xmlrpc_encode()

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

为 PHP 的值生成 XML

说明

xmlrpc_encode(mixed $value): string

Warning

此函数是实验性的。此函数的表象，包括名称及其相关文档都可能在未来的PHP 发布版本中未通知就被修改。使用本函数风险自担。

Warning

本函数还未编写文档，仅有参数列表。

Beware this quirk: when you xmlrpc_encode a hash into xmlrpc, numeric keys will not be kept. Even strings containing numbers-only will be lost.
i.e.: xmlrpc_decode(xmlrpc_encode(array('123'=>456)));
returns: array(0=>456);
Apparently this is intentional functionality (see http://bugs.php.net/bug.php?id=21949)
2 workarounds: 
1. prepend/append a string (even whitespace) to all keys, and strip them out at the other end. eg array('key_123'=>456);
2. create an array of hashes. array(array('key'=>123,'value'=>456));
I favour the second option because it's more deliberate.
... this also applies to xmlrpc_encode_request()

This function would be used by an XML-RPC server to convert PHP variables into an XML-RPC response.
It would be used within the PHP functions defined using xmlrpc_server_register_method()
Uses PHP variable reflection to assign the correct data types for the XML-RPC response. For example;
<?php
$params = array ( "one"=>"red","two"=>"blue","three"=>"green" );
$response = xmlrpc_encode ( $params );
echo ( $response );
?>
Produces;
<?xml version='1.0' encoding="utf-8" ?>
<params>
<param>
 <value>
 <struct>
  <member>
  <name>one</name>
  <value>
   <string>red</string>
  </value>
  </member>
  <member>
  <name>two</name>
  <value>
   <string>blue</string>
  </value>
  </member>
  <member>
  <name>three</name>
  <value>
   <string>green</string>
  </value>
  </member>
 </struct>
 </value>
</param>
</params>
While
<?php
$params = array ( "red", "blue", "green" );
$response = xmlrpc_encode ( $params );
echo ( $response );
?>
produces;
<?xml version='1.0' encoding="utf-8" ?>
<params>
<param>
 <value>
 <array>
  <data>
  <value>
   <string>red</string>
  </value>
  <value>
   <string>blue</string>
  </value>
  <value>
   <string>green</string>
  </value>
  </data>
 </array>
 </value>
</param>
</params>
And 
<?php
$params = 1;
$response = xmlrpc_encode ( $params );
echo ( $response );
?>
produces
<?xml version='1.0' encoding="utf-8" ?>
<params>
<param>
 <value>
 <int>1</int>
 </value>
</param>
</params>
It's useful to be aware of the settype() function (http://www.php.net/settype).
For binary base64 data and XML-RPC iso8601 date times the xmlrpc_set_type() function should be used on a PHP variable before using xmlrpc_encode()

Worth noting, you can use this function to generate fault response xml.
If you pass a pre-determined array into this function, as follows
<?
$myArray = array ("faultCode"=>1,"faultString"=>"Too many params");
$xml = xmlrpc_encode($myArray);
?>
... you will get output much like the following:
<?xml version="1.0" encoding="utf-8"?>
<fault>
<value>
 <struct>
 <member>
  <name>faultCode</name>
  <value>
  <int>4</int>
  </value>
 </member>
 <member>
  <name>faultString</name>
  <value>
  <string>Too many params</string>
  </value>
 </member>
 </struct>
</value>
</fault>
All that is needed to do here to make it valid XML-RPC is inject some of your own methodResponse tags.
Check the XML-RPC specification at http://www.xmlrpc.com/spec

Another quirk (more of a bug i think) is the automatic encoding of hashes where all keys that begin with a digit between 1 and 9 are lost:
http://bugs.php.net/bug.php?id=37746
Luckily I found a quick workaround. Just append chr(0x00) to your keys and the xmlrpc response will be correct. Maybe this will apply to encoding of hashes for requests too.

This xmlrpc_encode function doesn't generate the "methodResponse" tag required by some clients.
Using xmlrpc_encode_request seems better:
<?php
$xmlresponse = xmlrpc_encode_request(NULL, $phpresponse);
xmlrpc_encode(1) generate
<?xml version="1.0" encoding="utf-8"?>
<params>
<param>
 <value>
 <int>1</int>
 </value>
</param>
</params>
xmlrpc_encode_request(NULL,1) generate
<?xml version="1.0" encoding="iso-8859-1"?>
<methodResponse>
<params>
 <param>
 <value>
  <int>1</int>
 </value>
 </param>
</params>
</methodResponse>
?>