We have an idea of developing a SaaS application using below technology.
Frontend HTML5 UI Framework - ExtJS
Backend Application - Spring + JPA
Database - MySQL
Please clarify on below things.
Considering the fact 'Modern web application should be stateless' for scaling purpose how do i manage sessions in this case?
Is Spring Security is mature enough to support SaaS applications.
Being a SaaS application I need to have lot of customization per tenant(i.e Display custom fields in forms, Display custom column in tables). What is the recommended approach to achieve this?
I need different look and feel of application based on type of user logged in. Say I need to display/hide a tab based on user role. How to achieve this? Should these roles need to be downloaded to browser and toggle UI elements based on user role?
I choose to go with separate schema Multitenancy. Is Hibernate is way to go or I can go with any JPA(EclipseLink)?
Any other technology limitations which i need to aware of with this combination.
Any input will be helpful.
Thanks,
John
1: I reject the premise that "Modern web application should be stateless" and I would like to see some citations for that statement. You can achieve scalability in a statefull application same as you can build a stateless application that doesn't scale at all.
2: It's more a question of "is it mature enough for commercial applications?" and I would say yes, it is. Depending on the actual requirements of your application, it may or may not be suited, but that has less to do with maturity than features.
3: Hard to say based on the very limited information provided. Anything from creating custom view instances (jsps, velocity-files, JSF2 views or which ever view technology you use) to dynamic, database-driven views to a full-blown CMS platform.
4: See answer 3 above. I general though, you build views in such a way that elements a user is not authorized to view are not rendered. Spring-security has taglibs for this type of functionality
5: Again, not enough information. Hibernate 4 ostensibly has support for multitenancy, but you will have to verify that it fulfills your particular requirements. AFAIK, there is no concept of multitenancy in the JPA standard (yet).
6: No doubt, but can't say what based on the information you provided. There are no inherent incompatibilities between the technologies you mention, but there are always limitations. Spring can't make coffee. JPA is lousy at driving your kids to school.
Related
I completed a new MVC web application and my boss asked me to create a new version for a new custumer. Same web application but differente CSS and two new modules (for module I mean a new page used by user to interact with DB). It's not a big deal and quite easy to do, just duplicate the project in my Eclipse and modify it. Two days work and project completed. Well done, all happy but not me.
I was thinking to wordpress, it's really customizable, just create a new template and plugin and activate it. I'd like to do somenthing similar to reduce the new version deploy and the code mainteneance. My question is, how can I do something similar with Spring? or better, is it possible to create a new module and deploy it for a web application? is the Spring dynamic the right option for a MVC Spring application?
thanks,
Andrea
I don't think your approach is correct. You need to discuss with your manager whether this situation is likely to repeat. Because to me it looks like it might.
Let's imagine a scenario: you have a number of copies of your app with some minor enhancements or changes between them. A month later one customer reports about a bug that's really nasty and has to be fixed in every of your app instances. Imagine your pain.
Why don't you approach it with multi-tenancy in mind?
Implement white-labelling, so that depending on the customer your application can get different looks;
Extend the backend, so that customers don't ever see each other's data
Implement configurable features, so that one customer doesn't see extended features that your boss sold to another customer. When he does sell them - it's going to be a matter of toggling a few flags in the database/configs.
Don't want to support multi-tenancy or the product is physically deployed on different (customer) servers? Doesn't matter! If you find a bug, you fix it once and redeploy the jar-file to all the affected systems.
Granted, the above isn't two days of work, but down the road this approach may save a lot more.
As to your question, Spring allows you to customize its looks via changeable styles and layouts. I suggest you to create a sample web app with Spring Roo to see how it's done. However, if I were you I would still aim to have a shared codebase between the projects at the very least.
I have a asp.net project and Its in designing phase. Its about products and shops navigation system. Users can browse/search products. I want my web application to be extendable and flexible. What I initially planned was to make it an MVC and for database I propose ORM (Object Relational Mapping). Is that right? what could be the problems I face with this proposal. I am learning asp.net so I don't know much about the problems.What design do you people suggest?
It's great that you've decided to learn ASP.NET.
Regarding design approach, it sounds like your question is 2 part: a) MVC or traditional web forms ASP.NET, and b) ORM or no ORM.
a) Generally speaking, if you have a good programming background, I would recommend MVC over web forms for any consumer facing Internet product. It promotes testability, clear separation of concerns, and gives the developer finer grained control over the UI.
b) Regarding ORM or no ORM - first, its important to note that you still need to choose a database. ORM is merely a means of abstracting the data access logic away from the developer - but there still needs to be a database to store the data. If you're going with an all Microsoft stack, you'll probably choose SQL Server.
ORM is great for developer productivity - and generally speaking, there's no reason not to choose it for new projects unless you can identify up front that its not going to provide a productivity boost. An example reason why you would choose not to adopt ORM - you need to persist the data in a pre-defined format - or in an already existing database - and the persisted entities are not consistent with how your application is representing them (i.e. over-normalized). In this case, you may want to write your own data access logic, and not rely on an ORM.
Finally, if all you are looking to accomplish is putting a product catalog online, rather than building an application from scratch to do this - you may want to consider utilizing an existing CMS of some sort, or even use Wordpress with some plugins. Would save hours of time and still accomplish your stated goal.
Best of luck!
If you want a really good reference on how to build application using MVC and ORM, then read the following book : Professional ASP.NET Design Patterns
It explains in details as how to build application using MVC. It also covers other interesting topics like dependency injection, repository pattern(very important expecially if you have decided to go for ORM), TDD etc. I hope you will enjoy reading this text.
MVC sets up clear distinction between Model, View and Controller.
For the model, now adays, web frameworks provides ability to map the model directly to database entities (ORM), which, IMHO, end up causing performance issues at runtime due to direct database I/O.
The thing is, if that's really the case, why model ORM is so pupular and every web frameworks want to support it either organically or not.
To a web site has huge amount of traffic, it definitely won't work. But what's the work around? Connect directly to database is definitely not a wise solution here.
What's your question?
Is it a good idea to use direct db access from webpages?
A: No.
Is it a good idea to use ORM's?
A: Debatable : See How can I design a Java web application without an ORM and without embedded SQL
Is it a good idea to use MVC model?
A: Yes - it has nothing to do with "Direct" database access - it's about separating your application logic from your model and your display. (Put simply).
And the rationale for not putting database logic inside webpages has nothing to do with performance - it's about security/maintainability etc etc. Calling a usp from a webpage is likely to be MORE performant than using an ORM, but it's bad because the performance gain is negligible, and the cons are significant.
As to workaround: if you mean how do you hook up a database to a web application...?
The simplest way is to use something like Entity Frameworks or Linq-Sql with your Model - there are plenty of examples of this in tutorials on the web.
A better method IMO, is to have a separate Services layer (which may be WCF based), and have all the database access inside that, with DTO's transferring the data to your Web Application which has it's own ViewModel.
Mvc is not about orm but about separation of display logics and business logics. There is no reason your exposed model needs to be identical to you database model and many reasons to ensure that the exposed model closely matches what is to be displayed.
The other part of the solution to scale well would be to implement caching in the control and be able to distribute load on sevaral instances.
I think #BonyT has given a good answer, (and I've voted for it :) ), I'd just add that:
"web frameworks provide the ability to map the model directly to database entities (ORM), which, IMHO, ends up causing performance issues at runtime due to direct database I/O"
Even if this is true, using an ORM can solve a lot of problems with a model being easy to update and translate back and forth between a database. Solving a performance hit by buying extra web servers or cloud instances is much cheaper than having to buy extra developers or extra hours in development to solve things other people have already written ORMs to do for you.
I have an existing application written in Perl. Now I need to integrate this application with OBI. The plan is having a button the user can click on to open OBI in an iframe. OBI resides on a different server from the running application.
Has anyone done this before, know what is the best practice for doing this, and what is the effort of doing this?
Another question is is it possible to add customizations to the OBI displayed in the iframe.?
There are two ways to address the problem that I know of and tried out. According to your needs, one or the other might be more appropriate (or both, they're not mutually exclusive). In both cases, the documentation is good and readily available.
The "Go URL"
The Go URL is documented more thoroughly in the Oracle Business Intelligence Presentation Services Administration Guide. It provides a quick and easy interface to the reports you've already defined, in the form of a URL. All that's needed to get it running is to fill in a few query parameters to direct to the report you want. You might need to include authentication tokens too.
Pros: very easy to try out.
Cons: harder to get security right.
The web services
The presentation server comes with a series of web services that enable a more programmatic way of querying your repository. The functionality offered through this channel goes further: for example most catalog management, including report creation and editing is possible. The full list fills a guide of its own: the Oracle Business Intelligence Web Services Guide.
Pros: better integration (i.e., no need for an IFRAME); easier to get the security right.
Cons: harder to setup; lots of XML; more advanced features (e.g. in-place drilldown) need an HTTP bridge that was a bitch to get right in my case. The generated HTML might clash a bit with yours and require cleaning up, notably in the CSS.
Embedding OBIEE reports inside a non-ADF web app is tough. If you have an option to re-write your web application in ADF, your life will be a lot easier. Just drag and drop reports and visualizations into your web application. Oracle's own Fusion Applications also follow this approach. If your app is analytics heavy, it might be a good option to explore. Here's a link to the Oracle doc.
I've been reading through a couple of questions on here and various articles on MVC and can see how it can even be applied to GUI event intensive applications like a paint app.
Can anyone cite a situation where MVC might be a bad thing and its use ill-advised?
EDIT: I'm specifically talking about GUI applications here!
I tried MVC in my network kernel driver. The patch was rejected.
I think you're looking at it kind of backwards. The point is not to see where you can apply a pattern like MVC, the point is to learn the patterns and recognize when the problem you are trying to solve can naturally be solved by applying the pattern. So if your problem space can be naturally divided into model, view and controller then it is a good candidate for MVC. If you can't easily see which parts of your design fall into the three categories, it may not be the appropriate pattern.
MVC makes sense for web applications.
In web applications, you process some data (on SA: writing questions, adding comments, changing user info), you have state (logged in user), you don't have many different pages, but a lot of different content to fit into those pages. One Question page vs. a million questions.
For making CMS, for example, MVC is useless. You don't have any models, no controllers, just a pages of text with decorations and menus. The problem is no longer processing data - the problem now is serving that text content properly.
Tho, CMS Admin would build on top of MVC just fine, it's just user part that wouldn't.
For web services, you'd better use REST which, I believe, is a distinct paradigm.
WebDAV application wouldn't benefit greatly from MVC, either.
The caveat on Ruby for Web programming is that Rails is better suited for building Web applications. I’ve seen many projects attempt to create a WebDAV server or a content management system CMS with Rails and fail miserably. While you can do a CMS in Rails, there are much more efficient technologies for the task, such as Drupal and Django. In fact, I’d say if you’re looking at a Java Portal development effort, you should evaluate Drupal and Django for the task instead.
Anything where you want to drop in 3rd party components will make it tough to work in the MVC pattern. A good example of this is a CMS.
Each component you get will have their "own" controller objects and you won't be able to share "control" of model -> ui passing.
I don't necessarily know that MVC is ever really a bad idea for a GUI app. But there are alternatives that are arguably better (and also arguably worse depending on whose opinion you're asking). The most common is MVP. See here for an explanation: Everything You Wanted To Know About MVC and MVP But Were Afraid To Ask.
Although I suppose it might be a bad idea to use MVC if you're using a framework or otherwise interacting with software that wasn't designed with MVC in mind.
In other words, it's a lot like comparing programming languages. There's usually not many tasks that one can say that one is better than the other for. It usually boils down to programmer preference, availability of libraries, and the team's experience.
MVC shouldn't be used in applications where performance is critical. I don't know if this still applys with the increase of computing power but one example is a call center application. If you can save .5 seconds per call entering and updating information those savings add up over time. To get the last bit of performance out of your app you should use a desktop app instead of a web app and have it talk directly to the database.
When is it a bad thing? Where ever there is another code-structure that would better fit your project.
There's countless projects where MVC wouldn't "fit", but I don't see how a list of them would be of any benefit..
If MVC fits, use it, if not, use something else..
MVC and ORM are a joke....they are only appropriate when your app is not a database app, or when you want to keep the app database agnostic. If you're using an RDBMS that supports stored procedures, then that's the only way to go. Stored procs are the preferred approach for experienced application developers. MVC and ORM are only promoted by companies trying to sell products or services related to those technologies (e.g. Microsoft trying to sell VS). Stop wasting your time learning Java and C#, focus instead on what really matters, Javascript and SQL.