User Guide
Table Of Contents
- Contents
- The CFML Programming Language
- Elements of CFML
- Using ColdFusion Variables
- Using Expressions and Number Signs
- Using Arrays and Structures
- Contents
- About arrays
- Basic array techniques
- Populating arrays with data
- Array functions
- About structures
- Creating and using structures
- Structure examples
- Structure functions
- Extending ColdFusion Pages with CFML Scripting
- Using Regular Expressions in Functions
- Building Blocks of ColdFusion Applications
- Creating ColdFusion Elements
- Writing and Calling User-Defined Functions
- Contents
- About user-defined functions
- Creating user-defined functions
- Calling user-defined functions
- Working with arguments and variables in functions
- Handling errors in UDFs
- A user-defined function example
- Using UDFs effectively
- Building and Using ColdFusion Components
- Contents
- About ColdFusion components
- Creating ColdFusion components
- Using ColdFusion components
- Passing parameters to methods
- CFC variables and scope
- Using CFCs effectively
- ColdFusion component example
- Creating and Using Custom CFML Tags
- Building Custom CFXAPI Tags
- Developing CFML Applications
- Designing and Optimizing a ColdFusion Application
- Contents
- About applications
- Elements of a ColdFusion application
- Structuring an application
- Defining the application and its event handlers in Application.cfc
- Migrating from Application.cfm to Application.cfc
- Using an Application.cfm page
- Optimizing ColdFusion applications
- Handling Errors
- Contents
- About error handling in ColdFusion
- Understanding errors
- Error messages and the standard error format
- Determining error-handling strategies
- Specifying custom error messages with the cferror tag
- Logging errors with the cflog tag
- Handling runtime exceptions with ColdFusion tags
- Using Persistent Data and Locking
- Contents
- About persistent scope variables
- Managing the client state
- Configuring and using client variables
- Configuring and using session variables
- Configuring and using application variables
- Using server variables
- Locking code with cflock
- Examples of cflock
- Securing Applications
- Contents
- ColdFusion security features
- About resource and sandbox security
- About user security
- Using ColdFusion security tags and functions
- Security scenarios
- Implementing user security
- Developing Globalized Applications
- Debugging and Troubleshooting Applications
- Contents
- Configuring debugging in the ColdFusion MX Administrator
- Using debugging information from browser pages
- Controlling debugging information in CFML
- Using the cftrace tag to trace execution
- Using the cftimer tag to time blocks of code
- Using the Code Compatibility Analyzer
- Troubleshooting common problems
- Designing and Optimizing a ColdFusion Application
- Accessing and Using Data
- Introduction to Databases and SQL
- Accessing and Retrieving Data
- Updating Your Database
- Using Query of Queries
- Contents
- About record sets
- About Query of Queries
- Query of Queries user guide
- Using dot notation
- Using joins
- Using unions
- Using conditional operators
- Managing data types for columns
- Using the CAST function
- Using aggregate functions
- Using group by and having expressions
- Using ORDER BY clauses
- Using aliases
- Handling null values
- Concatenating strings
- Escaping reserved keywords
- Using Queries of Queries with dates
- Understanding Query of Queries performance
- Understanding Query of Queries processing
- Managing LDAP Directories
- Building a Search Interface
- Contents
- About Verity
- Creating a search tool for ColdFusion applications
- Creating a search page
- Enhancing search results
- Working with data returned from a query
- Using Verity Search Expressions
- Requesting and Presenting Information
- Introduction to Retrieving and Formatting Data
- Building Dynamic Forms with cfform Tags
- Validating Data
- Contents
- About ColdFusion MX validation
- Validating form fields
- Handling invalid data
- Masking form input values
- Validating form data with regular expressions
- Validating form data using hidden fields
- Validating form input and handling errors with JavaScript
- Validating data with the IsValid function and the cfparam tag
- Creating Forms in Macromedia Flash
- Creating Skinnable XML Forms
- Creating Charts and Graphs
- Creating Reports for Printing
- Contents
- About printable output
- Creating PDF and FlashPaper output with the cfdocument tag
- Creating reports with the ColdFusion MX 7 reporting
- Reporting features
- Reporting architecture
- Getting started
- Basic steps for creating reports
- Report definition guidelines
- Common reporting tasks and techniques
- Grouping and group breaks
- Defining, modifying, and using fields and input parameters
- Using toolbox elements on report bands
- Aligning elements
- Using text styles
- Previewing reports
- Displaying page numbers
- Using layered controls
- Using links
- Using the Properties sheet
- Displaying reports
- Using input parameters to pass variables and other data at runtime
- Configuring RDS
- Using the Report Creation Wizard
- Using the Query Builder
- Using CFML in reports
- Using charts
- Using subreports
- Font management with printable reports
- Creating reports with Crystal Reports (Windows only)
- Using the Flash Remoting Service
- Using Server-Side ActionScript
- Contents
- About server-side ActionScript
- Connecting to the Flash Remoting service
- Using server-side ActionScript functions
- Global and request scope objects
- About the CF.query function and data sources
- Using the CF.query function
- Building a simple application
- About the CF.http function
- Using the CF.http function
- Using Web Elements and External Objects
- Using XML and WDDX
- Contents
- About XML and ColdFusion
- The XML document object
- ColdFusion XML tag and functions
- Using an XML object
- Creating and saving an XML document object
- Modifying a ColdFusion XML object
- Validating XML documents
- Transforming documents with XSLT
- Extracting data with XPath
- Example: using XML in a ColdFusion application
- Moving complex data across the web with WDDX
- Using WDDX
- Using Web Services
- Contents
- Web services
- Working with WSDL files
- Consuming web services
- About the examples in this section
- Passing parameters to a web service
- Handling return values from a web service
- Using cfinvoke to consume a web service
- Using CFScript to consume a web service
- Consuming web services that are not generated by Macromedia ColdFusion MX
- Calling web services from a Macromedia Flash client
- Catching errors when consuming web services
- Handling inout and out parameters
- Configuring web services in the ColdFusion MX Administrator
- Data conversions between ColdFusion and WSDL data types
- Consuming ColdFusion web services
- Publishing web services
- Using request and response headers
- Handling complex data types
- Troubleshooting SOAP requests and responses
- Integrating J2EE and Java Elements in CFML Applications
- Integrating COM and CORBA Objects in CFML Applications
- Contents
- About COM and CORBA
- Creating and using objects
- Getting started with COM and DCOM
- Creating and using COM objects
- Getting started with CORBA
- Creating and using CORBA objects
- CORBA example
- Using XML and WDDX
- Using External Resources
- Sending and Receiving E-Mail
- Interacting with Remote Servers
- Managing Files on the Server
- Using Event Gateways
- Contents
- About event gateways
- Event gateway facilities and tools
- Structure of an event gateway application
- Configuring an event gateway instance
- Developing an event gateway application
- Deploying event gateways and applications
- Using the CFML event gateway for asynchronous CFCs
- Using the example event gateways and gateway applications
- Using the Instant Messaging Event Gateways
- Using the SMS Event Gateway
- Creating Custom Event Gateways
- Index
32 Chapter 2: Elements of CFML
User-defined functions
You can write your own functions, user-defined functions (UDFs). You can use these functions in
ColdFusion expressions or in CFScript. You can call a user-defined function anywhere you can
use a built-in CFML function. You create UDFs using the
cffunction tag or the CFScript
function statement. UDFs that you create using the cffunction tag can include ColdFusion
tags and functions. UDFs that you create in CFScript can only include functions. You can create
stand-alone UDFs or encapsulate them in a ColdFusion component.
User-defined functions let you encapsulate logic and operations that you use frequently in a single
unit. This way, you can write the code once and use it multiple times. UDFs ensure consistency of
coding and enable you to structure your CFML more efficiently.
Typical user-defined functions include mathematical routines, such as a function to calculate the
logarithm of a number; string manipulation routines, such as a function to convert a numeric
monetary value to a string such as “two dollars and three cents”; and can even include encryption
and decryption routines.
Note: The Common Function Library Project at www.cflib.org includes a number of free libraries of
user-defined functions.
For more information on user-defined functions, see Chapter 9, “Writing and Calling User-
Defined Functions,” on page 171.
ColdFusion components
ColdFusion components encapsulate multiple, related, functions. A ColdFusion component is
essentially a set of related user-defined functions and variables, with additional functionality to
provide and control access to the component contents. ColdFusion components can make their
data private, so that it is available to all functions (also called methods) in the component, but not
to any application that uses the component.
ColdFusion components have the following features:
• They are designed to provide related services in a single unit.
• They can provide web services and make them available over the Internet.
• They can provide ColdFusion services that Flash clients can call directly.
• They have several features that are familiar to object-oriented programmers, including data
hiding, inheritance, packages, and introspection.
For more information on ColdFusion components, see Chapter 10, “Building and Using
ColdFusion Components,” on page 201.
Constants
The value of a constant does not change during program execution. Constants are simple scalar
values that you can use within expressions and functions, such as “Robert Trent Jones” and
123.45. Constants can be integers, real numbers, time and date values, Boolean values, or text
strings. ColdFusion does not allow you to give names to constants.