Practical Code Generation with CF Template

1. Practical Code Generationwith CF Template • Peter Bell • SystemsForge Webmaniacs ‘08

2. Overview • Why Generate? • Types of Generation • How to Generate • Benefits of CF Template • Working with Metadata

3. Why Generate? • Duplicated code: • within applications • between applications

4. We Already Generate GENERATING HTML: <cfoutputquery="GetUser"datasource="Scratch"> FirstName; #FirstName#<br/> LastName; #LastName#<br/> </cfoutput> GENERATING SCRIPTS: <<cfoutputquery="ObjectList"datasource="Scratch">> <cfoutputquery="Get%ObjectName%"datasource="Scratch"> <<cflooplist="%ObjectFieldNameList%"index="ThisField">> %ThisField%: %#ThisField#%<br/> <</cfloop>> </cfoutput> <</cfoutput>>

5. Three Stages of Code • 1. Duplicated <cfqueryname="GetUserByEmail"datasource="Scratch"> select FirstName,LastName from tbl_User where Email = <cfqueryparamcfsqltype="cf_sql_varchar"value="#form.Email#"> </cfquery> <cfqueryname="GetProductByID"datasource="Scratch"> select Title,Price from tbl_Product where ProductID = <cfqueryparamcfsqltype="cf_sql_int"value="#form.ProductID#"> </cfquery>

6. Three Stages of Code • 2. Dynamic <cfqueryname="GetData"datasource="Scratch"> select #FieldNameList# from #TableName# <cfifListFind("varchar,datetime,text",FilterFieldType)> where #FilterFieldName# = '#form.FieldValue#' <cfelse> where #FilterFieldName# = #form.FieldValue# </cfif> </cfquery>

7. Three Stages of Code • 3. Generated <cfqueryname="Get%ObjectName%by%FilterFieldName%"datasource="Scratch"> select %FieldNameList% from %TableName% where %FilterFieldName% = <cfqueryparamcfsqltype= "%FilterFieldType%"value="form.%FilterFieldName%"> </cfquery> GENERATES: <cfqueryname="GetUserByEmail"datasource="Scratch"> select FirstName,LastName from tbl_User where Email = <cfqueryparamcfsqltype="cf_sql_varchar"value="form.Email"> </cfquery>

8. Reasons to Generate • Prototype with Dynamic Code • Generate for: • Performance • Language Limitations • Simplicity • IP

9. Types of Generation • Passive vs. Active • Passive (wizard) • Passive (automated) • Active (round trip)

10. Active Code Generation • Separate files: • Inheritance • Mixins • AOP • CF Includes • Protected blocks

11. Approaches To Generation • Approaches to Generation • Concatenation • Template • Transformation

12. Concatenation <cfset ScriptHTML = "<cfquery name=""Get#ObjectName#by#FilterFieldName#"" datasource=""Scratch"">"> <cfset ScriptHTML = ScriptHTML & NewLine & "select #FieldNameList#"> <cfset ScriptHTML = ScriptHTML & NewLine & "from #TableName#"> <cfset ScriptHTML = ScriptHTML & NewLine & "where #FilterFieldName# = <cfqueryparam cfsqltype=""#FilterFieldType#"" value=""form.#FilterFieldName#""> "> <cfset ScriptHTML = ScriptHTML & NewLine & "</cfquery>">

13. Generation: XML <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheetversion="1.0"xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:outputmethod="text"indent="no"/> <xsl:templatematch="/"> &lt;cfquery name="Get<xsl:value-of select="//query/@ObjectName"/>by<xsl:value-of select="//query/@FilterFieldName"/>" datasource="Scratch"&gt; select <xsl:value-of select="//query/@FieldNameList"/> from <xsl:value-of select="//query/@TableName"/> where ##FilterFieldName## = &lt;cfqueryparam cfsqltype="<xsl:value-of select="//query/@FilterFieldType"/>" value="form.<xsl:value-of select="//query/@FilterFieldName"/>"&gt; &lt;/cfquery&gt; </xsl:template> </xsl:stylesheet> Sample XML modified from Illudium Generator by Brian Rinaldi

14. Generation: CF Template <cfqueryname="Get%ObjectName%by%FilterFieldName%"datasource="Scratch"> select %FieldNameList% from %TableName% where %FilterFieldName% = <cfqueryparamcfsqltype="%FilterFieldType%"value="#form.%FilterFieldName%#"> </cfquery> GENERATES: <cfqueryname="GetUserByEmail"datasource="Scratch"> select FirstName,LastName from tbl_User where Email = <cfqueryparamcfsqltype="cf_sql_varchar"value="#form.Email#">

15. CF Template Syntax • Generation Time Tags: << >> vs. < > • Generation Time Variables % vs. # • That is IT! • ALL ColdFusion features available • Including cfscript (<<cfscript>>)

16. Benefits of CF Template • More Readable • no &lt;/&gt; • Less “Junk” • <xsl:stylesheetversion="1.0"xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> • Shorter Variables • %TableName% vs. <xsl:value-of select="//query/@ObjectName"/> • Full Power of ColdFusion • DateFormat(), cfif, cfloop, cfoutput, UDFs, etc. • Nothing New to Learn!

17. Sources of Metadata • Database metadata • Explicit Metadata • Static code analysis • Runtime reflection

18. Metadata Options • Comma delimited • "test.csv", ",", "FirstName,LastName,Email", "tbl_User", "update" • XML • <import filename="test.csv" record-delimiter="," field-name-list="FirstName,LastName,Email" source="tbl_User" method="update" /> • Databased • “Little Language” • Import test.csv using commas update tbl_User with FirstName,LastName,Email • Visual

19. Example Metadata Product extends: BaseObject tableName: tbl_Product Identity: ProductID Properties: Title title required Price money optional default:0 Description WYSIWYG optional ClassMethods: AdminList: Title,Price OrderBy Title DefaultAdd: Title,Price,Description QuickAdd: Title,Price multiple:5 DefaultEdit: ID, Title,Price,Description Relationship has-many Category associated optional

20. Samples/Questions • Find out more at http://cftemplate.riaforge.com • Presentation will be posted tomorrow • Check out http://www.pbell.com