Building + Consuming WebServices

CF StyleKevin Penny

MMCP (4.5/5/MX6)

Topics Covered

• Uses of Web Services • Advantages of Web Services• Web Service Diagram• Languages of Web Services• Creating Web Services• Accessing Web Services• Securing Web Services• Best Practices• References

Uses - Web Services in Action

• Remotely lookup Product Inventory on Vendor overseas on the Web

• Create a stock lookup that’s available to a Flash Mobile application

• Create an interface to an already existing application to share data internally with other systems at a company

• Time Card System that may ‘check-in’ / ‘check-out’ employees in one area of the company maintained at another Central Location.

• Search Term / Search Results interface (i.e. Google)• Others??

Advantages – Old vs. New• Old Method• Form post of an xml file or specific

value(s) as a name/value to a url• The url receives the post and

expects a certain ‘name(s)’ as input

• Processes the input and creates an XML document that the two parties agree on

• Response is a text/xml document that the sender receives back and parses and processes the response from the XML document.

• No Soap• No WSDL• No UDDI• Limited

• New Method – (Web Services)

• Cfc created in Cold Fusion <cfcomponent>

• Function (method) created to ‘do’ something

• <cffunction name=“fn” access = “remote”>

• Parameters can be passed to function as arguments

• <cfargument name=“x”>• WSDL file is Generated

automatically• SOAP message created and

accepted automatically• Returnvalue <Cfreturn> specifies

the value of the response.

Advantages (con’t)• STANDARDS BASED - all speaking the same language that’s Industry

Standard• Network/Language/System Neutral – Can be implemented in many different

languages behind the scenes, but can be made accessible via web services.

• WSDL File - describes what’s needed in a readable XML format that tells developers what to call, what to pass in, and what’s expected (if anything)

• Self Documenting – Write the code and the Documentation at the same time.

• Publicly Available (optionally) - Can be made publicly available in a web service directory as an API (application programming interface) to your application or a part of your application (see References area for UDDI)

• REUSE - you do not have to recreate application logic that someone else has already created and, therefore, you can build your applications faster

Example – Ask Geeves…(ripoff )

• Form Post

• Web Service Call

• Web Service Output

• CFAdministrator setup

• WSDL File

• ColdFusion Component Explorer for generated WSDL File

Languages - Your Web Service Toolkit

• You’ll need your…– XML (eXtensible Markup Language) **– WSDL (Web Services Definition Language) *– SOAP (Simple Object Access Protocol)– UDDI (Universal Description, Discovery, and

Integration) – Implementation Language of Choice **

• ColdFusion/.Net/Flash/Java etc…

– Familiarity with Structures and Arrays is a plus

– ** Denotes Most Important in the ToolKit for CF Developers

Diagram - Path of the Web Service

Creating Web Services• The CFC Creation

– <cfcomponent>

• The CFFunction Method/Function– <cffunction>

• The Access Method– <cffunction access=“remote”>

• The return ‘Datatype’– <cffunction access=“remote” returntype=“string”>

• The Code in the cffunction – business logic/database lookup/logging/tracking/permissions

• The CFRETURN value

Accessing Web Services

• Cfinvoke webservice= *– url to wsdl file on external server– Can be setup in CF Admin (just like a datasource)– Arguments can be passed to the web service as

<cfinvokeargument> or inline (name/value pairs)– Method = xyz The ‘function’ you want to access– Createobject() inside a cfscript to invoke a webservice– Cfobject tag to call a webservice

• All options give the same performance

• * deontes my preference

Securing Your Web Services

• Providing Access to your Web Service– Methods

• Login/Password

• Reference Key

• Encrypted Keys

• Cfid/cftokens

• Jsessions etc

• IP Restrictions

• Bottom Line: however you would secure your website, you can secure your Web Service

Best Practices

• KISS Principle – Basic datatypes are preferred to complex datatypes – i.e. Strings compared to CFusion Queries

• Test before you publish + error trap – – if the cfc works prior to publishing it, it should work

afterwards

• Caching can/may occur – be prepared for it

• Get familiar with One way of creating/consuming web services and use it (personal preference)

References

• ColdFusion Web Services – Beginners Guide• Googles Web Search API

– http://api.google.com/GoogleSearch.wsdl • XMethods.com

– www.xmethods.com• CFDOCS Online/Local• UDDI Registry

– IBM• “The Pragmatic Programmer”

– Book of the Month