1AnyEvent::XMPP::Writer(U3s)er Contributed Perl DocumentatAinoynEvent::XMPP::Writer(3)
2
6 AnyEvent::XMPP::Writer - "XML" writer for XMPP
7
9 use AnyEvent::XMPP::Writer;
10 ...
11
13 This module contains some helper functions for writing XMPP "XML",
14 which is not real XML at all ;-( I use XML::Writer and tune it until it
15 creates "XML" that is accepted by most servers propably (all of the
16 XMPP servers I tested should work (jabberd14, jabberd2, ejabberd,
17 googletalk).
18 I hope the semantics of XML::Writer don't change much in the future,
20 but if they do and you run into problems, please report them!
21 The whole "XML" concept of XMPP is fundamentally broken anyway. It's
23 supposed to be an subset of XML. But a subset of XML productions is not
24 XML. Strictly speaking you need a special XMPP "XML" parser and writer
25 to be 100% conformant.
26 On top of that XMPP requires you to parse these partial "XML"
28 documents. But a partial XML document is not well-formed, heck, it's
29 not even a XML document! And a parser should bail out with an error.
30 But XMPP doesn't care, it just relies on implementation dependend
31 behaviour of chunked parsing modes for SAX parsing. This functionality
32 isn't even specified by the XML recommendation in any way. The
33 recommendation even says that it's undefined what happens if you
34 process not-well-formed XML documents.
35 But I try to be as XMPP "XML" conformant as possible (it should be
37 around 99-100%). But it's hard to say what XML is conformant, as the
38 specifications of XMPP "XML" and XML are contradicting. For example
39 XMPP also says you only have to generated and accept UTF-8 encodings of
40 XML, but the XML recommendation says that each parser has to accept
41 UTF-8 and UTF-16. So, what do you do? Do you use a XML conformant
42 parser or do you write your own?
43 I'm using XML::Parser::Expat because expat knows how to parse broken
45 (aka 'partial') "XML" documents, as XMPP requires. Another argument is
46 that if you capture a XMPP conversation to the end, and even if a
47 '</stream:stream>' tag was captured, you wont have a valid XML
48 document. The problem is that you have to resent a <stream> tag after
49 TLS and SASL authentication each! Awww... I'm repeating myself.
50 But well... AnyEvent::XMPP does it's best with expat to cope with the
52 fundamental brokeness of "XML" in XMPP.
53 Back to the issue with "XML" generation: I've discoverd that many XMPP
55 servers (eg. jabberd14 and ejabberd) have problems with XML
56 namespaces. Thats the reason why I'm assigning the namespace prefixes
57 manually: The servers just don't accept validly namespaced XML. The
58 draft 3921bis does even state that a client SHOULD generate a 'stream'
59 prefix for the <stream> tag.
60 I advice you to explicitly set the namespaces too if you generate "XML"
62 for XMPP yourself, at least until all or most of the XMPP servers have
63 been fixed. Which might take some years :-) And maybe will happen
64 never.
65 And another note: As XMPP requires all predefined entity characters to
67 be escaped in character data you need a "XML" writer that will escape
68 everything:
69 RFC 3920 - 11.1. Restrictions:
71 character data or attribute values containing unescaped characters
73 that map to the predefined entities (Section 4.6 therein);
74 such characters MUST be escaped
75 This means: You have to escape '>' in the character data. I don't know
77 whether XML::Writer does that. And I honestly don't care much about
78 this. XMPP is broken by design and I have barely time to writer my own
79 XML parsers and writers to suit their sick taste of "XML". (Do I repeat
80 myself?)
81 I would be happy if they finally say (in RFC3920): "XMPP is NOT XML.
83 It's just XML-like, and some XML utilities allow you to process this
84 kind of XML.".
85
87 new (%args)
88 This methods takes following arguments:
89 write_cb
91 The callback that is called when a XML stanza was completely
92 written and is ready for transfer. The first argument of the
93 callback will be the character data to send to the socket.
94 And calls "init".
96 init
98 (Re)initializes the writer.
99 flush ()
101 This method flushes the internal write buffer and will invoke the
102 "write_cb" callback. (see also "new ()" above)
103 send_init_stream ($language, $domain, $namespace)
105 This method will generate a XMPP stream header. $domain has to be
106 the domain of the server (or endpoint) we want to connect to.
107 $namespace is the namespace URI or the tag (from
109 AnyEvent::XMPP::Namespaces) for the stream namespace. (This is used
110 by AnyEvent::XMPP::Component to connect as component to a server).
111 $namespace can also be undefined, in this case the "client"
112 namespace will be used.
113 send_whitespace_ping
115 This method sends a single space to the server.
116 send_handshake ($streamid, $secret)
118 This method sends a component handshake. Please note that $secret
119 must be XML escaped!
120 send_end_of_stream
122 Sends end of the stream.
123 send_sasl_auth ($mechanisms, $user, $hostname, $pass)
125 This methods sends the start of a SASL authentication. $mechanisms
126 is an array reference, containing the mechanism names that are to
127 be tried.
128 send_sasl_response ($challenge)
130 This method generated the SASL authentication response to a
131 $challenge. You must not call this method without calling
132 "send_sasl_auth ()" before.
133 send_starttls
135 Sends the starttls command to the server.
136 send_iq ($id, $type, $create_cb, %attrs)
138 This method sends an IQ stanza of type $type (to be compliant only
139 use: 'get', 'set', 'result' and 'error').
140 If $create_cb is a code reference it will be called with an
142 XML::Writer instance as first argument, which must be used to fill
143 the IQ stanza. The XML::Writer is in UNSAFE mode, so you can safely
144 use "raw()" to write out XML.
145 $create_cb is a hash reference the hash will be used as key=>value
147 arguments for the "simxml" function defined in
148 AnyEvent::XMPP::Util. "simxml" will then be used to generate the
149 contents of the IQ stanza. (This is very convenient when you want
150 to write the contents of stanzas in the code and don't want to
151 build a DOM tree yourself...).
152 If $create_cb is an array reference it's elements will be
154 interpreted as single $create_cb argument (which can either be a
155 hash reference or code reference themself) and executed
156 sequentially.
157 If $create_cb is undefined an empty tag will be generated.
159 Example:
161 $writer->send_iq ('newid', 'get', {
163 defns => 'version',
164 node => { name => 'query', ns => 'version' }
165 }, to => 'jabber.org')
166 %attrs should have further attributes for the IQ stanza tag. For
168 example 'to' or 'from'. If the %attrs contain a 'lang' attribute it
169 will be put into the 'xml' namespace. If the 'to' attribute
170 contains an undef it will be omitted.
171 $id is the id to give this IQ stanza and is mandatory in this API.
173 Please note that all attribute values and character data will be
175 filtered by "filter_xml_chars" (see also AnyEvent::XMPP::Util).
176 send_presence ($id, $type, $create_cb, %attrs)
178 Sends a presence stanza.
179 $create_cb has the same meaning as for "send_iq". %attrs will let
181 you pass further optional arguments like 'to'.
182 $type is the type of the presence, which may be one of:
184 unavailable, subscribe, subscribed, unsubscribe, unsubscribed, probe, error
186 Or undef, in case you want to send a 'normal' presence. Or
188 something completely different if you don't like the RFC 3921 :-)
189 %attrs contains further attributes for the presence tag or may
191 contain one of the following exceptional keys:
192 If %attrs contains a 'show' key: a child xml tag with that name
194 will be generated with the value as the content, which should be
195 one of 'away', 'chat', 'dnd' and 'xa'. If it contains an undefined
196 value no such tag will be generated, which usually means that the
197 'available' presence is meant.
198 If %attrs contains a 'status' key: a child xml tag with that name
200 will be generated with the value as content. If the value of the
201 'status' key is an hash reference the keys will be interpreted as
202 language identifiers for the xml:lang attribute of each status
203 element. If one of these keys is the empty string '' no xml:lang
204 attribute will be generated for it. The values will be the
205 character content of the status tags.
206 If %attrs contains a 'priority' key: a child xml tag with that name
208 will be generated with the value as content, which must be a number
209 between -128 and +127.
210 Note: If $create_cb is undefined and one of the above attributes
212 (show, status or priority) were given, the generates presence tag
213 won't be empty.
214 Please note that all attribute values and character data will be
216 filtered by "filter_xml_chars" (see also AnyEvent::XMPP::Util).
217 send_message ($id, $to, $type, $create_cb, %attrs)
219 Sends a message stanza.
220 $to is the destination JID of the message. $type is the type of the
222 message, and if $type is undefined it will default to 'chat'.
223 $type must be one of the following: 'chat', 'error', 'groupchat',
224 'headline' or 'normal'.
225 $create_cb has the same meaning as in "send_iq".
227 %attrs contains further attributes for the message tag or may
229 contain one of the following exceptional keys:
230 If %attrs contains a 'body' key: a child xml tag with that name
232 will be generated with the value as content. If the value of the
233 'body' key is an hash reference the keys will be interpreted as
234 language identifiers for the xml:lang attribute of each body
235 element. If one of these keys is the empty string '' no xml:lang
236 attribute will be generated for it. The values will be the
237 character content of the body tags.
238 If %attrs contains a 'subject' key: a child xml tag with that name
240 will be generated with the value as content. If the value of the
241 'subject' key is an hash reference the keys will be interpreted as
242 language identifiers for the xml:lang attribute of each subject
243 element. If one of these keys is the empty string '' no xml:lang
244 attribute will be generated for it. The values will be the
245 character content of the subject tags.
246 If %attrs contains a 'thread' key: a child xml tag with that name
248 will be generated and the value will be the character content.
249 Please note that all attribute values and character data will be
251 filtered by "filter_xml_chars" (see also AnyEvent::XMPP::Util).
252 write_error_tag ($error_stanza_node, $error_type, $error)
254 $error_type is one of 'cancel', 'continue', 'modify', 'auth' and
255 'wait'. $error is the name of the error tag child element. If
256 $error is one of the following:
257 'bad-request', 'conflict', 'feature-not-implemented', 'forbidden', 'gone',
259 'internal-server-error', 'item-not-found', 'jid-malformed', 'not-acceptable',
260 'not-allowed', 'not-authorized', 'payment-required', 'recipient-unavailable',
261 'redirect', 'registration-required', 'remote-server-not-found',
262 'remote-server-timeout', 'resource-constraint', 'service-unavailable',
263 'subscription-required', 'undefined-condition', 'unexpected-request'
264 then a default can be select for $error_type, and the argument can
266 be undefined.
267 Note: This method is currently a bit limited in the generation of
269 the xml for the errors, if you need more please contact me.
270
272 Robin Redeker, "<elmex at ta-sa.org>", JID: "<elmex at jabber.org>"
273
275 Copyright 2007, 2008 Robin Redeker, all rights reserved.
276 This program is free software; you can redistribute it and/or modify it
278 under the same terms as Perl itself.
279perl v5.30.1 2020-01-29 AnyEvent::XMPP::Writer(3)