SOAP

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SOAP

• Kanda Runapongsa
• (krunapon_at_kku.ac.th)
• Dept. of Computer Engineering
• Khon Kaen University

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Web Services Interaction Diagram
UDDI Registry
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Request WSDL location
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Download WSDL
WSDL
Send SOAP messages With XML documents
Web Services
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Why Do We Need SOAP?

• An acceptable standard for routing and packaging
  XML data exchanged between two applications on a
  network
• No need to define our own networking, addressing,
  and routing protocols

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What is SOAP?

• Simple Object Access Protocol
• It defines a standard packaging format for
  transmitting XML data between applications on a
  network
• It is not specific to any programming language,
  product, or hardware platform

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What is SOAP?

• SOAP is not a programming language or a business
  application component for building business
  applications
• SOAP is intended for use as a portable
  communication protocol to deliver SOAP messages,
  which have to be created and processed by an
  application

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A SOAP Message

• A SOAP message is just an XML document
• The message might be sent from one application to
  another to synchronize contact information on two
  different systems
• SOAP takes advantages of XML namespaces and XML
  schemas

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Anatomy of a SOAP Message

• The structural format of a SOAP message contains
  the following elements
• Envelope
• Header (optional)
• Body
• Attachments (optional)

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SOAP Envelope

• The SOAP envelope is the primary container of a
  SOAP messages structure
• It is the mandatory element of a SOAP message
• It is represented as the root element of the
  message as Envelope

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SOAP Envelope Example

• ltSOAP-ENVEnvelope
• xmlnsSOAP-ENVhttp//schemas.xmlsoap.org/soap/e
  nvelope/
• xmlnsxsihttp//www.w3c.org/2001/XMLSchema-inst
  ance
• xmlnsxsdhttp//www.w3.org/2001/XMLSchema
• SOAP-ENVencodinghttp//schemas.xmlsoap.org/
  soap/encoding/gt
• lt! SOAP Header element --gt
• lt! SOAP Body element ---/gt
• lt/SOAP-ENVEnvelopegt

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SOAP Header

• The SOAP header is represented as the first
  immediate child element of a SOAP envelope
• The Header element can also contain other
  attributes, such as
• mustUnderstand
• actor

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SOAP Header Example

• ltSOAP-ENVHeadergt
• ltwileyTransaction
• xmlnswileyhttp//jws.wiley.com/2002/booktx
• SOAP-ENVmustUnderstand1gt
• ltkeyValuegt5lt/keyValuegt
• lt/wileyTransactiongt
• lt/SOAP-ENVHeadergt

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SOAP Fault Example1

• ltSOAP-ENVFaultgt
• ltfaultcodegtSOAP-EnvMustUnderstandlt/faultcodegt
• ltfaultstringgtHeader element missinglt/faultstringgt
  
• ltfaultactorgthttp//jws.wiley.com/GetBookPricelt/fa
  ultactorgt
• ltdetailgtlt/detailgt
• lt/SOAP-ENVFaultgt

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SOAP Body

• A SOAP envelope contains a SOAP body as its child
  element
• A Body block of a SOAP message can contain any of
  the following
• RPC method and its parameters
• Target application (receiver) specific data
• SOAP fault for reporting errors and status
  information

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SOAP Body Example

• ltSOAP-ENVBodygt
• ltmGetBookPrice
• xmlnsmhttp//www.wiley.com/jws.book.priceList
  /gt
• ltbookname xsitypexsdstringgt
• Developing Java Web Serviceslt/booknamegt
• lt/mgetBookPricegt
• lt/SOAP

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SOAP Fault

• In a SOAP message, the SOAP Fault element is used
  to handle errors and to find out status
  information.
• This element provides the error and /or status
  information
• It can be used within a Body element or as a Body
  entry

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SOAP Fault

• It provides the following elements to define the
  error and status of the SOAP message
• Faultcode The faultcode element defines the
  algorithmic mechanism for the SOAP application to
  identify the fault
• Faultstring The faultstring element provides a
  readable description of the SOAP fault
• Faultactor The faultactor element provides the
  information about the ultimate SOAP actor
• Detail The detail element

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SOAP Fault Example1

• ltSOAP-ENVFaultgt
• ltfaultcodegtSOAP-ENVServerlt/faultcodegt
• ltfaultstringgtServer OS Internal Failure Reboot
  serverlt/faultstringgt
• ltfaultactorgthttp//abzdnet.net/keysoap.asplt/fault
  actorgt
• lt/SOAP-ENVFaultgt

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SOAP Fault Example2

• ltSOAP-ENVFaultgt
• ltfaultcodegtClientlt/faultcodegt
• ltfaultstringgtInvalide Requestlt/faultstringgt
• ltfaultactorgthttp//jws.wiley.com/GetCataloglt/faul
  tactorgt
• lt/SOAP-ENVFaultgt

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SOAP mustUnderstand

• The SOAP understand attribute indicates that the
  processing of a SOAP header block is mandatory
  (the attribute value is 1) or optional (the
  attribute value is 0) at the target SOAP node
• ltSOAP-ENVHeadergt
• ltwileyCatalog SOAP-ENVmustUnderstand1/gt
• lt/SOAP-ENVHeadergt

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SOAP Fault Example3

• ltSOAP-ENVBodygt
• ltSOAP-ENVFaultgt
• ltfaultcodegtSOAP- EnvMustUnderstandlt/faultcodegt
  
• ltfaultstringgtCould not understand Header
  elementlt/faultstringgt
• lt/SOAP-ENVFaultgt
• lt/SOAP-ENVFaultgt

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SOAP Attachments

• A SOAP message contains the primary SOAP envelope
  in an XML format and SOAP attachments in any data
  format that can be ASCII or binary
• SOAP attachments are not part of the SOAP
  envelope but are related to the message

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SOAP Attachments

• The SOAP attachment part of the message is
  contained to a MIME boundary (defined in the
  Context-Type header)
• Each MIME part in the structure of the SOAP
  message is referenced using either Content-ID or
  Content-Location as labels for the part

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SOAP Attachments

• Both the SOAP header and body of the SOAP message
  also can refer to these labels in the message
• Each attachment of the message is identified with
  a Content-ID (typically an href attribute using a
  URL scheme) or Content-Location (a URI reference
  associated to the attachment)

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SOAP Attachment in a MIME Structure

• MIME-Version 1.0
• Content-Type Multipart/Related
• boundaryMIME_boundary typetext/xml
• Content-Description SOAP message description

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SOAP Attachment in a MIME Structure

• --MIME_boundary --
• Content-Type text/xml charsetUTF-8
• Content-Transfer-Encoding 8bit
• Content-ID lthttp//jws.wiley.com/coverpagedetails
  .xmlgt
• Content-Location http//jws.wiley.com/coverpagede
  tails.xml

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SOAP Attachment in a MIME Structure

• lt?xml version1.0?gt
• ltSOAP-ENVEnvelope
• xmlnsSOAP-ENVhttp//schemas.xmlsoap.org/soap/e
  nvelope/gt
• ltSOAP-ENVBodygt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

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SOAP Attachment in a MIME Structure

• -- MIME_boundary --
• Content-Type image/gif
• Content-Transfer-Encoding binary
• Content-ID lthttp//jws.wiley.com/DevelopingWebSer
  vices.gifgt
• Content-Location http//jws.wiley.com/Developing
  WebServices.gif
• lt!-- binary GIF image --gt
• --MIME_boundary --

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What is MIME?

• MIME Multipurpose Internet Mail Extension
• A standard system for identifying the type of
  data contained in a file based on its extension.
• MIME is an Internet protocol that allows you to
  send binary files across the Internet as
  attachments to e-mail messages. This includes
  graphics, photos, sound and video files, and
  formatted text documents.

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SOAP Encoding

• The SOAP Encoding defines a set of rules for
  exposing its data types
• SOAP encoding also defines serialization rules
  for its data model using an encodingStyle
  attribute
• SOAP encoding supports both simple- and
  compound-type values

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SOAP Encoding Example

• Simple Type Values
• The definition of simple type values is based on
  the W3C XML Schema specification
• Examples
• ltintgt98765lt/intgt
• ltdecimalgt98675.43lt/decimalgt
• ltstringgtJava Ruleslt/stringgt

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SOAP Encoding Example

• Array Types example
• ltMyPortfolio xmlnshttp//www.w3.org/2001/XMLSchem
  a xmlsenchttp//schemas.xmlsoap.org/soap/encodi
  ng encarrayTypexsstring2gt
• ltsymbolgtSUNWlt/symbolgt
• ltsymbolgtIBMlt/symbolgt
• lt/MyPortfoliogt

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SOAP Message Exchange Model

• SOAP is a stateless protocol used to exchange
  messages between SOAP applications on a network,
  usually an intranet or the Internet
• A SOAP application is simply any piece of
  software that generates or processes SOAP
  messages

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SOAP Message Exchange Model

• For example, any Java application or J2EE
  component that uses JAX-RPC would be considered a
  SOAP application
• Because JAX-RPC is used to generate and process
  SOAP message
• The application sending a SOAP message is called
  the sender and the application receiving it is
  called the receiver

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SOAP Message Exchange Model

• As a SOAP message travels along the message path,
  its header blocks may be intercepted and
  processed by any number of SOAP intermediaries
  along the way
• A SOAP intermediary is both a receiver and a
  sender

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SOAP Message Exchange Model

• The applications along the message path (the
  initial sender, intermediaries, and ultimate
  receiver) are called SOAP nodes

Initial Sender
Sender
Intermediaries
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SOAP Message Exchange Model
Intermediaries
Ultimate receiver
Initial Sender
SOAP
SOAP
SOAP
Customer Node
Sales Node
Inventory Node
Shipping Node
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SOAP Actor

• The SOAP actor global attribute with a URI value
  can be used in the Header element
• SOAP defines an actor with a URI value, which
  identifies the name of the SOAP receiver node as
  an ultimate destination

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SOAP Actor Example

• ltSOAP-ENVHeadergt
• ltbName xmlnsbhttp//www.wiley.com/BookService
  / SOAP-ENVactorhttp//www.wiley.com/jws/
  SOAP-ENVmustUnderstand1gtWebServiceslt/bNamegt
• lt/SOAP-ENVHeadergt

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SOAP Communication

• To enable communication between SOAP nodes, SOAP
  supports the following two types of communication
  models
• SOAP RPC It defines a remote procedural
  call-based synchronous communication
• SOAP Messaging It defines a document-driven
  communication where SOAP nodes send and receive
  XML-based documents using synchronous and
  asynchronous messaging

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SOAP RPC

• The SOAP RPC representation defines a tightly
  coupled communication model based on requests and
  responses
• Using RPC conventions, the SOAP message is
  represented by method names with zero or more
  parameters and return values

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SOAP Request RPC-Based

• ltSOAP-ENVBodygt
• ltmGetBookPrice
• xmlnsmhttp//www.wiley.com/jws.book.priceList
  gt
• ltbookname xsitypexsdstringgtDeveloping Java
  Web Serviceslt/booknamegt
• lt/mgetBookPricegt
• lt/SOAP-ENVBodygt

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SOAP Response RPC-Based

• ltSOAP-ENVBodygt
• ltmGetBookPriceResponse xmlnsmhttp//www.wiley
  .com/jws.book.priceListgt
• ltpricegt50.00lt/pricegt
• lt/mGetBookPriceResponsegt
• lt/SOAP-ENVBodygt

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SOAP Messaging

• SOAP Messaging represents a loosely coupled
  communication model based on message notification
  and the exchange of XML documents
• The SOAP sender node sends a message with an XML
  document as its body message and the SOAP
  receiver node processes it

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SOAP Message-Based

• ltenvEnvelope xmlnsenvhttp//www.w3.org/2001/12
  /soap-envelopegt
• ltenvHeadergt
• ltnInventoryNotice xmlnsnhttp//jws.wiley.com/
  Inventorygt
• ltnproductCodegtJ687lt/nproductCodegt
• lt/nInventoryNoticegt
• lt/enveHeadergt

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SOAP Message-Based

• ltenvBodygt
• ltmproduct xmlnsmhttp//jws.wiley.com/product
  gt
• ltmnamegtDeveloping Java Web Serviceslt/mnamegt
• ltmquantitygt25000lt/mquantitygt
• ltmdategt2002-07-01lt/mdategt
• lt/envBodygt
• lt/envEnvelopegt

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SOAP Bindings for Transport Protocols

• The SOAP specifications do not specify and
  mandate any underlying protocols between the SOAP
  nodes
• SOAP can be used over a variety of transport
  protocols, such as HTTP, SMTP, POP3 and FTP

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SOAP Request Message Using HTTP

• POST /GetBookPrice HTTP/1.1
• User Agent Mozilla/4.0 (Linux)
• Host krunapon8080
• Content-Type text/xml charsetutf-8
• Content-length 546
• SOAPAction /GetBookPrice
• lt?xml version1.0?gtltSOAP-ENVEnvelopegt....
• lt/SOAP-ENVEnvelopegt

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SOAP Response Message Using HTTP

• HTTP/1.1 200 OK
• Connection close
• Content-Length 524
• Content-Type text/xml charsetutf-8
• Date Fri, 3 May 2002 050504 GMT
• Server Apache/1.3.0
• lt?xml version1.0?gt
• ltSOAP-ENVEnvelopegt
• lt/SOAP-ENVEnvelopegt

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SOAP Message Exchange Patterns

• The most common SOAP messaging patterns are as
  follows
• One-way message. The SOAP client application
  sends SOAP messages to its SOAP server without
  any response being returned
• Request/response exchange. In this pattern, the
  SOAP client sends a request message that results
  in a response message from the SOAP server to the
  client

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SOAP Message Exchange Patterns

• Common SOAP messaging patterns
• Request/NResponse pattern. It is similar to a
  request/response pattern, except the SOAP client
  sends a request that results in zero to many
  response messages from the SOAP server to the
  client
• Notification pattern. The SOAP server sends
  messages to the SOAP client like an event
  notification, without regard to a response

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SOAP Message Exchange Patterns

• Common SOAP messaging patterns
• Solicit-response pattern. The SOAP server sends
  a request message to the SOAP client like a
  status checking or an audit and the client sends
  out a response message

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SOAP Message Exchange Patterns
SOAP Client
SOAP Client
SOAP Client
Request/Response pattern
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SOAP Message Exchange Patterns
SOAP Request Message
SOAP Response Message
SOAP Client
SOAP Server
SOAP Response Message
Request/NResponse pattern
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SOAP Message Exchange Patterns
SOAP Message(s)
SOAP Server
SOAP Client
Notification pattern
SOAP Message
SOAP Server
SOAP Response Message
Solicit-response pattern