MODUL PERKULIAHAN
Server-Side
Programmin
g I
Servlet
Fundamenta
ls
Fakultas Program Studi Tatap eMuka Kode MK Disusun Oleh
Ilmu Komputer Sistem Informasi
04
Misbahul Fajri, ST., MTIAbstract
Kompetensi
Outline
Common server-side programming techniques
Revisiting the Three-tier Model
Web-based e-commerce applications are usually built according to the “Three-tier Model” (Fig. 4.1), which includes:
The First-tier: Web Client
Discussed in Chapter 3
The Second-tier: Server-side Application (SSA) Discussed in this chapter
The Third-tier: Database Management Systems (DBMS) Discussed in Chapter 5
Server-side programming
technologies
There are numerous ways to implement server-side applications. Common examples include:
CGI (Common Gateway Interface)
ASP (Active Server Page)
Java Servlets
PHP, Perl, & other server programming languages
Databa
First-tier : Web
Clients
Second-tier :
Server-side Web
Applications
Cluster(s)
QLSCommon Gateway Interface (CGI)
Early Web page designs were “static” in the sense that a client can only request for a static
HTML document from the Web server (Fig. 4.2).
Later, CGI programming techniques were introduced to remove this constraint by providing
dynamic Web pages via server-side interaction, as shown in Fig. 4.3.
Static Web Page Retrieval (Fig. 4.2)
CGI-based Web Application (Fig. 4.3)
HTTP Request
HTTP
Document
Retrieve
Document
Request
for
Web
Document
Documents
Web
Web Browser
Common Gateway Interface (CGI)
Fig. 4.3 explains the retrieval of a static Web page. The Web browser goes to the designated
URL on a specific Web server to retrieve the required static HTML document when it receives a client request.
Note the content is independent of the request, in the sense, everyone who makes a request
to that particular URL gets the same document.
Active Server Page (ASP)
ASP is a "scripting" technique that runs on Web servers rather than Web clients.This
contrasts with VBScript and JavaScript which run on web clients.
It basically generates HTML documents for the Web client.
Execution of the ASP code by the server returns the corresponding HTML document to the client.
Fig. 4.4 shows the schematic diagram of ASP model.
Get Data
Browser
Web Server
Databas
e
ASP Model (Fig. 4.4)
Disadvantages of CGI programs
Each new request activates a new process to run the CGI program
Creating a process requires time and resource so CGI programs is not as scaleable a solution Also, CGI programs may raise security problems
Java Servlet
A servlet is a small piece of server-side application, which can be viewed as the server-side analog of an applet.
In a typical servlet application, a servlet-enabled Web server receives an HTTP request from
the client.
ASP Engine
HTTP Request
HTTP Document
Web Browser
Web Server
It then forwards the request to the servlet engine for performing the necessary operations as
specified by the program.
Finally it returns a response (e.g., HTML document) to the client via the Web server (Fig. 4.5)
Typical Web-based Servlet Interaction (Fig. 4.5)
Revisiting the Three-tier Model
Web-based e-commerce applications are usually built according to the “Three-tier Model” (Fig. 4.1), which includes:
The First-tier: Web Client Discussed in Chapter 3
The Second-tier: Server-side Application (SSA)
Discussed in this chapter
The Third-tier: Database Management Systems (DBMS)
Discussed in Chapter 5
Servlet
Engine
HTTP Request
HTTP Response
Web
Browser
Web Server
Three-Tier Model (Fig. 4.1)
Server-side programming
technologies
There are numerous ways to implement server-side applications. Common examples include:
CGI (Common Gateway Interface) ASP (Active Server Page)
Java Servlets
PHP, Perl, & other server programming languages
Databa
First-tier : Web
Clients
Second-tier :
Server-side Web
Applications
Cluster(s)
QLSCommon Gateway Interface (CGI)
Early Web page designs were “static” in the sense that a client can only request for a static
HTML document from the Web server (Fig. 4.2).
Later, CGI programming techniques were introduced to remove this constraint by providing dynamic Web pages via server-side interaction, as shown in Fig. 4.3.
Static Web Page Retrieval (Fig. 4.2)
CGI-based Web Application (Fig. 4.3)
HTTP Request
HTTP
Document
Retrieve
Document
Request
for
Web
Document
Documents
Web
Web Browser
Common Gateway Interface (CGI)
Fig. 4.3 explains the retrieval of a static Web page. The Web browser goes to the designated
URL on a specific Web server to retrieve the required static HTML document when it receives a client request.
Note the content is independent of the request, in the sense, everyone who makes a request
to that particular URL gets the same document.
Active Server Page (ASP)
ASP is a "scripting" technique that runs on Web servers rather than Web clients.This
contrasts with VBScript and JavaScript which run on web clients.
It basically generates HTML documents for the Web client.
Execution of the ASP code by the server returns the corresponding HTML document to the client.
Browser
Web Server
Databas
e
ASP Model (Fig. 4.4)
Disadvantages of CGI programs
Each new request activates a new process to run the CGI program
Creating a process requires time and resource so CGI programs is not as scaleable a solution Also, CGI programs may raise security problems
Java Servlet
A servlet is a small piece of server-side application, which can be viewed as the server-side analog of an applet.
In a typical servlet application, a servlet-enabled Web server receives an HTTP request from
the client.
ASP Engine
HTTP Request
HTTP Document
Web Browser
Web Server
It then forwards the request to the servlet engine for performing the necessary operations as
specified by the program.
Finally it returns a response (e.g., HTML document) to the client via the Web server (Fig. 4.5)
