Going through the Symblog tutorial of Symfony2, While creating forms I came to a point where in I create Contact Entity (Entity/Enquiry.php) where I define some fields and some methods to access these fields. Then I create another folder Form/EnquiryType.php to build the form and then a contact.html.twig to display. I am unable to understand why we created 2 namespaces for Entity/Enquiry.php and Form/EnquiryType.php. when they have to deal with each other. Why dont we wrote both the classes within one folder or one file. And one more question. Do they belong to Controller or View part of MVC.
Form types are here to configure how data coming from objects (like Entities) are mapped to a form (and vice/versa).
Entities should'nt be named "entities", they should be just your buisness objects, that can be persisted through a layer called doctrine2.
To answer you on separation of concerns,
Entities are about M,
while form Types are about user inputs (so the VC).
View because it render a human interface to let user enter input,
Controller because that's where you handle the form lifecycle.
The reason is logical separation. Why don't we define all parts of MVC in one folder/namespace? Because it will be a mess. That's why logical separation is needed.
And not all entities have to have related form types — using entities without forms is normal.
Related
I am creating an mvc project, for simplification i have two entitys: Movies and MoviesGenre.
I want to display a list of genres and the amount of movies each of them contains.
Now i have a problem with the design. I am not sure who is responsible for it. I solved that by creating a method in MovieController that returns the amount of movies by genre id and created a method on the MoviesGenreController that select all the genres and uses the MovieController(By instantiating an object) method to get their count.
That doesn't seems like good design to me. Which controller is responsible for this? Do I maybe need to create an extra controller for this logic? Thanks.
You need a data layer project which will manage the access of each controller to the underlying database.
I would suggest the following design:
create a library project (DataLayer) project which connects to the database.
Potential methods exposed:
List GetAllGenres();
List GetMoviesByGenre()
You can either inject the DataLayer as a service or just simply allocate a new object in each controller ctor. This is more like a personal preference... The DI approach is more flexible a more in line with the DotNetCore architecture.
Both MovieController and MovieGenreController should use the methods from the DataLayer.
I'm trying to come up with a reusable pattern for updating MongoDB Documents when using Spring Data in conjunction with Spring MVC.
The use case can generally be summarized by:
A document is created in Mongo using repository.save()
Parts of that document are then presented in a Spring MVC editable form.
A user submits updated parts of that document which are then saved.
If I use the repository.save() method in step 3, I will lose any data in the document that was not bound to the form. Making the form responsible for the entire document is fragile so this is where it seems the findAndModify() method of the MongoTemplate comes in handy.
To use the findAndModify() method, I've created Form objects that support a toMap() method which takes the Form object's properties as a Map and removes some of the fields (e.g. class and id). This gets me a Map that contains only the fields that I care about from the Form object. Passing the object ID and this map to an update() method on my customized repository, I build Query and Update objects that I can pass to the findAndModify() method.
Using this approach, I'm able to add fields to my objects easily and only worry about instances when there are fields I don't want to update from a form posting. Document fields not manipulated by the Form should be retained. It still seems slightly convoluted to be using both the Repository and MongoTemplate so I'm wondering if there are better examples for how to handle this. It seems like this should be a consistent pattern when working with Mongo and Spring MVC (at the least).
I've created a sample project showing how I achieve this model on GitHub. The Spock Tests show how "updating" a Document using save() will blow away fields as expected and my update() method.
https://github.com/watchwithmike/diner-data
What are other people doing when dealing with partial updates to Documents using Spring MVC and Spring Data?
If you are taking whatever the user supplies and just shoving that in the database you are running the risk of doing something dangerous like updating or creating data that they shouldn't be able to. Instead, you should first query Mongo to get the most recent version of the document, change any fields (it looks like you are using Groovy so you could loop through all the properties and set them on the new document), and then save the new, complete document.
If you are making small, consistent updates (like increasing the number of votes, or something like that), you could create a custom MongoDB query using the MongoTemplate to do an update to a few fields. Check out the spring-data-mongodb docs for more. You can also add custom methods to the MongoRepository that use the MongoTemplate.
I have been reading about "Fat Controllers" but most of the articles out there focus on pulling the service/repository layer logic out of the controller. However, I have run into a different situation and am wondering if anyone has any ideas for improvement.
I have a controller with too many actions and am wondering how I can break this down into many controllers with fewer actions. All these actions are responsible for inserting/updating/removing objects that all belong to the same aggregate. So I'm not quiet keen in having a seperate controller for each class that belongs to this aggregate...
To give you more details, this controller is used in a tabbed page. Each tab represents a portion of the data for editing and all the domain model objects used here belong to the same aggregate.
Any advice?
Cheers,
Mosh
For all your tabs you can use one action, that have an tab parameter, that indicate what data you need to return.
The controller job is to cast this string tab into enum type variable. Then the tab will be send to the repository, and the repository job is to return data in response to the tab value.
The controller should do its job through to services: Input Validator and Mapper.
The mapper service job is to map the user input (typically strings) into actual typed value (int, System.DateTime, enum types, etc).
The validator job is to check that the input is valid.
Following this principles should keep your controllers really tiny.
If you wanted something simple and easy I'd suggest just splitting up the controller into partial classes based on the tabs. Of course, it's still a fat controller there's just some obvious separation between the various tab functionalities.
How would you tackle this problem:
I have data in my data store. Each item has information about:
URL = an arbitrary number of first route segments that will be used with requests
some item type = display will be related to this type (read on)
title = used for example in navigation around my application
etc.
Since each item can have an arbitrary number of segments, I created a custom route, that allows me to handle these kind of requests without using the default route and having a single greedy route parameter.
Item type will actually define in what way should content of a particular item be displayed to the client. I was thinking of creating just as many controllers to not have too much code in a single controller action.
So how would you do this in ASP.NET MVC or what would you suggest would be the most feasible way of doing this?
Edit: A few more details
My items are stored in a database. Since they can have very different types (not inheritable) I thought of creating just as many controllers. But questions arise:
How should I create these controllers on each request since they are related to some dynamic data? I could create my own Controller factory or Route handler or possibly some other extension points as well, but which one would be best?
I want to use MVC basic functionality of using things like Html.ActionLink(action, controller, linkText) or make my own extension like Html.ActionLink(itemType, linkText) to make it even more flexible, so Action link should create correct routes based on Route data (because that's what's going on in the background - it goes through routes top down and see which one returns a resulting URL).
I was thinking of having a configuration of relation between itemType and route values (controller, action, defaults). Defaults setting may be tricky since defaults should be deserialized from a configuration string into an object (that may as well be complex). So I thought of maybe even having a configurable relation between itemType and class type that implements a certain interface like written in the example below.
My routes can be changed (or some new ones added) in the data store. But new types should not be added. Configuration would provide these scenarios, because they would link types with route defaults.
Example:
Interface definition:
public interface IRouteDefaults
{
object GetRouteDefaults();
}
Interface implementation example:
public class DefaultType : IRouteDefaults
{
public object GetRouteDefaults()
{
return new {
controller = "Default",
action = "Show",
itemComplex = new Person {
Name = "John Doe",
IsAdmin = true
}
}
}
Configuration example:
<customRoutes>
<route name="Cars" type="TypeEnum.Car" defaults="MyApp.Routing.Defaults.Car, MyApp.Routing" />
<route name="Fruits" type="TypeEnum.Fruit" defaults="MyApp.Routing.Defaults.Fruit, MyApp.Routing" />
<route name="Shoes" type="TypeEnum.Shoe" defaults="MyApp.Routing.Defaults.Shoe, MyApp.Routing" />
...
<route name="Others" type="TypeEnum.Other" defaults="MyApp.Routing.Defaults.DefaultType, MyApp.Routing" />
</customRoutes>
To address performance hit I can cache my items and work with in-memory data and avoid accessing the database on each request. These items tend to not change too often. I could cache them for like 60 minutes without degrading application experience.
There is no significant performance issue if you define a complex routing dictionary, or just have one generic routing entry and handle all the cases yourself. Code is code
Even if your data types are not inheritable, most likely you have common display patterns. e.g.
List of titles and summary text
item display, with title, image, description
etc
If you can breakdown your site into a finite number of display patterns, then you only need to make those finite controllers and views
You them provide a services layer which is selected by the routing parameter than uses a data transfer object (DTO) pattern to take the case data and move it into the standard data structure for the view
The general concept you mention is not at all uncommon and there are a few things to consider:
The moment I hear about URL routing taking a dependency on data coming from a database, the first thing I think about is performance. One way to alleviate potentialy performance concerns is to use the built in Route class and have a very generic pattern, such as "somethingStatic/{*everythingElse}". This way if the URL doesn't start with "somethingStatic" it will immediately fail to match and routing will continue to the next route. Then you'll get all the interesting data as the catch-all "everythingElse" parameter.
You can then associate this route with a custom route handler that derives from MvcRouteHandler and overrides GetHttpHandler to go to the database, make sense of the "everythingElse" value, and perhaps dynamically determine which controller and action should be used to handle this request. You can get/set the routing values by accessing requestContext.RouteData.Values.
Whether to use one controller and one action or many of one or many of each is a discussion unto itself. The question boils down to how many different types of data do you have? Are they mostly similar (they're all books, but some are hardcover and some are softcover)? Completely different (some are cars, some are books, and some are houses)? The answer to this should be the same answer you'd have if this were a computer programming class and you had to decide from an OOP perspective whether they all have a base class and their own derives types, or whether they could be easily represented by one common type. If they're all different types then I'd recommend different controllers - especially if each requires a distinct set of actions. For example, for a house you might want to see an inspection report. But for a book you might want to preview the first five pages and read a book review. These items have nothing in common: The actions for one would never be used for the other.
The problem described in #3 can also occur in reverse, though: What if you have 1,000 different object types? Do you want 1,000 different controllers? Without having any more information, I'd say for this scenario 1,000 controllers is a bit too much.
Hopefully these thoughts help guide you to the right solution. If you can provide more information about some of the specific scenarios you have (such as what kind of objects these are and what actions can apply to them) then the answer can be refined as well.
I'm looking for some advice on storing views in a data-store (database, file, other) and display them based on routing data, all using ASP.NET MVC 2 and ASP.NET Routing.
For example, I'd like to be able to display different views based on the following route data:
/{country}/
/{country}/{area}
But in the same vein I'd like to display:
/{planet}/
/{planet}/{satellite}
All are based on strings, and the data isn't fixed. So based on the number of segments maybe, use that as the selection criteria into the data-store...additionally, I may not know the segments up front, so they'd all be dynamic.
I'm was hoping we could get a few different methods together here, as kind of a reference for all - I'm sure some methods won't suite everyone...
So, how would you do it?
Branislav Abadjimarinov suggested a Controller Factory which could be used to do the look-up and display the page dynamically. I like this idea, what do you think?
There is no way for MVC to understand from this url's which route to choose. You have to make the routes more specific. For example:
/planet/{planet}/{satelite}
/country/{country}/{area}
You also have the option to define your own controller factory. The controller factory decides which controller to instantiate based on the route. So you can put some custom logic in it like - check if the {planet} parameter exist and if yes instantiate Planet controller else instantiate Countries controller.
This Post could be really helpful for you.
Remember you always can add a new routing rule : )
Just like this