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Practical Uses for Web Services in Application Express
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product direction. It is intended for information
purposes only, and may not be incorporated into any
contract. It is not a commitment to deliver any
material, code, or functionality, and should not be
relied upon in making purchasing decisions.
The development, release, and timing of any
features or functionality described for Oracle’s
products remain at the sole discretion of Oracle.
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Agenda
• Web services introduction
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• Web service support in Application Express
• Amazon S3
• APEX_WEB_SERVICE API
• Web Service Tools and Debugging
• Additional resources
• Q&A
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Web Services Definition
http://en.wikipedia.org/wiki/Web_service
“Web services are typically application programming
interfaces (API) or web APIs that are accessed via
Hypertext Transfer Protocol and executed on a remote
system hosting the requested services. Web services tend
to fall into one of two camps: Big Web Services and
RESTful Web Services.”
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SOAP Web Services
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RESTful Style Web Services
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RESTful Style Web Services
• REpresentational State Transfer
• RESTful Web service request
– HTTP Method (GET, PUT, POST, DELETE, HEAD) indicates method of the
service
– HTTP URI (path) indicates the resource
– HTTP headers
– HTTP entity-body (parameter name/value pairs)
• RESTful Web service response
– XML
– Text
– JSON
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RESTful Support Application Express 4.x
• Expose report regions as RESTful Web service
• Wizard to create RESTful Web reference
– NEW in 4.1: Testing interface while creating the reference
• Test/Edit RESTful Web reference
• Wizard to create form on RESTful Web reference
• Wizard to create form and report on RESTful Web
reference
• NEW in 4.2: Support for JSON responses
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Amazon Simple Storage Service (S3)
• Storage for the Internet
– Designed to provide 99.99999999% durability and 99.99%
availability
– Designed to sustain the concurrent loss of data in two facilites
• Write, read, delete objects from 1 byte to 5 terabytes
• Objects are stored in “buckets” – a container for objects
• Common use cases:
– Content storage and distribution
– Backup or disaster recovery
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Amazon S3 – Technical Details
• Create an AWS account, http://aws.amazon.com/
• Sign up for an S3 account, http://aws.amazon.com/s3
• Authentication
– Authorization HTTP header
• AWS AWSAccessKeyId:Signature
• Signature is HMAC-SHA1 of selected elements from the
request, AWS Secret Key is used for the key
• Uses REST or SOAP interfaces
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Amazon S3 – Technical Details
• Endpoint: http(s)://s3.amazonaws.com
• Common HTTP Headers for all interactions
– Host: <bucket_name>.s3.amazonaws.com
– Date: Convert to GMT, and then use format Dy, DD Mon
YYYY HH24:MI:SS GMT
– Authorization: AWS <AWSAccessKeyId>:<Signature>
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Amazon S3 – Technical Details – Common
Operations
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List All Buckets
Create Bucket
Delete Bucket
List Bucket Contents
Get Object
Add Object
Delete Object
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apex_web_service API
• Allows you to interact with Web services (SOAP,
REST, RPC) in Application Express anywhere you
can write PL/SQL
• Includes functions to encode/decode binary data
to/from base64 encoding
• Contains function to parse response based on an
XPath expression
• Globals to retrieve/set HTTP Headers and cookies
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APEX_WEB_SERVICE
MAKE_REST_REQUEST Function - Syntax
APEX_WEB_SERVICE.MAKE_REST_REQUEST(
p_url
IN VARCHAR2,
p_http_method
IN VARCHAR2,
p_username
IN VARCHAR2 default null,
p_password
IN VARCHAR2 default null,
p_proxy_override IN VARCHAR2 default null,
p_body
IN CLOB default empty_clob(),
p_body_blob
IN BLOB default empty_blob(),
p_parm_name
IN WWV_FLOW_GLOBAL.VC_ARR2 default empty_vc_arr,
p_parm_value
IN WWV_FLOW_GLOBAL.VC_ARR2 default empty_vc_arr,
p_wallet_path
IN VARCHAR2 default null,
p_wallet_pwd
IN VARCHAR2 default null ) RETURN CLOB;
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Netflix API
• JavaScript, REST, Atom feeds
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search content
manage subscriber queue
display subscriber’s ratings
auto-complete
• Response is POX (plain old XML)
• Register for key and secret
– http://developer.netflix.com/apps/register/
• OAuth for authentication dealing with subscriber information
• Most requests are signed (much like Amazon s3)
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Web Service Tools and Debugging
• Web Service Reference testing interface
• Altova XMLSpy
– Good for inspecting response
– Has utility to give you XPath to response nodes
• ProxyTrace, http://www.pocketsoap.com/tcptrace/pt.aspx
– Allows you to inspect the exact HTTP traffic (including headers) for a
web service request/response
– Set proxy of your client to go through ProxyTrace to inspect the
traffic
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Additional Resources
• Application Express on OTN: http://otn.oracle.com/apex
• Application Express Web Service Integration Page:
http://www.oracle.com/technetwork/developertools/apex/application-express/integration-086636.html
– Application Express 4.0 Web Services Evaluation Guide
– Web Service Integration Sample Applications
– Web Service Integration Whitepapers
• Blog: http://jastraub.blogspot.com
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