Functional approach in PHP

The code snippet below will only work in PHP-5.3+!.
Isn’t it the famous functional programming with functions as first class citizens, closures and other functional bla-bla?

<?php
 
function one($a = 0) {
    return function(callable $b) use ($a) {
        return call_user_func($b, $a);
    };
}
 
print_r(call_user_func(one(1), function ($x) { return $x + 4; } ));

This was created just for fun. As you may see, in place of callable you can put any valid PHP callable, e.g.in a form ['Class', 'method']

Use your imagination for other real things, but also try to stay not cursed later by those who will inherit your untraversable codebase :LOL:

[SOLVED] Upgrading from PHP 5.5 to PHP 5.6 on Ubuntu 12.04 LTS

Recently I had to upgrade PHP version on the build server based on Ubuntu 12.04 LTS to PHP 5.6 At that moment there was PHP 5.5 installed on the server. Everything should have been as easy and promising as described, for example, in this post. Yes, it was going well to the moment

sudo apt-get dist-upgrade

Then dpkg claimed unmet dependencies… You know, as usual. I decided – f…k it, I will remove existing php and everything related. Simple removal with

sudo apt-get remove php*

did not work fine and stuck on removing phpmyadmin.

That guysexited with an error code 10 being reported from its post-remove script. After pretty short googling, I found the solution which worked for me.

The similar shit happened with php5-imagick package, so the solution I used was similar to phpmyadmin removal. Afterwards, I checked for presence anything starting with or inlcuding php:

sudo dpkg -l | grep php

Everything was clean. OK, here we go…

sudo apt-get clean && sudo apt-get autoclean
sudo apt-get udpate && sudo apt-get upgrade && sudo apt-get dist-upgrade

…and still the same error in result:

Reading package lists… Done Building dependency tree Reading state information… Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: php5 : Depends: libapache2-mod-php5 (>= 5.6.16+dfsg-2+deb.sury.org~precise+1~) but it is not going to be installed or libapache2-mod-php5filter (>= 5.6.16+dfsg-2+deb.sury.org~precise+1~) but it is not going to be installed or php5-cgi (>= 5.6.16+dfsg-2+deb.sury.org~precise+1~) but it is not going to be installed or php5-fpm (>= 5.6.16+dfsg-2+deb.sury.org~precise+1~) but it is not going to be installed E: Unable to correct problems, you have held broken packages.

I tried install with -f flag, package-by-package. Nothing worked. The final unmet dependency was:

sudo apt-get -f install php5-json
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
 
The following packages have unmet dependencies:
 php5-json : Depends: phpapi-20121212
E: Unable to correct problems, you have held broken packages.

And here I stuck, as googling at this point didn’t help me at all… I visited the home of php5.6 PPA hoping to find something there. And a brilliant idea came to my mind – I should check APT’s sources list! I saw this files inside /etc/apt/sources.list.d:

/etc/apt/sources.list.d$ ll
total 32
drwxr-xr-x 2 root root 4096 Jan  5 11:12 ./
drwxr-xr-x 6 root root 4096 Jan  5 11:11 ../
-rw-r--r-- 1 root root  138 Jan  5 10:32 chris-lea-node_js-precise.list
-rw-r--r-- 1 root root  138 Jan  5 10:32 chris-lea-node_js-precise.list.save
-rw-r--r-- 1 root root   60 Jan  5 10:32 nginx-stable-lucid.list
-rw-r--r-- 1 root root   60 Jan  5 10:32 nginx-stable-lucid.list.save
-rw-r--r-- 1 root root  134 Jan  5 10:32 ondrej-php5-5_6-precise.list
-rw-r--r-- 1 root root  134 Jan  5 10:32 ondrej-php5-5_6-precise.list.save
-rw-r--r-- 1 root root  126 Jan  5 10:32 ondrej-php5-precise.list
-rw-r--r-- 1 root root  126 Jan  5 10:32 ondrej-php5-precise.list.save

I realised, the problem could be that packages were overwritten from older php-5.5, which apparently was installed manually to the server some time earlier. Once I removed these two files:

ondrej-php5-precise.list ondrej-php5-precise.list.save

and updated apt one more time, I was able to install PHP 5.6 as usual:

sudo apt-get install php5
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  shtool libc-client2007e node-node-uuid libicu52 libicu48 libv8-3.7.12.22 libmcrypt4 libt1-5 mlock libssl-dev libvpx1 libssl-doc zlib1g-dev libgd3 libev4 libv8-dev libc-ares2 libev-dev
  libc-ares-dev
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libapache2-mod-php5 php5-cli php5-json php5-readline
Suggested packages:
  php-pear
The following NEW packages will be installed:
  libapache2-mod-php5 php5 php5-cli php5-json php5-readline
0 upgraded, 5 newly installed, 0 to remove and 0 not upgraded.
Need to get 5,575 kB of archives.
After this operation, 18.9 MB of additional disk space will be used.
Do you want to continue [Y/n]? Y

The main idea of this story, before adding new custom repository for PHP, make sure you removed any other old ones! Good luck and happy coding!

Firefox Java Plugin – Debian Wheezy

By default Firefox has no Java plugin because of security issues.
One can install plugin by following next steps:
0. Exit Firefox browser if it is running
1. Make directory if it does not exist -> /usr/lib/mozilla/plugins
2. Make a symbolic link for libnpjp2.so file which resides in JRE directory, e.g.:

sudo ln -s /usr/lib/jvm/jdk1.8.0_20/jre/lib/amd64/libnpjp2.so /usr/lib/mozilla/plugins/libnpjp2.so

Please note, that amd64 is an architecture of the OS you have installed, possibly it could be i386 in your case.
3. Start Firefox and type about:plugins in address box to check if browser able to see Java plugin.

Install proprietary Oracle JDK in Debian 7.0 Wheezy

This is a YAP (yet another post) about how one can manually install Oracle’s proprietary JDK/JRE version (in Debian 7.0 Wheezy as an example).

First of all, download fresh version of JDK/JRE from the Oracle website.
Copy archive to desired location, in the following example we will use

/usr/lib/jvm

as an installation source directory.
Unpack the archive and run next commands:

sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk/bin/java 1071
sudo update-alternatives --install /usr/bin/javac javac /media/mydisk/jdk/javac 1071
sudo update-alternatives --install /usr/bin/jcontrol jcontrol /media/mydisk/jdk/bin/jcontrol 1071

You may need read man pages for update-alternatives to check out the parameters and what they mean.

Now, if you want freshly installed version of java/javac to be default in your system, run next commands:

sudo update-alternatives --config java
sudo update-alternatives --config javac
sudo update-alternatives --config jcontrol

Follow the instructions issued by update-alternatives to select default version among the list of available installations.
After that, check if everything worked fine by issuing commands

java -version
javac -version

You should see 1.8.0 for both.

Having error while trying use jqFileUpload with RequireJS?

Once upon a time, I needed to use jqFileUPload plugin (actually modified version which provides Angular’s directive around native jqFileUpload plugin).
In the same time, my Angular-base project was configured to be used together with RequireJS.
I spend few ours trying to figure out what I was doing wrong – why I was getting errors in my browser’s console.
Those errors were about something weird… Something in `load-image-exif` and `load-image` files.

My require.js main config file looked like this:

require.config({
  paths: {
    'semantic': '../../bower_components/semantic-ui/build/packaged/javascript/semantic.min',
    'jquery': '../../bower_components/jquery/dist/jquery.min',
    'domReady': '../../bower_components/requirejs-domready/domReady',
    'angular': '../../bower_components/angular/angular.min',
    'angular-route': '../../bower_components/angular-route/angular-route.min',
    'angular-resource': '../../bower_components/angular-resource/angular-resource.min',
    'jquery.fileupload': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload',
    'jquery.fileupload-angular': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-angular',
    'jquery.ui.widget': '../../bower_components/angular-jqfile-upload/js/vendor/jquery.ui.widget',
    'jquery.fileupload-image': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-image',
    'jquery.fileupload-process': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-process',
    'jquery.fileupload-audio': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-audio',
    'jquery.fileupload-video': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-video',
    'jquery.fileupload-validate': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-validate',
    'jquery.fileupload-ui': '../../bower_components/angular-jqfile-upload/js/jquery.fileupload-ui',
    'jquery.iframe-transport': '../../bower_components/angular-jqfile-upload/js/jquery.iframe-transport',
    'canvas-to-blob': '../../bower_components/blueimp-canvas-to-blob/js/canvas-to-blob.min',
    'load-image': '../../bower_components/blueimp-load-image/js/load-image.min',
    'load-image-exif': '../../bower_components/blueimp-load-image/js/load-image-exif',
    'load-image-ios': '../../bower_components/blueimp-load-image/js/load-image-ios',
    'load-image-meta': '../../bower_components/blueimp-load-image/js/load-image-meta',
    'load-image-orientation': '../../bower_components/blueimp-load-image/js/load-image-orientation'
  },
 
  // angular does not support AMD out of the box, put it in shim
  shim: {
	  'semantic': {
		  exports: 'semantic',
		  deps: ['jquery']
	  },
    'angular': {
      exports: 'angular'
    }
  },
 
  // kick start application
  deps: ['./bootstrap']
});

Those errors made me crazy so I even decided to get rid of using RequireJS with Angular app at all!
Next day, I decided Google for a bit and I was extremly lucky to get to this answer – http://stackoverflow.com/a/20734214.
No votes for it, but that is correct answer and helps resolve the issue.

To recall here, the reason is – I used minified version of `load-image` script, which includes all dependencies in it…
So, all I had to do is replace this line with a path to not minified version:

    .....
    'load-image': '../../bower_components/blueimp-load-image/js/load-image<span style="text-decoration: line-through;">.min</span>',
    .....

After had that done everything started up.

How to add role to the PostgreSQL

If you need have superuser access to PostgreSQL via command line psql utility, create needed username first:

sudo -u postgres createuser NEEDED_USERNAME

You will be asked whether role should be a superuser:

Shall the new role be a superuser? (y/n)

answer Y (yes) if so and hit Enter.
Now you have NEEDED_USERNAME allowed to access databases as a superuser via psql.

Postgres and earthdistance extension

First of all, let me describe how one can install extensions for your Postgresql.
It depends whether you have version 8.4+ or 9.1+ installed.

In following sections I will describe procedure related to Debian based OSes.

First of all, you have to install contrib packages for corresponding version:

root@debian:/home/web# apt-cache search postgres | grep contrib
postgresql-contrib - additional facilities for PostgreSQL (supported version)
postgresql-contrib-8.4 - additional facilities for PostgreSQL
postgresql-contrib-9.1 - additional facilities for PostgreSQL

with command:

apt-get install postgresql-contrib postgresql-contrib-x.y

After that, restart postgresql daemon:

/etc/init.d/postgresql restart

Change to the database owner account, e.g.:

su postgres

Change to the contrib modules’ directory:

cd /usr/share/postgresql/8.4/contrib/

Now, there are 2 different way how you could install extensions for your database.

1. Postgres-8.4.x
Load the SQL files for needed extension using command:

psql -U user_name -d database_name -f module_name.sql

for example,

psql -U postgres -d your_database_name -f cube.sql
psql -U postgres -d your_database_name -f earthdistance.sql

2. Postgres-9.1.x
Extensions are stored under /usr/share/postgresql/9.1/extension directory,
so you need to cd to it:

cd /usr/share/postgresql/9.1/extension

and then launch psql.
In opened database console run this query:

CREATE EXTENSION "cube"; -- you will not be able install "earthdistance" w/o "cube" extension
CREATE EXTENSION "earthdistance"; --or any other extension you need

That is all – you can use installed extension.

Okay, now lets proceed to the main topic of the post.
What is earthdistance?
It is a simplified solution to make calculations over spatial coordinates (latitude, longitude), calculate distance between two points in the Earth.
In case if you do not want install and learn PostGIS extension for the Postgres DB, although that extension provides much more functionality, you can go with earthdistance.
In earthdistance the Earth is treated as an ideal sphere and if it works for you – you don’t have too precise calculations -, then you can earthdistance.
Otherwise you definitely should take a look at PostGIS.

So, here is the main point – what the SQL should look like when you want to search location of some subject based on its coordinates?
Just use such expression in WHERE part of you SQL (for example):

... WHERE earth_box(ll_to_earth({longitude_float_value}, {latitude_float_value}), {radius_in_meters}) @> ll_to_earth(some_table.latitude, some_table.longitude)

of course values in curly braces should be just numbers, no need to put { and } outside.

Install PHP 5.4 from DotDeb

(Русский) http://www.jasonashdown.co.uk/2012/08/gpg-error-no_pubkey-apt-get/

In case if you want have latest php-5.4 both in CLI and with Apache-2.x it is better to install it through apt-get
You need to add these source to sources.list file:

deb http://packages.dotdeb.org squeeze all
deb-src http://packages.dotdeb.org squeeze all
deb http://packages.dotdeb.org squeeze-php54 all
deb-src http://packages.dotdeb.org squeeze-php54 all

If you are getting this error

W: GPG error: http://packages.dotdeb.org stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY E9C74FEEA2098A6E
W: GPG error: http://nginx.org squeeze Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY ABF5BD827BD9BF62

you need follow such steps:

gpg --keyserver keys.gnupg.net --recv-key 89DF5277
gpg -a --export 89DF5277 | sudo apt-key add -
gpg --keyserver keyserver.ubuntu.com --recv-key ABF5BD827BD9BF62
gpg -a --export ABF5BD827BD9BF62 | sudo apt-key add -
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

HowTo Compile and Install php-5.4.x on Debian OS (squeeze)

(Русский) l

Recently I was trying install latest PHP 5.4.x (at the moment of writing this is 5.4.10) version on my stable Debian OS (v6.0-squeeze-32bit).
As far as you may know, stable Debian proposes PHP-5.3.4 as latest available release. I wanted to use embedded into PHP-5.4 web-server.
I was thinking that install PHP-5.4 would be faster process then configuring new virtual host in Apache. Yep, lazy me! 🙂
Well, spoiling the story, I would like to say, that the overall process took 2-2.5 hours from me before I was able to launch my scripts.
To be honest, that was my first time when I was compiling PHP from source, and I feel I got great experience with that!
But okay, let’s look at the process step-by-step.

First of all, you may need install “libxml2-dev” linux library (don’t remember why, though :-)).
Oh, wait! Looks like it needed for you be able to configure you PHP installator.

sudo apt-get install libxml2-dev

I also believe that most web developers need to use DB with theirs scripts, thus they may need PDO php extension.
So, you need to compile PHP with this directive:

configure --with-pdo-mysql --with-mysql

(see http://php.net/manual/en/ref.pdo-mysql.php for more details)

Usually, good devloper uses debug tools extensively. As we all know most popular PHP debugger is a xdebug.
This package could be installed from pecl repository.
Before asking pecl to install xdebug, make sure you have php5-dev package installed in your system. With that package phpize is being shipped, which is required to install PHP extensions through pecl.
If you don’t have php5-dev install, you are going get this error message:

ERROR: `phpize’ failed

and here is your next command:

sudo apt-get install php5-dev

After that, you will be able install xdebug extension with help of pecl:

sudo pecl install xdebug

Next. Let’s assume you work with not only documents written solely in English, but with some other languages (Italian, Portugeese, Russion, Dutch, etc.)
Also let’s assume you need to handle dates written in non-english format (btw, about that look for my article about how one can handle dates written in languages different from English). php5-intl extension comes to help! Here http://php.net/manual/en/intl.installation.php you will find information how to enable this extension:

configure --enable-intl

If PHP’s configurator shows error message

“configure: error: Unable to detect ICU prefix or no failed. Please verify ICU install prefix and make sure icu-config works.”

you need install this Linux package:

apt-get install libicu-dev

These are development files for International Components for Unicode.

Next, it may happen that you need load remote http resources. Usually, that is done with curl (php5-curl).
I was not enable that extension because faced such message:

configure: error: Please reinstall the libcurl distribution

In such case you need install this Linux package:

sudo apt-get install libcurl4-gnutls-dev

(thanks to http://phpconfigure.com/2011/04/configure-error-please-reinstall-the-libcurl-distribution/)

In case if you need to deal with multibyte encodings and use PHP’s functions prefixed with mb_*, you need enable that as well:

configure --with-mbstring

Okay, as I said, after couple hours of fight I was able to finish with this configuration options and directives:

sudo ./configure --with-pdo-mysql --with-mysql --with-curl --enable-intl --enable-mbstring=all

As I said at the beginning, I was hoping that install PHP-5.4 would be faster then configure virtual host. How far away from truth was I!..
But I do not regret about my choice, because now I feel strong in believe that I have mastered some important things and have grown my professional level!

Fell free to add comments and ask things that left unclear for you.

Fn keys stopped work Lenovo on Thinkpad Edge with Debian

Once upon a time ALL functional keys (brightness, volume control, camera, microphone, wi-fi) of my Lenovo Thinkpad Edge 15 suddenly stopped work. I’m not a guru-guy in all that Linux’s low-level bullshit like acpi events, etc. So, I periodically tried to find a solution for the problem in the INet, but having no idea what to search for – I was searching for acpi, fakekeys, Debian (that is the OS installed on my laptop), – I didn’t find any solution. But with help of luck suddenly I discovered one great forum about Ubuntu OS, where there was an unexpected solution of absolutely similar trouble…
Well, all the deal is about BIOS issues on Lenovo Thinkpad Edge!! 🙁
So far, to restore previous BIOS’s state, all you need is unplug an AC adapter and remove battery for approx. 1 minute or a little bit longer. That is all! Fn keys are work again like a charm!
Thanks to guys who proposed the solution!