php/yaz

I asked some time ago about a program to retrieve book
details in XML
given the ISBN number,
and a number of suggestions were made, all of which I
followed up.
[In particular, I tried zoomsh + XSLT, but  this turned out
to be
too difficult for me to implement.]

In brief, I found I had to delve into PHP
(a language I knew nothing about)
to get a satisfactory solution.

I give my php program at the end -
however, this is more for interest than out of any pride in
it!
I'm sure it is far from the polished program
many of you would produce.
Though I did look around for such a program, without luck.

Any suggestions for the improvement of my program
will be gratefully received.

My solution leaves one simple question unanswered:

I based the program on the output of the Library of
Congress
Z39.50 server, using their XML format.
However, I found that other servers, eg Oxford University
(the URLs are given at the start of the program)
gave the result in a different XML format from LoC.

I actually prefer the Oxford XML format,
and wondered if there is a simple 1-1 mapping
between the two?
Or indeed between Marc and Oxford XML?

Maybe it would be better to retrieve the data
in MARC format, even if it is to be stored in XML?

------------------------- isbn.php -----------------------
<html>
<body>

<?php

// For list of servers see http://targettest.in
dexdata.com/

$servers = array("z3950.loc.gov:7090/voyager", 
  "library.tcd.ie:210/advance",
  "library.ox.ac.uk:210/ADVANCE",
  "library2.open.ac.uk:7090/voyager");

function isbncheck($entry) {
	if (ereg('[^-0-9X]$', $entry)) {
		echo "ISBN number can only contain digits 0-9, letter
X and hyphens (-'s)";
		return 0;
	}
	$isbn=ereg_replace("-","",$entry);
	if (strlen($isbn)!=10) {
		echo "Number must be of length 10 (excluding
-'s)";
		return 0;
	}
	$j=0;
	for ($i = 0; $i < 9; $i++)
		$j += $isbn[$i] * (10 - $i);
	if ($isbn[9] == "X")
		$j += 10;
	else
		$j += $isbn[9];
	if ($j % 11 == 0)
		return $isbn;
	else {
		echo "ISBN has wrong checksum (last
character)";
		return 0;
	}
}

if (!isset($_REQUEST["ISBN"])) {
  echo '<form method="post">
  <br />
  ISBN number: <input type="text"
size="15" name="ISBN" /><br />
  <input type="submit" name="action"
value="Submit" />
  </form>
  ';
} else {
  $entry=$_REQUEST["ISBN"];
  $isbn=isbncheck($entry);
  echo "ISBN $isbn: ";

// Look up ISBN number at Z39.50 servers

  for ($server = 0; $server < count($servers); $server++)
{
    $id = yaz_connect($servers[$server]);
    $query = "attr 1=7 $isbn";
    yaz_syntax($id, "xml");
    yaz_range($id, 1, 10);
    yaz_search($id, "rpn", $query);
    yaz_wait();
    $error = yaz_error($id);
    if (!empty($error)) 
      echo "Error: $error";
    else {
      $hits = yaz_hits($id);
      if ($hits > 0)
        break;
    }
  }
  if ($hits == 0) {
    echo "Sorry, cannot find book with IBSN number
$isbn<br />";
    break;
  } elseif ($hits == 1)
    echo "1 match<br />";
  else
    echo "$hits matches<br />";

// Display entry

  $rec =
"<catalog>".str_replace("xmlns",&q
uot;ns",yaz_record($id, 
1, "string"))."</catalog>";
echo htmlentities($rec);
  $xml = new SimpleXMLElement($rec);

  $author = array("");
  $authors = 0;

  foreach ($xml->record->datafield as $datafield) {
      switch((string) $datafield['tag']) { // Get attributes
as element 
indices
      case '100':
  	foreach ($datafield->children() as $subfield) {
  	    switch((string) $subfield['code']) { // Get
attributes as element 
indices
  	    case 'a':
  		$author[$authors] = $subfield;
  		$authors++;
  		break;
      	    }
  	}
          break;
      case '700':
  	foreach ($datafield->children() as $subfield) {
  	    switch((string) $subfield['code']) { // Get
attributes as element 
indices
  	    case 'a':
  		$author[$authors] = $subfield;
  		$authors++;
  		break;
      	    }
  	}
          break;
      case '245':
  	foreach ($datafield->subfield as $subfield) {
  	    switch((string) $subfield['code']) { // Get
attributes as element 
indices
  	    case 'a':
  		$title = strtr($subfield,"/"," ");
  		break;
      	    }
  	}
          break;
      case '260':
  	foreach ($datafield->children() as $subfield) {
  	    switch((string) $subfield['code']) { // Get
attributes as element 
indices
  	    case 'b':
  		$publisher = strtr($subfield,",."," 
");
  		break;
  	    case 'c':
  		$date = strtr($subfield,"c,.","  
");
  		break;
      	    }
  	}
          break;
      }
  }

  print "<table border='2' cellpadding='6'
align='center'";
  print "summary='Output of Z39.50 server'>";
  print
"<tr><td><b>ISBN</b></td>
<td>$isbn</td></tr>";
  if ($authors==1) {
      print
"<tr><td><b>Author</b></td&g
t;<td>$author[0]</td></tr>";
  } else {
      print "<tr><td 
rowspan=$authors><b>Authors</b></td><
;td>$author[0]</td></tr>";
      for ($i = 1; $i < $authors; $i++) {
  	print
"<tr><td>$author[$i]</td></tr>&
quot;;  
      }
  }
  print
"<tr><td><b>Title</b></td>
;<td>$title</td></tr>";
  print
"<tr><td><b>Publisher</b></t
d><td>$publisher</td></tr>";
  print
"<tr><td><b>Date</b></td>
<td>$date</td></tr>";
  print "</table>";

// Add new book to catalog

$docA = new DOMDocument;
$docA->formatOutput=true;
$docA->preserveWhiteSpace=false;

if ($docA->load("catalog.xml")) {
  echo "Catalog parsed<br />";
} else {
  echo "Error while parsing catalog<br />";
  exit;
}

$docB = new DOMDocument;
$docB->formatOutput=true;
$docB->preserveWhiteSpace=false;

if ($docB->loadXML($rec)) {
  echo "New entry parsed<br />";
} else {
  echo "Error while parsing new entry<br
/>";
  exit;
}

$xpath = new DOMXPath($docB);
$nodes = $xpath->query('//catalog/record');
foreach($nodes as $n) {
  $new = $docA->importNode($n, true);
  $docA->documentElement->appendChild($new);
}

$output = $docA->save("/tmp/catalog.xml");
echo "Output: $output bytes<br />";

}

?><br />

</body>
</html>
------------------------------------------------------------
-

The program assumes the existence of catalog.xml,
possibly empty as 

<?xml version="1.0"
encoding="iso-8859-1" ?>
<catalog>
</catalog>

-- 
Timothy Murphy  
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2,
Ireland

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