CIS5930 Internet Computing

1
CIS5930Internet Computing

• XML Web Services Basics
• Prof. Robert van Engelen

2
Web Services Basics

• Interoperability has highest priority
• XML over HTTP
• Web services can be created regardless of the
  programming language
• Reusable application components
• Software can be reused as service components in a
  service-oriented architecture, i.e. to support
  the requirements of software users
• Compositionality is realized with open standards
• Connect existing software
• Publish the application as a service
• Applications connect and interact by encoding and
  decoding data in XML

3
XML Web Services Protocols

• SOAP
• Simple Object Access Protocol is an XML
  messaging protocol
• Typically remote procedure call (RPC)
  request-response messages
• Or XML-based messages (document/literal style)
• WSDL
• Web Service Description Language is an XML
  document that defines the service interface,
  protocol bindings, and service endpoint addresses
• Uses XML schema to define XML types
• Typically uses SOAP to bind the messaging
  protocol
• UDDI
• Universal Description, Discovery and
  Integration is a repository/database of services
  (e.g. defined by WSDLs)
• Not very popular, wont discuss

4
WSDL

• WSDL represents a contract between the service
  requestor and the service provider
• WSDL is an XML specification that defines four
  critical pieces of information of an XML Web
  service
• Interface information describing all publicly
  available functions
• Data type information for all message requests
  and message responses
• Binding information about the transport protocol
  to be used
• Address information for locating the specified
  service

5
WSDL Specification

• The definitions root element defines the name and
  namespace of the web service
• The types element contains a set of XML schemas
  with all the data types (XML elements and types)
  used between the client and server
• One or more message elements define the names of
  the messages, each contains zero or more message
  part elements, which can refer to message
  parameters or message return values
• The portType element combines multiple message
  elements to form a complete one-way or round-trip
  operation
• The binding element describes how the service
  will be implemented on the wire
• The service element defines the endpoint address
  for invoking the service

6
Example WSDL

• The HelloService service provides a single
  publicly available function sayHello
• The function expects a single string parameter,
  and returns a single string greeting
• Request-response message pattern over HTTP using
  HTTP POST

7
WSDL definition Root Element

• Defines the name and targetNamespaceltdefinition
  s name"HelloService targetNamespace"http//www
  .ecerami.com/wsdl/HelloService.wsdl
  xmlns"http//schemas.xmlsoap.org/wsdl/
  xmlnssoap"http//schemas.xmlsoap.org/wsdl/soap/
  xmlnstns"http//www.ecerami.com/wsdl/HelloServ
  ice.wsdl xmlnsxsd"http//www.w3.org/2001/XMLSc
  hemagt
• Typically the xmlns namespace bindings are
  included in the root element and are used in the
  remainder of the WSDL
• Note that the WSDL namespace is declared as the
  default namespace for all of the other WSDL
  elements (http//schemas.xmlsoap.org/wsdl/) so
  these elements are not explicitly namespace
  qualified

8
The WSDL message Elements

• Two message elements are defined
• The first represents a request message,
  SayHelloRequest, and the second represents a
  response message, SayHelloResponseltmessage
  name"SayHelloRequest"gt ltpart name"firstName"
  type"xsdstring"/gtlt/messagegtltmessage
  name"SayHelloResponse"gt ltpart name"greeting"
  type"xsdstring"/gtlt/messagegt
• For the request, the part specifies the function
  parameters
• For the response, the part specifies the function
  return values
• The type is a QName value, indicating the schema
  type of the part

9
Built-in XSD SimpleTypes
Simple type Example Value(s) string Web
Services boolean true, false, 1, 0 float -INF,
-1E4, -0, 0, 12.78E-2, 12, INF, NaN double -INF,
-1E4, -0, 0, 12.78E-2, 12, INF,
NaN decimal -1.23, 0, 123.4, 1000.00 integer -12
6789, -1, 0, 1, 126789 nonPositiveInteger -126789,
-1, 0 negativeInteger -126789, -1 long -1,
12678967543233 int -1, 126789675 short -1,
12678 byte -1, 126 nonNegativeInteger 0, 1,
126789 unsignedLong 0, 12678967543233 unsignedInt
0, 1267896754 unsignedShort 0, 12678 unsignedByte
0, 126 positiveInteger 1, 126789 date 1999-05-31
time 132000.000, 132000.000-0500
10
The WSDL portType Element

• The portType element defines a single operation,
  sayHello
• The operation consists of a single input message
  (SayHelloRequest) and a single output message
  (SayHelloResponse)ltportType name"Hello_PortTyp
  e"gt ltoperation name"sayHello"gt ltinput
  message"tnsSayHelloRequest"/gt ltoutput
  message"tnsSayHelloResponse"/gt
  lt/operationgtlt/portTypegt
• The input/output elements specify a message
  attribute of tnsSayHelloRequest or
  tnsSayHelloResponse
• The tns prefix references the targetNamespace
  defined within the definitions element

11
Message Exchange Patterns

• The operation in portType uses input and/or
  output to define the message exchange pattern
• WSDL supports four basic patterns of operation
• One-way
• Request-response
• Solicit-response
• Notification
• The one-way and request-response are most often
  used

12
The WSDL binding Element

• The binding element provides specific details on
  how a portType operation will actually be
  transmitted over the wire
• Bindings can be made available via multiple
  transports
• Multiple bindings for a single portType can be
  specified
• The binding element itself specifies name and
  type attributesltbinding name"Hello_Binding"
  type"tnsHello_PortType"gt
• The type attribute references the portType

13
WSDL SOAP Bindings

• WSDL 1.1 includes built-in extensions for SOAP
  1.1ltbinding name"Hello_Binding"
  type"tnsHello_PortType"gt
• ltsoapbinding style"rpc"
  transport"http//schemas.xmlsoap.org/soap/http"/gt
  ltoperation name"sayHello"gt
  ltsoapoperation soapAction"sayHello"/gt
  ltinputgt ltsoapbody
  encodingStylehttp//schemas.xmlsoap.org/soap/enc
  oding/ namespace"urnexampleshel
  loservice use"encoded"/gt
  lt/inputgt ltoutputgt
  ltsoapbody encodingStylehttp//sc
  hemas.xmlsoap.org/soap/encoding/
  namespace"urnexampleshelloservice
  use"encoded"/gt lt/outputgt
  lt/operationgt lt/bindinggt

14
WSDL SOAP Bindings (contd)

• The soapbinding element indicates a SOAP binding
  over HTTP transport
• The style attribute indicates rpc for an RPC
  format or document for a document-oriented
  message format
• The transport attribute defines the transport
  mechanism
• The soapoperation element indicates the binding
  of a specific operation to a SOAP implementation
• The soapAction attribute specifies that the
  SOAPAction HTTP header should be used for
  identifying the service (SOAP 1.1 only)
• The soapbody element specifies the details of
  the input and output messages
• The encodingStyle attribute defines the encoding
  format when the use attribute is encoded (RPC
  encoded) and the namespace attribute defines the
  RPC message namespace
• For document/literal messaging, the use attribute
  is literal

15
SOAP Request Message

• An RPC request message uses the encodingStyle and
  namespacelt?xml version'1.0'
  encoding'UTF-8'?gtltsoapEnvelope
  xmlnsxsi'http//www.w3.org/2001/XMLSchema-instan
  ce xmlnsxsd'http//www.w3.org/2001/XMLSchema
  xmlnssoap'http//schemas.xmlsoap.org/soap/e
  nvelope/ xmlnssoapenc'http//schemas.xmlsoap
  .org/soap/encoding/ soapencodingStyle'http/
  /schemas.xmlsoap.org/soap/encoding/'gt
  ltsoapBodygt ltnsayHello xmlnsn'urnexample
  shelloservice'gt ltfirstName
  xsitype'xsdstring'gtWorldlt/firstNamegt
  lt/nsayHellogt lt/soapBodygtlt/soapEnvelopegt

16
SOAP Response Message

• An RPC request messagelt?xml version'1.0'
  encoding'UTF-8'?gtltSOAP-ENVEnvelope
  xmlnsSOAP-ENV'http//schemas.xmlsoap.org/soap/en
  velope/ xmlnsxsi'http//www.w3.org/1999/XMLS
  chema-instance xmlnsxsd'http//www.w3.org/19
  99/XMLSchema'gt ltSOAP-ENVBodygt
  ltns1sayHelloResponse xmlnsns1'urnexampleshell
  oservice' SOAP-ENVencodingStyle
  'http//schemas.xmlsoap.org/soap/encoding/'gt
  ltgreeting xsitype'xsdstring'gtHello,
  World!lt/greetinggt lt/ns1sayHelloResponsegt
  lt/SOAP-ENVBodygtlt/SOAP-ENVEnvelopegt

17
Using WSDL

• Most Web service development toolkits support
  WSDL
• Generate WSDL from server (interface) code
• Translate WSDL to server objects and client
  proxies
• Dynamic invocation obtains the WSDL, select an
  operation, populate the parameters and send the
  request message
• Generic SOAP client http//www.soapclient.com/soa
  ptest.html
• http//services.xmethods.net/soap/urnxmethods-del
  ayed-quotes.wsdl
• Find more WSDLs and code at http//www.xmethods.co
  m

18
Generating WSDL and Server Code with gSOAP

• Suppose we implement a HelloService with one
  operation sayHello that takes a string parameter
  s and returns the string Hello s
• To bind XML namespaces to C (and C) code, gSOAP
  uses a prefix convention for function names and
  type names prefix_ _name
• The service interface is defined in a header file
  containing the lineint ns__sayHello(char
  firstName, char greeting)
• To generate WSDL and server code (-S) or client
  code (-C) in C (-c) for SOAP RPC encoding
  (-e) soapcpp2 -S -c -e hello.h

input
output
19
Implementing a Web Service with gSOAP

• Add directives to the header file specification
  to define the service name, namespace, and
  endpoint//gsoap ns service name hello//gsoap
  ns service namespace urnhello//gsoap ns
  service location
  http//www.cs.fsu.edu/engelen/hello.cgiint
  ns__sayHello(char firstName, char greeting)

20
Implementing a Web Service with gSOAP (contd)

• The following files are generatedsoapStub.h a
  nnotated copy of the header filesoapH.h XML
  serializer declarationssoapC.c XML serializers
  for C/C typessoapServer.c SOAP server
  skeleton and dispatcherhello.nsmap XML
  namespace mapping tablehello.wsdl the service
  WSDLhello.sayHello.req.xml sample request
  messagehello.sayHello.res.xml sample response
  message
• To complete the service, we create a C
  implementation of the sayHello function with the
  following parametersint ns__sayHello(struct
  soap soap, char firstName, char greeting)
• The first arg is the gSOAP engine context
  (runtime environment)

21
Implementing a Web Service with gSOAP (contd)

• Implementation of the sayHello function in
  hello.cint ns__sayHello(struct soap soap,
  char firstName, char greeting) if
  (!firstName) return soap_sender_fault(soap,
  No name!, NULL) greeting
  (char)soap_malloc(soap, strlen(firstName)8)
  strcpy(greeting, Hello ) strcat(greeting,
  firstName) strcat(greeting, !) return
  SOAP_OK
• For a simple CGI-based service, add the service
  dispatcherinclude hello.nsmapint main()
  return soap_serve(soap_new())
• Compile with gcc -o hello.cgi hello.c stdsoap2.c
  soapC.c soapServer.c

22
Implementing a Web Service with gSOAP (contd)

• Deploy hello.cgi as a service in Apache (e.g.
  cgi-bin dir) and publish hello.wsdl on the Web
  site
• To test the service over stdin/stdout, modify
  hello.sayHello.req.xml to include a name string
  and run hello.cgi from the command line
  ./hello.cgi lt hello.sayHello.req.xml
• To deploy as an iterative stand-alone service,
  use the followinginclude hello.nsmapint
  main() struct soap soap soap_new()
  soap_bind(soap, NULL, 8080, 100) for ()
  if (soap_accept(soap) lt 0) break
  soap_serve(soap) soap_destroy(soap)
  soap_end(soap) soap_print_fault(soap,
  stderr) soap_done(soap) free(soap)
  return 0

23
Implementing a Concurrent Web Service with gSOAP

• include hello.nsmapint main() pthread_t
  tid struct soap soap soap_new()
  soap_bind(soap, NULL, 8080, 100) for ()
  if (soap_accept(soap) lt 0) break
  pthread_create(tid,NULL,(void()(void))serve,(v
  oid)soap_copy(soap)) soap_print_fault(soap
  , stderr) soap_done(soap) free(soap)
  return 0void serve(void soap)
  pthread_detach(pthread_self())
  soap_serve((struct soap)soap)
  soap_destroy((struct soap)soap)
  soap_end((struct soap)soap) soap_done((struct
  soap)soap) free(soap) return NULLint
  ns__sayHello(struct soap soap, char firstName,
  char greeting)

24
Implementing a Client with gSOAP

• Since we already have a gSOAP header file with
  the service definitions, we can also create a
  client from it soapcpp2 -C -c -e hello.h
• The client uses the stub call defined in
  soapClient.cinclude hello.nsmapint main()
  struct soap soap soap_new() char s if
  (soap_call_ns__sayHello(soap, NULL, NULL,
  Robert, s)) soap_print_fault(soap,
  stderr) else printf(The response is
  s\n, s) soap_destroy(soap)
  soap_end(soap) soap_done(soap) free(soap)
  return 0
• Compile with gcc -o client client.c stdsoap2.c
  soapC.c soapClient.c

25
Implementing a Service with ASP.NET in VB

• lt_at_ WebService Language"VB" Class"TempConvert"
  gtImports SystemImports System.Web.ServicesPu
  blic Class TempConvert Inherits
  WebServiceltWebMethod()gt Public Function
  FahrenheitToCelsius(ByVal Fahrenheit As Int16)
  As Int16 Dim celsius As Int16
  celsius ((((Fahrenheit) - 32) / 9) 5)
  Return celsiusEnd FunctionltWebMethod()gt
  Public Function CelsiusToFahrenheit(ByVal
  Celsius As Int16) As Int16 Dim fahrenheit
  As Int16 fahrenheit ((((Celsius) 9) /
  5) 32) Return fahrenheitEnd
  FunctionEnd Class

26
Implementing a Client with SOAPLite for Perl

• Example in Perl using the SOAPLite
  packageuse SOAPLite print "Connecting to
  Hello Service...\n"print SOAPLite -gt
  service('http//www.cs.fsu.edu/engelen/hello.wsdl
  ') -gt sayHello ('World')
• The program generates the following
  outputConnecting to Hello Service...Hello
  World!

27
SOAP Fault messages

• The gSOAP service may return a SOAP Fault
  return soap_sender_fault(soap, description,
  detail)
• If the problem is at the receiving side
  (SOAP-ENVServer) use return
  soap_receiver_fault(soap, description, detail)
• Example SOAP Fault messageHTTP/1.1 500 Internal
  Server ErrorServer gSOAP/2.7Content-Type
  text/xml charsetutf-8Content-Length
  520Connection closelt?xml version"1.0"
  encoding"UTF-8"?gtltSOAP-ENVEnvelope
  xmlnsSOAP-ENV"http//schemas.xmlsoap.org/soap/en
  velope/ xmlnsSOAP-ENC"http//schemas.xmlsoap.
  org/soap/encoding/ xmlnsxsi"http//www.w3.org
  /2001/XMLSchema-instance xmlnsxsd"http//www.
  w3.org/2001/XMLSchema xmlnsns"urnhello"gt
  ltSOAP-ENVBody SOAP-ENVencodingStyle"http//sche
  mas.xmlsoap.org/soap/encoding/"gt
  ltSOAP-ENVFaultgt ltfaultcodegtSOAP-ENVClientlt/
  faultcodegt ltfaultstringgtNo
  name!lt/faultstringgt lt/SOAP-ENVFaultgt
  lt/SOAP-ENVBodygtlt/SOAP-ENVEnvelopegt

28
SOAP 1.1 Faults

• The SOAP Fault element has the following sub
  elements
• ltfaultcodegt A code for identifying the fault
• ltfaultstringgt A human readable explanation of the
  fault
• ltfaultactorgt Information about who caused the
  fault to happen (opt)
• ltdetailgt Holds application specific error
  information
• The faultcode values defined below must be used
  in the faultcode element when describing faults
• VersionMismatch Invalid namespace for the SOAP
  Envelope element
• MustUnderstand An immediate child element of the
  Header element, with the mustUnderstand attribute
  set to "1", was not understood
• Client Message was incorrectly formed or
  contained incorrect info
• Server There was a problem with the server and
  processing could not proceed
• Note SOAP 1.2 differs slightly (mostly element
  naming)

29
WSDL and SOAP Faults

• Faults in portType operations specify which
  faults may be returnedltmessage
  name"AuthenticationFault"gt ltpart
  name"AuthenticationFault elementfAuthenticati
  onFault"/gtlt/messagegtltportType namemyPortgt
  ltoperation namegetStatusgt ltinput
  messagetnsgetStatusRequest/gt ltoutput
  messagetnsgetStatusResponse/gt ltfault
  namefault messagetnsAthenticiationFault/gt
  lt/operationgtlt/portTypegtltbinding
  namemyBinding typemyPortgt ltoperation
  name"getStatus"gt ltwsdlinputgt
  ltsoapbody use"literal"/gt lt/wsdlinputgt
  ltwsdloutputgt ltsoapbody use"literal"/gt
  lt/wsdloutputgt ltwsdlfault
  name"AuthenticationFault"gt ltsoapfault
  name"AuthenticationFault" use"literal"/gt
  lt/wsdlfaultgt lt/operationgtlt/bindinggt

30
SOAP Headers

• The optional SOAP Header element contains SOAP
  processing information in one or more
  subelements, such as addressing and
  authentication, for exampleltSOAP-ENVEnvelope
  gt ltSOAP-ENVHeadergt ltwsseSecurity
  SOAP-ENVmustUnderstand"1"gt
  ltwsseUsernameToken wsuId"User"gt
  ltwsseUsernamegtengelenlt/wsseUsernamegt
  ltwssePassword Type"http//docs.oasis-open.org/ws
  s/2004/01/oasis-200401-wss-username-token-profile-
  1.0PasswordDigest"gt/u5faawcfIeve1yHCsdXAWyIlbUlt/
  wssePasswordgt ltwsseNoncegtNDU0MGE5YjljYT
  UzYzAzZjA2MTclt/wsseNoncegt
  ltwsuCreatedgt2006-10-26T122737Zlt/wsuCreatedgt
  lt/wsseUsernameTokengt lt/wsseSecuritygt
  lt/SOAP-ENVHeadergt ltSOAP-ENVBodygt
  lt/SOAP-ENVBodygtlt/SOAP-ENVEnvelopegt

31
SOAP Headers (contd)

• The optional actor attribute may be used to
  address the Header element to a particular
  endpointltSOAP-ENVHeadergt ltmTransaction
  SOAP-ENVactorendpoint URL
  SOAP-ENVmustUnderstand1gt
  lt/mTransactiongt ltwsseSecuritygtlt/wsseSecurity
  gtlt/SOAP-ENVHeadergt
• This allows the header information to be targeted
  at any intermediate SOAP processors for which
  this information is intended
• The SOAP mustUnderstand attribute is used to
  indicate whether a header entry is mandatory or
  optional for the recipient to process

32
SOAP Headers (contd)

• The SOAP Header is a struct in gSOAP, defined in
  the header fileimport wsse.h // get WSSE
  Security elementsstruct SOAP_ENV__Header
  mustUnderstand _m__Transaction m__Transaction
  mustUnderstand _wsse__Security wsse__Security
  and accessible in the soap context, for
  examplesoap.header.m__Transaction new
  _m__Transaction()

33
SOAP RPC Encoding

• SOAP RPC encoding defines rules on representing
  primitive types, xssimpleTypes (e.g.
  enumerations), array, and records (structs) as
  xscomplexTypes in XML
• Closer to the notion of programming language
  types
• Full XML schema support is not possible
• XML attributes not supported
• No element repetitions with maxOccursunbounded
• Only xssequence and xsall, no xschoice

34
SOAP RPC Encoding (contd)

• Primitive types
• Built-in XSD types, such as xsstring (see Schema
  specification)
• Schema xssimpleTypes for elements, such as
  enumerationsltxssimpleType nameswitch"gt
  ltxsrestriction base"xsdtoken"gt
  ltxsenumeration valueon"/gt
  ltxsenumeration valueoff"/gt
  lt/xsrestrictiongtlt/xssimpleTypegt
• Base64 (xsbase64Binary) and hex (xshexBinary)
  types

35
SOAP RPC Encoding (contd)

• Arrays are SOAP encoded arrays
  ltxscomplexType name"ArrayOfstring"gt
  ltxscomplexContentgt ltxsrestriction
  base"SOAP-ENCArray"gt ltxssequencegt
  ltxselement name"item" type"xsdstring
  minOccurs"0"
  maxOccurs"unbounded/gt lt/xssequencegt
  ltxsattribute ref"SOAP-ENCarrayType
  wsdlarrayType"xsdstring"/gt
  lt/xsrestrictiongt lt/xscomplexContentgt
  lt/xscomplexTypegt
• Arrays are encoded in SOAP messages
  followsltinputStringArray SOAP-ENCarrayType"xs
  dstring2"gt ltitem xsitypexsdstringgthellolt
  /itemgt ltitem xsitypexsdstringgtworld!lt/itemgt
  lt/inputStringArraygt

36
SOAP RPC Encoding (contd)

• Struct are just xscomplexTypes with xssequence
  (or xsall) ltxscomplexType
  namelightSwitch"gt ltxssequencegt
  ltxselement namelight typetnsswitch/gt
  ltxselement namelevel typexsint/gt
  ltxselement nameimage typexsbase64Binary/gt
  lt/xssequencegt lt/xscomplexTypegt

37
RPC versus Doc/lit in WSDL

• Document/literal SOAP messages dont include
  encodingStyle and XML types for request/responses
  are not constraint by the SOAP RPC encoding rules
• Document style and literal use are declared in
  the bindingsltbinding type"glossaryTerms"
  name"b1"gtltsoapbinding style"document
  transport"http//schemas.xmlsoap.org/soap/http"/gt
  ltoperationgt ltsoapoperation
  soapAction"http//example.com/getTerm"/gt
  ltinputgt ltsoapbody use"literal"/gt
  lt/inputgt ltoutputgt ltsoapbody
  use"literal"/gt lt/outputgt
  lt/operationgtlt/bindinggt

38
RPC versus Doc/lit in WSDL (contd)

• The parts in messages now refer to elements,
  which will be the request/response elements in
  the SOAP Bodyltdefinitions xmlnsmurnexample
  stempservice gt ltmessage name"getTermRequest
  "gt ltpart name"term" elementmgetTemp"/gt
  lt/messagegt ltmessage name"getTermResponse"gt
  ltpart name"value" elementmgetTempResult"/gt
  lt/messagegt ltportType name"glossaryTerms"gt
  ltoperation name"getTerm"gt ltinput
  message"getTermRequest"/gt ltoutput
  message"getTermResponse"/gt lt/operationgt
  lt/portTypegt

39
RPC versus Doc/lit in WSDL (contd)

• The parts in messages refer to elements that
  define the request and response elements in the
  SOAP Body of a messagelttypesgt ltxsschema
  xmlnsxshttp//www.w3.org/2001/XMLSchema
  targetNamespaceurnexamplestempservice
  elementFormDefaultqualified
  attributeFormDefaultunqualifiedgt
  ltxselement namegetTempgt
  ltxscomplexTypegt ltxssequencegt
  ltxselement namezipCode typexsstring/gt
  lt/xssequencegt lt/xscomplexTypegt
  lt/xselementgt ltxselement namegetTempResult
  gt ltxscomplexTypegt ltxssequencegt
  ltxselement nametemp typexsfloat/gt
  lt/xssequencegt lt/xscomplexTypegt
  lt/xselementgt lt/xsschemagt lt/typesgt

40
SOAP Request Message in Doc/Lit Style

• Note the absence of SOAP-ENCencodingStyle and
  xsitype in the messagelt?xml version'1.0'
  encoding'UTF-8'?gtltsoapEnvelope
  xmlnsxsi'http//www.w3.org/2001/XMLSchema-instan
  ce xmlnsxsd'http//www.w3.org/2001/XMLSchema
  xmlnssoap'http//schemas.xmlsoap.org/soap/e
  nvelope/'gt ltsoapBodygt ltngetTemp
  xmlnsn'urnexamplestempservice'gt
  ltnzipCodegt32306lt/nzipCodegt lt/ngetTempgt
  lt/soapBodygtlt/soapEnvelopegt

41
SOAP Multi-ref Encoding

• SOAP operation (request/response)
• The XSD type system to represent values of
  primitive types in XML, such as bool, integer,
  float, string, base64
• A SOAP array type to encode sparse and partial
  arrays
• Id-href XML attributes to implement graph edges
  to encode multi-ref objects

ltenvEnvelopegt ltenvBody envencodingStylegt
ltnsmyRemoteOpgt ltarg1 xsitypexsdintgt123lt/
arg1gt ltarg2 encarrayTypexsdstring5gt
ltitemgtabclt/itemgt ltitem href_1/gt ltitem
href_1/gt ltitem href_2/gt ltitem
encposition5gtxyzlt/itemgt lt/arg2gt
lt/nsmyRemoteOpgt ltmref id_1gtabclt/mrefgt
ltmref id_2gtdeflt/mrefgt lt/envBodygtlt/envEnvelo
pegt
42
Static Structure Analysis forSOAP RPC Encoding
Structure
XML Schema ltcomplexType nameXgt ltsequencegt ltelement namey typetnsY/gt ltelement namez typetnsZ/gt lt/sequencegt lt/complexTypegt ltcomplexType nameXgt ltsequencegtlt/sequencegtlt/complexTypegtltcomplexType nameYgt ltsequencegtlt/sequencegtlt/complexType ltcomplexType nameXgt ltsequencegtlt/sequencegtlt/complexType
Example XML Instance ltxgt ltygtlt/ygt ltzgtlt/zgt lt/xgt ltxgt lty href123/gt lty href123/gt lt/xgtltmref id123gtlt/mrefgt ltxgt ltx href456/gt ltx href456/gt lt/xgtltmref id456gtlt/mrefgt
43
gSOAP Constructs a Plausible Object Model for
Serialization
typedef int SSNstruct Node int val int
ptr float num struct Node next
val
ptr
num
next
Node
SSN
Data model graph(arcs denote all
possiblepointer references)
Source code typedefinitions
44
Generating an XML Schema Definition for
Serialized XML
ltsimpleType nameSSNgt ltrestriction
baseint/gtlt/simpleTypegtltcomplexType
nameNodegt ltsequencegt ltelement
nameval typeint/gt ltelement
nameptr typeint
minOccurs0/gt ltelement namenum
typefloat/gt ltelement namenext
typetnsNode
minOccurs0/gt lt/sequencegtlt/complexTypegt
val
ptr
num
next
Node
SSN
Data model graph
45
Generating Code for Runtime Points-To Analysis
serialize_pointerToint(int p) if (p ! NULL)
// lookup and mark (p,TYPE_int) // as
target in ptr hash table serialize_Node(str
uct Node p) if (p ! NULL) // lookup and
mark (p,TYPE_Node) // as target in ptr hash
table mark_embedded(p-gtval,TYPE_int)
serialize_pointerToint(p-gtptr) // skip
p-gtnum serialize_pointerToNode(p-gtnext)
val
ptr
num
next
Node
SSN
Data model graph
46
Generating Serialization Code
put_pointerToint(int p) if (p ! NULL) //
lookup (p,TYPE_int) // if embedded, then
output ref // if single, then output value
// if multi, then output value // with
id and mark embedded put_Node(struct
Node p) if (p ! NULL) // lookup
(p,TYPE_Node) // if embedded, then output
ref // if single, then output value //
if multi, then output value // with id
and mark embedded put_int(p-gtval)
put_pointerToint(p-gtptr) put_float(p-gtnum)
put_pointerToNode(p-gtnext)
val
ptr
num
next
Node
SSN
47
Serialization Example
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
NodelocA
NodelocB
789
Ptr hash table after runtime points-to analysis
by thegenerated algorithm constructed from the
data model
SSNlocC
ID PtrLoc PtrType PtrSize PtrCount RefType
1 A Node 16 2 multi
2 B int 4 1 embedded
3 B Node 16 1 single
4 C int 4 1 single
48
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
SSNlocC
49
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt lt/Nodegt
SSNlocC
50
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt lt/Nodegt
SSNlocC
51
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt lt/Nodegt
SSNlocC
52
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt lt/Nodegt
SSNlocC
53
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt lt/nextgt
lt/Nodegt
SSNlocC
54
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt lt/nextgt lt/Nodegt
SSNlocC
55
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
lt/nextgtlt/Nodegt
SSNlocC
56
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
ltnumgt2.3lt/numgt lt/nextgtlt/Nodegt
SSNlocC
57
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
ltnumgt2.3lt/numgt ltnext ref_1/gt
lt/nextgtlt/Nodegt
SSNlocC
58
Serialization Example (contd)
multi, id1
single
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
multi, id1
NodelocA
NodelocB
single
embedded, id2
789
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
ltnumgt2.3lt/numgt ltnext ref_1/gt
lt/nextgtlt/Nodegt
SSNlocC
59
Deserialization Example
ltNode id_1gt lt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val?
ptr?
num?
next?
id1
Node
60
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt lt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptr?
num?
next?
id1
Node
61
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt lt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptr?
num?
next?
id1
Node
ref2(unresolved)
62
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptr?
num1.4
next?
id1
Node
ref2(unresolved)
63
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt
lt/nextgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptr?
num1.4
nextB
val?
ptr?
num?
next?
id1
Node
Node
ref2(unresolved)
64
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt lt/nextgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptrB
num1.4
nextB
val456
ptr?
num?
next?
id1
id2
Node
Node
65
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
lt/nextgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptrB
num1.4
nextB
val456
ptrC
num?
next?
id1
id2
Node
Node
789
66
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
ltnumgt2.3lt/numgt lt/nextgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
next?
id1
id2
Node
Node
789
SSN
67
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
ltnumgt2.3lt/numgt ltnext ref_1/gt
lt/nextgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
id1
Node
Node
789
SSN
68
Deserialization Example (contd)
ltNode id_1gt ltvalgt123lt/valgt ltptr
ref_2/gt ltnumgt1.4lt/numgt ltnextgt ltval
id_2gt456lt/valgt ltptrgt789lt/ptrgt
ltnumgt2.3lt/numgt ltnext ref_1/gt
lt/nextgtlt/Nodegt
Recursive descent parsingwith object
deserializationoperations as semantic actions
val123
ptrB
num1.4
nextB
val456
ptrC
num2.3
nextA
id1
Node
Node
789
SSN
69
Converting a WSDL to Code with gSOAP

• The wsdl2h tool converts a (set of) WSDL files
  and schemas to a header file
• The header file is then processed by soapcpp2 as
  before

70
WS- Protocols and Plugins
71
SOAP With MTOM Attachments

• Raw binary data can be transported in a SOAP
  message as base64
• MTOM (Message Transmission Optimization
  Mechanism) using MIME attachments to carry binary
  data with a SOAP message
• Supports embedding of type and other information
• Allows streaming (attachments produced on demand)
• Example HTTP header for SOAP with MTOMPOST /
  HTTP/1.1Host www.example.comContent-Type
  multipart/related boundarymimeboundary" ty
  pe"application/xopxml" start"ltsoapmsggt" s
  tart-info"application/soapxml charsetutf-8"

72
SOAP With MTOM Attachments (contd)

• Example HTTP body with SOAP message and MTOM
  attachment--mimeboundaryContent-Type
  application/xopxmlcharsetutf-8typeapplication
  /soapxmlContent-Transfer-Encoding
  binaryContent-ID ltsoapmsggtltSOAP-ENVEnvelope
  xmlnsSOAP-ENV xmlnsxop"http//www.w3.org/
  2004/08/xop/include" xmlnsxmlmime"http//www.
  w3.org/2004/11/xmlmime" ltSOAP-ENVBodygt
  ltmPutImage xmlnsm"http//www.example.com/test.w
  sdl"gt ltmdata xmlmimecontentTypeimage/jpe
  g"gt ltxopInclude href"cidimage"/gt
  lt/mdatagt lt/mPutImagegt lt/SOAP-ENVBodygtlt/S
  OAP-ENVEnvelopegt--mimeboundaryContent-Type
  image/jpegContent-Transfer-Encoding
  binaryContent-ID ltimagegt image data
  --mimeboundary--

73
WS-Addressing

• WS-Addressing is a Web services protocol for
  routing messages (request, response, and faults)
• Supports message transmission through networks
  with processing nodes such as endpoint managers,
  firewalls, and gatewaysltSEnvelope
  xmlnsS"http//www.w3.org/2003/05/soap-envelope"
  xmlnswsa"http//schemas.xmlsoap.org/ws/
  2004/08/addressing"gt ltSHeadergt
  ltwsaMessageIDgt uuid6B29FC40-CA47-1067-B31D-
  00DD010662DA lt/wsaMessageIDgt
  ltwsaReplyTogt ltwsaAddressgthttp//business456
  .example/client1lt/wsaAddressgt lt/wsaReplyTogt
  ltwsaTogthttp//fabrikam123.example/Purchasinglt/w
  saTogt ltwsaActiongthttp//fabrikam123.example/S
  ubmitPOlt/wsaActiongt lt/SHeadergt ltSBodygt
  ... lt/SBodygtlt/SEnvelopegt

74
WS-Addressing (contd)

• WS-Addressing header elements within the SOAP
  Header
• ltwsaMessageIDgt xsanyURI lt/wsaMessageIDgtdefines
  a unique message ID, e.g. UUID (optional)
• ltwsaRelatesTo RelationshipType"..."?gt xsanyURI
  lt/wsaRelatesTogtconveys the message ID of the
  related message, e.g. the request message ID when
  this is a reply message (required for responses)
• ltwsaTogt xsanyURI lt/wsaTogtthe destination
  address (required)
• ltwsaActiongt xsanyURI lt/wsaActiongtconveys the
  SOAP action property (required)
• ltwsaFromgt endpoint-reference lt/wsaFromgtthe
  source endpoint information (optional)
• ltwsaReplyTogt endpoint-reference
  lt/wsaReplyTogtthe reply endpoint (required for
  request with an expected reply)
• ltwsaFaultTogt endpoint-reference lt/wsaFaultTogt
  the fault endpoint (optional)

75
WS-Security

• WS-Security provides message-level security
• HTTPS provides end-to-end transport-level
  security
• Authentication
• Username and (digest) password (with nonce,
  timestamps)
• Digital signatures
• XML DSig with DSA, HMAC,
• Can sign all or specific parts of the message
• Embedding of security tokens such as certificates
• Support for SAML
• Encryption
• XML Enc with RSA,

76
Username Token

• The Username token security header in
  wsseSecurity contains a username and password in
  plain text or a digest passwordltSOAP-ENVEnvelo
  pe xmlnsSOAP-ENV xmlnswsse
  xmlnswsugt ltSOAP-ENVHeadergt
  ltwsseSecurity SOAP-ENVmustUnderstand"1"gt
  ltwsseUsernameToken wsuId"User"gt
  ltwsseUsernamegtengelenlt/wsseUsernamegt
  ltwssePassword Type"http//docs.oasis-open.org/ws
  s/2004/01/oasis-200401-wss-username-token-profile-
  1.0PasswordDigest"gt/u5faawcfIeve1yHCsdXAWyIlbUlt/
  wssePasswordgt ltwsseNoncegtNDU0MGE5YjljYT
  UzYzAzZjA2MTclt/wsseNoncegt
  ltwsuCreatedgt2006-10-26T122737Zlt/wsuCreatedgt
  lt/wsseUsernameTokengt lt/wsseSecuritygt
  lt/SOAP-ENVHeadergt ltSOAP-ENVBodygt
  lt/SOAP-ENVBodygtlt/SOAP-ENVEnvelopegt

77
Security Timestamps

• A timestamp can be included to define the
  lifetime of a message
• The timestamp will only be tamper proof when
  digitally signed, hence the wsuId which is
  referenced by the signature infoltSOAP-ENVEnvelo
  pe gt ltSOAP-ENVHeadergt ltwsseSecuritygt
  ltwsuTimestamp wsuId"timestamp"gt
  ltwsuCreatedgt2001-09-13T084200Zlt/wsuCreatedgt
  ltwsuExpiresgt2001-10-13T090000Zlt/wsuExpir
  esgt lt/wsuTimestampgt ...
  lt/wsseSecuritygt ... lt/SOAP-ENVHeadergt
  ltSOAP-ENVBodygt ... lt/SOAP-ENVBodygtlt/SOAP-EN
  VEnvelopegt

78
Signatures

• The wsseBinarySecurityToken contains the public
  key
• The dsSignature element contains signature info
  with digest value for each signed message part
  and the signature valueltwsseSecuritygt
  ltwsseBinarySecurityToken wsuIdX509Token gt
  public key lt/wsseBinarySecurityTokengt
  ltdsSignaturegt ltdsSignedInfogt what is
  signed reference URI to signed part with digest
  of that XML message part how it is signed
  digests algorithms and canonicalization of XML
  lt/dsSignedInfogt ltdsSignatureValuegt
  signature lt/dsSignatureValuegt
  ltdsKeyInfogt ltwsseSecurityTokenReferencegt
  ltwsseReference URI"X509Token"/gt
  lt/wsseSecurityTokenReferencegt lt/dsKeyInfogt
  lt/dsSignaturegtlt/wsseSecuritygt

79
Signature Example
ltwsseSecuritygt ltwsseBinarySecurityToken gt
lt/wsseBinarySecurityTokengt ltdsSignaturegt
ltdsSignedInfogt ltdsCanonicalizationMethod
Algorithm"http//www.
w3.org/2001/10/xml-exc-c14n"/gt
ltdsSignatureMethod Algorithm"http//www.w3.org/2
000/09/xmldsigrsa-sha1"/gt ltdsReference
URI"myBody"gt ltdsTransformsgt
ltdsTransform Algorithm"http//www.w3.org/2001/10
/xml-exc-c14n"/gt lt/dsTransformsgt
ltdsDigestMethod Algorithm"http//www.w3.org/200
0/09/xmldsigsha1"/gt ltdsDigestValuegtEULdd
ytSo1...lt/dsDigestValuegt lt/dsReferencegt
lt/dsSignedInfogt ltdsSignatureValuegtBL8jdfTo
Eb1l/vXcMZNNjPOV...lt/dsSignatureValuegt
ltdsKeyInfogt ltwsseSecurityTokenReferencegt
ltwsseReference URI"X509Token"/gt
lt/wsseSecurityTokenReferencegt lt/dsKeyInfogt
lt/dsSignaturegtlt/wsseSecuritygt
80
List of WS- Protocols

• Messaging
• SOAP
• SOAP with Attachments (SwA)
• SOAP with MTOM (Message Transmission Optimization
  Mechanism)
• XML-RPC a simpler XML RPC format (no WSDL or
  schemas)
• WS-Addressing routing, endpoints, and addressing
  properties
• Service description
• WSDL
• WS-MetadataExchange how an endpoint can request
  the various types of metadata it may need to
  effectively communicate with the service
• WS-Policy describes the capabilities,
  requirements, and general characteristics of a
  service

81
List of WS- Protocols

• Directory access and discovery
• UDDI (Universal Description, Discovery, and
  Integration) v2/v3
• WS-Discovery a multicast discovery protocol to
  locate services on a network
• Managing services
• WS-Management for management of servers,
  devices, applications
• Transaction-based services
• WS-Transaction describes the coordination types
  atomic transaction (TA) and business activity
  (BA)
• Publish/subscribe
• WS-Eventing
• WS-Notification
• Security and reliability
• HTTPS (transport-level)
• WS-Security (message-level)
• WS-ReliableMessaging

82
Other Notable WS- Protocols

• Managing resources Web Services Resource
  Framework (WSRF)
• WS-ResourceProperties defines are resources
  properties
• WS-ResourceLifetime inspect and monitor the
  lifetime of a resource
• WS-ServiceGroup defines how resources are
  grouped together for a domain specific purpose
  (service classification and constraints)
• WS-BaseFaults defines faults related to resource
  management
• Managing resources
• WS-Transfer operations for sending and receiving
  the representation of a given resource and
  operations for creating and deleting a resource
• Best practices
• Provide additional information to improve
  interoperability between vendor implementations
• WS-I Basic profile (BP1.0a, BP1.1)
• WS-I Basic security profile

83
Other Notable WS- Protocols

• Device Profile for Web Services (DPWS)
• Goals similar to universal plug and play (UPnP)
• Seamless integration and discovery of devices
  over the Internet
• Printing, scanning, etc. over Internet by
  discovering these services
• Uploading images from camera to PC over the
  (wireless) Internet
• Microsoft Vista natively integrates DPWS
• Builds on
• WS-Eventing (publish/subscribe)
• WS-Discovery
• WS-Addressing
• WS-Security
• WS-Policy
• WS-MetaExchange

84
To be continued