I know the question is about solving the problem probably by different approach but let me specify in details what I want to ask and how much I understand about it.
We have two mvc approach used in ATG(or many other framework) pull based and push based.
As I understand it formhandlers and droplet both are playing the part of controller in different need, repositories are our model and jsps are providing views..
And if i am right till this point then what purpose the servlet chain is solving?How it fits into this picture of MVC?
Please If possible explain with the help of flow diagram from request to response (end to end).
Thanks a lot in advance to experts.
Please help.I could not find this kind of explanation anywhere.
The first thing to remember with ATG is that it is an old platform. So when trying to understand the different mechanisms through an MVC lens, remember that nothing was designed with MVC in mind-the platform predates widespread knowledge and acceptance of the MVC pattern in web development.
Droplets are a generalized mechanism for invoking Java code from a JSP (and previously, JHTML) template. The closest analogue in J2EE-land would be tag libraries. So you can use them to accomplish many different tasks. You can also use them as a poor man's MVC controller. This is done by coding a custom droplet class dedicated to handling the business logic of your page, and setting relevant page state as request parameters. Then you invoke the droplet as the first step in your JSP page. This is not very different from J2EE model 2 with the odd quirk that first your compiled JSP begins executing, then invokes your "controller" code and then resumes with processing the "view."
Form handlers, as the name indicates, are designed for processing form submissions. These are executed by a link in the servlet pipeline (DAFDropletEventServlet), before the page which was posted to begins rendering. Typical usage with form handlers is that they will send a redirect after executing, and cancel rendering of the page, which will abort any further processing by the servlet pipeline. Form handlers are the closest thing to a "controller" ATG provides. But they are awful for handling GET requests and result in some very unfortunate URLs when used for this purpose.
Why did they create two different mechanisms? Why have they not subsequently introduced an updated MVC model as part of the platform? These questions I cannot answer.
ATG, at the page rendering level, is not MVC. Don't look at it as MVC. ATG, at its core, is an extension of the basic Servlets API.
Forms and form-processing, with the successUrl and errorUrl is kind-of MVC. Droplets certainly are not.
It is perfectly acceptable in an ATG application to be fetching data as the page is rendering (i.e. Droplets)
Related
I hope you can help me. I've tried to look for a solution to this problem or for a similar question here in StackOverflow but couldn't find any, so here it is.
We must develop a feature in which we will have a multi-page form. After filling all the pages of the form, the user will submit it. The problem is that the final submit will send many parameters (around 500), and we're afraid we may encounter problems with request size in many cases.
An initial approach would be having an object in session, which would be partially filled when the user navigates through the pages. I.e. when the user fills the fields in page 1, the object in session is partially filled with that data, and so on. That way, we wouldn't have to pass all the request parameters in every step and the final submit wouldn't have to send so many data. But we don't want to use this approach because we don't want to use the session to store data that are specific to a single functionality or bunch of pages.
Another approach would be saving data to a database after the user fills each page of the form, and retrieving it after the final submit so we can deal with the whole thing. Maybe we could do this, but it would delay the development of the project since it's not a trivial task.
I wonder if there's a better approach to handle this. Maybe using #Cacheable in some intelligent way, maybe using Spring WebFlow (which I've never worked with), maybe other alternatives I can't think of. Is there any strategy or technology I could use for this? Currently we are working with Spring 3.2. We are using jQuery as well, just in case it's relevant.
Thank you.
Writing as answer as I would not fit into comment:
There is no limit to request body size for POST requests. Only GET requests are limited (i.e. when parameters are sent via query parameters). No need to worry here.
I don't understand why you don't want to use session (#SessionAttributes). Having multi-step forms is one of the use-case this was designed for I would say.
Storing incomplete model objects in database is also a good approach as it is very close to REST principles. We have used this multiple times in our company.
Spring WebFlow is also a good approach if you don't want to handle all the transitional logic yourself. However SWF is not that simple technology to learn and you should include that fact in your effort estimations.
There is another approach, which I would say is becoming more and more popular: doing all the logic dynamically on a single webpage (e.g. via AngularJS or some jQuery plugin) and submit the result as a JSON object.
There is no definitive answer to your question without being very specific about your use-case and your application. And even with exhaustive description it is question about personal preference.
The single dynamic page approach (e.g. AngularJS) would be good if your overall application architecture is going to be designed that way.
Spring WebFlow would be nice if you are familiar with that technology or if you are planning on having more multi-step forms throughout the application (i.e. I would not go for SWF if I need to solve just one use-case with it).
I would probably go for #SessionAttributes if I need to quickly solve a single multi-step form. There are some complexities connected to that (partial validation and partial binding namely)... so again this might not be the simplest approach in the end.
Spring Webflow would handle your use case nicely through its flowScope.
Anyway, I you don't want to go through the pain of integrating its infrastructure only for that, the session attribute you mentioned will work perfectly and it's a correct approach. Just make sure you remove it when it's not neccesary anymore to prevent memory leaks.
I own a Play 2.1 application.
Initially, I used the default template mechanisms from Play 2.1 until I .. learned AngularJS.
Now, I clearly want my client side to be an AngularJS app.
However, while surfing the net, I find there are no clear way to achieve it:
Letting Play behave as a simple RESTful application (deleting the view folder) and making a totally distinct project to build the view (AngularJS app initialized by grunt.js).
Advantage: Likely to be less messy, and front and backend teams would work easily separately.
Drawback: Need another HTTP server for the AngularJS app.
Try to totally integrate AngularJS app with the traditional Play's workflow.
Drawback: With a pretty complex framework like AngularJS, it would lead to a confusion of templates managementfor instance : scala.html (for Play) / tpl.html (for Angular) ... => messy.
Making a custom folder within the play project but distinct from the initial folders created by the Play scaffolding. Let's call it myangularview instead of traditional view for instance. Then, publish static contents generated by grunt.js into the Play's public folder, in order to be reachable from browser through Play's routing.
Advantage: SRP between components is still fairly respected and no need to use another light HTTP server for the client-side like in 1.
I pointed out my own views of advantage and drawbacks.
What would be a great way to achieve the combination of Play with Angular?
Yes, I'm answering to my own question :)
I came across this way of doing:
http://jeff.konowit.ch/posts/yeoman-rails-angular/
Rails?? No matter the framework is, the need remains exactly same.
It advocates a real separation between APIs (backend side), and front-end side (in this case making AJAX calls to backend server).
Thus, what I've learned is:
During development phase, a developer would use two servers: localhost on two distinct ports.
During production phase, the front-end elements would be encompassed into the whole backend side (the article would deal with a kind public folder, aiming to serve static contents: HTML, angular templates (for instance), CSS etc... Advantage? => dealing with a one and unique serving server's APIs exposition as well as static assets for the UI.
With this organization, some tools like Yeoman would be able to bring some really awesome handy things to developers like for instance: the livereload feature. :):)
Of course, during development phase, we end up with two different domains, (localhost:3000 and localhost:9000 for instance) causing issues for traditional ajax requests. Then, as the article points out, a proxy may be really useful.
I really find this whole practice very elegant and pleasant to work with.
There was an interesting discussion on the play mailinglist a couple of days ago about frontend-stack/solution, could be something in it for you, quite some people using angular it seems: https://groups.google.com/forum/#!searchin/play-framework/frontend/play-framework/IKdOowvRH0s/tQsD9zp--5oJ
Alright, so a better title here may have been "Progressive Enhancement with REST in CakePHP", but at least now I'll know you didn't read the question if your answer just refers to the difference between the two ;)
I'm pretty familiar with REST and how to integrate it with CakePHP, but I'm not 100% on board with how to still maintain a conventionally functioning website. Using Router::mapResources sounds like a great idea, but this creates a problem with maintaining the "gracefully degradation" version of the site, because both POST requests to /resource/ AND GET requests for /resource/add will route to the same action (add). Clearly I'll want this action to return a JSON object if they're using the REST api, but if they're using the degraded version of the site (no JS perhaps), it should be a add form, right?
What's the best way to deal with this. Do you route your REST requests to other action names using Router::resourceMap()? Do you do that crazy hack I saw to have the /api/ prefix part of the resourceMap so you can use api_action functions? Do you have the actions handle both REST and conventional requests via checking isAjax()? If so, how do you ensure that you can rely on the browser to properly support the other two request types?
I've searched around quite a bit but haven't found anything about how to keep conventional requests available in Cake along side REST, so if anyone has any advice or experience, I'd love to hear it!
CakePHP uses extension routing as well, via Router::parseExtension() so;
/test/action will render views/test/action.ctp
/test/action.html also
/test/action.json will render views/test/json/action.ctp
/test/action.xml will render views/test/xml/action.ctp
If all views are designed to handle the same data as set by your controller, you'll be able to show a regular HTML form and handle the posted data the same way as you'd handle the AJAX request.
You'll probably might have to add checks if any data is posted/submitted inside the /add, /edit, /delete actions to prevent items being deleted without a form being posted (haven't tested that though, it might be that cake blocks these urls if mapresources is set for the controller)
REST in CakePHP:
http://book.cakephp.org/2.0/en/development/rest.html
(Extension) Routing
http://book.cakephp.org/2.0/en/development/routing.html#file-extensions
I am developing the administration part of a site. It mostly consist of manipulating list of data such as:
Products
Suppliers
Tax profiles
...
I find the task of creating a controller that handle the CRUD operations of each model a little too repeating and prone to mistake from one controller to another.
I would still need to adapt some of these controller for additional operation, but not all.
Does someone know a proven approach for reducing the implication of controller for the usual CRUD operations?
One suggestion would be to look at tweaking the T4 template that is used to generate the scaffold methods. Check out Rob Conery's MVC Starter Site to see what he's done (look in /Web/CodeTemplates in the source for the general idea).
There are also some other MVC libraries out there such as FubuMVC that aim to cut down on code repetition, but it's not based on the actual ASP.NET MVC framework (and it's not really my thing).
I'm in the middle of converting an existing app built on top of zend framework to work as a plugin within wordpress as opposed to the standalone application it currently is.
I've never really used zend so I've had to learn about it in order to know where to begin. I must say that at first I didn't think much of zend, but it's funny because the more I understand how it works the more I keep questioning why I'd want to remove dependency when it's a clearly well thought out framework. Then I'm reminded that it's because of wordpress.
Now I already know there are WP plugins to make zend play nice with WP. In fact I'm aleady using a zend framework plugin just to get the app functional within the WP admin area which is allowing me to review code, modify code, refresh the browser, review changes, debug code, again and again.
Anyway, I really don't have a specific question but instead I'm looking for advice from any zend masters out there to offer advice on how to best go about a task like this one.... so any comments, advice, examples or suggestions would be super.
One area I'm a little stuck on is converting parts of zend->db calls to work as wpdb calls instead... specifically the zend->db->select.... not sure what to do with that one.
Also on how to handle all the URL routing with automatic calls to "whatverAction" within thier respective controllers files.
Any help would be great! Thanks
You're probably facing an uphill battle trying to get some of the more major components of ZF to work in harmony with Wordpress. It sounds like you've got a full MVC app that you're trying to integrate into a second app that has very different architecture.
You probably want to think about which components handle which responsibilities. Wordpress has it's own routing and controller system that revolves around posts, pages and 'The Loop'. This is entirely different from Zend's Action Controllers and routing system.
It's possible you could write a WP hook to evaluate every incoming request and decide if it should be handled by WP or a ZF controller. However, it is doubtful you would be able to replace WP's routing system outright with ZF's or vice versa.
Same idea, where Zend_Db is concerned. There's nothing stopping you from using Zend_Db to access Wordpress's database, but trying to somehow convert or adapt Zend_db calls into wpdb calls sounds painful. If you have a large model layer, you probably want to hang on to it, and find a way to translate data from those models into the posts/pages conventions that Wordpress uses.
Personally, I would use ZF to build a robust business layer that can be queried through an object model via a Wordpress plugin, and then rely on Wordpress to do the routing and handle the views.
Zend_DB_Select is simple SQL query (but created using objects) that can be used like any other query. Just turn it into string. Ex.:
mysql_query((string)$zendDbSelectObject);