Tag: PHP

Say you need to fill a file or a sheet of paper (if you print the output) with a range of consecutive dates (or dates with equal space between them). Then, the following PHP one-liner might be handy some day:

for ($i=1; $i<=365; $i++) echo date( “Y-m-d”, mktime( 0, 0, 0, 1, $i)). “\n”;

The above snippet prints each day of current year on its own line. If you want one day per week, then you can change accordingly the values of for-loop variable, for example:

for ($i=4; $i<=365; $i+=7) […]

 Or, for next year’s calendar:

for ($i=1; $i<=365; $i++) echo date( “Y-m-d”, mktime( 0, 0, 0, 1, $i, 1+date(“Y”))). “\n”;

Don’t forget to change 365 with 366 for a leap year.

Recently I had an interesting problem.  I had a lot of files in a directory, all photos, with their filenames messed up, especially their extensions.  So, in order to clear them and keep only the good ones, I had first to rename them in a more consistent manner (the JPEG photos ending with .jpeg, the PNGs with .png and so on).

I guess there is probably a plethora of appropriate tools, but I had no time to search in the chaotic internet, so I wrote a small PHP script (with a little help from the shell: command ‘file‘) and run it from the command line.

The script just parses the output of the file command and renames each file accordingly.

I’m putting this here, just in case it will be useful to someone else also:

#!/usr/bin/php
<?php

$res = array();
exec( "file *", $res);

foreach( $res as $f) {
 list( $fn, $ft) = split( ':', $f);
 if (strpos( $ft, "JPEG") !== false) {
  rename( $fn, $fn .".jpeg");
 } else if (strpos( $ft, "PNG") !== false) {
  rename( $fn, $fn .".png");
 } else
  echo "cannot rename $fnn";
}
?>

I’m actually testing only for JPEG & PNG files since I know that I have only these two types.
Don’t forget to make this file executable if you want to run it from the command line.

Working with the command-line version of PHP can be very enlightening some times. For example, consider the following situations:

• Instead of having a test page with only phpinfo() in it, just to view PHP’s current settings, you can issue:
  

  php -i

• Suppose you want to check your PHP code quickly for any errors. Executing
  

  php -l filename.php

  can easily reveal any pitfalls.

• If you want to employ your code in a production environment, your don’t need any textual redundancies, so you can strip all the comments and whitespace by using
  

  php -w filename.php > ../production_directory/filename.php

• Finally, suppose you’ve just added/enabled a new module and you want to know if you did everything correctly. Then
  

  php -m | grep “modulename”

  will answer this question.

For more information, read the manual page of php!

Of course, to be able to do all the above, you have to install the CLI of PHP. For a system that uses the apt-get family of scripts, this is as easy as running:

sudo apt-get install php5-cli

For other systems, I believe that commands like

yum install php5-cli

or

rpm -Uhv php5-cli

will work the same. Check your system’s documentation about the correct command and syntax.

Being able to run PHP scripts from the shell is a very powerful capability, especially if one doesn’t feel comfortable with shell scripts or other interpreted languages, such as PERL or Python.

For a PHP programmer, I can recommend two web-based resources, full of useful information.

• PHP Classes has a vast amount of useful PHP packages in source code with examples.
• Chris Shiflett is a blogger who writes on advanced topics about PHP programming.

Both sites have RSS feeds and are updated frequently with new stuff.

A very useful function to determine first if the visitor is the developer or not and then act accordingly.

Code:

/* check if client is me */
function is_me()
{
    $ip=$_SERVER["REMOTE_ADDR"];
    $br=$_SERVER["HTTP_USER_AGENT"];
    if (($ip=="127.0.0.1") and (strstr( $br, "Firefox")))
           return true;
    return false;
}

Explanation:
If the visitor’s IP is 127.0.0.1 (=localhost) and the browser is “Firefox” then the visitor is me!

Usage example:

if (is_me()) { error_reporting( E_ALL); } else { error_reporting( 0); }

With the above snippet, one developer can check for errors and warnings in a running system without the casual visitor noticing a thing. It is very easy also to view the web-page with another browser to check what the visitor actually sees.