PunBB modification – Implementing iconized categories for forum topics

PunBB is one of the fastest and minimal forum softwares powered by PHP. PunBB says about itself:

PunBB is a fast and lightweight PHP-powered discussion board. It is released under the GNU General Public License. Its primary goals are to be faster, smaller and less graphically intensive as compared to other discussion boards. PunBB has fewer features than many other discussion boards, but is generally faster and outputs smaller, semantically correct XHTML-compliant pages.

You can see a detailed review about PunBB from forum-software.org.

What’s the purpose this mod?

PunBB has categories for forum. But there is no categorization for Topics like many other forums. This mod implements an iconized category for topics. The end result of this mod is -

• It will add an excellent looking “Category Icons” fieldset in “Post new topic” form. (see Image#1)
• Users can (optionally) select a topic category while posting a topic.
• The category icon will be displayed beside the topic title in forum index page, topic detail page, search result etc. (see Image#2 and Image#3)
• Clicking on a category icon will show all topics under that category.(see Image#4)

Lets see some screenshot of this modification :

Image#1:  Category icons in Post new topic form

Image#2: Category icons before topic title in forum page

Image#3: Category icon in topic page

Image#4: Filtering by category

(more…)

Join Problems with Zend_Paginator and Zend_Db_Select objects

Zend_Paginator is one of the newest members of Zend framework family. It’s surely a rich addition with Zend’s power. Moreover, It’s handling the main data of pagination, not only pagination links. Which I didn’t found in any other pagination library.

But, when I (and many other developers) start to working with this library, found many problems/bugs. The matter is, they are being solved very fast and hope to get a bullet-proof pagination library soon. For example, here is tow important fixings about Zend_Paginator and Zend_Db_Table_Select.

I had to face a problem with Zend_Paginator when using Join in Zend_Db_Select object. I am explaining here how the problem arises and how to solve it.

The Problem

One of the 4 Adapters for Zend_Paginator is DbSelect which uses a Zend_Db_Select instance. Now, the problem occurred if I need to have some calculative data from other tables and use join with the Zend_Db_Select object for them. For example, I am retrieving data from `deals` table and collecting number of comments from `comments` table and total votes from `votes` table. So, with other conditions, I had to add this lines with select object:

   1: $select->joinLeft(array('c' => 'comments'), 'deals.id = c.deal_id', array('total_comments'=> 'count(c.id)') );

   2: $select->joinLeft(array('v' => 'votes'),    'delas.id = v.deal_id', array('total_votes'   => 'count(v.id)') );

   3: $select->group($this->_name . '.id');

Now, the Zend_Paginator will always calculate the TotalRows as 1. That means, $this->totalItemCount; will always print 1 in “view partial“.

Why it happens?

Let’s take a look to the count function of DbSelect Adaptor of Zend_Paginator:

   1: public function count()

   2: {

   3:     if ($this->_rowCount === null) {

   4:         $expression = new Zend_Db_Expr('COUNT(*) AS ' . self::ROW_COUNT_COLUMN);

   5:         

   6:         $rowCount   = clone $this->_select;

   7:         $rowCount->reset(Zend_Db_Select::COLUMNS)

   8:                  ->reset(Zend_Db_Select::ORDER)

   9:                  ->reset(Zend_Db_Select::LIMIT_OFFSET)

  10:                  ->columns($expression);

  11:                  

  12:         $this->setRowCount($rowCount);

  13:     }

  14:  

  15:     return $this->_rowCount;

  16: }

Here, at line 7, the column list is being removed. But we have a `Group By` clause in our select object which is not cleared by this function and the result is always 1. At this point, if we add “->reset(Zend_Db_Select::GROUP)” after line 9, the calculation will get rid from always being 1. But there will arise another problem. That is, joined tables are still remaining in `From` clause. You can see them by adding “die(print_r($rowCount->getPart(Zend_Db_Select::FROM)));” after line 10. This join tables will make the calculation inconsistence because there is no expression columns now to summarize their result.

The Solution

Just alter this function as following to prevent this problem:

   1: public function count()

   2: {

   3:     if ($this->_rowCount === null) {

   4:         $expression = new Zend_Db_Expr('COUNT(*) AS ' . self::ROW_COUNT_COLUMN);

   5:        

   6:         $rowCount   = clone $this->_select;

   7:         $rowCount->reset(Zend_Db_Select::FROM);

   8:         

   9:         foreach($this->_select->getPart(Zend_Db_Select::FROM) as $name => $table)

  10:         {

  11:             if(empty($table['joinCondition']))        

  12:             {

  13:                 $rowCount->from(array($name => $table['tableName']));

  14:             }

  15:             elseif($table['joinType'] == 'inner join')        

  16:             {

  17:                 $rowCount->join(array($name => $table['tableName']), $table['joinCondition']);

  18:             }

  19:         }

  20:         

  21:         $rowCount->reset(Zend_Db_Select::COLUMNS)

  22:                  ->reset(Zend_Db_Select::ORDER)

  23:                  ->reset(Zend_Db_Select::GROUP)

  24:                  ->reset(Zend_Db_Select::LIMIT_OFFSET)

  25:                  ->columns($expression);

  26:  

  27:         $this->setRowCount($rowCount);

  28:     }

  29:  

  30:     return $this->_rowCount;

  31: }

At line 9, I am running a foreach which will remove the `from` clause and again assign only the main table and inner join tables. And, at line 23, just removing the `Group By` clause from query. Now, this function will provide right calculation even when there is some joins like this. But, if you use inner join in your Zend_Db_Select object (which is very rare for pagination), this function may not serve properly.

If there is any mistake in this alternation or any other way can make it better, please let me know. And… let’s meet power with simplicity.

UPDATE [26/08/08] : The function is updated and hopefully it will work fine for inner joins too.

UPDATE [24/09/08] : This issue is solved in ZF 1.6. Jurrien Stutterheim has reported about this post in Zend Framework Issue tracker and worked on it. After the release of 1.6, he requested me to check if this issue still exist. I’ve checked and found it solved. Thanks to Jurriën Stutterheim.

PHP UUID generator function

Universally Unique Identifier is an identifier standard which is used in a varieties of software construction. When I was writing the RSS Writer class for Orchid, I needed to generate UUID to implement with ATOM id. I searched the web for a simple solution, but didn’t find any that suffices my need. Then I wrote the following function to generate it. I’ve use the standard of canonical format here.

Let’s take a look what Wikipedia has to say about the format of UUID :

A UUID is a 16-byte (128-bit) number. The number of theoretically possible UUIDs is therefore 216*8 = 2128 = 25616 or about 3.4 × 1038. This means that 1 trillion UUIDs would have to be created every nanosecond for 10 billion years to exhaust the number of UUIDs.

In its canonical form, a UUID consists of 32 hexadecimal digits, displayed in 5 groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters.

Enough said. Here is the function.

/**

  * Generates an UUID

  * 

  * @author     Anis uddin Ahmad <admin@ajaxray.com>

  * @param      string  an optional prefix

  * @return     string  the formatted uuid

  */

  function uuid($prefix = '')

  {

    $chars = md5(uniqid(mt_rand(), true));

    $uuid  = substr($chars,0,8) . '-';

    $uuid .= substr($chars,8,4) . '-';

    $uuid .= substr($chars,12,4) . '-';

    $uuid .= substr($chars,16,4) . '-';

    $uuid .= substr($chars,20,12);

    return $prefix . $uuid;

  }

Example of using the function -

//Using without prefix.

echo uuid(); //Returns like ‘1225c695-cfb8-4ebb-aaaa-80da344e8352′ 

 

//Using with prefix

echo uuid(‘urn:uuid:’);//Returns like ‘urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344e8352′

 

See you.

UPDATE : The PHP Universal Feed Generator class, for which I wrote this function is released.

UPDATE : The method of getting random string changed based on Davids comment. (Thanks to David)