Month: July 2012

Anonymous Objects in PHP

A little known but often useful feature of PHP’s object oriented functionality is anonymous objects which are generally used as value stores. Here’s an example:

$valueStore = (object) array(
    'name' => 'John Smith',
    'address' => array(
        '1 Some Street',
        'Some Town, Post Code',
        'Ireland'
    )
);

If you were to dump the resultant object, you’d get:

object(stdClass)#1 (2) {
    ["name"] => string(10) "John Smith"
    ["address"] => array(3) {
        [0] => string(13) "1 Some Street"
        [1] => string(20) "Some Town, Post Code"
        [2] => string(7) "Ireland"
    }
}

You can now add new items ($valueStore->item = 'qwerty'), check is items are set (isset()), remove items (unset()), and retrieve items ($valueStore->item).

But why? Well, a reason I use these anonymous objects for frequently is when I need to pass around a value store between different functions, objects, registries and so forth. With standard arrays, these are passed by value meaning you are making copies but also that changes on one won’t affect another.

If we use anonymous objects then these are passed by reference and no copies are created. We could use the reference operator I hear you scream. Yes, we could. But that is more prone to forgetful errors and is not as elegant as the above!

If you want to take it further, you can add functionality via anonymous functions and closures.

Try Git In Your Browser

I know, I know. The fourth Git post in a row…

But, in case you missed it or in case you’d like to try Git without installing any software, then checkout http://try.github.com/

Today [GitHub are] launching a unique and easy way, in the format of a Code School interactive course, for new Git and GitHub users to try both the tool and the service without a single bit of software installation.

If you know of a developer, designer, or other knowledge worker that would benefit from using Git but that hasn’t made the leap just yet, send them over to try.github.com when they have a spare 15 minutes.

Two Git Branching Models

In current projects, we tend to float between two branching models depending on the requirements of the customer / project and the planned deployment process.

git-flow

This was previously known as A successful Git branching model with an extremely detailed overview and instructions here. It has since spawned a project to help make using this model easier – git-flow.

This is a great branching model for a team of people who work towards creating planned versioned deployments (whether it be time based such as every second Tuesday, or milestone based).

In essence, this model uses two main branches:

  • origin/master – the main branch where the source code of HEAD always reflects aproduction-ready state.
  • origin/develop - where the source code of HEAD always reflects a state with the latest delivered development changes for the next release. Some would call this the “integration branch”. This is where any automatic nightly builds are built from.

Then developers create supporting branches as part of their development process:

  • feature branches – branched off origin/develop for active development of a new feature / enhancement;
  • hotfix branches – a branch off origin/master to apply a critical fix to production code;
  • release branches – short lived branches off origin/develop which are used for final testing and patched before being merged to origin/master.

The model works very well in practice and the above linked document is a excellent read on Git branching practices in general as well as git-flow in particular.

Github Flow

This is the model used at Github and discussed by Github developer Scott Chacon here.

This is suited for projects that deploy continuously rather than around the concept of releases and so it’s less constrained than git-flow. These are two very different models and Scott puts forth his arguments in favour of the Github model in his post linked above.

In essence, Github flow works as follows:

  • origin/master is always deployable. Always.
  • Similarly to git-flow, new features are done in their own branch – but off of origin/master in this case.
  • Now, when you believe your new feature is complete, a merge request is opened so someone else can review and check your work. This is the QA process.
  • Once someone else signs off, you merge back into origin/master.
  • This is now deployable and can and will be deployed at anytime.

 

Specifying Specific SSH Keys for Git Remotes

When using Git via SSH with services such as GitHub and Gitorious, it can be useful to use specific / different ssh keys than your default.

This is accomplished with an entry such as the following in your ~/.ssh/config:

Host some-alias
    IdentityFile /home/username/.ssh/id_rsa-some-alias
    IdentitiesOnly yes
    HostName git.example.com
    User git

You then specify this remote as follows in .git/config:

url = some-alias:project/repository.git