I keep seeing this line of code in many plugins. What exactly does it do, and what other possibilities are there other than Request_Http
if (!$request instanceof Zend_Controller_Request_Http)
return;
I believe that originally all of ZF's routing was based on the REQUEST_URI, so many of the routing classes operated on $request which was a string. In order to facilitate things such as routing for subdomains this was changed so that the whole request object was passed in. So checks such as the one in your example are merely checking that $request is a request object (and not a string) before calling its methods.
(Disclaimer: this is speculation based on my knowledge of ZF's routing classes, I may be wrong!)
Sifting through the Zend Framework docs, I see that a sibling class of Zend_Controller_Request_Http is Zend_Controller_Request_Simple, which is used to get information about command-line requests to a ZF application. The plugins in question probably only work for web apps requested using a browser (or whatever HTTP client), so these plugins back out otherwise.
Even it is unusual every class, that extends Zend_Controller_Request_Abstract can occur.
Related
Below are two ways a service layer can be implemented in an CodeIgniter application.
1st method
1.send request to the controller
2.calling service layer methods from controller
3.return processed result data set(D1) from service layer to controller
4.then according to that data set controller demand data from model
5.model return data set(D2) to the controller
6.then controller send second data set(D2) to view.
2nd method
1.send request to the controller
2.calling service layer methods from controller
3.service layer demand data from model
4.model send requested data set(d1) to the service layer
5.after some processing return generated data(d2) to controller from service layer
6.then controller send data set(d2) to view.
What is the correct way of implementing a service layer in CodeIgniter? Other than these two methods, are there any other good ways?
if you can provide an example in Code it will be great
Please note, this is not necessarily the correct way of doing it, but I'm going to explain how a framework like might typically do it and then you can learn about other methods and decide the best one for your use-case. Therefore, I do not expect this answer to be the correct one, but I hope it imparts at least a little knowledge on how things are done before someone who actually knows what they're talking about comes along and chimes in (also to those people - please feel free to edit / downvote this answer :D). Finally this also has nothing to do with CodeIgniter but frameworks in general. Your question should not only be framed as framework-agnostic, but language-agnostic also.
So I'm going to offer an opinion here and that is of the fact that all modern frameworks, specifically in PHP, do not do MVC. Why is this important? Because we all need to be speaking the same language, and 'mvc' does not exist in PHP. That's a fact. Accept that and then we can move forward onto the bastardization of the concept that frameworks use; and CodeIgnitor is a particularly great example of 'MVC' bastardization; henceforth known as "mvc" with quotes.
The plus side is that frameworks like Symfony, for example, provide an initial opinionated architecture that at least contains some form of consistency across the application, and it goes something like this:
A standard HTTP request comes in and hits the front-controller, typically app.php or app_dev.php depending on whether or not you are in development or production; one involves a lot of caching that needs to be run on each change and the other doesn't - which is perfect for development.
A router matches the current url to a controller class and an 'action' (method) within that class.
The dependency injection part of the framework figures out what objects are needed for everything from the controller forward into the model layer and back, and either instantiates or prepares to instantiate them when needed.
The controller is instantiated with any required dependencies and the relevant method is executed. This is typically where you would start your development and 'hook your code in' to the framework.
This is where you decide on your architecture, however, the most important thing from both a developer perspective and business perspective (for lower costs for future maintenance) is consistency.
I personally prefer to ensure my code is decoupled from the framework. I pass in scalars taken from the request into an application-layer service, which uses objects from the model layer (passed-in via DI) to use domain objects. The point here is that domain objects are not directly passed into the controller, they are proxied through an application-layer medium, so you can theoretically replace the entire framework surrounding this and still, all you need to do is pass those scalars into this layer before they hit the model layer and it'll all still work (think CLI calls, no more controllers).
The application-level service uses any required Repositories, Services etc (and passes those scalars into them, remember the separation?), which perform business logic, (typically these are where your design patterns come into play on a day-to-day basis), and then return that data to the application-level service.
The service then returns the data to the controller and guess what? This is where frameworks tend to fuck up! Because there is no concept of a "View" in today's frameworks. There is only a template, and you pass that data to a template and bam that's it. So in your diagram, there is absolutely no concept of a view because that's not how things are done. And to be entirely honest, I'm still using templates because they're the fastest way of doing things, but until modern frameworks get their shit together and actually start using Views, we're out of luck and have to remain steadfast when confronting the fact that some (like Laravel) refer to themselves as "mvc" frameworks.
Note, Fabien Potencier explicitly states that Symfony was not an MVC framework - at least he knows what he's talking about there. Again, this is not purist, it's important we're all speaking the same, factually correct language in computing.
So, because you like diagrams so much, here's how some might do it with today's frameworks...
This is for an application that has the concept of a Review and Criteria for each Review. And don't even get me started on Symfony forms, they're so coupled to everything they're not a serious part of any architecture.
How many effing layers do you need? We already have "MVC", in DDD we have the concept of "Application", "Domain" and "Infrastructure" seperation, so get those two working together first, then this "service layer"? Do you really need another layer, or is the above enough? Things to think about...
See, you're not stuck with the framework / http request to get the application going as a result of this separation.
See the "services" in the above diagram? They're separated from the controller so you can throw scalars from anywhere and the application will still work. I think this will give you the separation you need. It's great to do things the right way, learn how to do it, and then learn how to control yourself and be pragmatic about it when it comes to the business and it's needs, but frameworks need to sort their stuff out - and you certainly wont be writing lovely code with CodeIgniter ;)
Dependency Injection and the Adapter pattern would be a good place to start.
CodeIgniter support's neither out of the box, so you would need to write a wrapper or maybe a hook.
Your view could only support xml|html as json would need to be pre-rendered to a .json file and then returned as output but this would need to be done via code, it's easier just to return the object in that case and altered on the frontend. PHP is an embedded language which works with (xml|html)
A service model works best when it is injected(dependency injection)
into a controller/model and is listed as a property of that controller/model.
The service is then bound to an interface
For example facebook/twitter
They both have a request and response function but both follow similar patterns, yet have different endpoints.
interface SocialMediaAdapter{
public request(url);
public response();
}
public class FaceBookProvider implements SocialMediaAdapter
{
public request(url){
}
public response(){
}
}
public class TwitterProvider implements SocialMediaAdapter
{
public request(url){
}
public response(){
}
}
public class SocialMediaServiceProvider{
protected $provider = null;
public function constructor(SocialMediaAdapter $provider){
$this->provider = $provider;
}
public function fetch($url){
return $this->provider->request($url);
}
}
Dependency Injection required here
new MyController( new SocialMediaServiceProvider ( new FacebookService ) )
IMHO there is no right or wrong here:
option #1 -
If you want to re-use the service layer in multiple controllers / actions
and feed it data from different models based on the request it makes sense to go for the first one.
option 2# - However the first option could be problematic if your data model is more complicated. What if a second call to the model is needed based on the data of a first call? Using the controller for this business logic defies the whole purpose of the service layer. In this case it might be better to go for the second one.
I think the second one is the more common one.
You should use first one. Because in MVC web application, controller is used to separate your business logic from view, it's something like a gateway. You need to start processing your info using controller, from controller you should call model or service layer or anything you need & finally you should return back data to any other source from here. Your view or service layer should not directly access model.
In modern web frameworks (Laravel, Symfony, Silex, to name a few), there seems to be a pattern of using a routes.php file or similar to attach URIs to controllers. Laravel makes it a bit easier with an option to use PHP annotations.
But to me all this feels like a bit of a code repetition, and when you are creating/modifying controller logic, you have to keep routes file always at hand. Interestingly, there's a simpler way I saw in several old frameworks, and I used to use this in my old projects as well:
Controller. All classes in src/controllers folder (old way) or all classes in YourApp\Controllers namespace are being automatically mapped to the first part of the URL by adding "Controller" to it. Example: /auth gets mapped to AuthController, /product/... — to ProductController, and / — to default IndexController.
Action. Action is the second part of the URL, and it gets mapped to the method name. So, /auth/login will call AuthController::loginAction() method. If no second part provided, we try indexAction(). Don't want people to access some internal method? Don't make it public.
Parameters. Next parts of the URL are being mapped to the arguments of the method; if there are Application and/or Request type hintings in the argument list, they are skipped so they can be properly injected; we can access GET/POST variables as usual through Request.
Here's the full example, using all these features together:
URL: https://example.com/shop/category/computers?country=US&sort=brand
namespace MyApp\Controllers;
class ShopController extends BaseController {
public function categoryAction(Application $app, Request $req, $category, $subcategory = null) {
echo $category; // computers
echo $subcategory; // null, it's optional here
echo $req->get('country'); // US
echo $req->get('sort'); // brand
}
}
I'm sure it seems to lack some familiar features at first, but all features that I can think of could be easily added if needed — using attachable providers, connecting middlewares, branching controllers to subcontrollers, specifying HTTP methods, and even performing a bit of a pre-validation on the arguments. It's very flexible.
This approach would really speed up the routing creation and management. So besides having all the routes in one file (which is also not always true, considering various providers, using ->mount() in Silex or bundles in Symfony), what are the reasons modern frameworks seem to prefer this way of doing MVC routing over the simpler way I've described? What am I missing?
I'll speak here from Symfony/Silex perspective:
Decoupling. routes.php provide separation of URL mapping and controllers. Do you need to add or change URL? You go straight to routes.php. Very handy if you want to change a lot of them.
Flexibility. Generally, routes.php is a bit more flexible approach. SEO might go crazy and might require you to have route like /shop_{shopName}/{categoryName}/someStaticKeyword/{anotherVar}. With routes.php you can easily map this to your code, but this might become a problem if your routes are directly mapped to the code. Even more, you can have this only controller, you don't need to write controllers for each slash part. You can even have different controllers handling the same URL with different variable parts, for example /blog/[\d]+ or /blog/[a-z-]+ being handled by different controllers (one might generate redirect to another). You might never need to do something like this, but this is just a demonstration of flexibility of this approach - with it anything is possible.
Validation. Another thing to consider is that routes.php provide simple means of validation via ->assert method. That is, routes.php does not only map URLs to controller methods, but also ensure that these URLs match specific requirements, and you don't have to do this in code (which in most scenarios would take a bit more code to write). Also, you can create default asserts for some variables, for instance, you may ensure that {page} or {userId} are always \d+, single line in routes.php that would take care of all usages of {page} or {userId}.
URL Generation. One more feature of routes.php is url generation. You can assign any route any name (via ->bind() method) and then generate URLs based on that name, and providing variables for parts of URL that change. And once we have this system and use URL generator throughout our code we can change URLs as much as we want, but we won't have any need to edit anything but routes.php. And once again - these are flexible names, that you won't have to change everywhere throughout your project once URL has changed and you are not limited choosing the name. It might be much shorter than the URL, or a bit more verbose.
Maintainability. Say, you might want to change some urls (as in example above - from /blog/[\d+] to /blog/[a-z-]+. Also, you might want to keep both of them for some time, and make old one redirect to the new one). With routes.php you simply add a new line and add a todo memo to remove it in some time if you want to remove it later.
Sure, all of this might be achieved with any aproach. But would that be this simple, flexible, transparent and compact as this approach?
Just as note, the standard edition of Symfony is shipped with SensioFrameworkExtraBundle, that allows to use annotations instead of file-based declaration:
/**
* #Route("/")
*/
public function indexAction()
{
// ...
}
In the same manner, you can set the prefix for the whole controller file:
/**
* #Route("/blog")
*/
class PostController extends Controller
{
/**
* #Route("/{id}")
*/
public function showAction($id)
{
}
}
Still, we have to declare it. I think the main reason is that routing requirements are heavily influenced by SEO optimizations. For anything that faces the public you want some keyword-rich URL. The "public" logic organization may also be different, you may have only one controller to deliver all your static pages, still you want those to be /contact, /about...
In some domains, routes can be inferred with conventions. If you create a REST API using FosRestBundle, it will auto-generate routes based on your controllers/actions names on the ressource approach. In general I think the FosRestBundle got a lot of things in their approach, you can easily parse and validate query parameters at the same time:
class FooController extends Controller
{
/**
* This action route will be /foo/articles, GET method only
*
* #QueryParam(name="val", default="75 %%")
*/
public function getArticlesAction(ParamFetcher $paramFetcher)
{
...
}
I always prefer having the routes in a config file rather than using annotations because, firstly, I feel it's more maintainable and easier to have an oversight. It's easier to ensure that you don't have any conflicting routes when you can see them all together.
Additionally, it's theoretically faster. Annotations require reflection, where the application needs to scan the file system and parse each controller to collect the set of routes.
The reason is probably maintainability for the long term. It doesn't matter how the routes are set up but generally, Laravel as a framework focuses on the simplicity and the small things that make the framework great. As long as it is easy to use for the user (web developer in this case), the goal is reached.
You can use a different name for the routes.php file and also use multiple route files, if you have a lot of routes in your application.
You can try and rethink the whole concept to improve it but I don't think that Laravel's routes need really a big change to make it even easier. It's already simple. Maybe it will be changed for the better in the future but for now, I think it's fine.
I come from a Java/Grails background and cannot seem to find a definite answer online as to where the service logic for a CakePHP application should be stored. By "Services", I am talking about classes that are usually instantiated through dependency injection to conduct business logic on domain objects. They should be able to query any domain object and make changes in response to a controller action.
Currently, CakePHP's "Component" class seems to be the closest match to this behavior. I can load a component into any controller and execute its methods as needed. However, I have read in several places that components should never access the database and that doing so will result in some steep performance hits.
I have also looked into CakePHP's "Behavior" class and it doesn't seem to fit the ticket at all. It seems well-equipped to organize domain objects into a data structure setting, but that's not the kind of logic that a service would execute. Also, to import any model definition into a Behavior, I would have to edit the model definition itself to allow access, which is very awkward.
So I ask this question: Where should service logic be stored? Certainly not the controller, as it should only contain the minimal logic to process a request and send a response.
Components are the service layer in CakePHP. They are constructed by a dependency injection container (Components Collection) and get passed the controller, request and response that is to be handled.
There are no restrictions in what Components can do other than maintaining separation between layers. It is fine to use database connections, or use models, directly from a component and modify the request.
Components are actually very light-weighted if you only make them act for specific cases. Inspecting the action name, is a common way of limiting the reach of a component. You can also inject setting so it can know when is OK to execute custom service logic.
So I ask this question: Where should service logic be stored?
Certainly not the controller, as it should only contain the minimal
logic to process a request and send a response.
Sounds like the ideal use case for a Dispatcher Filter. It gets called even before a controller is instantiated. If you need to query the database simply load a model via ClassRegistry::init('YourModelName') and pass the request params to the model method and return whatever you need in your request. No controller needed at all. We've implemented oauth + xhttp using Dispatcher Filters without calling ever a controller.
How using a model inside a component should effect the performance... I don't know who got that strange idea, sounds like not the best article you found. It is true that you should not put model layer related logic in them but you can call a model for example through the controller instance and the controllers models.
Over the last few weeks I've been learning about iOS development, which has naturally led me into the world of APIs. Now, searching around on the Internet, I've come to the conclusion that using the REST architecture is very much recommended, due to its supposed simplicity and ease of implementation.
However, I'm really struggling with the implementation side of REST. I understand the concept; using HTTP methods as verbs to describe the action of a request and responding with suitable response codes, and so on. It's just, I don't understand how to code it.
I don't get how I map a URI to an object. I understand that a GET request for domain.com/api/user/address?user_id=999 would return the address of user 999 - but I don't understand where or how that mapping from /user/address to some method that queries a database has taken place.
Is this all coded in one PHP script? Would I just have a method that grabs the URI like so:
$array = explode("/", ltrim(rtrim($_SERVER['REQUEST_URI'], "/"), "/"))
And then cycle through that array, first I would have a request for a "user", so the PHP script would direct my request to the user object and then invoke the address method. Is that what actually happens?
The main thing I'm not getting is how that URI /user/address?id=999 somehow is broken down and executed - does it actually resolve to code?
class user(id) {
address() {
//get user address
}
}
Actually the API you're trying to describe now is not RESTful. There are many sources describing how to make RESTful APIs. So you should first define your API (taking in account how your client software would use it) and then implement it. I'm quite sure that almost any RESTful API can be implemented in PHP.
Here are some other tips on how to make a RESTful API.
In my opinion GlassFish Server REST Interface is a good example of RESTful design.
That's two questions.
To honor RESTful HTTP verbs, you have to query $_SERVER["REQUEST_METHOD"]. It will contain the usual GET or POST unless a more specialized HTTP request was received. The whole REST buzz is somewhat misleading in itself, and also in misusing the HTTP verbs just for routing.
Anyway, the mapping of request URLs to functions can be achieved in two ways. It's most reliable to use a static map, for example an array that lists URL patterns and destination methods. Most PHP frameworks use an implicit mapping like so:
$args = explode("/", trim($_SERVER['REQUEST_URI'], "/"));
$class = array_shift($args);
$method = array_shift($args);
call_user_func_array("$class::$method", $args);
Note how this is a bad example, security-wise. Only allowed and specifically prepared classes and methods should be able to receive requests. Most frameworks just check if it was derived from an acceptable base class after loading it from a known path and/or instantiating. But a static map is really preferable.
Anyway, regular expression mapping or handling by mod_rewrite is also common. And for utilizing HTTP verbs, just include it as method name.
Have a look at FRAPI - http://getfrapi.com/
As it says focus on your business logic, not presentation.
In a classic Zend Framework MVC setup, there seems to be access to a generic _request object from within the model/view/controller instance as outlined here:
$this->_request->getPost('variablename');
is this request object somehow available in a non-MVC setup as well?
If yes: how would I initialize and access it?
I would not use the Zend_Controller_Request_* objects outside ZF's MVC structure (even if possible). You can see by the class name already that it belongs to the controller package and it's API exposes a number of methods that are completely targeted at being used within ZF's MVC and these are inherited by all subtypes.
That's okay when using ZF's MVC, but for usage outside of that the Request Objects do too much. The idea of a Request object is to encapsulate and maybe decouple the current Request environment from the Superglobals (which ZF doesn't. It just sits on top). All that extra stuff about modules, controllers and actions shouldn't be part of it in my opinion. It makes only sense in ZF.
Writing a Request object isn't difficult, so I'm sure you can easily come up with a more lightweight version. Here is some basic examples:
http://www.phpdesignpatterns.de/auflage-2/downloads/code/PHP-Design-Pattern-Kapitel-8.zip
http://github.com/sebastianbergmann/php-mvc-ukernel/blob/master/Request.php
http://github.com/spriebsch/MVC/blob/master/src/Request.php
In the end it's your choice though.
The front controller initalizes the request and response objects and passes them to the router. The router calls the requested action, and (usually) appends the returned content to the response. So these objects are available in the Controller layer from the MVC.
Edit:
The frontController uses the following code to set up the request:
$request = new Zend_Controller_Request_Http();
Using the request object this way is very straighforward, so using it outside from the Zend Controller or the Application module shouldn't be a problem. Zend_Controller_Request_Http uses Zend_Uri.