Simple Object Access Protocol (SOAP)

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1 Simple Object Access Prtcl (SOAP) Languages fr web Prf. Eugeni Di Sciasci Master s Degree Curse in Cmputer Engineering - (A.Y. 2016/2017)

2 Web service architecture (1/2) A ppular interpretatin f Web services is based n IBM s Web service architecture based n three elements: Service requester: The ptential user f a service Service prvider: The entity that implements the service and ffers t carry it ut n behalf f the requester Service registry: A place where available services are listed and which allws prviders t advertise their services and requesters t query fr services The gal is just-in-time integratin f applicatins by discvering and rchestrating netwrk-available services Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 2 f 26

3 Web service architecture (2/2) The architecture has a remarkable client/server flavr It reflects nly what can be dne with SOAP (Simple Object Access Prtcl) UDDI (Universal Descriptin and Discvery Prtcl) WSDL (Web Services Descriptin Language) UDDI SOAP WSDL Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 3 f 26

4 What is SOAP? The Simple Object Access Prtcl (SOAP) was initiated by W3C in 1999 SOAP 1.0 was entirely based n HTTP SOAP 1.1 (May 2000) was mre generic since it included ther transprt prtcls. SOAP 1.2 (2007) has a number f changes in syntax SOAP was riginally cnceived as the minimal pssible infrastructure necessary t perfrm RPC thrugh the Internet use f XML as intermediate representatin between systems very simple message structure mapping t HTTP fr tunneling thrugh firewalls and using the Web infrastructure Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 4 f 26

5 SOAP specificatin SOAP specificatin cvers the fllwing fur main areas A message frmat fr ne-way cmmunicatin describing hw a message can be packed int an XML dcument A descriptin f hw (the XML dcument that makes up) a SOAP message shuld be transprted thrugh the Web (using HTTP) r (using SMTP). A set f rules that must be fllwed when prcessing a SOAP message and a simple classificatin f the entities invlved in that prcessing. It als specifies what parts f the messages shuld be read by whm and hw t react in case the cntent is nt understd A set f cnventins n hw t turn an RPC call int a SOAP message and back as well as hw t implement the RPC style f interactin (hw the client side RPC call is translated int a SOAP message, frwarded, turned int a server side RPC call, the reply cnverted int a SOAP message and returned t the client) Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 5 f 26

SOAP messages <Envelpe>: rt element in every SOAP message <Header>: ptinal subelement f the SOAP envelpe, and is used t pass applicatin-related infrmatin that is t be prcessed by SOAP ndes alng the

6 SOAP messages <Envelpe>: rt element in every SOAP message <Header>: ptinal subelement f the SOAP envelpe, and is used t pass applicatin-related infrmatin that is t be prcessed by SOAP ndes alng the message path <Bdy>: a mandatry subelement f the SOAP envelpe, which cntains infrmatin intended fr the ultimate recipient f the message; see The SOAP bdy. <Fault>: a subelement f the SOAP bdy, which is used fr reprting errrs Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 6 f 26

7 SOAP Message Prcessing SOAP assumes messages have an riginatr, ne r mre ultimate receivers, and zer r mre intermediaries The reasn is t supprt distributed message prcessing SOAP prcessing rules are directly related t the SOAP message envelpe: The Bdy is nly fr final recipients. Header sectins may be prcessed by ne r mre intermediaries as well as final recipient ndes. Originatr Recipient Intermediary Intermediary Intermediary Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 7 f 26

8 SOAP Ndes and Rles Originatrs, intermediaries, and receivers f SOAP messages are all called SOAP Ndes. Each nde is labeled with a URI Fr a particular message, the Nde can act in ne r mre SOAP Rles. Each rle is labeled with a URI Rles can be user-defined Lg message rle Check authrizatin rle When a nde receives a message, it must examine the message fr a rle definitin and prcess the headers as required. The SOAP specificatin itself des nt specify hw yu assign a rle t a nde. Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 8 f 26

9 SOAP header The immediate child elements f the header are called header blcks A header blck is an applicatin-defined XML element, and represents a lgical gruping f data which can be targeted at SOAP ndes that might be encuntered in the path f a message frm a sender t an ultimate receiver SOAP header blcks can be prcessed by SOAP intermediary ndes, and by the ultimate SOAP receiver nde. Hwever, in a real applicatin, nt every nde prcesses every header blck Each nde is typically designed t prcess particular header blcks, and each header blck is prcessed by particular ndes The SOAP header enables users t add features t a SOAP message in a decentralized manner withut prir agreement between the cmmunicating parties Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 9 f 26

10 SOAP header Althugh the header blcks are applicatin-defined, SOAP-defined attributes n the header blcks indicate hw the header blcks must be prcessed by the SOAP ndes. encdingstyle rle indicates the rules used t encde the parts f a SOAP message. SOAP defines a narrwer set f rules fr encding data than the flexible encding that XML enables specifies whether a particular nde will perate n a message. If the rle specified fr the nde matches the rle attribute f the header blck, the nde prcesses the header. If the rles d nt match, the nde des nt prcess the header blck. In SOAP 1.1, the actr attribute perfrms the same functin. Rles can be defined by the applicatin, and are designated by a URI Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 10 f 26

11 SOAP header: rle attribute The SOAP 1.2 specificatin defines three standard rles in additin t thse which are defined by the applicatin: Nne f the SOAP ndes n the message path shuld prcess the header blck directly. Header blcks with this rle can be used t carry data that is required fr prcessing f ther SOAP header blcks. All SOAP ndes n the message path are expected t examine the header blck (prvided that the header has nt been remved by a nde earlier in the message path). Only the ultimate receiver nde is expected t examine the header blck. Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 11 f 26

12 SOAP header mustunderstand This attribute is used t ensure that SOAP ndes d nt ignre header blcks which are imprtant t the verall purpse f the applicatin. 1 (SOAP 1.1) r true (SOAP 1.2): The nde must either prcess the header blck in a manner cnsistent with its specificatin, r nt at all (and thrw a fault). 0 (SOAP 1.1) r false (SOAP 1.2): The nde is nt bliged t prcess the header blck. relay (SOAP 1.2 nly) When a SOAP intermediary nde prcesses a header blck, the SOAP intermediary nde remves the header blck frm the SOAP message. By default, the SOAP intermediary nde als remves all header blcks that it ignred (because the mustunderstand attribute had a value f false). Hwever, when the relay attribute is specified with a value f true, the SOAP intermediary nde retains the unprcessed header blck in the message. Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 12 f 26

13 SOAP header example <?xml versin='1.0'?> <env:envelpe xmlns:env=" <env:header> <m:reservatin xmlns:m= " env:rle=" env:mustunderstand="true"> <m:reference>uuid:093a2da1-q r-ba5d-pqff98fe8j7d </m:reference> <m:dateandtime> t13:20: :00 </m:dateandtime> </m:reservatin> <n:passenger xmlns:n= " env:rle=" env:mustunderstand="true"> <n:name>åke Jógvan Øyvind</n:name> </n:passenger> </env:header> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 13 f 26

14 Rles, Understanding, and Relays Rle? Yes must Understand Yes Prcess Header N N Frward Header Yes N Relay? Remve Header Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 14 f 26

15 SOAP bdy The bdy is intended fr the applicatin specific data cntained in the message A bdy entry (r a bdy blck) is syntactically equivalent t a header entry with attributes rle = ultimatereceiver and mustunderstand = 1 Unlike fr headers, SOAP des specify the cntents f sme bdy entries: mapping f RPC t a cllectin f SOAP bdy entries the Fault entry (fr reprting errrs in prcessing a SOAP message) The fault entry has fur elements (in 1.1): fault cde: indicating the class f errr (versin, mustunderstand, client, server) fault string: human readable explanatin f the fault (nt intended fr autmated prcessing) fault actr: wh riginated the fault detail: applicatin specific infrmatin abut the nature f the fault Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 15 f 26

16 SOAP Fault element (1.2) In versin 1.2, the fault element is specified in mre detail. It must cntain tw mandatry sub-elements: Cde: cntaining a value (the cde f the fault) and pssibly a subcde (fr applicatin specific infrmatin) Reasn: same as faultstring in 1.1 This string can be prvided in different languages: <env:text xml:lang="en-us">header nt understd</env:text> <env:text xml:lang="fr">en-tête nn cmpris</env:text> and may cntain any f the fllwing ptinal elements: Nde: the URI identifying the nde prducing the fault Rle: the rle played by the nde that generated the fault Detail Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 16 f 26

17 SOAP Fault structure (1/2) <env:envelpe xmlns:env=" <env:header>... </env:header> <env:bdy> <env:fault> <env:cde> (required) <env:value>env:versinmismatch env:mustunderstand Sender DataEncdingUnknwn Receiver</env:Value> (required) <env:subcde> (ptinal) <env:value>text</env:value> (required) <env:subcde> (ptinal)... </env:subcde> </env:subcde> </env:cde> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 17 f 26

18 SOAP Fault structure (2/2) <env:reasn> (required) <env:text xml:lang="languagecde">text<env:text> (required) <env:text xml:lang="languagecde">text<env:text> (pitnal)... </env:reasn> <env:nde> (ptinal) </env:nde> <env:rle> (ptinal) </env:rle> <env:detail...> (ptinal)... (any XML structure) </env:detail> </env:fault> </env:bdy> </env:envelpe> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 18 f 26

19 SOAP Fault: example <env:fault> <env:cde> <env:value>env:sender</env:value> <env:subcde> <env:value>rpc:badarguments</env:value> </env:subcde> </env:cde> <env:reasn> <env:text xml:lang="en-us">prcessing errr</env:text> <env:text xml:lang="fr-ca">errr</env:text> </env:reasn> <env:detail> <e:myfaultdetails xmlns:e=" <e:message>name des nt match card number</e:message> <e:errrcde>999</e:errrcde> </e:myfaultdetails> </env:detail> </env:fault> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 19 f 26

20 SOAP and HTTP A binding f SOAP t a transprt prtcl is a descriptin f hw a SOAP message is t be sent using that transprt prtcl The typical binding fr SOAP is HTTP SOAP can use GET r POST GET: the request is nt a SOAP message but the respnse is a SOAP message POST: bth request and respnse are SOAP messages (in v1.2, v1.1 mainly cnsiders using POST) SOAP uses the same errr and status cdes as thse used in HTTP s that HTTP respnses can be directly interpreted by a SOAP mdule HTTP POST SOAP Envelpe SOAP header Transactinal cntext SOAP Bdy Name f Prcedure Input parameter 1 Input parameter 2 Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 20 f 26

21 SOAP request ver HTTP (v1.2) POST /WSShakespeare.asmx HTTP/1.1 Hst: Cntent-Type: applicatin/sap+xml; charset=utf-8; actin= ; Cntent-Length: length <sap:envelpe xmlns:sap=" sap:encdingstyle=" <sap:bdy> <m:getprice xmlns:m=" <m:item>apples</m:item> </m:getprice> </sap:bdy> </sap:envelpe> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 21 f 26

22 SOAP request ver HTTP (v1.1) POST /WSShakespeare.asmx HTTP/1.1 Hst: Cntent-Type: text/xml; charset=utf-8 Cntent-Length: length SOAPActin: " <?xml versin="1.0" encding="utf-8"?> <env:envelpe xmlns:xsi=" xmlns:env=" <env:bdy> <GetSpeech xmlns=" <Request>string</Request> </GetSpeech> </env:bdy> </env:envelpe> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 22 f 26

23 SOAP respnse ver HTTP HTTP/ OK Cntent-Type: text/xml; charset="utf-8" Cntent-Length: nnnn <SOAP-ENV:Envelpe xmlns:soap-env=" SOAP-ENV:encdingStyle=" <SOAP-ENV:Bdy> <m:getlasttradepricerespnse xmlns:m="sme-uri"> <Price>34.5</Price> </m:getlasttradepricerespnse> </SOAP-ENV:Bdy> </SOAP-ENV:Envelpe> ETH Zürich Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 23 f 26

24 RPC ver SOAP Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 24 f 26

25 SOAP RPC representatin SOAP RPC Presentatin is an extensin f the SOAP framewrk specificatin that defines hw RPC requests and respnses shuld be presented by SOAP The fllwing issues are invlved t carry ut a remte prcedure call: The target system which will perfrm the prcedure and return the result. The prcedure name used t identify the prcedure n the target system. Input parameters that need t be passed t the prcedure n the target system. Return value which is returned directly by the prcedure. Output parameters that cntain infrmatin affected indirectly by the prcedure. SOAP RPC Presentatin defines the fllwing rules t reslved the issues listed abve: If the nature f the prcedure is a request fr infrmatin retrieval, and the prcedure name and input parameters can be entirely represented in the target SOAP nde URI, RPC invcatin shuld be carried as a Web methd defined in the SOAP Web Methd Feature specificatin. If a RPC can nt be carried ut as a Web methd, it shuld be invked by as SOAP message with a SOAP bdy element. The bdy element shuld use SOAP encding and cntains a single "struct" nde representing the prcedure name. All input parameters shuld be represented as utbund edges riginated frm this nde. Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 25 f 26

26 Using Web methds t invke RPC Example 1 - A user needs t invke the fllwing RPC n a target system called "inventry": getquantityinstck(partnumber="123") This invcatin can be dne as a Web methd f "GET" type with a target SOAP nde URI like: Example 2 - Anther user needs t invke the fllwing RPC n a target system called "inventry": updatequantityinstck(partnumber="123", NewQuantity="200") This invcatin can still be dne as a Web methd f "GET" type with a target SOAP nde URI like: It can als be invked as a Web methd f "POST" type with a target SOAP nde URI like: and transmit input parameters: PartNumber="123", NewQuantity="200", in the HTTP request bdy. Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 26 f 26

27 Using SOAP methds t invke RPC Example 3 - A user wants t update prices f a list f part numbers in an inventry system with the fllwing RPC: updateprice(list=arrayofstructures) <env:envelpe xmlns:env=" <env:bdy env:encdingstyle=" xmlns:enc=" <rpc:updateprice enc:ndetype="struct" xmlns:rpc=" <rpc:list enc:arraysize="2"> <rpc:item> <rpc:partnumber>123</rpc:partnumber> <rpc:price>99.00</rpc:price> </rpc:item> <rpc:item> <rpc:partnumber>321</rpc:partnumber> <rpc:price>199.00</rpc:price> </rpc:item> </rpc:list> </rpc:updateprice> </env:bdy> </env:envelpe> Prf. Eugeni Di Sciasci Languages fr web: Simple Object Access Prtcl 27 f 26

Web Services SOAP. Lecture "XML in Communication Systems" Chapter 12

Web Services SOAP. Lecture XML in Communication Systems Chapter 12 Web Services SOAP Lecture "XML in Cmmunicatin Systems" Chapter 12 Prf. Dr.-Ing. Nrbert Luttenberger Research Grup fr Cmmunicatin Systems Dept. f Cmputer Science Christian-Albrechts-University in Kiel Recmmended