Jabber-RPC

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Jabber-RPC This specification defines a method for transporting XML-RPC encoded requests and responses over Jabber/XMPP. &LEGALNOTICE; 0009 Final Standards Track Standards XMPP Core XML-RPC jabber-rpc http://www.xmpp.org/schemas/jabber-rpc.xsd DJ Adams dj.adams@pobox.com dj@gnu.mine.nu 2.1 2006-02-09 psa Defined error handling, service discovery, security considerations, and XMPP Registrar considerations. 2.0 2002-12-09 psa Per a vote of the Jabber Council, changed status to Final. 1.0 2001-09-27 psa Changed status to Draft 0.1 2001-09-14 dja Initial version

&xmlrpc; is a method of encoding RPC requests and responses in XML. The original specification defines HTTP (see &rfc2068;) as the only valid transport for XML-RPC payloads.

Various initiatives exist already to transport XML-RPC payloads over Jabber. These initiatives were independent of each other and used slightly differing methods (e.g. carrying the payload in a element as opposed to an &IQ; stanza), resulting in potential interoperability problems.

A working session during JabberCon 2001 resulted in a formalisation of a single method. This document describes that method, which is labelled as Jabber-RPC to differentiate it from XML-RPC itself.

The &IQ; stanza is used to transport XML-RPC payloads. XML-RPC requests are transported using an &IQ; stanza of type "set", and XML-RPC responses are transported using an &IQ; stanza of type "result". An &IQ; stanza MUST NOT contain more than one request or response.

The &IQ; stanza contains a single &QUERY; sub-element in the jabber:iq:rpc namespace. The direct child of the &QUERY; element will be either a single <methodCall/> element (in the case of a request) or a single <methodResponse/> element (in the case of a response). This child element will contain the XML-RPC payload. Note that the XML declaration that normally appears at the head of an XML-RPC request or response when transported as the payload of an HTTP POST request MUST BE omitted when it is transported via a Jabber &IQ; stanza.

The encoding of the Jabber XML stream is UTF-8. It is assumed that the encoding of the XML-RPC payload is also UTF-8.

Application-level errors will be indicated within the XML-RPC payload (as is the case with the traditional HTTP-based XML-RPC mechanism). Transport level errors will be indicated in the normal way for &IQ; stanzas -- namely, by an &IQ; stanza of type "error" and the addition of an <error/> tag as a direct child of the &IQ; stanza. There are no specific XML-RPC-related, transport-level errors.

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If the requesting entity does not have sufficient permissions to perform remote procedure calls, the responding entity MUST return a &forbidden; error:

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If an entity supports the Jabber-RPC protocol, it SHOULD advertise that fact in response to &xep0030; information ("diso#info") requests by returning an identity of "automation/rpc" and a feature of "jabber:iq:rpc":

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An entity that supports Jabber-RPC SHOULD establish a "whitelist" of entities that are allowed to perform remote procedure calls and MUST return a &forbidden; error if entities with insufficient permissions attempt such calls.

This document requires no interaction with &IANA;.

The ®ISTRAR; includes 'jabber:iq:rpc' in its registry of protocol namespaces.

The XMPP Registrar includes a Service Discovery type of "rpc" within the "automation" category in its registry of service discovery identities.





  
    
      The protocol documented by this schema is defined in
      XEP-0009: http://www.xmpp.org/extensions/xep-0009.html

      There is no official XML schema for XML-RPC. The main body 
      of this schema has been borrowed from an unofficial schema 
      representation contained in the book "Processing XML With 
      Java" by Elliotte Rusty Harold, as located at:

      http://www.ibiblio.org/xml/books/xmljava/chapters/ch02s05.html
    
  

  
    
      
        
        
      
    
  

  
    
      
        
          
            
              
            
          
        
        
          
            
              
            
          
         
      
      
  

  
    
      
        
          
            
              
            
          
        
        
          
          
            
              
                
                  
                     
                       
                         
                          
                          
                          
                          
                        
                      
                    
                  
                
              
            
          
         
      
      
  

  
    
      
    
  

  
    
      
      
      
      
      
      
      
      
      
    
  

  
    
      
    
  

  
    
      
      
    
  

  
    
      
        
          
            
          
        
      
    
  

  
    
      
    
  

  
    
      
    
  


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