#27242 [Com]: XML parser returs some weird outputs when you handle large files (500 MB++)

ID: 27242 Comment by: adam at trachtenberg dot com Reported By: amix at amix dot dk Status: Bogus Bug Type: XML related Operating System: WIndows and Mac OS X PHP Version: 4.3.5RC2 New Comment: Your character data handler receives data two bytes at a time, so you need to use ".=" instead of "=" when you do: $values[$count] = mysql_escape_string($data). Previous Comments: ------------------------------------------------------------------------ [2004-02-14 11:20:49] amix at amix dot dk "Of course you get strange results if you try to parse 2 bytes per time.." Please the whole text - the problem isn't that I parse 2 bytes per time - but my main problem is that same problem happens if I parse large XML files! If you parse huge files, you get same output error - and it does not matter if you use 2 bytes per time or 100000 (trust me I have tried it). How do I fix this problem - by NOT loading the whole file in the memory?? It seems to me that the problem is located in the php-xml-parse core. ------------------------------------------------------------------------ [2004-02-14 11:04:30] sniper@php.net Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php Of course you get strange results if you try to parse 2 bytes per time.. ------------------------------------------------------------------------ [2004-02-13 12:35:06] amix at amix dot dk Description: ------------ I am have made a script to parse the DMOZ RDF XML files. Which are HUGE (one is 500 MB and the other is 1.2 GB). The major problem I've got is that the XML parser outputs some bullshit when parsing those large files! The problem is how many bytes to read. I.e. this code: while ($data = fread($fp, 4096)) Now I have fixed this problem by loading the whole file into the memory: while ($data = fread($fp, filesize($this->xml_file))) { It takes some minutes to loade the 500 MB file, but can't do that with the 1.2 GB file. Ok, now I have searched a big deal on google. I have looked on how other parse XML files - and all I have seen use fread (including some PEAR scripts etc.) I have also made an example which shows the code on a smaller scale. If you set fread to read 2 bytes per time - then it makes some weird output. Reproduce code: --------------- This example is taken from a book. <?php $currentTag = ""; $fields = array(); $values = array(); $xml_file="data.xml"; function startElementHandler($parser, $name, $attributes) { global $currentTag, $table; $currentTag = $name; if (strtolower($currentTag) == "table") { $table = $attributes["name"]; } } function endElementHandler($parser, $name) { global $fields, $values, $count, $currentTag; global $connection, $table; if (strtolower($name) == "record") { $query = "INSERT INTO $table"; $query .= "(" . join(", ", $fields) . ")"; $query .= " VALUES(\"" . join("\", \"", $values) . "\");"; echo "$query\n"; $fields = array(); $values = array(); $count = 0; $currentTag = ""; } } function characterDataHandler($parser, $data) { global $fields, $values, $currentTag, $count; if (trim($data) != "") { $fields[$count] = $currentTag; $values[$count] = mysql_escape_string($data); $count++; } } $xml_parser = xml_parser_create(); xml_parser_set_option($xml_parser,XML_OPTION_SKIP_WHITE, TRUE); xml_parser_set_option($xml_parser, XML_OPTION_CASE_FOLDING, FALSE); xml_set_element_handler($xml_parser, "startElementHandler", "endElementHandler"); xml_set_character_data_handler($xml_parser, "characterDataHandler"); if (!($fp = fopen($xml_file, "rb"))) { die("File I/O error: $xml_file"); } while ($data = fread($fp, 2)) { if (!xml_parse($xml_parser, $data, feof($fp))) { $ec = xml_get_error_code($xml_parser); die("XML parser error (error code " . $ec . "): " . xml_error_string($ec) . "<br>Error occurred at line " . xml_get_current_line_number($xml_parser)); } } xml_parser_free($xml_parser); ?> data.xml <?xml version="1.0"?> <table name="readings"> <record> <a>56565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656</a> <b>12565656565656565656565656565656565656565656565656565656565656565622</b> <c>785656565656565656565656565656565656565656565656565656565656565656.5</c> </record> <record> <x>456565656565656565656565656565656565656565656565656565656565656565</x> <y>-565656565656565656565656565656565656565656565656565656565656565610</y> </record> <record> <x>156565656565656565656565656565656565656565656565656565656565656562</x> <b>105656565656565656565656565656565656565656565656565656565656565656459</b> <a>7565656565656565656565656565656565656565656565656565656565656565656</a> <y>95656565656565656565656565656565656565656565656565656565656565656</y> </record> </table> Expected result: ---------------- INSERT INTO readings(a, b, c) VALUES("56565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656", "12565656565656565656565656565656565656565656565656565656565656565622", "785656565656565656565656565656565656565656565656565656565656565656.5"); INSERT INTO readings(x, y) VALUES("456565656565656565656565656565656565656565656565656565656565656565", "-565656565656565656565656565656565656565656565656565656565656565610"); INSERT INTO readings(x, b, a, y) VALUES("156565656565656565656565656565656565656565656565656565656565656562", "105656565656565656565656565656565656565656565656565656565656565656459", "7565656565656565656565656565656565656565656565656565656565656565656", "95656565656565656565656565656565656565656565656565656565656565656"); Actual result: -------------- INSERT INTO readings(a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c) VALUES("56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "12", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "22", "78", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", ".5"); INSERT INTO readings(x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y) VALUES("4", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "5", "-", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "10"); INSERT INTO readings(x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y) VALUES("1", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "2", "1", "05", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "64", "59", "75", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "6", "9", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56"); 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