Node.js is a framework that executes Javascript server-side through Google’s V8 Javascript engine. The idea behind node.js, or Node, is to handle a higher number of concurrent server requests than the traditional thread-based servers that are employed today. This is done by running an event loop in a single thread, allowing traditional Javascript callbacks to be employed when events completed their tasks. For my first post regarding Node, I will show how to write to a log file, similar to Apache’s access_log in order to keep track of HTTP requests.

If you are not familiar with Node, be sure to check out the Hello World example on the node homepage. In my access_log, I want to store the date and time, the remote address, the method of the request, and the requested URL. I want to make sure I append to the log file, as I do not want to write over the previous logs, so I will use the ‘a+’ flag to ensure that.

Here is the simple logging function:

Please note that the ‘request’ parameter in the function is the same variable ‘request’ from within the http.createServer function. For review, here is an example output of the log:

Perhaps you want to find out the total number of hits per page? This is very easy to do with bash:

This is just a very simple logging function, and if you want a more robust tool, please check out the node-elf-logger for more features.

Tags: access_log, file, log, node.js, write

This entry was posted on Sunday, July 11th, 2010 at 5:19 pm and is filed under node.js. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.