Dependency Injection Explained

Dependency Injection Explained

The following example is a bit lengthy, but it attempts to explain why Phalcon uses service location and dependency injection. First, let’s pretend we are developing a component called SomeComponent. This performs a task that is not important now. Our component has some dependency that is a connection to a database.

In this first example, the connection is created inside the component. This approach is impractical; due to the fact we cannot change the connection parameters or the type of database system because the component only works as created.

class SomeComponent
{
    /**
     * The instantiation of the connection is hardcoded inside
     * the component, therefore it's difficult replace it externally
     * or change its behavior
     */
    public function someDbTask()
    {
        $connection = new Connection(
            [
                "h
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