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Phing CopyTask

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Phing is a PHP build tool that you might be familiar with or you might be already using. The official Phing website can be found at http://www.phing.info/ and the initials stand for PHing Is Not GNU make. You can download or install it as a PEAR package and as long as you are a bit familiar with XML it is really easy to learn how to use. So, if you are reading past this point it means that you have actually used Phing before and that you are familiar with its CopyTask for copying individual files or filesets from one location to another.

Recently I was trying a new build file with Phing and came accross an interesting issue. The result of building a target that included copying a previously defined fileset from one location to another had a somewhat unexpected  result. An empty folder that was contained in the source location for which all users had read, write and execute permissions on, was copied accross but the permissions were not kept. I was not receiving any errors and the folder was actually created in the destination folder. As it turns out the version of Phing that I was using did not support copying an empty folder with its permissions to a new location. So if you are having a similar issue do upgrade your  package to the 2.5.0 version of Phing (as of the time of writting this is the latest stable release of Phing on PEAR). You can perform the upgrade quite easily as you would with any other PEAR package.

JQuery textarea text limit counter

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This is slightly different implementation of the jquery textarea text limit counter found at: http://www.scriptiny.com/2012/09/jquery-input-textarea-limiter/. The main difference is that the user is not cutoff when he reaches the limit of the allowed characters but he is notified via the counter that his text is longer than expected.

The idea behind it is to have a textarea that accepts user input and there is  a limit in the characters that you want you are allowed to type in the textarea. While you type in characters in the textarea a counter is updated that shows the remaining characters. The number is correct even when you reload the page and the area is pre-populated with text. This particular demo uses jquery 1.5.1

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How to set/unset options in Vim

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Vim is a very powerful text editor and as such it has lots of options which allows you to configure it “just right” for you! In order to configure it you can set up values to its various options either in the current window you are working on or in configuration file so that every new instance launched will have common settings. This file is usually called vimrc and is located under your home catalog.

But what happens if you wish to reset the value of an option you have configured in this configuration file for just this window that you are currently working in? I found that to be more difficult than expected so, here is how you can:

  1. Start a clean instance of vim with all its default options that ignores all the settings in all the user defined configuration files
  2. Get the currently set options and their values
  3. Disable/reset options that I will call switches
  4. Reset any option to each default value (whatever that might be)
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How to disable the pager in PostgreSQL

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PostgreSQL uses a pager to display the results of an operation you performed when you are using the command line tool (psql).

You can disable the pager by issuing:

pset pager off

with which you specifically request that the pager is disabled. You can re-enable the pager by issuing:

pset pager on

with which you specifically request that the pager is enabled. Alternatively you can toggle the status of the pager by issuing

pset pager

which depending on the current status of the pager will either enable or disable it.

PHP: The Scope Resolution Operator (::)

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In PHP the Scope Resolution Operator (which is actually the double colon or Paamayim Nekudotayim as it is its official name) has many uses. From the PHP manual pages (Manual) I quote

The Scope Resolution Operator (also called Paamayim Nekudotayim) or in simpler terms, the double colon, is a token that allows access to static, constant, and overridden properties or methods of a class. When referencing these items from outside the class definition, use the name of the class.

So, I recently decided to go ahead and test this operator in a bit more detail and discovered something I did not know about the way PHP decides to give you access to its public methods.
Let us consider the following php class

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Vertical display output in MySQL and Postgresql

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When using the command line clients of MySQL or Postgresql it is often the case that the output of some select statement does not display very well, either because the query returns too many columns or the contents of a column are too long. In such cases it would be really nice to display the query results line by line in a vertical listing instead of the horizontal listing. A similar display can be found in both MySQL and Postgresql. So, let’s assume that you have a table that was created with the following SQL statement:

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How to add Captcha verification in the comments of the Yii blog demo

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This post is about adding captcha verification in the comments section of the Yii demo blog. This post was triggered from two comments posted on the page of the tutorial (Comment 1 and Comment 2). In order for you to follow through the current post you need to have the Yii framework in place and you need to have followed all the steps of the Blog Tutorial up untill the “Creating and Displaying Comments” section. So, let’s start:

If you have followed the tutorial you should by now have a working Leave a comment form in place that is displayed underneath each individual post of your blog web application. The form should contain the Name, Email, Website and Comment fields that will populate the corresponding properties of your Comment model. The Post ID should be set on submit, the Status of the Comment should also be set on submit and the Time Created should be set just before saving the Comment (if this is a newly created comment).

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How to get your Error reporting constant values

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PHP lets you specify the Error Reporting level, so that when a piece of your code is run based on this setting of the php.ini file the generated errors and/or warnings will be shown or not. Generally speaking in a development environment it is recommended to set this as high as possible so that you are informed about all the little details of your code whereas in  a production environment this setting is usually set to something less “explanatory”.

In order to set the value of the error_reporting directive php constant values and bitwise operators are used, as they are described in the PHP manual . The setting can be set during runtime using the php error_reporting() function (manual) passing as a parameter the int value calculated based on the constant values and bitwise operators used. The function returns the integer value of the previous error_reporting level.

Now if you wish to find out what is your current error_reporting level you could go and have a look in your php.ini file or you could use the error_reporting() function with no parameters, in which case the function will return an integer value representing the current error reporting level. If you go via the php.ini file you will see the names of the constants used and the operations applied to produce your current reporting level but if you try to get a similar result via a php file that you have written you might notice that it is more difficult to understand  what is going on since now you are only dealing with an integer value and not with the named constants. So which is the description of your error reporting level and how can you retrieve it from within a php file?

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How to create a symbolic link

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A symbolic link is a “connection” we create between a location and a physical file or directory. The file or directory exists in a known location A in our system and we wish to create a connection to that location from a different location in our system B. An easy way to think of a symbolic link is like a shortcut from one location to another.

A symbolic link is created with the following command

ln -s TARGET NAME_OF_LINK

where ln is the basic unix command, the parameter -s specifies that we wish to create a symbolic link, TARGET should be replaced with the destination of our link and NAME_OF_LINK should be replaced with what we want our link to be named after.

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Value of an environment variable

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If you wish to see the value of an environment variable the easiest way to do so is to print the contents of the variable in your shell. To do so you have to use the following command:

echo $var_name

If there is an environment variable defined named var_name then the above command will output its contents in standard output (your shell). If there is no variable with that name defined the above command will output an empty line. If you see var_name outputed in your shell you probably forgot to type in the $ sign before the name of your variable. Remember that echo simply echoes a string in standard output so if you do not specify that the string you typed is a variable ($ sign) then it will simply output your string.

Now if you do not exactly remember the name of your environment variable the easiest way to find out if it is defined or not would be to output all the environment variables defined and either move your way through the list like

printenv

or pipe the output to grep providing a part of the name of the variable like

printenv | grep name