1 soap simple object access protocol 大葉大學資工系. 2 purpose of soap developers need to...

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SOAPSimple Object Access Protocol

大葉大學資工系

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Purpose of SOAP

Developers need to establish a standard transport and data-exchange framework to achieve XML-based interaction.

The reasons for using SOAP

• Web services require a protocol that uses a standard, open data format.

• Web services need a way to work with the basic security mechanisms of remote networks.

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Nature of SOAP

SOAP is a software system that enables applications to communicate with one another using XML-based message, called SOAP message.

SOAP messages encapsulate the information exchanged.

• SOAP messages don’t provide programming instructions, rather, specify the operations to invoke.

SOAP supports features such as attachments, security, routing information and transaction.

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Flow of a SOAP Request

Client-Side

ConsumerSOAP

MessageProxySerialize

Deserialize

Server-SideIIS

ASPNET_ISAPI.DLL

HTTP Handlers

HTTP Web Service HandlerWeb

ServiceSerialize

Deserialize

NetworkNetwork

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SOAP Specifications

SOAP envelope describes the format of a SOAP message.

The second part defines a set of rules that encode data types.

The third part defines how a SOAP message can execute remote procedure call (RPC).

The last part specifies the message binding protocol.

• HTTP, HTTPS, SMTP

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Anatomy of a SOAP Message

A SOAP message is composed of an envelope that contains the body of the message and any header information used to describe the message.

The root element of the document is the Envelope element.

• The envelope can contain an optional Header element, which contains information about the message.

• The envelope must contain one Body element.

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A SOAP Envelop

A SOAP Envelop

Header

Body

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SOAP Actors

A SOAP actor is anything that acts on the content of the SOAP message.

There are two types of SOAP actors:

• The default actor is the intended final recipient of a SOAP message.

• An intermediary receives a SOAP message and might act on the message before forwarding it along the intended message path.

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Header Element

The optional Header element is used to pass data that might not be appropriate to encode in the body.

• Authentication, Security digest information, Routing information, Transactions, Payment information.

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Header> <Digest>B839D234A3F87</Digest> </soap:Header> <soap:Body> <StockReport> <Symbol>MSFT</Symbol> <Price>74.56</Price> </StockReport> </soap:Body></soap:Envelope>

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Body Element

The body contains the payload of the message and there are no restrictions on how the body can be encoded.

SOAP messages are placed into two categories:

• Procedure-oriented messages provide two-way communication and are commonly referred to as remote procedure call (RPC) messages.

• Document-oriented messages generally facilitate one-way communication. Business documents such as purchase orders are examples of document-oriented messages.

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SOAP 1.1 XML Schema Definition

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tns="http://schemas.xmlsoap.org/soap/envelope/" targetNamespace="http://schemas.xmlsoap.org/soap/envelope/" >  <xs:element name="Envelope" type="tns:Envelope" /> <xs:complexType name="Envelope" > <xs:sequence> <xs:element ref="tns:Header" minOccurs="0" /> <xs:element ref="tns:Body" minOccurs="1" /> <xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded" processContents="lax" /> </xs:sequence> <xs:anyAttribute namespace="##other" processContents="lax" /> </xs:complexType>

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<xs:element name="Header" type="tns:Header" /> <xs:complexType name="Header" > <xs:sequence> <xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded" processContents="lax" /> </xs:sequence> <xs:anyAttribute namespace="##other" processContents="lax" /> </xs:complexType> <xs:element name="Body" type="tns:Body" /> <xs:complexType name="Body" > <xs:sequence> <xs:any namespace="##any" minOccurs="0" maxOccurs="unbounded" processContents="lax" /> </xs:sequence> <xs:anyAttribute namespace="##any" processContents="lax" /> </xs:complexType>

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 <xs:attribute name="mustUnderstand" default="0" > <xs:simpleType> <xs:restriction base='xs:boolean'> <xs:pattern value='0|1' /> </xs:restriction> </xs:simpleType> </xs:attribute> <xs:attribute name="actor" type="xs:anyURI" />

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<xs:simpleType name="encodingStyle" > <xs:list itemType="xs:anyURI" /> </xs:simpleType>

<xs:attribute name="encodingStyle" type="tns:encodingStyle" /> <xs:attributeGroup name="encodingStyle" > <xs:attribute ref="tns:encodingStyle" /> </xs:attributeGroup>

<xs:element name="Fault" type="tns:Fault" /> <xs:complexType name="Fault" final="extension" > <xs:sequence> <xs:element name="faultcode" type="xs:QName" /> <xs:element name="faultstring" type="xs:string" /> <xs:element name="faultactor" type="xs:anyURI" minOccurs="0" /> <xs:element name="detail" type="tns:detail" minOccurs="0" /> </xs:sequence> </xs:complexType>

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<xs:complexType name="detail"> <xs:sequence> <xs:any namespace="##any" minOccurs="0" maxOccurs="unbounded" processContents="lax" /> </xs:sequence> <xs:anyAttribute namespace="##any" processContents="lax" /> </xs:complexType>

</xs:schema>

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SOAP Message Example

<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>

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

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

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Procedure-oriented Messages

Two SOAP messages are paired together to facilitate an RPC method call with SOAP:

• the request message

• Information about the targeted method along with any input parameters is passed to the server via a request message.

• the corresponding response message

• The server invokes some behavior (or procedure) and returns the results and any return parameters.

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Document-oriented Messages

A business document such as a purchase order or an invoice can be encoded within the body of a SOAP message and routed to its intended recipient.

The recipient of the document might or might not send an acknowledgment message back to the sender.

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SOAP RPC Messages

Remote Procedure Call (RPC) is a technology by which one application invokes a procedure residing on another computer.

The SOAP message body contains the Web service method to be invoked, any parameters the method takes and the target procedure’s URI.

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SOAP Example

Add(1, 2)

<?xml version="1.0"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <Add> <x>1</x> <y>2</y> </Add> </soap:Body></soap:Envelope>

<?xml version="1.0"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <Add> <x>1</x> <y>2</y> </Add> </soap:Body></soap:Envelope>

<?xml version="1.0"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <AddResult> <result>3</result> </AddResult> </soap:Body></soap:Envelope>

<?xml version="1.0"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <AddResult> <result>3</result> </AddResult> </soap:Body></soap:Envelope>

public int Add(int x, int y){ return x + y;}

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SOAP Encoding

SOAP Encoding defines the way data can be serialized within a SOAP message.

SOAP Encoding builds on the types defined in the XML specification.

Simple Types

• An instance of a data type is encoded as an XML element.

• integer called Age would be encoded as<Age>31</Age>

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SOAP Encoding

Compound Type – Structures

• Each of the variables contained within the instance of the structure is serialized as a child element of the parameter element.

public struct RectSolid{ public int length; public int width; public int height;}

public int CalcVolume(RectSolid r){ return (r.length * r.width * r.height);}

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap= "http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <CalcVolume> <r> <length>2</length> <width>3</width> <height>1</height> </r> </CalcVolume> </soap:Body></soap:Envelope>

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SOAP Encoding

Compound Type – Array

• SOAP 1.1 specifies the encoding of Array type.public int AddArray(int[] numbers){ ...}

int[] a = {1, 2, 3};int total;

total = AddArray(a);

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soap-enc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <soap:Body> <AddArray> <a soap-enc:arrayType="xsi:int[3]"> <int>1</int> <int>2</int> <int>3</int> </a> </AddArray> </soap:Body></soap:Envelope>

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SOAP Encoding

string[][] teams = new string[3][];

teams[0] = new string[3];teams[0][0] = "Bob";teams[0][1] = "Sue";teams[0][2] = "Mike";

teams[1] = new string[2];teams[1][0] = "Jane";teams[1][1] = "Mark";

teams[2] = new String[4];teams[2][0] = "Mary";teams[2][1] = "Jill";teams[2][2] = "Jim";teams[2][3] = "Tom";

RegisterTeams(teams);

public void RegisterTeams(string[][] teams){ // ...} <?xml version="1.0" encoding="utf-8"?>

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soap-enc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <soap:Body> <RegisterTeams> <teams soap-enc:arrayType="xsi:string[3]"> <team soap-enc:arrayType="xsi:string[3]"> <player>Bob</player> <player>Sue</player> <player>Mike</player> </team> <team soap-enc:arrayType="xsi:string[2]"> <player>Jane</player> <player>Mark</player> </team> <team soap-enc:arrayType="xsi:string[4]"> <player>Mary</player> <player>Jill</player> <player>Jim</player> <player>Tom</player> </team> </teams> </RegisterTeams> </soap:Body></soap:Envelope>

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Passing Parameters by Reference

Fibonacci series

public void FibonacciIncrement(ref int n1, ref int n2){ int temp = n2;

n1 += n2; n2 = temp + n1;}

int x = 1;int y = 1;

for(int i = 1, i < 11, i += 2){ Console.Write("{0}, {1}", x, y); FibonacciIncrement(x, y);}

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <FibonacciIncrement> <n1>1</n1> <n2>1</n2> </FibonacciIncrement> </soap:Body></soap:Envelope>

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <FibonacciIncrement> <n1>1</n1> <n2>1</n2> </FibonacciIncrement> </soap:Body></soap:Envelope>

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <FibonacciIncrementResponse> <n1>2</n1> <n2>3</n2> </FibonacciIncrementResponse> </soap:Body></soap:Envelope>

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <FibonacciIncrementResponse> <n1>2</n1> <n2>3</n2> </FibonacciIncrementResponse> </soap:Body></soap:Envelope>

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Protocol Binding

SOAP messages can be sent over any transport protocol that is capable of carrying XML.

The SOAP specification describes only one protocol binding: sending SOAP messages via HTTP POST.

• It is firewall friendly.

• It has a robust supporting infrastructure.

• It is inherently stateless.

• It is simple.

• It maps nicely to RPC-style message exchanges.

• It is open.

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Protocol Binding

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HTTP Request

Header: contains information about the request and about the client that sent the request.

Body: follows the header and is delimited by two carriage-return/linefeed pairs.

POST /SomeWebService HTTP/1.1 Content-Type: text/xml SOAPAction: "http://somedomain.com/SomeWebService.wsdl" Content-Length: 243 Host: sshort3

<?xml version="1.0" encoding="utf-8"?> <soap:Envelope

xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soap-enc="http://schemas.xmlsoap.org/soap/encoding/"> <soap:Body>

<Add> <x>2</x> <y>2</y>

</Add> </soap:Body>

</soap:Envelope>

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