This document provides an overview of enterprise systems and web frameworks. It discusses multi-tier architectures, with presentation, logic and data tiers typically running on separate servers. Web frameworks are presented as assisting with common tasks like database access. Scaffolding, which automatically generates application skeletons from data models, is explained for Ruby on Rails and ASP.NET. Object-relational mapping is discussed as mapping data between relational and object formats. Many frameworks also adopt the MVC pattern, separating applications into models, views, and controllers. Finally, application servers are introduced as optimizing performance and managing deployment of enterprise applications.

1. Enterprise Systems & Frameworks
CS25010 - Web Programming
Connor Goddard
5th November 2015
Aberystwyth University
1

2. INTRODUCTION
In today’s session, we will aim to cover the following:
• Multi-tier Architectural Patterns
• Enterprise Systems
• Web Frameworks
2

3. INTRODUCTION
If you’re on Twitter, jump on your phones!
During the presentation, look out for tweets from @cgddrd with
the hashtag #cs25010.
These tweets will contain links to other material you may find
useful.
Feel free to tweet back with any questions.
3

4. A LITTLE BIT ABOUT ME
I’m a fifth-(and final!)-year MEng Software Engineering student.
Previous web modules include: CS15020, CS25010, CS25210, SE31520 &
SEM5640 (so pretty much them all…)
I spent my IY working at Renishaw plc, developing advanced web and
mobile applications (Android, iOS & hybrid)
I’ve played around with most web-related technologies including:
• PHP, ASP.NET, Node.js, Ruby-on-Rails, Python & OO-Javascript
4

5. WEB APPLICATIONS
• What do we mean by a “web application”?
• What makes a web application different to other
applications?
• Where does “the cloud” fit into it all?
5

6. WEB APPLICATIONS
To a typical consumer, web applications can appear… mystical.
Most do not appreciate all that has to go on “under the hood”.
What problems could this present on development projects?
6
[1]
[1] http://imgflip.com

7. ENTERPRISE SYSTEMS
When designing non-trivial web applications, we typically will
want to decompose the system into smaller parts.
• Separate presentation from business logic and data sources.
• Possibly delegate across multiple servers.
These are known as “multi-tier/n-tier” or “enterprise” systems.
As a consequence, interconnectivity between separate systems
and their servers becomes essential.
7

8. MULTI-TIER ARCHITECTURES
8
Web
Server
Application
Server
Database
Server
[1] https://en.wikipedia.org/wiki/Multitier_architecture

9. MULTI-TIER ARCHITECTURES
9
Web
Server
Application
Server
Database
Server
Model View Controller
e.g. HTML, ASP.NET, PHP, JSP, XML, JSON
e.g. PHP, JavaBeans,
C#, Ruby
Business Logic
Business Objects
Business Objects
RDBMS File StoresOO-DMS
e.g. MySQL, PostgreSQL, MongoDB, XML
Presentation Tier
Logic Tier
Data Tier

10. MULTI-TIER ARCHITECTURES
10
Example: Online Store
Presentation
Layer
Logic Layer Data Layer

11. MULTI-TIER ARCHITECTURES
There is a distinction between tiers and layers.
What is the difference between the two terms?
11

12. MULTI-TIER ARCHITECTURES
There is a clear distinction between tiers and layers.
What is the difference between the two terms?
‣ Layer: Logical organisation/separation of code (e.g. separating code
associated with presentation from that of business logic)
‣ Tier: Physical deployment of layers (e.g. across multiple servers)
12

13. MULTI-TIER ARCHITECTURES
Why would we want to use multi-tier systems?
• What would be the advantages?
• What would be the disadvantages?
13

14. MULTI-TIER ARCHITECTURES
Why would we want to use multi-tier systems?
Advantages:
• Separation of concerns
• Improved scalability
• Help to avoid single point of failure
• Improved problem solving/bug tracking (isolation of issues to specific part of system)
• Easier mapping of system entities to developer workload
Disadvantages:
• Could prove to be ‘overkill’ for very small projects
• Likely increase in code size and complexity
• Steeper learning curve - greater potential for bugs to be introduced
• Use of M-TA introduces greater risk for poor design choices - these can become expensive to fix later
• Easier mapping of system entities to developer workload - “Too many cooks spoil the broth.”
14

15. WEB FRAMEWORKS
15

16. WEB FRAMEWORKS
What frameworks do people know about?
Has anyone got any preferred frameworks?
16

17. WEB FRAMEWORKS
17
PHP
C# / VB / F#
Adobe Coldfusion
Javascript
PHP
Javascript
Ruby

18. WEB FRAMEWORKS
18
Good community
support
High feature
set
Long history
Fast and easy
to scale
Simple to set-up
Lightweight +
good community
support
Many tools ‘out
of the box’

19. WEB FRAMEWORKS
Frameworks aim to assist in the development of web
applications by alleviating some of the overhead associated
with common tasks:
• Database access, ORM, templates, authorisation, web services,
scaffolding, testing, caching, session management etc.
Web frameworks are not the same as CMS software (e.g.
Wordpress or Drupal)
• Frameworks provide general solutions to developing web applications.
• CMS software builds on top of underlying frameworks.
19

20. SCAFFOLDING
Scaffolding refers to a process whereby the ‘skeleton’ of an
application is automatically generated by the web framework.
20
Typically the reference to a database
is given, from which the code
relating to standard CRUD operations
is enacted without input from the
developer.
Scaffolded systems provide a good
starting point from which the main
application can be built upon.
[1] https://scaffoldinginsouthwest.wordpress.com/
[1]

21. SCAFFOLDING - RoR
One of the first ‘mainstream’ frameworks to support scaffolding
was Ruby-on-Rails.
Generating a new web application in RoR takes 3 lines of code:
21
1 # Step 1: Generate new web application.
2 rails new mywebapp && cd mywebapp
3
4 # Step 2: Create new model entity and scaffold
5 CRUD operations (controller and views).
6 rails generate scaffold User surname firstname
7 age:integer is_student:boolean
8
9 # Step 3: Migrate the new model into SQLite
10 database (pre-created)
11 rake db:migrate
12
13 # Step 4: Start the server (navigate to http://<url>/users)
14 rails server

22. SCAFFOLDING - ASP.NET
ASP.NET is another framework that provides automatic creation
of web controllers and views from a pre-existing data model.
This is particularly useful within MVC projects where we are also
utilising object-relational mapping.
22

23. OBJECT-RELATIONAL MAPPING
Object-relational mapping (ORM) provides a mechanism for
representing and querying relational entities using an object-
based paradigm.
In other words: ORM allows us to map data stored in a
relational/tabular format into an OO format for use in
applications.
ORM helps to address an issue known as ‘Object-Relational
Impedance Mismatch’.
23

24. OBJECT-RELATIONAL MAPPING
Relational - Object mapping:
With ORM, it doesn’t matter what persistent storage mechanism we are
using (e.g. MySQL, NoSQL, XML data files etc.)
The framework handles this all for us.
24
Relational Model ORM
Table Class
Row Instance
Field Property

25. FRAMEWORKS, ORM & MVC
Many frameworks adopt an MVC pattern, supported by
mechanisms including scaffolding and ORM.
25
Generated via
ORM
Class for each model
responsible for:
• Handling incoming requests
• Retrieving model data
• Re-directing user to
appropriate view templates
Template files used
to render dynamic
data to end user (e.g.
HTML, XML, JSON)
[1] https://en.wikipedia.org/wiki/Model–view–controller
[1]

26. MVC - MODEL
26
ASP.NET (C#) PHP
1 namespace HelloMVC.Models
2 {
3 public class BlogPost
4 {
5
6 public virtual int Id
7 {
8 get; set;
9
10 }
11
12 public virtual string Title
13 {
14 get; set;
15
16 }
17
18 }
19 }
1 <?php
2
3 class BlogPost {
4
5 public $id;
6 public $title;
7
8 public function __construct($id, $title) {
9 $this->id = $id;
10 $this->title = $title
11 }
12
13 function save();
14 function setTitle();
15 ...
16
17 } ?>

27. 1 namespace HelloMVC.Controllers
2 {
3 public class BlogPostController : Controller
4 {
5 private HelloMVCContext db = new HelloMVCContext();
6
7 public ActionResult Index()
8 {
9 return View(db.BlogPosts.ToList());
10 }
11
12 public ActionResult Create()
13 {
14 return View();
15 }
16
17 [HttpPost]
18 [ValidateAntiForgeryToken]
19 public ActionResult Create([Bind(Include = "Id,Title")] BlogPost blogPost)
20 {
21 if (ModelState.IsValid)
22 {
23 db.BlogPosts.Add(blogPost);
24 db.SaveChanges();
25 return RedirectToAction("Index");
26 }
27
28 return View(blogPost);
29 }
30 }
31 }
MVC - CONTROLLER
27
ASP.NET (C#) PHP
1 <?php
2
3 class BlogController {
4
5 function indexAction();
6 function createAction();
7
8 ...
9
10 } ?>
GET Request
POST Request

28. MVC - VIEW
28
1 {% block title %}Blog Posts{% endblock %}
2
3 {% block body %}
4
5 <h2>List of Posts</h2>
6
7 <ul>
8 {% for item in blog_posts %}
9 <li>
10 <a href="{{ path('blog_show', {'id': post.id}) }}">{{ post.title }}</a>
11 </li>
12 {% endfor %}
13 </ul>
14
15 {% endblock %}
1 @model IEnumerable<HelloMVC.Models.BlogPost>
2
3 @{
4 ViewBag.Title = "Blog Posts";
5 }
6
7 <h2>List of Posts</h2>
8
9 <ul>
10 @foreach (var item in Model) {
11
12
13 <li>
14 <a href="@Html.ActionLink("Details", "Details", new { id=item.id })">
15 @Html.DisplayFor(modelItem => item.Title)
16 </a>
17 </li>
18 }
19
20 </ul>
ASP.NET (Razor)
PHP

29. APPLICATION SERVERS
Of course, once we have developed our web application, we need to be able to
host and run it.
Application Server: Software designed to handle communication between a
front-end website, and a business back-end system.
Features include:
• Performance optimisation (caching, profiling etc.)
• Database management (population, transactions etc.)
• Load Balancing
• Logging/Debugging
• Security
• Data integrity support
• Deployment
• Recovery management (application isolation)
29

30. APPLICATION SERVERS
Application servers provide services and features appealing for
enterprise systems.
Remember: Enterprise systems imply large volumes of data,
high potential for scalability and co-ordination of business
processes across multi-tier architecture.
30[1] http://maaw.info/ArticleSummaries/ArtSumDavenport98.htm
[1]

31. APPLICATION SERVERS
31
Glassfish (Oracle)
JavaEE
IIS (Microsoft)
ASP.NET
Wildfly (Red Hat)
Java
Zend Server
PHP
Tomcat (Apache)
Java Servlets & JSP

32. IDEAS FOR ASSIGNMENT
32
While use of frameworks and multi-tier architectures is not an
explicit requirement for the assignment, you could always
investigate their use for your own learning…
… plus perhaps for some extra marks (cough cough)
Ideas to consider include:
• Database management functions
• Templates/server-side includes
• ORM

33. 33
Many thanks for your time.
Questions?
@cgddrd
clg11@aber.ac.uk
http://cgddrd.me