Transcript Techniques to Invoke Web Services from SAS

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Techniques to Invoke
Web Services from SAS
Leveraging Web Services within
your SAS Programs
“Come out of the desert of ignorance to the OASUS of knowledge”
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Agenda
• Introduction to Web Services
– SOAP
– WSDL
– Using Services
• Techniques to Invoke Web Services
– What SAS offers
– Benefits and Limitations
– An alternative Approach
• Demonstration
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Greg Ludwinski, Statistics Canada
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What is a Web Service?
• A software application identified by a URI
• Defined, described and discovered as xml
artifacts (WSDL).
• Supports direct interactions with other
software agents using XML-based messages
(SOAP) exchanged via standard network
protocols (HTTP).
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QOS
Management
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Security
Web Services Stack
UDDI
Discovery & publication
WSDL
Service description
SOAP
Messaging
HTTP, TCP
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Transportation
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SOAP
• SOAP is an XML based markup
language for messaging between
applications.
• Web Services expose functionality to
users through SOAP.
• Transport protocol neutral
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SOAP Message Structure
SOAP Message (an XML document)
SOAP Envelope
WS-Security
WS-Addressing
SOAP Header (optional)
Header
Header
SOAP Body (payload)
XML content
Request/
Response Data
Error handling
SOAP Fault (optional)
Attachment
(optional)
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Allows for
different encoding
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WSDL
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(Web Service Description Language)
• A contract between the Web service and
the client who uses it.
• An XML document that describes the
Web Service and defines the functions
that are exposed.
• It also defines where the service is
available and what communication
protocol is used to talk to the service.
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WSDL Structure
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Service
Port
Port
Where is it and how
to use it.
(eg. ftp://...)
(e.g. http://...)
Binding
Binding
(e.g. SOAP)
(e.g. ebXML)
Interface for service
operations
Port Type
Operations
Input
Output
message
message
Abstract Interface
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1 or more service
operations
Description of
inputs and outputs
using types and
schemas
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RESTful Web Services
• A lightweight alternative to SOAP
based web services
• Plain XML and JSON are popular
message protocols
• Standards are not as well defined
• HTTP header is used for security
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Calling Web Services
from SAS
• RESTful Web Services
– Proc Http
– URL file reference
• SOAP based Web Services
– Proc SOAP
– Functions SOAPWEB, SOAPWS, . . . .
– The WSDL markup type dropped in 9.3
• Custom Java Objects
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Proc Http
proc http
method=<post|get>
in=<fileref for request parameters(post)>
out=<fileref for response>
url=“<Path to service endpoint>”
.....
;
run;
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Proc SOAP
proc soap
in=<fileref for request>
out=<fileref for response>
url=“<Path to service endpoint>”
soapaction=“<Path to service operation>”
.....
;
run;
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Preparing for Proc SOAP
1. Use a tool such as SOAPUI to create a
service request template
2. Invoke the web service to get a sample
response
3. Create an XMLMap to convert the response
4. Determine additional requirements
(Security, Timeout Settings, Timestamp)
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Using
Custom
Java
Objects
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• Why use Java?
– SAS uses Java (Proc SOAP)
– Rich class libraries available (Web Service
Frameworks, Security . .. )
• How?
1. Develop a class and put it in a JAR file
2. Update your SAS Configuration file:
a) Add the JAR file to the Classpath
b) Set any required JREOptions
3. Java objects will be available in your SAS session
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Java objects in SAS
• Created within a data step
• SAS provides methods to;
– Call static & non-static methods (9 types)
– Get/Set static & non-static fields (9 types)
– Detect & Clear exceptions
– Flush output
– Delete objects
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Using Java Objects
Data _null_;
/* Declared and instantiate */
declare javaobj myJavaObject;
myJavaObject = _new_ javaobj("<classname>");
/* Call static/non static methods */
myJavaObject.callVoidMethod("<methodname>",
<parm1>);
myJavaObject.callStringMethod("<methodname>",
<parm1>,
<outstringVar>);
/* Object clean up */
myJavaObject.delete();
run;
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Comments / Questions
Statistics
Canada
Statistique
Canada
Greg Ludwinski
Project Leader - SAS Technology Centre
System Engineering Division
R.H. Coats Building, 14th Floor, Section Q
Ottawa, Ontario, Canada K1A 0T6
(613) 951-2768 Fax (613) 951-0607
[email protected]
Canada
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