筑巢時間(Nesting Time)
前面的例子只是用來說明問題的。如果你真想把RDF內(nèi)容插入到Web站點當中,就需要把事情做的更好一些。所以把前面的腳本的作了改進,新增了一些東西,從而簡化格式化RDF數(shù)據(jù)的任務。
<html> <head> <basefont face="Verdana"> </head> <body> <table border="0" cellspacing="5" cellpadding="5"> <tr> <td><b>New releases on freshmeat.net today:</b></td> </tr> <?php // XML file $file = "http://www.freshmeat.net/backend/fm-releases.rdf"; // set up some variables for use by the parser $currentTag = ""; $flag = ""; $count = 0; // this is an associative array of channel data with keys ("title", "link", "description") $channel = array(); // this is an array of arrays, with each array element representing an <item> // each outer array element is itself an associative array // with keys ("title", "link", "description") $items = array(); // opening tag handler function elementBegin($parser, $name, $attributes) { global $currentTag, $flag; $currentTag = $name; // set flag if entering <channel> or <item> block if ($name == "ITEM") { $flag = 1; } else if ($name == "CHANNEL") { $flag = 2; } } // closing tag handler function elementEnd($parser, $name) { global $currentTag, $flag, $count; $currentTag = ""; // set flag if exiting <channel> or <item> block if ($name == "ITEM") { $count++; $flag = 0; } else if ($name == "CHANNEL") { $flag = 0; } } // character data handler function characterData($parser, $data) { global $currentTag, $flag, $items, $count, $channel; $data = trim(htmlspecialchars($data)); if ($currentTag == "TITLE" || $currentTag == "LINK" || $currentTag == "DESCRIPTION") { // add data to $channels[] or $items[] array if ($flag == 1) { $items[$count][strtolower($currentTag)] .= $data; } else if ($flag == 2) { $channel[strtolower($currentTag)] .= $data; } } } // create parser $xp = xml_parser_create(); // set element handler xml_set_element_handler($xp, "elementBegin", "elementEnd"); xml_set_character_data_handler($xp, "characterData"); xml_parser_set_option($xp, XML_OPTION_CASE_FOLDING, TRUE); xml_parser_set_option($xp, XML_OPTION_SKIP_WHITE, TRUE); // read XML file if (!($fp = fopen($file, "r"))) { die("Could not read $file"); } // parse data while ($xml = fread($fp, 4096)) { if (!xml_parse($xp, $xml, feof($fp))) { die("XML parser error: " . xml_error_string(xml_get_error_code($xp))); } } // destroy parser xml_parser_free($xp); // now iterate through $items[] array // and print each item as a table row foreach ($items as $item) { echo "<tr><td><a href=" . $item["link"] . ">" . $item["title"] . "</a><br>" . $item["description"] . "</td></tr>"; } ?>
</body> </html> 與先前的那段的主要區(qū)別在于,這段腳本創(chuàng)建了兩個數(shù)組,用于保存分析過程中所提取的信息。其中,$channel是聯(lián)合性數(shù)組(associative array),存放被處理的頻道的基本描述信息,而$items是一個二維數(shù)組,包含關(guān)于單獨的頻道條目(channel intems)的信息。$items數(shù)組中的每一個元素本身又是一個聯(lián)合性數(shù)組,包含title,URL和description關(guān)鍵字。$items數(shù)組中元素總數(shù)與RDF文檔中的<item>區(qū)塊總數(shù)相同。
還需注意$flag變量的變化,根據(jù)被處理的是<channel></channel>區(qū)塊還是<item></item>區(qū)塊,它現(xiàn)在保存兩個值。這一點很有必要,因為只有這樣,分析器才能把信息放入正確的數(shù)組里面。
一旦文檔分析完畢,事情就簡單了——遍歷$items 數(shù)組,以表格形式打印其中的每一個條目(item)。
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