Cheking if a webpage is online (best practices for making a Uptime Bot)

Question

Hello, im making a investigation and i need to check every 15 min for about 7 days if a web site is online. I have the url and high programing skills in VB6 and PHP, and some ideas of how to do that (like making a ping to the port 80 of the url), but due the important of this investigation i need recomendation from professionals, so if you have ideas of how to to this, or codes examples, even a free online service who is secure and made this, or a windows program already made, or any other thinks that can help me. Thanks.

I forgot to mention that i have a server that i can use for running the bot 24/7.

Answer 1

You should be doing a HEAD and looking at the response header, if it's 200, then it's up.

Answer 2

The simplest method is to fetch the contents of a fixed url from the monitored server. It can be a static text/html file, or a script that does some internal checks and outputs its status. All you need to do is a simple timed script that fetches the output and sees if it's what's expected.

Of course, just because the output isn't the expected value(s) doesn't mean the server's having trouble. There's always network burps to take into account. Things might be entirely ok, but some overeager backhoe dug through a cable between you and the server, making it appear down.