Back to basics: Simple database web services without the need for SOA

Back to Basics:Simple Database Web Services

SAGE Computing ServicesCustomised Oracle Training Workshops and

Consulting

Chris Muir Oracle Consultant and Trainer

Oracle ACE Director - Fusion Middleware

http://one-size-doesnt-fit-all.blogspot.com

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Agenda

• Part I: Understanding web services

• Part II: Consuming web services from the database

• Part III: Publishing web services from 11g

Part I: Understanding Web Services

SOAP, WSDL, RPC Style, Document Style, XML, XML

Namespaces, HTTP request/response .

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SOAP vs REST Web Services

SOAP Web Services DefinedHost: http://www.sagecomputing.com.au

Web

Web Service /bookings

/employees

/timesheets

InternetHTTP Request/Response

Endpoints

Server

Web Service

Web Service

SOAP Web Services Defined

Endpoint: http://www.sagecomputing.com.au/employeesWeb

ServiceEmployees

getAddress

getName

updateAddress

XML Namespace: http://www.sagecomputing.com.au/emp

Operation

Operation

Operation

Uniquely identified in an XML

Namespace

SOAP Web Service API Styles:

1.Remote Procedure Call (RPC)2.Document

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Remote Procedure Call (RPC) StyleHost: http://www.sagecomputing.com.au

Endpoint: http://www.sagecomputing.com.au/employees

Namespace: http://www.sagecomputing.com.au/emp

Operation: getName

In: integer employeeNumber

Return: string name

In: string nameCase http://www.w3.org/2001/XMLSchema

Request:

<sage:getName xmlns:sage="http://www.sagecomputing.com.au/emp"> <employeeNumber>1234</employeeNumber> <nameCase>U</nameCase></sage:getName>

Response:

<sage:getName xmlns:sage="http://www.sagecomputing.com.au/emp"> <name>CHRISTOPHER MUIR</name></sage:getName>

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Remote Procedure Call (RPC) Style

Request:

<sage:getName xmlns:sage="http://www.sagecomputing.com.au/emp" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-Instance"> <employeeNumber xsi:type="xsd:integer">1234</employeeNumber> <nameCase xsi:type="xsd:string">L</nameCase></sage:getName>


Response:

<sage:getName xmlns:sage="http:// www.sagecomputing.com.au/emp" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-Instance"> <name xsi:type="xsd:string">christopher muir</name></sage:getName>

Document StyleHost: http://www.sagecomputing.com.au

Endpoint: http://www.sagecomputing.com.au/employees

Namespace: http://www.sagecomputing.com.au/emp

Operation: getName

In: XML-Schema getNameInput

Return: XML-Schema getNameOutput

Photo thanks to ARS

<xsd:schema xmlns="http://www.w3.org/2001/XMLSchema targetNamespace="http://www.sagecomputing.com.au/emp"> <xsd:element name="getNameInput"> <xsd:complexType> <xsd:sequence> <xsd:element name="employeeNumber" type="xsd:integer"/> <xsd:element name="nameCase" type="xsd:string"/> </xsd:sequence> </xsd:complexType> </xsd:element></xsd:schema>

Document Style "In" XML SchemaXML Schema:


Request:

<sage:getNameInput xmlns:sage="http://www.sagecomputing.com.au/emp"> <employeeNumber>1234</employeeNumber> <nameCase>M</nameCase></sage:getNameInput>

<xsd:schema xmlns="http://www.w3.org/2001/XMLSchema targetNamespace="http://www.sagecomputing.com.au/emp"> <xsd:element name="getNameInput"> <xsd:complexType> <xsd:sequence> <xsd:element name="employeeNumber" type="xsd:integer"/> <xsd:element name="nameCase" type="xsd:string"/> </xsd:sequence> </xsd:complexType> </xsd:element> <xsd:element name="getNameOutput" type="xsd:string"/></xsd:schema>

Document Style "In + Return" XML SchemaXML Schema:


Response:

<sage:getNameOutput xmlns:sage="http://www.sagecomputing.com.au/emp">Christopher Muir</sage:getNameOutput>

SOAP Envelope

Request:

<?xml version="1.0" encoding="UTF-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Header/> <soap:Body> ... Request XML payload ... </soap:Body></soap:Envelope>

Response:

<?xml version="1.0" encoding="UTF-8"?><env:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope/"> <env:Header/> <env:Body> ... Response XML payload ... </env:Body></env:Envelope>

Web Service Description Language (WSDL)


• De facto standard for describing web services• XML based + W3C standards based• Publish web service API

http://www.sagecomputing.com.au/employees?wsdl

• Assists consumer in assembling request• Not actually required in web service calls

• Port types = grouped operations• Bindings = data exchange protocol (eg. SOAP over HTTP)• Ports = endpoints/services

WSDL example

01 <?xml version="1.0" encoding="UTF-8" ?>

02 <definitions targetNamespace="http://www.sagecomputing.com.au/emp"

03 xmlns="http://schemas.xmlsoap.org/wsdl/"

04 xmlns:sage="http://www.sagecomputing.com.au/emp"

05 xmlns:xsd="http://www.w3.org/2001/XMLSchema"

06 xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"

07 <types/>

08 <message name="getNameInput">

09 <part name="employeeNumber" type="xsd:int"/>

10 <part name="nameCase" type="xsd:string"/>

11 </message>

12 <message name="getNameOutput"><part name="name" type="xsd:string"/></message>

13 <portType name="employees">

14 <operation name="getName" parameterOrder="employeeNumber nameCase">

15 <input message="sage:getNameInput"/>

16 <output message="sage:getNameOutput"/>

17 </operation></portType>

18 <binding name="empSoapHttp" type="sage:employees">

19 <soap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http"/>

20 <operation name="getName">

21 <input><soap:body use="literal" namespace="http://www.sagecomputing.com.au/emp"

22 parts="employeeNumber nameCase"/></input>

23 <output><soap:body use="literal" namespace="http://www.sagecomputing.com.au/emp"

24 parts="name"/></output>

25 </operation></binding>

26 <service name="employees">

27 <port name="empSoapHttpPort" binding="sage:empSoapHttp">

28 <soap:address location="http://www.sagecomputing.com.au/employees"/>

29 </port>

30 </service>

31 </definitions>

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Part II: Consuming Web Services from the

Database

utl_httputl_dbws

Consuming Web Servicesfrom the Database

• Database provides 2 packages for accessing web services– utl_http – low level http assembler– utl_dbws – high level web service package

• 3rd (alternative) method:– Load Apache Common's Java HttpClient into db– Write Java program in db– Generate PL/SQL wrapper

utl_http• Available as of 8.0.5• Send/receive raw HTTP request/responses to external servers• Advantages:– Simplistic– Installed (completely) in the database– Passed and returns a VARCHAR2 XML payload– Very easy if you know the XML payload structures– Doesn't require a WSDL at publisher's site– Good examples available on the internet– 3rd party PL/SQL wrappers available (Tim Hall: soap_api)

• Disadvantages:– Low level with no smarts to support web services– Cryptic HTTP error messages– Oracle documentation is less than useful

utl_http example

01 PROCEDURE call_web_service(i_payload IN VARCHAR2, o_response OUT VARCHAR2) IS

02 v_http_req utl_http.req;

03 v_http_resp utl_http.resp;

04 v_part_response VARCHAR2(32767);

04 BEGIN

05 utl_http.set_proxy('cmuir:[email protected]:80 ');

06 utl_http.set_wallet('file:/oracle/owallets/', 'pwd'); 07

08 v_http_req := utl_http.begin_request(

09 'http://www.sagecomputing.com.au/employees', 'POST', 'HTTP/1.1');

10 utl_http.set_authentication(v_http_req, 'cmuir', 'pwd', 'Basic', TRUE);

11

12 utl_http.set_header(v_http_req, 'Content-Type' ,'text/xml');

13 utl_http.set_header(v_http_req, 'Content-Length' ,length(i_payload));

14 utl_http.set_header(v_http_req, 'SOAPAction' ,'getName');

15

16 utl_http.write_text(v_http_req, i_payload);

17

18 v_http_resp := utl_http.get_response(v_http_req);

19 -- Add handler for HTTP error v_http_resp.status_code >= 500 <= 599

20 BEGIN

21 LOOP

22 utl_http.read_text(v_http_resp, v_part_response);

23 o_response := o_response || v_part_response;

24 END LOOP;

25 EXCEPTION WHEN utl_http.end_of_body THEN

26 NULL;

27 END;

28 utl_http.end_response(v_http_resp);

29 -- Add exception handler

30 END call_web_service;

01 DECLARE02 v_request VARCHAR2(5000);03 v_response VARCHAR2(5000);0405 v_soap_req VARCHAR2(5000);06 v_soap_resp VARCHAR2(5000);07 08 v_xml_resp XMLType;0910 BEGIN11 v_request := '<sage:getNameInput xmlns:sage="http://www.sagecomputing.com.au/emp">'12 || '<employeeNumber>1234</employeeNumber>'13 || '<nameCase>M</nameCase>'14 || '</sage:getNameInput>';1516 v_soap_req := '<?xml version = "1.0" encoding = "UTF-8"?>'17 || '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">'18 || '<soapenv:Header/>'19 || '<soapenv:Body>'20 || v_request21 || '</soapenv:Body>'22 || '</soapenv:Envelope>';23 24 call_web_service(v_soap_req, v_soap_resp);2526 -- Strip the SOAP XML envelope from the response27 v_xml_resp := XMLType.createXml(v_soap_resp);28 v_response := v_xml_resp.extract(29 '/soap:Envelope/soap:Body/child::node()'30 ,'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"').getStringVal();3132 END;

Oracle 11g utl_http Security Caveats

• New: Network Access Control Lists (ACLs)

• Purpose: Fine grained host access

• Affects: utl_tcp, utl_http, utl_smtp, utl_mail, utl_inaddr

• Documentation: Oracle Database Security Guide 11gR1 Chapter 4

• Simple Workaround: Metalink Note 453786.1

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utl_dbws• Available as of 10gR1• PL/SQL Java wrapper on oracle.jpub.runtime.dbws.DbwsProxy• Part of JPublisher

• Advantages:– High(er) level web service handler

• Disadvantages:– Not completely installed by default (bah!)– Poor error reporting (in particular HTTP)– Queries external WSDL each request– Oracle documentation is dismal– Use of HttpUriType does not support wallets or proxies– Minor bugs in 10gR2 version with external authentication– Minor issues on calling .Net web services– Uses database JVM

• Source: Tim Hall's bloghttp://www.oracle-base.com/articles/10g/utl_dbws10g.php

Download: http://download.oracle.com/technology/sample_code/

tech/java/jsp/dbws-callout-utility-10131.zip

Extract: dbwsclientws.jar + dbwsclientdb11.jar -> ORACLE_HOME/sqlj/lib

Execute: ORACLE_HOME/sql/lib/loadjava -u sys/password -r -v -f -genmissing -s -grant public dbwsclientws.jar dbwsclientdb11.jar

utl_dbws Installation

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• Slow to install & will produce class loading errors at end

• Consider reinstalling in separate schema from sys as per Metalink note: 469588.1

utl_dbws example

01 DECLARE

02 v_namespace VARCHAR2(1000) := 'http://www.sagecomputing.com.au/emp';

03 v_service_qname utl_dbws.qname := utl_dbws.to_qname(v_namespace,'employees');

04 v_port_qname utl_dbws.qname := utl_dbws.to_qname(v_namespace,'employeesSoapHttpPort');

05 v_operation_qname utl_dbws.qname := utl_dbws.to_qname(v_namespace,'getName');

06

07 v_service utl_dbws.service;

08 v_call utl_dbws.call;

09

10 v_int_type utl_dbws.qname;

11 v_string_type utl_dbws.qname;

12

13 v_request_params utl_dbws.anydata_list; -- RPC style only

14 v_response_anydata AnyData; -- RPC style only

15

16 v_request_xmltype XmlType; -- Document style only

17 v_response_xmltype XmlType; -- Document style only

18

19 BEGIN

20 v_service := utl_dbws.create_service(

21 HttpUriType('http://www.sage.com.au/employees?wsdl'), v_service_qname);

22

23 v_call := utl_dbws.create_call(v_service, v_port_qname, v_operation_qname);

24

25 utl_dbws.set_property(v_call, 'SOAPACTION_USE', 'TRUE');

26 utl_dbws.set_property(v_call, 'SOAPACTION_URI', 'getName');

27 utl_dbws.set_property(v_call, 'ENCODINGSTYLE_URI',

28 'http://schemas.xmlsoap.org/soap/encoding/');

29 utl_dbws.set_property(v_call, 'OPERATION_STYLE', 'rpc');

29 utl_dbws.set_property(v_call, 'OPERATION_STYLE', 'document');Pick one

29 utl_dbws.set_property(v_call, 'OPERATION_STYLE', 'rpc');

30

31 v_int_type := utl_dbws.to_qname('http://www.w3.org/2001/XMLSchema', 'int');

32 v_string_type := utl_dbws.to_qname('http://www.w3.org/2001/XMLSchema', 'string');

33

34 utl_dbws.add_parameter(v_call, 'employeeNumber', v_int_type, 'ParameterMode.IN');

35 utl_dbws.add_parameter(v_call, 'nameCase', v_string_type, 'ParameterMode.IN');

36 utl_dbws.set_return_type(v_call, v_string_type);

37

38 v_request_params(0) := AnyData.convertNumber(1234);

39 v_request_params(1) := AnyData.convertVarchar('M');

40

41 v_response_anydata := utl_dbws.invoke(v_call, v_request_params);

42 dbms_output.put_line('Result = ' || v_response_anydata.accessVarchar2);

43

44 utl_dbws.release_call(v_call);

45 utl_dbws.release_service(v_service);

46 END;

47 /

Result = Christopher Muir

29 utl_dbws.set_property(v_call, 'OPERATION_STYLE', 'document');

30

31 v_string_type := utl_dbws.to_qname('http://www.w3.org/2001/XMLSchema', 'string');

32

33 utl_dbws.add_parameter(v_call, 'Request', v_string_type, 'ParameterMode.IN');

34 utl_dbws.set_return_type(v_call, v_string_type);

35

36 v_request_xmltype := XmlType('<?xml version="1.0" encoding="utf-8"?>'

37 || '<getNameInput xmlns="' || v_namespace || '">'

38 || '<employeeNumber>1234</employeeNumber>'

39 || '<nameCase>U</nameCase>'

40 || '</getNameInput>');

41

42 v_response_xmltype := utl_dbws.invoke(v_call, v_request_xmltype);

43

44 dbms_output.put_line('Result = ' || v_response_xmltype.getStringVal());

45

46 utl_dbws.release_call(v_call);

47 utl_dbws.release_service(v_service);

48 END;

49 /

Result = <ns0:getNameOutput xmlns:ns0="http://www.sagecomputing.com.au/emp/">CHRISTOPHER MUIR</ns0:getNameOutput>

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Part III: Publishing Web

Services from the Database

Native Web Services

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11g Native Web Services• Available as of RDBMS 11gR1 • Provided through Oracle XML DB feature set• Publishes:

– SQL & XQuery query facility– Stored PL/SQL procedures and functions including packages

• SOAP 1.1 compliant, WSDL automatically generated

• Advantages:– Simple, no application server required

• Disadvantages:– No control over WSDL naming conventions and payload

structures– Security concerns as web services are exposed directly from

database layer

11g Native Web Services Installation

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Native PL/SQL Web Services• Publish any procedure, function or package module• Support for parameters using most primitive datatypes and object

types, not %rowtype• Endpoint format:

http://<host>:<port>/orawsv/<schema>/<methodname>

http://<host>:<port>/orawsv/<schema>/<package>/<methodname>

• WSDL format:http://<host>:<port>/orawsv/<schema>/<methodname>?wsdl

http://<host>:<port>/orawsv/<schema>/<package>/<methodname>?wsdl

• Example:http://www.sagecomputing.com.au:8080/orawsv/SAGE/TEST?wsdl

• Schema/package/module names must match database case name• Requires HTTP basic authentication with schema username/pwd

Native PL/SQL Web Service "Example"

FUNCTION get_name(employeeNumber IN NUMBER, nameCase IN VARCHAR2)

RETURN VARCHAR2 AS

CURSOR c_name IS

SELECT decode(nameCase,'U',upper(name),'L',lower(name),initcap(name)) name

FROM employees

WHERE emp_no = employeeNumber;

v_name VARCHAR2(100);

BEGIN

OPEN c_name;

FETCH c_name INTO v_name;

CLOSE c_name;

RETURN v_name;

END get_name;

Native PL/SQL Web Service "Request"

Request

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:get="http://xmlns.oracle.com/orawsv/SAGE/GET_NAME">

<soapenv:Header/>

<soapenv:Body>

<get:SVARCHAR2-GET_NAMEInput>

<get:EMPLOYEENUMBER-NUMBER-IN>1234</get:EMPLOYEENUMBER-NUMBER-IN>

<get:NAMECASE-VARCHAR2-IN>U</get:NAMECASE-VARCHAR2-IN>

</get:SVARCHAR2-GET_NAMEInput>

</soapenv:Body>

</soapenv:Envelope>

Native PL/SQL Web Service "Response"

Response

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

<soap:Body>

<GET_NAMEOutput xmlns="http://xmlns.oracle.com/orawsv/SAGE/GET_NAME">

<RETURN>CHRISTOPHER MUIR</RETURN>

</GET_NAMEOutput>

</soap:Body>

</soap:Envelope>

Native Query Web Services• Queries & DML supported on any objects accessible via schema• Endpoint format:

http://<host>:<port>/orawsv

• WSDL format:http://<host>:<port>/orawsv?wsdl

• Example:http://www.sagecomputing.com.au:8080/orawsv?wsdl

• Requires HTTP basic authentication with schema username/pwd• Takes a basic SQL string with bind parameters• Returns XML structure containing data• Number of parameters to influence result

Native Query Web Service "Request"

Request

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:oraw="http://xmlns.oracle.com/orawsv">

<soapenv:Header/>

<soapenv:Body>

<oraw:query>

<oraw:query_text type="SQL">

<![CDATA[SELECT * FROM employees WHERE emp_id = :vEmpId]]>

</oraw:query_text>

<oraw:bind name="vEmpId">1234</oraw:bind>

</oraw:query>

</soapenv:Body>

</soapenv:Envelope>

Native Query Web Service "Response"

Response

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

<soap:Body>

<queryOut xmlns="http://xmlns.oracle.com/orawsv">

<ROWSET>

<ROW>

<EMP_ID>1234</EMP_ID>

<NAME>Christoper Muir</NAME>

</ROW>

</ROWSET>

</queryOut>

</soap:Body>

</soap:Envelope>

Summary

SAGE Computing ServicesCustomised Oracle Training Workshops and

Consulting

Questions and Answers?

Presentations are available from our website:www.sagecomputing.com.au

[email protected]@sagecomputing.com.auhttp://one-size-doesnt-fit-all.blogspot.com

utl_http ReferencesTim Hall's bloghttp://www.oracle-base.com/articles/9i/

ConsumingWebServices9i.php

http://www.oracle-base.com/dba/Script.php?category= miscellaneous&file=soap_api.sql

Oracle documentationhttp://download.oracle.com/docs/cd/B28359_01/appdev.111/

b28419/u_http.htm#CHDIAFFA

utl_dbws ReferencesTim Hall's bloghttp://www.oracle-base.com/articles/10g/utl_dbws10g.php

Marc Kelderman's bloghttp://orasoa.blogspot.com/2006/11/calling-bpel-process-with-

utldbws.html

Stellan's bloghttp://www.selectedthoughts.com/2007/04/problems-calling-net-

web-services-from.html

Henry Cortez on the OraFAQ forumhttp://www.orafaq.com/forum/t/99528/0/

Oracle 10g documentation http://download.oracle.com/docs/cd/B19306_01/appdev.102/

b14258/u_dbws.htm#i1001769

Native Web Services ReferencesTim Hall's bloghttp://www.oracle-base.com/articles/11g/

NativeOracleXmlDbWebServices_11gR1.php

Paul Gallagher's bloghttp://tardate.blogspot.com/2007/08/first-tests-of-11g-

native-web-services.html

Marc Thompson's bloghttp://marc-on-oracle.blogspot.com/2007/12/11g-database-

installation-and-native.html

Oracle 11g documentationhttp://download.oracle.com/docs/cd/B28359_01/appdev.111/

b28369/xdb_web_services.htm

Back to basics: Simple database web services without the need for SOA

Software

Transcript of Back to basics: Simple database web services without the need for SOA