Pretty Print JSON With Python

23rd December 2014 - 3 minutes read time

JSON is a very common data format, but reading it can be a little difficult, especially if the JSON contains very little white space. If you have Python 2.6 or above you have use the json.tool to format the JSON so that you can read it correctly. This is also a good way to validate JSON strings that you have had to hand edit before they cause errors upstream.

If you have a file called file.json, which contains a bunch of JSON output, you can use Python to format this into a readable structure in the following way.

python -m json.tool file.json

You can also write this output directly into a file, in this case called formatted.json.

python -m json.tool file.json > formatted.json

The most common use of this tool is to pipe JSON to it from the command line (either directly or via a script).

PHPNW14: A Review

7th November 2014 - 15 minutes read time

The annual PHPNW conference, now in it’s 7th year, was held on the 4th and 5th of October in Manchester, again in the Mancester Conference Centre. The conference was attended by over 400 people with over 30 speakers from all over the world who talked about everything from project management to the internals of PHP. I have been volunteering at PHPNW for a few years now, but this year I was able to attend as a delegate with a number of colleagues from Access. It’s been a few weeks since the event, but I haven’t had a chance to publish this review, so here it is.

Find Architecture And Version Of A Linux Box

12th August 2014 - 4 minutes read time

When doing an audit of an existing Linux server a good first step is to find out what distribution is running and if the server is running a 32 or 64 bit architecture.

To find out what architecture a server is running you can run the uname command, which will print out certain system information. This must be supplied with the -a flag in order to print out as much information as possible.

uname -a

This will print out a line similar to the following on an Ubuntu system.

Linux vlad 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

This can be broken down bit by bit and will contain the following information.

Speeding Up Apache And Drupal With Varnish

8th June 2014 - 33 minutes read time

Varnish is a web application accelerator that provides an easy speed increase to most web applications and Drupal is no exception. It works by creating a reverse proxy service that sits in front of your web server and caches traffic that comes through it. When the page is requested, Varnish forwards the request to the web server to complete the request, the response that comes back from the web server is then cached by Varnish. This means that the next request to the same page is served by Varnish and not the web server, which results in a large speed increase.

The upshot of using Varnish with an application like Drupal is that when a request is made there is no hit to the web server (and thus PHP) and no hit to the database. Varnish works best with Drupal with anonymous traffic, as authenticated traffic requires cookies and custom HTML. Even so, you can see massive speed increases for any anonymous traffic on the site.

Print A Specific Block Of Lines From A File In Linux

20th May 2014 - 2 minutes read time

If you have a large file of data that you are trying to import, or a log file you are trying to dissect then you'll rarely want to print it directly out to the screen. Using commands like more or programs like vim can make things a little easier but you still have to run through potentially thousands of lines to find the correct block.

To load a few specific lines from a file you can use a combination of the head and tail commands. The following command will print out lines 200 to 220 from a large file called 'bigfile. The head command will print out the first 220 lines from a file, which is then piped into a tail command that prints out only the last 20 lines of the output generated by the previous command.

head -n 220 bigfile | tail -n 21

Alternatively, you can use sed to print out the same block from the large file.

Connecting To A Vagrant Box Without The 'vagrant ssh' Command

18th May 2014 - 4 minutes read time

When Vagrant sets up a virtual machine it will set up a port on your local machine that you can use to connect to the box via SSH. By default this is usually port 2222, which Vagrant maps to port 22 on the virtual machine. All this is essentially transparent so that when you type vagrant ssh you connect to the box without any problems. Vagrant handles all of the port matching and key finding behind the scenes.

DrupalCamp London 2014: A Review

12th March 2014 - 18 minutes read time

The City University London campus was the venue for Drupalcamp London 2014 and I went along for the weekend as a delegate. This was the first conference for a while where I wasn’t helping out, speaking, or organising in some form so it was good to just turn up and relax. I travelled down on the Friday night from Manchester and successfully booked into my Airbnb room.

Saturday

The (pre-breakfast) keynote was from Mark O’Neil and was about the Government Digital Service (GDS) and about how they are working towards making the UK government IT service better and more open. Mark is Head of Innovation and Delivery at GDS and has had a hand in most of the projects that the organisation is involved with. The team he runs is only a dozen or so developers, but they are producing things that are used by millions of people right now. The most prominent of these is the gov.uk website.

PHP Password Functions In 5.5

4th March 2014 - 5 minutes read time

New in PHP 5.5 is a group of functions that deal with password hashing and verification. This is such a common thing for PHP applications to do that it was decided to include it into the core of PHP. They effectively solve the problem of hashing and comparing passwords that just about every PHP developer has implemented at one point or another.

There are only a few functions available but they provide all of the functionality needed to create a hash value from a password, check if the hash is valid and to check if the password hash needs to be recreated.

To create a hash value from a password use the password_hash() function. The first parameter is the password string and the second value is the hashing algorithm to use. The value PASSWORD_DEFAULT here is a PHP constant that is currently set to the bcrypt algorithm and will be changed to better algorithms when and if they are found in newer versions of PHP.

Adding iptables Rules With Ansible

16th February 2014 - 4 minutes read time

Many systems and applications require certain access to certain ports and protocols. When installing these systems using Ansible it is necessary to also open up the needed ports so that the systems can function correctly. As there is no iptables module in Ansible the shell command is needed to add the iptables rules.

As an example, here is a task that adds a iptables rule to allow Apache to communicate on port 80.

Installing sshpass On OSX Mavericks

16th February 2014 - 3 minutes read time

When setting up a server for the first time with Ansible you will need to pass ssh credentials to Ansible directly to set up ssh keys. This is done by the use of the sshpass program which allows Ansible to pass your user credentials directly to ssh in order to open a connection to the server. The sshpass program is easily installed on Linux systems with the apt or yum package managers, but on OSX you will need to install it manually.