CLIII. WDDX Functions

简介

These functions are intended for work with WDDX.

需求

In order to use WDDX, you will need to install the expat library (which comes with Apache 1.3.7 or higher).

安装

After installing expat compile PHP with --enable-wddx.

PHP 的 Windows 版本已经内置该扩展模块的支持。无需加载任何附加扩展库即可使用这些函数。

运行时配置

本扩展模块在 php.ini 中未定义任何配置选项。

资源类型

本扩展模块未定义任何资源类型。

预定义常量

本扩展模块未定义任何常量。

范例

All the functions that serialize variables use the first element of an array to determine whether the array is to be serialized into an array or structure. If the first element has string key, then it is serialized into a structure, otherwise, into an array.

例子 1. Serializing a single value with WDDX


<?php
echo wddx_serialize_value("PHP to WDDX packet example", "PHP packet");
?>

This example will produce:

<wddxPacket version='1.0'><header comment='PHP packet'/><data>
<string>PHP to WDDX packet example</string></data></wddxPacket>

例子 2. Using incremental packets with WDDX


<?php
$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);
echo $packet;
?>

This example will produce:

<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>

注: If you want to serialize non-ASCII characters you have to convert your data to UTF-8 first (see utf8_encode() and iconv()).

目录
wddx_add_vars -- Add variables to a WDDX packet with the specified ID
wddx_deserialize -- 别名 wddx_unserialize()
wddx_packet_end -- Ends a WDDX packet with the specified ID
wddx_packet_start -- Starts a new WDDX packet with structure inside it
wddx_serialize_value -- Serialize a single value into a WDDX packet
wddx_serialize_vars -- Serialize variables into a WDDX packet
wddx_unserialize -- Unserializes a WDDX packet

add a note User Contributed Notes

npac at nospam dot spikesource dot com
26-Apr-2005 09:31


Contrary to a note on this page, the "datetime" type is actually supported by PHP. It turns out that the parser expects the type to be encoded exactly as <dateTime>. The string comparison is case sensitive - which means that if the WDDX packet contains <datetime> or <DATETIME>, then that particular var will simply be ignored. 



Of course, this can easily be worked around to replace all <datetime> and </datetime> tags in the WDDX package with <dateTime> and </dateTime> tags before passing it on to the wddx_deserialize() function.

Jimmy Wimenta
16-Jul-2004 08:53


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 09:08


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 08:11


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)) { //checks if the value is an object

        $valueType = get_class($value); //gets the NAME of the class, so the type of the current value

        $value = $value->date; //gets the value of the date property of the current Date Object

    } else {

        $valueType = gettype($value);

    }

    echo("Value = " . $value . "&nbsp;&nbsp;&nbsp;(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 10:29


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 01:11


a good FAQ on WDDX can be found here:

http://www.macromedia.com/v1/handlers/index.cfm?id=5622&method=full

bradburn at kiwi dot de
30-Jul-2002 10:02


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 @ http://www.openwddx.org/downloads/dtd/wddx_dtd_10.txt)  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 05:32


Tutorial here :





XML and PHP. Part 1: Using the WDDX functions


http://www.phpbuilder.net/columns/jesus20000402.php3

djm at web dot us dot uu dot net
02-Mar-2000 07:50


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 07:36


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 04:30


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="http://www.scripted.com/wddx/">http://www.scripted.com/wddx/</a>

djm at web dot us dot uu dot net
19-Oct-1999 11:45


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 03:29


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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