by szigyarto tamas, spbu applied mathematics, department of computer modelling and multiple...

by Szigyarto Tamas, SPBU Applied Mathematics, Department of Computer Modelling and Multiple Processors Systems

SOAPSOAP

Overview

AgendaAgenda

► Introduction

• Software as a service

• Starting with the service

► What is SOAP?

• SOAP how it is

• SOAP messaging framework

• Extensibility

• SOAP processing model

• Protocol binding

► Why SOAP?

► Web Services Solution

• What is the Web Service?

• Stack of layers

• Demo example

SOAP -> Introduction -> Software as a service

““Software as a service”Software as a service”

What is it?

• providing unified software, which every customer will

able to use

• building IT-systems ultimately utility like electricity and gas to provide ability for everyone plug into it

• deliver the SOA (Service Oriented Architecture) in the more natural way ‘cause widespread acceptance of the Internet

SOAP -> Introduction -> Software as a service

Private IT “generating” stationsPrivate IT “generating” stations

EJB

EJB

EJB

EJB

Today organizations build their own home-grown, large and

complex IT “generating” stations using existed technologies like

J2EE, CORBA, DCOM and others.

CORBA Broker

CORBA BrokerCORBA Broker

CORBA Broker

DCOM

DCOM DCOM

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> Introduction -> Starting with the service

Service oriented architecture (SOA)Service oriented architecture (SOA)

• Previously

The way a service was created and delivered to the customer was dictated by the available technology

• Our goal

To start with the service we want to provide and then work backwards into the technology


Delivering SOA Delivering SOA

Natural way to provide SOA is to reverse above trend

Choosing the technology

ProvidingService

Working underService we want

to provide

Backwards into the technology


Delivering SOA (2)Delivering SOA (2)

The quote from IBM:

”So it (SOA) basically boils down to distributed computing with standards that tell us how to invoke different applications as services in a secure and reliable way and then how we can link the different services together using choreography to create business processes. And then finally so that we can manage these services so that ultimately we can manage and monitor our business performance.”

Resume: while this is technologically valid, it is missing the point of SOA – we are focused on the technology that enables SOA and not on SOA itself.

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> What Is SOAP? -> SOAP how it is

SOAP philosophySOAP philosophy

• SOAP is stands by Simple Object Access Protocol

• SOAP is a simple and flexible messaging framework for transferring information specified in the form of an XML infoset between an initial SOAP sender and ultimate SOAP receiver

• SOAP does not define any application semantics but defines the mechanism to express application messaging semantics


SOAP philosophy (2)SOAP philosophy (2)

More formal SOAP definition:

SOAP is a lightweight protocol intended for exchanging structured information in a decentralized, distributed environment. SOAP uses XML technologies to define an extensible messaging framework, which provides a message construct that can be exchanged over a variety of underlying protocols. The framework has been designed to be independent of any particular programming model and other implementation

specific semantics.


SOAP terminologySOAP terminology

• Node: Enforcing the rules that govern the exchange of SOAP messages. It accesses the services provided by the underlying protocols through one or more SOAP bindings

• Role: A SOAP node’s expected function in message processing

• Binding: Formal set of rules for carrying a SOAP message within or on the top of another protocol (underlying protocol) for the purpose of exchange

• SOAP Application: Software entity that produces, consumes or otherwise acts upon SOAP message in a manner conforming to the SOAP processing model

• Message path: Set of SOAP nodes through which a single SOAP message passes

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> What Is SOAP? -> SOAP messaging framework

SOAP messagesSOAP messages

Standard SOAP message:

<?xml version=“1.0”?><soap:Envelope

xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/> <soap:Header>   </soap:Header> <soap:Body>

 </soap:Body>

</soap:Envelope>

Envelope

Header: Contains requirements

specific to messageoptional

Body: Information used by application

(object data, error messages, return values)required


SOAP requestSOAP request

Example of the SOAP message that represents a request to transfer funds between bank accounts:

<?xml version=“1.0”?>

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body>

<x:TransferFunds xmlns:x="urn:examples-org:banking"> <from>22-342439</from>

<to>98-283843</to>

<amount>100.00</amount>

</x:TransferFunds>

</soap:Body>

</soap:Envelope>


SOAP responseSOAP response

Response :


<x:TransferFundsResponse xmlns:x="urn:examples-org:banking">

<balances>

<account>

<id>22-342439</id>

<balance>33.45</balance>

</account>

<account>

<id>98-283843</id>

<balance>932.73</balance>

</account> </balances>

</x:TransferFundsResponse>

</soap:Body> </soap:Envelope>


SOAP fault codesSOAP fault codes

Name Meaning

VersionMismatch The processing party found an invalid namespace for the SOAP Envelope element

MustUnderstand An immediate child element of the SOAP Header element that was either not understood or not obeyed by the processing party contained a SOAP mustUnderstand attribute with a value of ”1”

Client The Client class of errors indicates that the message was incorrectly formed or didn’t contain the appropriate information in order to succeed. It is generally an indication that the message should not be resent without change

Server The Server class of errors indicates that the message could not be processed for reasons not directly attributable to the contents of the message, but rather to the processing of the message. For example, processing could include communicating with an upstream processor, which didn’t respond. The message may succeed if re-sent at a later point in time


SOAP fault exampleSOAP fault example

The following sample SOAP message contains Fault element that indicates an “Insufficient Funds” error occurred while processing the previous request:


<soap:Fault>

<faultcode>soap:Server</faultcode>

<faultstring>Insufficient funds</faultstring>

<detail>

<x:TransferError xmlns:x="urn:examples-org:banking">

<sourceAccount>22-342439</sourceAccount> <transferAmount>100.00</transferAmount> <currentBalance>89.23</currentBalance>

</x:TransferError>

</detail> </soap:Fault>

</soap:Body> </soap:Envelope>

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> What Is SOAP? -> Extensibility

SOAP HeaderSOAP Header

• Header element, like the Body element, is a generic container for control information

• Elements placed in the Header are referred to as header blocks

• Header should contain information that influences payload processing

• Header is the right place to put some credential information that helps control access to the operation

SOAP -> What Is SOAP? -> Extensibility

SOAP Header (example)SOAP Header (example)

This example related to our previous example dedicated to bank accounts:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

<soap:Header>



<s:credentials xmlns:s="urn:examples-org:security“ mustUnderstand=“1”>

<username>dave</username>

<password>evad</password>

</s:credentials>

</soap:Header>

<soap:Body>

<x:TransferFunds xmlns:x="urn:examples-org:banking">

<from>22-342439</from>

<to>98-283843</to>

<amount>100.00</amount>

</x:TransferFunds>

</soap:Body>

</soap:Envelope>

SOAP -> What Is SOAP? -> Processing Model

Simple messaging scenarioSimple messaging scenario

• SOAP defines a processing model that outlines rules for processing a SOAP message as it travels from SOAP sender to a SOAP receiver

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example


Sophisticated SOAP messagingSophisticated SOAP messaging

• However, SOAP processing model allows for more interesting architectures, which contains multiple intermediary nodes


Intermediaries nodesIntermediaries nodes

• while processing a message, a SOAP node assumes one or more roles that influence how SOAP header is processed

• roles are given unique names (in the form of URIs), so they can be identified during processing

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Header>

<wsrp:path xmlns:wsrp="http://schemas.xmlsoap.org/rp" soap:actor="http://schemas.xmlsoap.org/soap/actor/next" soap:mustUnderstand="1"

>

...


SOAP 1.2 RolesSOAP 1.2 Roles

Remark: SOAP 1.1 defines only one role next. Every node must acts as next role

SOAP role name Description

http://www.w3.org/2002/06/soap-envelope/role/next

Each SOAP intermediary and the ultimate SOAP receiver MUST act in this role and MAY additionally assume zero or more other SOAP roles

http://www.w3.org/2002/06/soap-envelope/role/none

SOAP nodes MUST NOT act in this role

http://www.w3.org/2002/06/soap-envelope/role/ultimateReceiver

To establish itself as an ultimate SOAP receiver, a SOAP node MUST act in this role. SOAP intermediaries MUST NOT act in this role

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> What Is SOAP? -> Protocol Bindings

Protocol BindingsProtocol Bindings

• each intermediary could choose to use different communication protocol without affecting the SOAP message

• standard protocol binding is required to ensure high level of interoperability across SOAP applications and infrastructure

• a concrete protocol binding defines exactly how SOAP message should be transmitted with given protocol

• it defines the details of how SOAP fits within the scope of another protocol, which probably has its own messaging framework with a variety of headers

SOAP -> What Is SOAP? -> Protocol Bindings

SOAP HTTP BindingsSOAP HTTP Bindings

SOAP 1.1 specification only codifies a protocol binding for HTTP, due to its wide useRemark: the context type header for both HTTP request and response messages must be set

to txt/xml (application/soap+xml in SOAP 1.2)

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> Why SOAP?

Industry acceptance for SOAPIndustry acceptance for SOAP

• developers have been able to download and use the technology, rather than just read specifications and industry analysis

• SOAP changes both the way software will be developed and the way industry rivals and cooperating

• many of the key industry software leaders have announced their support for SOAP, including, HP, SAP, Software AG, Sun Microsystems, and Oracle

• Microsoft and IBM have lead to the release of Web Services platform, with SOAP services being the core technology in the initial releases

• emergence of Web Services Definition Language (WSDL) and Universal Description, Discovery and Integration (UDDI)

SOAP -> Why SOAP?

SOAP transportSOAP transport

Most of SOAP servers currently use HTTP as the transport protocol for the XML payload in SOAP message ‘cause HTTP satisfies a number of requirements:

• Ubiquity• Firewall friendliness• Simplicity• Scalability• Readily capable of being secure

There are a number of SOAP implementations that support other transport layers, such as

• HTTPS – using SSL provides security• SMTP – enables asynchronous SOAP requests / SOAP report

It can be expected that other transport protocols, such as MSMQ or FTP, will be supported eventually. IBM has an interesting for HTTPR to provide a reliable transport layer for SOAP messages

SOAP -> Why SOAP?

SOAP extensibilitySOAP extensibility

SOAP defines a communication framework that allows for such features to be added down the road as layered extensions. Microsoft, IBM and other software vendors working out a common suite of SOAP extensions that will add many of these features that most developers expect. SOAP extensibility is key.

SOAP -> Why SOAP?

Enterprise Application Integration Enterprise Application Integration (EAI)(EAI)

• There has been considerable speculation that current Enterprise Application Integration (EAI) products will be made redundant by SOAP.

• But, there is still a role for heavy-duty, enterprise-grade EAI products that integrate with more obscure legacy systems or provide unusually high qualities of service.

• Significant: SOAP will encourage and enable a whole new generation of EAI projects that were not previously possible due to technical and cost constraints.

SOAP -> Why SOAP?

SOAP: advantages and disadvantagesSOAP: advantages and disadvantages

Advantages

• Human readable XML• Easy to debug• SOAP runs over HTTP• Firewalls not affected• Services can be written in any language,

platform or operating systemDisadvantages

• S-L-O………………..-W• XML produces a lot of overhead for small messages • Web Services speed relies on Internet traffic conditions• Not strictly-typed XML

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> Web Services Solution -> What Is the Web Service?

What about definition?What about definition?

Each software vendor defines Web Service in a slightly different way:

Gartner: “WS is loosely coupled software components that interact with one another dynamically via standard Internet technology.”

Forrest Research: “WS is a formatted connection between people, systems and applications, that expose elements of business functionality as a software service and create new business value.”

Common feature: WS is components that you can use, re-use, mix, and match to enhance Internet and Intranet applications.

SOAP -> Web Services Solution -> What Is the Web Service?

At the basic levelAt the basic level

Web Service is:

• universal client/server architecture that allows disparate systems to communicate with each other without using proprietary client libraries

• architecture that simplifies the development process typically associated with client/server applications by effectively eliminating code dependencies between client and server

• architecture where server interface information is disclosed to the client via a configuration file encoded in a standard format (WSDL). Doing so allows the server to publish a single file for all target client platforms

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> Web Services Solution -> Stack of Layers

What’s from WebServices.org?What’s from WebServices.org?

Layer Example

Service Negotiation Treading partner agreement

Workflow, discovery and Register

UDDI (Universal Description, Discovery & Integration)

Service description language WSDL (Web Services Definition Language)

Messaging SOAP

Transport protocol HTTP, HTTPS, SMTP

Business Issues Management, Quality of service, Security, Open standards


Interaction with Web ServiceInteraction with Web Service


Accessing & publicationAccessing & publication

AgendaAgenda

► Introduction



► What is SOAP?

• SOAP how it is


• Extensibility



► Why SOAP?



• Stack of layers

• Demo example

SOAP -> Web Services Solution -> Example

Demo service main pageDemo service main page


Demo service method call pageDemo service method call page


SOAP request SOAP request


SOAP responseSOAP response


HTTP POST request and responseHTTP POST request and response


2 + 3 = what’s the answer?2 + 3 = what’s the answer?


Simple VB script clientSimple VB script client

Everything alrightWith your message

Something gowrong


Everything alright? But, where’s my Everything alright? But, where’s my answer?answer?

Don’t worry! Here is!!!


What’s go wrong?What’s go wrong?

Here’s the answer:

Thank you for your attention!!!

Case studiesCase studies

Grandma

Mother’s cakesLittle Red

Riding Hood

How we can help Little Red Riding Hoodreach the grandma with mother’s cakes?

by szigyarto tamas, spbu applied mathematics, department of computer modelling and multiple...

Documents

soap philosophy soap

soap introduction

ultimate soap receiver

service software

initial soap sender

service private

technology slide

agenda introduction