1MAGPIERSS RECIPES:  Cooking with Corbies
2
3         "Four and twenty blackbirds baked in a pie."
4
51. LIMIT THE NUMBER OF HEADLINES(AKA ITEMS) RETURNED.
6
7PROBLEM:
8
9You want to display the 10 (or 3) most recent headlines, but the RSS feed
10contains 15.
11
12SOLUTION:
13
14$num_items = 10;
15$rss = fetch_rss($url);
16
17$items = array_slice($rss->items, 0, $num_items);
18
19DISCUSSION:
20
21Rather then trying to limit the number of items Magpie parses, a much simpler,
22and more flexible approach is to take a "slice" of the array of items.  And
23array_slice() is smart enough to do the right thing if the feed has less items
24then $num_items.
25
26See: http://www.php.net/array_slice
27
28
292. DISPLAY A CUSTOM ERROR MESSAGE IF SOMETHING GOES WRONG
30
31PROBLEM:
32
33You don't want Magpie's error messages showing up if something goes wrong.
34
35SOLUTION:
36
37# Magpie throws USER_WARNINGS only
38# so you can cloak these, by only showing ERRORs
39error_reporting(E_ERROR);
40
41# check the return value of fetch_rss()
42
43$rss = fetch_rss($url);
44
45if ( $rss ) {
46...display rss feed...
47}
48else {
49	echo "An error occured!  " .
50	     "Consider donating more $$$ for restoration of services." .
51		 "<br>Error Message: "	. magpie_error();
52}
53
54DISCUSSION:
55
56MagpieRSS triggers a warning in a number of circumstances.  The 2 most common
57circumstances are:  if the specified RSS file isn't properly formed (usually
58because it includes illegal HTML), or if Magpie can't download the remote RSS
59file, and there is no cached version.
60
61If you don't want your users to see these warnings change your error_reporting
62settings to only display ERRORs.  Another option is to turn off display_error,
63so that WARNINGs, and NOTICEs still go to the error_log but not to the webpages.
64
65You can do this with:
66
67ini_set('display_errors', 0);
68
69See: http://www.php.net/error_reporting,
70     http://www.php.net/ini_set,
71	 http://www.php.net/manual/en/ref.errorfunc.php
72
733. GENERATE A NEW RSS FEED
74
75PROBLEM:
76
77Create an RSS feed for other people to use.
78
79SOLUTION:
80
81Use Useful Inc's RSSWriter (http://usefulinc.com/rss/rsswriter/)
82
83DISCUSSION:
84
85An example of turning a Magpie parsed RSS object back into an RSS file is forth
86coming.  In the meantime RSSWriter has great documentation.
87
884. DISPLAY HEADLINES MORE RECENT THEN X DATE
89
90PROBLEM:
91
92You only want to display headlines that were published on, or after a certain
93date.
94
95
96SOLUTION:
97
98require 'rss_utils.inc';
99
100# get all headlines published today
101$today = getdate();
102
103# today, 12AM
104$date = mktime(0,0,0,$today['mon'], $today['mday'], $today['year']);
105
106$rss = fetch_rss($url);
107
108foreach ( $rss->items as $item ) {
109	$published = parse_w3cdtf($item['dc']['date']);
110	if ( $published >= $date ) {
111		echo "Title: " . $item['title'];
112		echo "Published: " . date("h:i:s A", $published);
113		echo "<p>";
114	}
115}
116
117DISCUSSION:
118
119This recipe only works for RSS 1.0 feeds that include the <dc:date> field.
120(which is very good RSS style)
121
122parse_w3cdtf is defined in rss_utils.inc, and parses RSS style dates into Unix
123epoch seconds.
124
125See: http://www.php.net/manual/en/ref.datetime.php
126