5

snortfearServers

Dec 4, 2013 (3 years and 6 months ago)

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1

B
est s
ecurity through nature
….

5

Web Service


5.1

What is
W
eb
S
ervice?

Web service is a new
technique

of performing remote method calls over HTTP that can make use of the
SOA
P

(Simple Object Access Protocol). SOAP simplifies matters immensely. This is an XML based
standard that details
how methods calls may be made over HTTP in a reproducible manner. A remote
SOAP server is capable of understanding these calls and performing
the
work, such as instantiating the
required objects, making the call, and returning a SOAP formatting response to

the client.

In addition Web services may be completely described using WSDL (Web Service Description
Language), allowing dynamic discovery of web services at run time. WSDL provides description of all
methods
(along

with the

data

types required to call t
hem) using XML with XML schemas. There are wide
varieties of
data
types available to web services which range from simple primitive
data
types to fully
complex dataset objects, which can result in a dramatic reduction
i
n load on a database server.


5.2

We
b Service Technologies

Currently there are several Web Service technologies to choose from.


5.2.1

Axis

Axis is a
n

open source
SOAP

engine which is

a framework for constructing SOAP processors such as
clients, servers, gateways, etc. The current version o
f Axis is written in Java
.

Axis is

n
o
t just a SOAP
engine,

it also
includes;

a server which plugs into servlet engines such as Tomcat, support for the
WSDL
.

JBuilder 8
and later version

comes with the AXIS support where deployment

and client side
stub crea
ting

can be done using the JBuilder

IDE
.

During a
survey on
A
xis
it was
found that current AXIS version can
no
t pass vector data types
within

a
SOPA message and also it gives errors when passing 16 distinct array types. Next
A
xis version
(i.e.
Mora

A
xis
) c
an support
arrays but does

n
o
t support vector transmission.


5.2.2

Wasp

WASP (Web Applications and Services Platform) is a platform
-
independent, standards
-
compliant set of
infrastructure products for building Java and C/C++ Web services.
WASP is a commerc
ial product. Where
licensing has to be get from Systinet for the

use of

W
eb service.
WASP Server for Java is supported by
WASP Developer, a free suite of development tools that extend the most popular IDEs to support Web
services creation and
deployment
.



2

B
est s
ecurity through nature
….

It supports
transmitting vector or array objects through SOPA
messages
. However to be used WASP
licensing has to be
obtained from Systinet
.


5.2.3

Microsoft
.Net
C# Web service

The .NET framework makes it very easy for us to make use of all
difficulties
th
at were
motioned above.

Combination of C# and .NET allows range of techniques on the server side; on the client side could be
any platform that has HTTP access to the server.

There
are
no
identified
error
s

for data types such as bit array, dataset, and oth
er important object types.
When changing the
methods
server side
method, just
compilation is enough no deployment is needed
and client can simply add the web reference to obtain the changed methods.

.Net C# Web services works with Microsoft IIS and it is
the most suitable technology for the Universal
BioSys project since
it supports binary data and complex data type transmission.


5.3

D
ata transmission in C#
W
eb
S
ervice
s

SOAP is an XML
-
based protocol that provides a way of encoding and
wrapping

data for t
ransmission
across a network
.

SOAP

can

communicate with any XML Web service, even
with a one
not developed
or

running on the Microsoft .NET platform

and
it
also

supports encoding of complex data types.
T
he
structure and syntax of SOAP
is

simple

but

when it

is
manually
encoded with complex data it
can

result in
long and confusing XML documents.

Where creating
and processing SOAP messages is a
tedious and
error prone process.

Proxy classes
do not require

the
developers
to
work

with
SOAP messages directly. A p
roxy is a .NET
f
ramework class with methods that
represent

the functionality exposed by a Web service. Each proxy
method takes the same number and type of arguments and returns the same data type as its Web
service equivalent.

When invoking

the Web servic
e’s functionality, a client application calls the
method in the
proxy class.
The proxy class
handles

all communications with the Web service and returns the response it receives
from the service.
For

the client application, the XML Web service invocation a
ppears to be a
s a

local
method call, while in
reality

the call could be serviced by a Web service anywhere on the Internet
.


5.4

References

1.

Lakshmi Ana
nthamurthy
, ”Introduction to Web Service”

Available:
http://www.developer.com/services/article.php

2.

Heather Kreger, IBM Software Group, “Web Services Conceptual Architecture (WSCA
1.0)“, May

2001.

Available:
http://www
-
306.ibm.com/software/solutions/webservices/pdf/WSCA
.
pdf





3

B
est s
ecurity through nature
….

5.5

Abbreviations

HTTP

Hyper Text Transfer Protocol

IDE

Integrated Development Enviro
nment

IIS

Internet Information Server

SOAP

Simple

Object Access Protocol

WA
S
P

Web Applications and Services Platform

WSS

Web Service Security

WSDL

Web Service De
scription

Language

XML

eXtensible Markup language