Friday, July 13, 2012

Using CRON and PHP scripts with Dreamhost

As a followup to my previous post regarding inserting RSS feed data into a MySQL database, I wanted to quickly explain how I used DreamHost's CRON to create an automated news feed.

First make sure you have a script ready to use. Something that you want to run at certain time intervals. This could be the RSS feed script from before, something that scans user accounts, looks at site data and publishes an XML document, whatever. Just make sure it works (connects to DB, grabs or modifies data without problems, and closes the connection). Also be sure to change any local settings. For instance, if your script still says "localhost" for the connection string, it's not going to work!

Next we need to set up a Shell account, which is really easy in DreamHost:




It may take a few minutes for the new user to be created. After it's done, FTP into your web server using the new Shell account. I use Filezilla for this. If you don't know how to FTP in or setup Filezilla, this guide will probably help (or just Google it). Once you're in, create a folder called "cron" (or whatever you want to name it) and upload your scripts.




Almost done. Head back to DreamHost and click on "Cron Jobs", then "Add New Cron Job".



Finally we need to enter the cron settings. Select the shell user account you just created and title this cron job whatever you'd like. For "email output to", optionally enter an email address. If you do this, it will email you the results of your script. For instance, if you wrote your script in PHP and had any echo statements, you'll receive them. This is handy for when you first test your cron job so you can check that each part is running successfully. For example, you may want to echo/output any possible errors, success messages for DB connections/inserts/selects/etc., and a message at the end saying "script successful" or "script failed". After a few successful iterations of the cron job you can turn it off if you please.


For status we obviously want it enabled, although you can disable it later if you deem this script unnecessary. I prefer this as opposed to deleting it in case you want it later. For the command, we enter the path to the script. You can also write command code here, but I prefer having an external script I can modify and play with. I also leave locking on. And lastly, you can set your cron interval. This particular script runs every 15 minutes since I need fresh news frequently.




And that should be it. Once you submit it the cron job will run at the next interval and hopefully the script will execute successfully! For me, this allows me to read incoming RSS feeds, insert it into the DB, and then use the data on my website. It works great and I haven't had any problems since implementation. Good luck!


UPDATE: that space between php and /home/ in the command is on purpose! Be sure to do the same.

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