In an older post about Calculating the Moon Phase, I converted the some code I found to PHP. However the Lunar Phase Calculator has some more information (ecliptic latitude and longitude in degrees, the moon’s distance in Earth radii, etc.), the other one doesn’t, so I went ahead and converted it from JavaScript to PHP.
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Archive for the ‘Web’ Category
Calculating the Moon Phase Part 2
Monday, January 4th, 2010Posted in Web Development · Tags: code, php
RSS Cron Job
Monday, December 14th, 2009Posted in Web Development · Tags: code, php
If you are on shared web host, you might not have the ability to run lots of cron jobs or be limited to a certain number per hour or day. You might know about the “Poor Man’s Cron Job”, which is basically not to run a task (usually caching some data or fetching a feed, api, etc.) in the background until someone visits a page. Which isn’t ideal, because often the page will be slow or sometimes it won’t be up to date until the second visit (if you run that task after outputting the cached data).
Well one way to get around this is to setup an RSS feed for the data you are caching or outputting and access it with a query string such as “?rss=2.0″ or http://example.com/index.php?rss=2.0. Then you can check to see if the RSS variable was passed and output a RSS feed with just enough data for a feed, no need to put sensitive data in there or anything. I would suggest putting in a ttl node in the RSS feed and set it to something the aggregators like Google Reader, should obey (that way they hit your page more or less frequently, depending on your needs). The item portion of an RSS feed only needs a title or a description, although its probably a good idea to put some kind of guid in there (check the RSS 2.0 spec for more info on creating RSS feeds).
Anyway here is some sample code. It isn’t complete but gives you an idea what I mean.
if ($_GET['rss'] == 2.0)
{
//create RSS 2.0 feed
header('Content-Type: text/xml');
$output = '<' . '?xml version="1.0"?' . '>' . "\n";
$output .= '<rss version="2.0">' . "\n";
$output .= '<channel>' . "\n";
//...
//process your data and output it into RSS 2.0 format
//...
$output .= '</channel>' . "\n";
$output .= '</rss>';
}
else
{
//process your data as normal
}
Then to make sure the page is hit often, place your RSS feed into Google Reader or Bloglines or some other RSS aggregator. Then your site will be visited often and forced to update. No one else really needs to know about your RSS feeds, unless you want them to be public as well.
WordPress Email Exposure
Tuesday, November 3rd, 2009Posted in Web Apps · Tags: code, wordpress
I’ve noticed WordPress’s blog by email feature has the possibility of allowing anyone to see other email addresses. This feature can be turned on in the Admin in Settings->Writings and then Post via e-mail. Let’s say you set that email address as wordpressposts@example.com, that address will stay hidden. However anyone that emails that address will can have their address exposed on your blog by going to http://example.com/wp-mail.php (assuming that’s where you have WordPress installed at http://example.com). Chances are most people will have this set to a cron job and have it check it every so often, but it might be possible for others to request the page beforehand. And when you do go to that page, it shows something like this:
Author is myworkaddress@example.net Author: 1 Posted title: Some Blog Post Title Mission complete. Message 1 deleted.
Thus, if you are using your a email address you’d like to keep private and you are emailing wordpressposts@example.com, that email address has the possibility of showing up to people. Which is not good if you email from the same email address that checks the posts. And even worse if you email from a email address for a user in WordPress and has the rights to post contents because the email will get “publish” status rather than “pending” and will go live on the site. And if someone has the email address that is a user and has posting rights, they can easily send fake emails from that address, because all WordPress checks is the From or Reply-To line (whichever it finds first).
It’s easy to prevent it from showing email addresses by opening up wp-mail.php and looking for this line of code
echo '<p>' . sprintf(__('Author is %s'), $author) . '</p>';
And this line of code
echo "\n<p>" . sprintf(__('<strong>Author:</strong> %s'), esc_html($post_author)) . '</p>';
And then you could comment those lines out by putting // in front of both of them.
I understand WordPress outputs this information so you can see logged from any cron jobs you have setup or if you visit the page manually, as a way of just knowing whats going on. However, it could be done better to prevent the addresses from being shown to everyone. A simple solution is to setup a query string and have a secretkey (don’t make this your blog’s password however). For example, lets say your blog is installed at http://example.com/, we are going to know require the following URL to check Posts via e-mail http://example.com/wp-mail.php?secretkey=abc123. And if someone doesn’t send the right secretkey, it won’t check the email address or echo anything out.
So before this line of code
/** Make sure that the WordPress bootstrap has run before continuing. */
Let’s add
if ($_GET['secretkey'] != 'abc123')
exit();
Feel free to change the secretkey to whatever you wish. You can also change it to be called something other than secretkey. If you have a cron job, you’ll have to point to that new URL as well http://example.com/wp-mail.php?secretkey=abc123. If you use the secretkey method you can leave the lines where it echoes out the email address if you like (the 2 lines I showed you could comment out).
CSS3 Validation Debate Reponse
Tuesday, September 1st, 2009Posted in Web Development · Tags: css
There is a post on CSS3.info, The Big CSS3 Validation Debate where I left a comment I figured I’d make into a post here. It’s about how adding CSS3 rules to your style sheet result in errors with validation and what we think the W3C should do about it. Anyway, my response is below (edited, because I pressed submit too soon). 
No need to have the W3C mess with their validator just to work with all the possible browser extensions. This would most likely introduce bugs and cause too much of a headache for them.
Here are 2 things you can do to get by the errors
- Put all your CSS3 rules in a css3.css file and then when you validate everything in your regular .css files should pass and the css3.css should fail.
- Or put a /*CSS3*/ comment for each CSS3 rule you have in your style sheet, so when it gives an error you know why. This would work best if you put each css3 rule on a separate line.
Grooveshark Review
Saturday, June 27th, 2009Posted in Web · Tags: music
Grooveshark is another online music site, however I isn’t like all the other radio sites online. Let’s say you find a band you are interested in from Pandora or Last.fm. Pandora won’t let you just listen to one full song from a band in particular, only short clips. Last.fm will let you listen to whatever song you want, but you have to do a lot of clicking to listen to a bunch of them. Even if you add them to a playlist and going through the process of their “pseudo-popups”, you still can’t just tell Last.fm to play each song from the playlist (or at least I was unable to figure out how). This is where Grooveshark comes in. Grooveshark will let you listen to as many songs from a particular band that you want and you can even do it based on one of their albums. This is really great for exploring a band that may have peaked your interest.
However, it is not without faults. The biggest problem right now is that there are duplicate music files, because many songs are spelled differently or differ by a few seconds. It’s really annoying to try to clean up your queue of the duplicates, because you end up losing how far foward or back you are in the navigation. The other issue is that their music library isn’t as in depth as Pandora and definitely not as huge as Last.fm’s. I’ve also noticed that the “Recent songs listened to” RSS feed you get will only pull songs if they fit a certain time period, so if you go without using Grooveshark for awhile that feed will be empty, rather than remembering what you last listened to.