Tag Archives: PHP

How to install PHP Data Structures (DS) extension on Ubuntu 16.04

First, you will need to install PEAR via apt-get to get the necessary package and distribution system that both PEAR and PECL use. From a shell prompt enter:

sudo apt-get install php-pear

You will be prompted to confirm the install. Just press “y” and enter. If all goes well you should see it download and install the php-pear package.

Now you will need to install the php-dev package to get the necessary PHP7 source files to compile additional modules. Enter the following from a shell prompt:

sudo apt-get install php-dev

If you do not install the php-dev package and try to install a PECL extension using “pear install”, you will get the following error:

sh: phpize: not found
ERROR: `phpize’ failed

The PECL_HTTP extension requires an additional dependency package to be installed. You can probably skip this for other extensions:

sudo apt-get install libcurl4-openssl-dev

Now we are finally ready to actually install the extension. From a shell prompt enter following:

sudo pecl install ds

The installer may ask you about some specific options for the extension you are installing.  Just accept the defaults and go ahead.

Once the install is complete, it’s time to enable the extension.
First, edit the following file (create it if it does not exist already):

sudo vi /etc/php/7.0/mods-available/ds.ini

and change it’s contents to:


; configuration for php ds module
; priority=30
extension=ds.so

Than check and remove any symbolic links to 20-ds.ini file, such as:

sudo rm /etc/php/7.0/fpm/conf.d/20-ds.ini
sudo rm /etc/php7.0/apache2/conf.d/20-ds.ini
sudo rm /etc/php7.0/cli/conf.d/20-ds.ini

You need to remove above listed symlinks because of bug: there is hard dependency on the json extension. DS extension shouldn’t try to implement JsonSerializable if the json extension is not loaded, but actually do it and it will complain with exception if it is not found:


PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/lib/php/20151012/ds.so'
 - /usr/lib/php/20151012/ds.so: undefined symbol: php_json_serializable_ce in Unknown on line 0

That’s why we removed 20-ds.ini symlinks and specified ds.so to load after json is already enabled.

Now, disable and then re-enable the extension:

sudo phpdismod ds
sudo phpenmod ds

You may need to restart your HTTP server:

# If you are on apache
sudo service apache2 restart
# if you are on nginx
sudo service nginx restart

How to parse a csv file in php when the delimiter is unknown

There are plenty of MS Excel alternatives out there – OpenOffice, LibreOffice, Kingsoft, Google Spreadsheets and many more. The problem is that CSV files created by different softwares may vary (, or ; to name a few options). If you need to process CSV files exported from different systems and software and handle the delimiter automatically, you can benefit from using SplFileObject::getCsvControl method.

Example usage:

<?php $csvFileObject = new SplFileObject($_FILES["csv"]["tmp_name"]); list($delimiter, $enclosure) = $csvFileObject->getCsvControl();

$lines = fopen($_FILES["csv"]["tmp_name"], 'r');
if($lines) {
while (($line = fgetcsv($lines, 4096, $delimiter, $enclosure)) !== false) {
//do something
}
}

Reference: http://php.net/manual/en/splfileobject.getcsvcontrol.php

Generate huge JSON files with custom PHP >5.3 class

Lately, I’ve been working on transitioning XML feeds to JSON format on big video site.  We generate these feeds in order to feed external search service with results. It’s similar to sitemap, but it provides more detailed information about the pages.

This task is challenging because of the following problems that need to be resolved:

  1. The feed need to represent over 500 000 database entries i.e. videos. It’s just not possible to generate huge PHP multidimensional array with more than 500 000 elements and pass it to json_encode(). Obviously, you need to generate small JSON objects (chunks) concatenated with hand-coded strings and so build the full feed.
  2. The development and production servers we use are equipped with outdated PHP version 5.3.27. That means:
    – No meaningful error messages because json_last_error_msg() function it’s not available prior PHP 5.5
    – No JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, and JSON_UNESCAPED_UNICODE
  3. The code should be easy to test and maintain, so it should provide meaningful debug information and error handling.

Continue reading →

Enabling SSH Upgrade Access on WordPress on Ubuntu Server

As you may be already know, WordPress allows you to install and update plugins,  widgets, themes etc, as well as whole system trough the admin panel. It’s very convenient time-saving feature but it requires you to provide FTP or FTPS credentials every time when its used. It could be really frustrating!

SFTP (SSH over FTP) should not be confused with FTPS (File Transfer Protocol Over SSL). FTP is vulnerable to attacks and should be avoided because the server can only handle usernames and passwords in plain text. So, as many people, I don’t have it installed on my virtual private server. If you feel that you need to install and enable a FTP server, just for WordPress, think twice – you can use SSH instead and I’ll show you how! Continue reading →