back to basics: simple database web services how to consume and publish web services with an oracle...
TRANSCRIPT
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
Agenda
• Part I: Understanding web services
• Part II: Consuming web services from the database
• Part III: Publishing web services from 11g
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>
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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
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<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:
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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:
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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)
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• 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