TechNote (Archived)

ColdFusion MX: How to log errors when using a site-wide error handler

Issue

When using the Site-wide Error Handler option in the ColdFusion MX Administrator, error messages are not logged to the Application log by design. However, the page you use for your site-wide error handler is designated to handle the errors and acts as ifcferror type="exception" had been called. Therefore, you have full access to error variables such as error.diagnostics and error.httpReferer. When used in combination with thecflog tag, you can write a custom entry to the Application.log or a custom log file and choose to output some, none, or all of the error.

Note: cflog can only write to .log files located in the cf_root\logs directory.

Solution

This example demonstrates how to log errors usingcflog and a site-wide error handler.

Create the site-wide handler template.

site_wide_error_handler.cfm:

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>Error Cleanup</title></head><body><h2>Sorry, there's been an error.</h2><BR><cftry><cflog     text="#error.diagnostics#, #error.httpReferer#, #error.template##error.querystring#"     log="APPLICATION" type="Error" application="yes"><CFOUTPUT><FONT face="Arial" ><strong>Diagnostic Information:</strong><BR><FONT face="Arial" color="800000" >#error.diagnostics#</FONT><P><strong>Generated Content:</strong><BR><FONT face="Arial" color="800000" >#error.generatedContent#</FONT><P><strong>Referring Page:</strong><BR><FONT face="Arial" color="800000" >#error.httpReferer#</FONT><P><strong>Template in Error:</strong><BR><FONT face="Arial" color="800000" >#error.template#?#error.querystring#</FONT></FONT></CFOUTPUT><CFCATCH></CFCATCH></CFTRY></body></html>

In the ColdFusion MX Administrator ServerSettings/Settings section, specify the site_wide_error_handler.cfm file in the Site-Wide Error Handler field and click Submit.

Create a template called make_error.cfm:

make_error.cfm:

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>Make An Error</title></head><body><cfoutput><A href="#CGI.SCRIPT_NAME#?make_error=YES">Throw an error!</A></cfoutput><CFIF IsDefined("url.make_error")><!--- Output a nonexistent variable to force error. ---><CFOUTPUT>#variables.blah#</CFOUTPUT></CFIF></body></html>

Run make_error.cfm in your browser and click the link displayed. The browser should display:

 Sorry, there's been an error.Diagnostic Information:Element BLAH is undefined in VARIABLES. The error occurred on line 7.Generated Content:Throw an error!Referring Page:http://localhost:8500/make_error.cfmTemplate in Error:/make_error.cfm?make_error=YES

Check the cf_root\logs\application.log and you should see an entry similar to the following:

 "Error","web-3","02/20/04","09:39:03",,"Element BLAH is undefined in VARIABLES. The error occurred on line 7., http://localhost:8500/make_error.cfm, /make_error.cfm make_error=YES