WDDX Case Study: Building a Cross CFUG Search

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WDDX Case Study Building a Cross CFUG Search

• April Fleming

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Introduction

• Real world WDDX (not just a short introduction)
• Problem I encountered developing an application
• How I used WDDX to solve the problem
• Benefits of using WDDX

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Scenario

• Data stored on 3 separate servers across the
  country
• Using CFHTTP to access remote server
• Remote server built query searching all fields on
  criteria entered by user.
• Remote server performs query, outputs the query
  results with a set of predetermined display
  fields
• Local server parses query results, stores each
  parsed record in a database, to be used and
  displayed.

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Problem

• Parsing routine had to be written
• If remote server output changed the parsing
  routine would no longer work until it was
  modified.
• Required strict communication/cooperation between
  nodes, not practical
• Needed to allow user to search on any given
  field, using logical operators
• EX FirstName contains A and FirstName
  contains B
• Needed knowledge of data on remote server to
  avoid rewriting the parsing routine if the remote
  server changed its structure
• Needed to allow user to specify any or all fields
  to display in search results in any given order.
• Needed knowledge of data on remote server to give
  user all possible return fields
• Local parsing routine needed to be able to parse
  any possible combination of fields returned by
  remote server.

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Problem - contd

• Storing Search Results
• Needed to be able to store any given set of
  fields in any order
• Current storage of search records to local table
  could not accommodate
• If we stored return fields as text, could not
  access them as a recordset
• Individually inserting records into the database
  was processor intensive and very slow.
• All of the writing and reading from the ACCESS
  database were causing it to be corrupt.

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Solution
Enter WDDX.
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What is WDDX?

• WDDX is a tag Markup language written in XML.
• The markup language describes the data which is
  being marked up
• Serialization and Deserialization functions
  written for CFML, ASP, JavaScript,Java, PERL, and
  Python
• Facilitates passing objects
• Recordsets
• Arrays
• Structures

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WDDX Tag

• ltCFWDDX ACTION""
• INPUT""
• OUTPUT""
  TOPLEVELVARIABLE"gt
• ACTION
• CFML2WDDX - Serialize to WDDX Format
• WDDX2CFML - Deserialize WDDX to CFML
• CFML2JS - Serialize CFML to Javascript
• WDDX2JS - Deserialize WDDX to Javascript
• INPUT - Data to be Serialized/Deserialized
• OUTPUT - Output variable for Serialized/Deserializ
  ed Data
• TOPLEVELVARIABLE - Output variable for Javascript
  Object

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Terms

• Serialize - converting data to WDDX format
• Deserialize - extracting data in native language
  format
• Packet - serialized data

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WDDX In Action

• Had the remote server output a WDDX packet
  describing their data
• Does not matter what language they use
• Used ltCFWDDXgt to deserialize their packet
• Was able to output over the deserialized query to
  create form for users to choose the fields they
  want to search
• Used ltCFWDDXgt to serialize a structure containing
  search criteria.
• Remote server outputs search results in packets
• Local server deserializes results packets and
  manipulates as if queries had been run locally

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WDDX In Action - Contd
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Benefits

• Parsing routine was already written, performed by
  WDDX tag
• Remote server could return any data, WDDX packets
  are self-describing
• User could specify any fields since parser could
  now parse any fields returned.
• Packets could be written to files, or entire
  packets could be stored in database requiring
  less load on the database.
• Surprisingly fast!

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Other Uses for WDDX

• Syndication
• Stocks quotes
• News feeds
• http//cfug.itcenter.org/ - Greg Wittes Digital
  Daily
• Using JavaScript to allow for multiple user input
  for a given field
• Parent/child relationship
• Multiple phone numbers
• Transferring Data from Browser to Server
• Wizard interface
• Maintain state in an inherently stateless medium

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Resources

• http//www.wddx.org/
• http//www.allaire.com/developer/
• http//www.xml.Com/
• Advanced ColdFusion 4.0 application development
  (ISBN 0-7897-1810-3)
• Advanced ColdFusion development
• XML journal (http//www.coldfusionjournal.Com/)