The Clean Architecture in php

interface
GeocoderInterface {
public function
geocodeAddress
(
$address
);
}
This is fairly straight forward. We need this in a controller which interacts with some mapping:
class
AddressController
{
protected
$geocoder
;
public function
__construct
(
GeocoderInterface
$geocoder
) {
$this
->
geocoder
=
$geocoder
;
}
public function
geocode
() {
return
$this
->
geocoder
->
geocodeAddress
(
$this
->
params
(
'address'
)
);
}
}
Now all we need to do to make this code work is provide something that implements
GeocoderInterface
,
and inject that into the controller when it is instantiated. Our adapter provides the needed
concrete implementation:
class
GeocoderPhpAdapter
{
protected
$geocoder
;
public function
__construct
(Geocoder
$geocoder
) {
$this
->
geocoder
=
$geocoder
;
}
public function
geocodeAddress
(
$address
) {
$results
=
$this
->
geocoder
->
geocode
(
$address
);
return
[
'longitude'
=>
$results
[
'longitude'
],
'latitude'
=>
$results
[
'latitude'
]
];
}
}
We’re also injecting the
$geocoder
into this adapter as we may want to have different
configurations for different circumstances:

---

External Agency Independence
96
$geocoder
=
new
GeocoderPhpAdapter(
new
Geocoder(
new
GoogleMapsProvider(
new
CurlHttpAdapter())
)
);
That’s a lot of dependency injection!
Benefits
We want to make sure we have flexibility and freedom in our applications. Specifically, we need
the ability to switch out third party libraries, whenever necessary, for whatever reason, easily
and quickly.
Not only does it safeguard us against a library going away or no longer providing what we
need, but it can make testing easier through mocking, and also makes refactoring easier, as it
encapsulates all functionality of the third party library into one place.
We’ll use this strategy extensively whenever we use third party libraries throughout the
Case
Study
.

---