RSS the generator

What is RSS? If it is short, it is a format of an exchange of a content, basing on XML. Any Internet - resource containing the updated or filled up content, can zaimet` at itself RSS a tape and then users of this resource will receive a fast and convenient way to receive fresh materials. By the way, show RSS in a legible kind the same can Opera, and IE gives out simply formatted XML a file.

So, a problem : to write simple generator RSS of a tape for a site containing often the filled up content. The decision we write on PHP. And you as thought?:) Recordings of a tape we shall store{keep} in a separate file that it was easier to throw out out-of-date. Who it has suggested « to generate a tape dynamically, choosing the freshest recordings from MySQL »? Not prokatit, taking into account what to address to a database and to do{make} sample to us it is necessary each time at viewing a tape by the user. In our variant we have simple caching, and regeneration RSS occurs only at the moment of addition of new recording, and in general without the reference{manipulation} to base.

The circuit is simple: podgruzhaem the file with a tape, obrezaem old recording if it is too much them, also is finished new. A piece of a code, the explanatory on a course:

$rss_header_file = "rss/header.inc";

$rss_content_file = "rss/content.inc";

$rss_footer_file = "rss/footer.inc";

$rss_document_file = "rss/export.xml";

$rss_temp_file = "rss/tempfile";

$rss_miss_lines = 8; // Quantity{Amount} of lines in one recording

$rss_max_records = 10; // the Maximum quantity of recordings in a tape

// We load contents

$rss_content = file ($rss_content_file);

// If recordings more than it is necessary, we throw out the oldest

if (count ($rss_content)> $rss_miss_lines * $rss_max_records)

  $rss_content = array_slice ($rss_content, $rss_miss_lines);

// We add I skin recording

// In corresponding variables the data should contain

// At addition / removal of fields to correct $rss_miss_lines

array_push (

  $rss_content,

  " <item> \n ",

  "<title.>" $author. " </title> \n ",

  "<link.>" $link. " </link> \n ",

  "<guid.>" $link. " </guid> \n ",

  "<description.>" $message. " </description> \n ",

  "<pubDate>" .date ("r.") " </pubDate> \n ",

  "<author.>" $author. " </author> \n ",

  " </item> \n "

);

$fp = fopen ($rss_content_file, "w");

foreach ($rss_content as $rss_content_line) {

if ($rss_content_line! = "\n")

  fwrite ($fp, $rss_content_line);

}

fclose ($fp);

// We collect a tape

$rss_document = array_merge (

  file ($rss_header_file),

  file ($rss_content_file),

  file ($rss_footer_file)

);

// We use a temporary file that there were no conflicts of access

$rnd = rand (0, 1000);

$rss_temp_file = $rss_temp_file. $ rnd;

$fp = fopen ($rss_temp_file, "w");

foreach ($rss_document as $rss_document_line)

fwrite ($fp, $rss_document_line);

fclose ($fp);

unlink ($rss_document_file);

rename ($rss_temp_file, $rss_document_file);

All files for a tape are in a folder rss. It is useful to put also there an index file, pereadresujuhhij us on export.xml. In files header.inc and footer.inc contain, accordingly, heading and, khm... zavershitel` tapes. It is possible, certainly, was to register them in a code obviously but then the opportunity to correct them without zalezanija in a code is lost. Yes, also do not forget to format the added text properly, for example, with the help htmlspecialchars (nl2br ()).