October 2020

Overriding Composer packages at the source level

I think we all have been in that situation where we had to extend some library class but there was something preventing us from doing it the normal way. A common example of this would be overriding private methods, or accessing private variables, or dealing with final classes. Another maybe less obvious case is when the class you want to extend is a hardwired dependency for code that you have no control over. In that that case, even if everything were public and overridable you would not be able to inject your subclass.

The scenario

In a previous blog post I wrote about wanting to override the function cleanBindings on the Builder class (source) from the Laravel framework. Extending the class itself is no problem because the function is public and the class is not marked final. The real problem here is that the Builder is a hard-coded dependency multiple levels deep in the framework code.

Now, as a disclaimer, there are other ways to accomplish this task that are a lot more conventional than what I am about to show you. And I generally do not recommend that you use my solution for production code. With that out of the way, let’s look at the mechanism.

Postgres Arrays and PHP -Part 1

The other day I found myself designing a database schema for a collection of musicians each of which plays one or more instruments. The result looked something like this.

CREATE TABLE musicians
(
    id bigserial NOT NULL,
    name text NOT NULL,
    PRIMARY KEY (id)
);

CREATE TYPE musical_instrument AS ENUM
    ('guitar', 'piano', 'bass', 'trumpet', 'drums');

CREATE TABLE musician_instruments
(
    musician_id bigint NOT NULL,
    instrument musical_instrument NOT NULL,
    "position" integer NOT NULL,
    PRIMARY KEY (musician_id, instrument)
);

As you can see the table musician_instruments is used to associate musical instruments to a musician. It has an additional column called position because the order of instruments is relevant for the application.

When I squinted real hard I saw that I had in front of me a simple array disguised table. So I thought, why not use the array type that Postgres provides and see where it leads me. A research project if you might.

ALTER TABLE public.musicians
    ADD COLUMN instruments musical_instrument[] NOT NULL;

Add columns with custom types in Laravel Migrations

I was certainly surprised when I found out that there is no built-in method to create table columns with custom types in Laravel migrations. The default list of column types available in Laravel may be more than enough for most applications, but, I think there are some valid use cases for opening the hood and directly working on the engine.

The scenario

Many DBMS offer non-standard column types that you might want to use to unlock some untapped potential. For me this was adding support for PostgreSQL’s built in enumerated types (enums) and arrays. Now, I am not claiming that using these particular types is generally a good idea (especially arrays). As always, you need to evaluate the upsides and downsides for your specific application.