HTML part of your page without mixing the two so badly that you don't understand anything the next week .

===FANCY TABLES===
It is easy -- and it also looks really cool 8) -- to generate a table with alternating coloured rows from PHP. What you have to do is
#Declare a CSS style class for each background colour.
#Create an array with the background colours in the order you want them to appear in the table.
#Place some code in the loop which generates the table, to set a background colour for each row while recirculating the array.
The following code snippets should make it clear.
====Defining CSS Classes (outside <? ?>)====
:<tt>.DARKBG {background-color: #bbbbbb}</tt>
:<tt>.MIDDLEBG {background-color: #cccccc}</tt>
:<tt>.LIGHTBG {background-color: #dddddd}</tt>
====Initialising the array (inside <? ?>)====
:<tt>$backgrounds = array("LIGHTBG", "MIDDLEBG", "DARKBG", "MIDDLEBG");</tt>
====Building up the table (inside <? ?>)====
:<tt>foreach ($foo as $i => $j) {</tt>
::<tt>array_push($backgrounds, ($bg = array_shift($backgrounds));</tt>
::<tt>echo "<TR CLASS=\"$bg\">";</tt>
::<tt>echo "<TD>$i</TD><TD>$j</TD>";</tt>
::<tt>echo "</TR>\n";</tt>
:<tt>};</tt>
====Explanation====
Each time around the loop (here I've used a <tt>foreach</tt> but it could be any kind of loop), the <tt>array_shift</tt> (in the innermost brackets, so it gets evaluated first) causes a variable $bg to be set to the first element in $backgrounds and the others to be shifted down a place. Then, this is pushed onto the tail end of the shortened array by the <tt>array_push</tt>. So the whole array just gets recirculated, each time a value is read from the beginning it is moved to the end. As the <tt>array_push</tt> and <tt>array_shift</tt> functions do not care about the length of the array, you could go through a whole rainbow of colours, or you could just alternate white and coloured rows.

Note that if you want to use more than one table in your page, and you want them all to start on the same colour, you will have to re-create the array between finishing one table and starting the next. This is because the array actually gets altered each time we go around the loop.