CFTRY  
Description

Used with one or more cfcatch tags. Together, they catch and process exceptions in ColdFusion pages. Exceptions are events that disrupt the normal flow of instructions in a ColdFusion page, such as failed database operations, missing include files, and developer-specified events.

 
Category

Exception handling tags

 
Syntax
    <cftry>
   code here
<cfcatch type = "exceptiontype">
   Exception processing code here
</cfcatch>
   Optional: More cfcatch blocks here
</cftry>

  
 
See also

cfcatch, cferror, cfrethrow, cfthrow

 
History

New in ColdFusion MX: The SQLSTATE return value in a cfcatch tag depends on the database driver type:

  • Type 1 (JDBC-ODBC bridge): the value is the same as in ColdFusion 5
  • Type 4 (100% Java, no native methods): the value might be different

If your application depends on SQLSTATE values for flow control, the application might produce unexpected behavior with ColdFusion MX.

New in ColdFusion MX: it is not necessary, when you include a cfcatch tag with type="any", to do so in the last cfcatch tag in the block, to ensure that all other tests are executed before it. ColdFusion finds the best-match cfcatch block.

New in ColdFusion MX: the cftry and cfcatch tags can be used as cfscript constructs, and for handling component method invocation errors.

New in ColdFusion MX: you cannot modify the structure returned by cfcatch.

New in ColdFusion MX: The cfcollection, cfindex, and cfsearch tags can throw the SEARCHENGINE exception. In earlier releases, an error in processing these tags threw only an UNKNOWN exception.

 
Usage

Within a cftry block, you must code at least one cfcatch tag. Put cfcatch tags at the end of a cftry block. ColdFusion tests cfcatch tags in the order in which they appear.

If type="any", ColdFusion Server catches exceptions from any CFML tag, data source, or external object. To get the exception type use code such as the following:

   #cfcatch.type#

Applications can use the cfthrow tag to throw developer-defined exceptions. Catch these exceptions with any of these type options:

  • "custom_type"
  • "Application"
  • "Any"

The custom_type type is a developer-defined type specified in a cfthrow tag. If you define a custom type as a series of strings concatenated by periods (for example, "MyApp.BusinessRuleException.InvalidAccount"), the cfcatch tag can catch the custom type by its character pattern. The tag searches for a matching exception type, starting with the most specific (the entire string), and ending with the least specific.

For example, you could define a type as follows:

   <cfthrow type = "MyApp.BusinessRuleException.InvalidAccount">

The cfcatch tag first searches the cfthrow tag for the entire type string:

   <cfcatch type = "MyApp.BusinessRuleException.InvalidAccount"> 

If it does not find a match, it searches for the next most specific:

<cfcatch type = "MyApp.BusinessRuleException"> 

Finally, it searches for the least specific:

   <cfcatch type = "MyApp"> 

You can code cfcatch tags in any order to catch a custom exception type.

If you specify type = "Application", the cfcatch tag catches only custom exceptions that have the Application type in the cfthrow tag that defines them.

The cfinclude, cfmodule, and cferror tags throw an exception of type = "template".

An exception that is thrown within a cfcatch block cannot be handled by the cftry block that immediately encloses the cfcatch tag. However, you can rethrow the currently active exception with the cfrethrow tag.

The following example shows how to throw an exception from a component method:

<cfcomponent>
   <cffunction name="getEmp">
   <cfargument name="lastName" required="yes">    
       <cfquery name="empQuery" datasource="ExampleApps" >
          SELECT LASTNAME, FIRSTNAME, EMAIL
          FROM tblEmployees
         WHERE LASTNAME LIKE '#arguments.lastName#'
       </cfquery>
       <cfif empQuery.recordcount LT 1>
          <cfthrow type="noQueryResult" 
            message="No results were found. Please try again.">
         <cfelse>
              <cfreturn empQuery>
        </cfif>
   </cffunction>
</cfcomponent>

For an explanation of the example and more information, see the "Building and Using ColdFusion Components" chapter in Developing ColdFusion Applications.

The cfcatch variables provide the following exception information:

cfcatch variable  Content

cfcatch.type

Type: Exception type, as specified in cfcatch.

cfcatch.message

Message: Exception's diagnostic message, if provided; otherwise, an empty string; in the cfcatch.message variable

cfcatch.detail

Detailed message from CFML interpreter. The message contains HTML formatting. It can help determine which tag threw the exception.

cfcatch.tagcontext

Tag stack name, position of each tag in the stack, and absolute pathnames of the files that contain the tags in the stack.

cfcatch.NativeErrorCode

Applies to type = "database". Native error code associated with exception. Database drivers typically provide error codes to diagnose failing database operations. Default: -1.

cfcatch.SQLState

Applies to type ="database". SQLState associated with exception. Database drivers typically provide error codes to help diagnose failing database operations. Default: -1.

cfcatch.ErrNumber

Applies to type="expression". Internal expression error number.

cfcatch.MissingFileName

Applies to type="missingInclude". Name of file that could not be included.

cfcatch.LockName

Applies to type="lock". Name of affected lock (if the lock is unnamed, the value is "anonymous").

cfcatch.LockOperation

Applies to type="lock". Operation that failed (Timeout, Create Mutex, or Unknown).

cfcatch.ErrorCode

Applies to type="custom". String error code.

cfcatch.ExtendedInfo

Applies to type="application" and "custom". Custom error message; information that the default exception handler does not display.

 
Advanced Exception types

You can specify the following advanced exception types in the type attribute:

ColdFusion Advanced Exception type

COM.Allaire.ColdFusion.CFEXECUTE.OutputError

COM.Allaire.ColdFusion.CFEXECUTE.Timeout

COM.Allaire.ColdFusion.FileException

COM.Allaire.ColdFusion.HTTPAccepted

COM.Allaire.ColdFusion.HTTPAuthFailure

COM.Allaire.ColdFusion.HTTPBadGateway

COM.Allaire.ColdFusion.HTTPBadRequest

COM.Allaire.ColdFusion.HTTPCFHTTPRequestEntityTooLarge

COM.Allaire.ColdFusion.HTTPCGIValueNotPassed

COM.Allaire.ColdFusion.HTTPConflict

COM.Allaire.ColdFusion.HTTPContentLengthRequired

COM.Allaire.ColdFusion.HTTPContinue

COM.Allaire.ColdFusion.HTTPCookieValueNotPassed

COM.Allaire.ColdFusion.HTTPCreated

COM.Allaire.ColdFusion.HTTPFailure

COM.Allaire.ColdFusion.HTTPFileInvalidPath

COM.Allaire.ColdFusion.HTTPFileNotFound

COM.Allaire.ColdFusion.HTTPFileNotPassed

COM.Allaire.ColdFusion.HTTPFileNotRenderable

COM.Allaire.ColdFusion.HTTPForbidden

COM.Allaire.ColdFusion.HTTPGatewayTimeout

COM.Allaire.ColdFusion.HTTPGone

COM.Allaire.ColdFusion.HTTPMethodNotAllowed

COM.Allaire.ColdFusion.HTTPMovedPermanently

COM.Allaire.ColdFusion.HTTPMovedTemporarily

COM.Allaire.ColdFusion.HTTPMultipleChoices

COM.Allaire.ColdFusion.HTTPNoContent

COM.Allaire.ColdFusion.HTTPNonAuthoritativeInfo

COM.Allaire.ColdFusion.HTTPNotAcceptable

COM.Allaire.ColdFusion.HTTPNotFound

COM.Allaire.ColdFusion.HTTPNotImplemented

COM.Allaire.ColdFusion.HTTPNotModified

COM.Allaire.ColdFusion.HTTPPartialContent

COM.Allaire.ColdFusion.HTTPPaymentRequired

COM.Allaire.ColdFusion.HTTPPreconditionFailed

COM.Allaire.ColdFusion.HTTPProxyAuthenticationRequired

COM.Allaire.ColdFusion.HTTPRequestURITooLarge

COM.Allaire.ColdFusion.HTTPResetContent

COM.Allaire.ColdFusion.HTTPSeeOther

COM.Allaire.ColdFusion.HTTPServerError

COM.Allaire.ColdFusion.HTTPServiceUnavailable

COM.Allaire.ColdFusion.HTTPSwitchingProtocols

COM.Allaire.ColdFusion.HTTPUnsupportedMediaType

COM.Allaire.ColdFusion.HTTPUrlValueNotPassed

COM.Allaire.ColdFusion.HTTPUseProxy

COM.Allaire.ColdFusion.HTTPVersionNotSupported

COM.Allaire.ColdFusion.POPAuthFailure

COM.Allaire.ColdFusion.POPConnectionFailure

COM.Allaire.ColdFusion.POPDeleteError

COM.Allaire.ColdFusion.Request.Timeout

COM.Allaire.ColdFusion.SERVLETJRunError

COMCOM.Allaire.ColdFusion.HTTPConnectionTimeout

This tag requires an end tag.

 
Example
<!--- cftry example, using TagContext to display the tag stack. --->
<h3>cftry Example</h3>
<!--- open a cftry block --->
<cftry>
   <!--- note misspelled tablename "employees" as "employeeas" --->
   <cfquery name = "TestQuery" dataSource = "cfsnippets">
      SELECT *
      FROM EMPLOYEEAS
   </cfquery>

   <!--- <p>... other processing goes here --->
   <!--- specify the type of error for which we search --->
   <cfcatch type = "Database">
   <!--- the message to display --->
      <h3>You've Thrown a Database <b>Error</b></h3>
      <cfoutput>
         <!--- and the diagnostic message from the ColdFusion server --->
         <p>#cfcatch.message#</p>
         <p>Caught an exception, type = #CFCATCH.TYPE# </p>
         <p>The contents of the tag stack are:</p>
         <cfloop index = i from = 1 
               to = #ArrayLen(CFCATCH.TAGCONTEXT)#>
            <cfset sCurrent = #CFCATCH.TAGCONTEXT[i]#>
            <br>#i# #sCurrent["ID"]# 
               (#sCurrent["LINE"]#,#sCurrent["COLUMN"]#) 
               #sCurrent["TEMPLATE"]#
         </cfloop>
      </cfoutput>
   </cfcatch>
</cftry>
TYPE  
  Optional
 
Default value: "Any"
  • application: catches application exceptions
  • database: catches database exceptions
  • template: catches ColdFusion page exceptions
  • security: catches security exceptions
  • object: catches object exceptions
  • missinginclude: catches missing include file exceptions
  • expression: catches expression exceptions
  • lock: catches lock exceptions
  • custom_type: catches developer-defined exceptions, defined in the cfthrow tag
  • searchengine: catches Verity search engine exceptions
  • any: catches all exception types