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CXVIII. WDDX funkce
Tyto funkce jsou ur�eny pro pr�ci s .
Pokud chcete pou��vat WDDX, budete muset nainstalovat expat knihovnu
(kter� je u Apache 1.3.7 a vy���ch).
Po instalaci expatu zkompilujte PHP s volbou
--enable-wddx.
Verze PHP pro Windows
m� vestav�nou podporu pro toto roz���en�. K pou�it� t�chto funkc� nen� t�eba
na��tat ��dn� dal�� roz���en�. Toto roz���en� nem� definov�no ��dn� konfigura�n�
direktivy. Toto roz���en� nem� definov�n ��dn� typ prost�edku
(resource). Toto roz���en� nem� definov�ny ��dn�
konstanty.
V�echny funkce, kter� serializuj� prom�nn�, pou��vaj� prvn� element
pole k rozhodnut� jestli se toto pole serializuje do pole nebo struktury.
Pokud m� prvn� element �et�zec jako index, serializuje se do struktury,
jinak do pole.
P��klad 1. Serializace jedin� hodnoty |
<?php
print wddx_serialize_value("Uk�zka p�evodu paketu z PHP do WDDX", "PHP packet");
?>
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Tato uk�zka vytvo��:
<wddxPacket version='1.0'><header comment='PHP packet'/><data>
<string>Uk�zka p�evodu paketu z PHP do WDDX</string></data></wddxPacket> |
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P��klad 2. Pou�it� inkrement�ln�ch paket� |
<?php
$pi = 3.1415926;
$packet_id = wddx_packet_start("PHP");
wddx_add_vars($packet_id, "pi");
$cities = array("Austin", "Novato", "Seattle");
wddx_add_vars($packet_id, "cities");
$packet = wddx_packet_end($packet_id);
print $packet;
?>
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Tato uk�zka vytvo��:
<wddxPacket version='1.0'><header comment='PHP'/><data><struct>
<var name='pi'><number>3.1415926</number></var><var name='cities'>
<array length='3'><string>Austin</string><string>Novato</string>
<string>Seattle</string></array></var></struct></data></wddxPacket> |
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Pozn�mka:
If you want to serialize non-ASCII characters you have to set
the appropriate locale before doing so (see
setlocale()).
Jimmy Wimenta
16-Jul-2004 12:53
PHP's WDDX is useful only for exchanging data between PHP applications, but definetly not for exchanging data between different languages (which actually defeats the purpose of WDDX).
For example:
$hash1 = array ("2" => "Two", "4" => "Four", "5" => "Five");
$hash2 = array ("0" => "Zero", "1" => "One", "2" => "Two");
$hash1 will be serialized as hash, but
$hash2 will be serialized as array/list, because the key happen to be a sequence starting from 0.
Unless the library provide a way for users to specify the type, it can never be used for cross-platform data exchange.
Q1tum at hotmail dot com
21-Nov-2003 01:08
To insert arrays into a wddx variable here is a fine way to do it:
<?php
$sql = 'SELECT * FROM example';
$query = mysql_query($sql, $db) or die(mysql_error());
while($result = mysql_fetch_array($query)) {
$id[] = $result[ 'id'];
$name[] = $result['name'];
$description[] = $result[$prefix . 'description'];
}
mysql_free_result($query);
wddx_add_vars($packet_id, "id");
wddx_add_vars($packet_id, "name");
wddx_add_vars($packet_id, "description");
$wddxSerializeValue = wddx_packet_end($packet_id);
?>
pierre dot jeunejean at adnexus dot be
26-Sep-2003 12:11
This is, to me, a nice way to solve the date problem.
In this example, we use a custom Date Object to store a date.
We show the serialized value in a textarea. We unserialize the packet and then we loop trough the returned array to get each element value and the data type of each of those values.
Here is the code, and after it its ouptut:
<?PHP
class Date {
var $date = null;
function Date ($date) {
$this->date = $date;
}
}
$textValue = "Per idem tempus annorum.";
$numberValue = 23;
$booleanValue = true;
$null = null;
$dateValue = new Date('22/03/2003');
$packet_id = wddx_packet_start();
wddx_add_vars($packet_id, "dateValue");
wddx_add_vars($packet_id, "textValue");
wddx_add_vars($packet_id, "numberValue");
wddx_add_vars($packet_id, "booleanValue");
wddx_add_vars($packet_id, "null");
$wddxSerializeValue = wddx_packet_end($packet_id);
echo("<FORM><TEXTAREA rows=15 cols=80>" .
$wddxSerializeValue .
"</TEXTAREA></FORM>");
$wddxDeserialize = wddx_deserialize($wddxSerializeValue);
foreach ($wddxDeserialize as $key => $value) {
if(is_object($value)) { $valueType = get_class($value); $value = $value->date; } else {
$valueType = gettype($value);
}
echo("Value = " . $value . " (Value type = " . $valueType . ")<br>");
}
?>
<wddxPacket version='1.0'>
<header/>
<data><struct>
<var name='dateValue'><struct>
<var name='php_class_name'><string>date</string></var>
<var name='date'><string>22/03/2003</string></var>
</struct></var>
<var name='textValue'><string>Per idem tempus annorum.</string></var>
<var name='numberValue'><number>23</number></var>
<var name='booleanValue'><boolean value='true'/></var>
<var name='null'><null/></var>
</struct></data>
</wddxPacket>
Value = 22/03/2003 (Value type = date)
Value = Per idem tempus annorum. (Value type = string)
Value = 23 (Value type = integer)
Value = 1 (Value type = boolean)
Value = (Value type = NULL)
12-Sep-2003 02:29
wddx isn't 100% perl compatible .. I have an wddx file infront of me and it only works with php so better don't use it
pointsystems.com, sbarnum
04-Sep-2002 05:11
a good FAQ on WDDX can be found here:
bradburn at kiwi dot de
30-Jul-2002 02:02
With ref to the above comment about typing, I have found that -- oddly enough -- PHP's WDDX supports the following WDDX types: null, boolean (true/false), number and string, *but* not date-time.
as an example, use the following values in an array that you then serialize:
$number = 5,
$null = NULL,
$bool = true,
$string = 'this is a string'.
they will all serialize correctly, e.g. the third entry comes out as:
<var name='bool'><boolean value='true'/></var>
i have tried with the 'official' format for WDDX 'datetime', e.g. '1998-9-15T09:05:32+4:0' (from the DTD @ ) but have only succeeded in getting this encoded as a 'string' type.
if anyone else has any more information on this, it would be welcome. i would like to store the variables in 'appropriate' fields in a database, and the fact that only datetime is not supported is slightly irritating -- otherwise it would be a very useful function.
philip at thepr()jects dot ()rg
17-Nov-2000 09:32
Tutorial here :
XML and PHP. Part 1: Using the WDDX functions
djm at web dot us dot uu dot net
02-Mar-2000 11:50
Here's a rewrite of the deserializing Perl code that uses variable names consistently with the serializing example. Sorry for any confusion....
<PRE>
#!/usr/bin/perl
use WDDX;
open(FP, "<cities.wddx");
undef $/; # Slurp the whole file.
$packet = <FP>;
close(FP);
$wddx = new WDDX;
$packet_id = $wddx->deserialize($packet);
$value = $packet_id->as_hashref();
print "pi is:<br>" . $value->{"pi"} . "<p>\n";
print "cities is:<br>\n";
$key = 0;
foreach $val (@{$value->{"cities"}}) {
print "$key => $val<br>\n";
$key++;
}
</PRE>
djm at web dot us dot uu dot net
02-Mar-2000 11:36
I think it would be helpful for passing data between languages to show a direct translation of the above examples into Perl, using WDDX.pm 1.00 from CPAN. It took me awhile to figure out. To serialize:
<PRE>
#!/usr/bin/perl
use WDDX;
$wddx = new WDDX;
$packet_id = $wddx->struct({});
$pi = 3.1415926;
$packet_id->set("pi" => $wddx->number($pi));
# Suppose @cities came from database
@cities = ("Austin", "Novato", "Seattle");
$packet_id->set("cities" => $wddx->array([map $wddx->string($_), @cities]));
$packet = $wddx->serialize($packet_id);
open(FP, ">cities.wddx");
print FP $packet;
close(FP);
</PRE>
<P>
To deserialize:
<PRE>
#!/usr/bin/perl
use WDDX;
open(FP, "<cities.wddx");
undef $/; # Slurp the whole file.
$packet = <FP>;
close(FP);
$packet_id = new WDDX;
$wddx_obj = $packet_id->deserialize($packet);
$value = $wddx_obj->as_hashref();
print "pi is:<br>" . $value->{"pi"} . "<p>\n";
print "cities is:<br>\n";
$key = 0;
foreach $val (@{$value->{"cities"}}) {
print "$key => $val<br>\n";
$key++;
}
</PRE>
djm at web dot us dot uu dot net
20-Oct-1999 08:30
The PHP WDDX module encodes all scalars as strings in the XML packet, due to PHP's loose typing. The current Perl WDDX module takes a different approach, requiring the caller to mark each variable with a type. This is helpful if the reader of the packet is a more strongly typed language that distinguishes between string, int, float, and bool; but it's more cumbersome to use than the PHP approach. The Perl module is hard to find right now; its home page is:
<br>
<a href="">
djm at web dot us dot uu dot net
19-Oct-1999 03:45
Since there aren't any examples of reversing the process, here's one. If you had the packet produced by the above example (without the htmlentities() call), you could retrieve the values like this:
<pre>
$value = wddx_deserialize($packet);
print "pi is:<br>" . $value["pi"] . "<p>\n";
print "cities is:<br>\n";
while (list($key, $val) = each($value["cities"])) {
print "$key => $val<br>\n";
}
</pre>
which outputs:
<pre>
pi is:
3.1415926
cities is:
0 => Austin
1 => Novato
2 => Seattle
</pre>
yzhang at sfu dot ca
26-May-1999 07:29
To make these examples work, you'll probably want to format the output with a call to htmlentities:
$pi = 3.1415926;
$packet_id = wddx_packet_start("PHP");
wddx_add_vars($packet_id, "pi");
/* Suppose $cities came from database */
$cities = array("Austin", "Novato", "Seattle");
wddx_add_vars($packet_id, "cities");
$packet = wddx_packet_end($packet_id);
print htmlentities($packet);
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w32api_set_call_method
