1 Introduction
2 ============
3
4 The fburl software provides an extension for Lightning/Iceowl (the calendar
5 extension for Mozilla Thunderbird/Icedove) that can obtain free/busy URL
6 details from LDAP directories registered as address books. Thus, when the
7 free/busy dialogue is opened, availability information for event participants
8 may be shown if their contact details are supplied by an LDAP directory, if
9 those details include an FBURL property, and if that property refers to a
10 valid iCalendar VFREEBUSY component residing on an accessible Web server.
11
12 More information about FBURL can be found in the following document:
13
14 http://tools.ietf.org/html/rfc2739
15
16 Other Sources of Free/Busy Information
17 ======================================
18
19 Although not currently supported by this software, FBURL information could be
20 obtained from vCard objects:
21
22 https://tools.ietf.org/html/rfc6350#section-6.9
23
24 In Thunderbird, this would involve opening an address book and obtaining a
25 card object (from a non-LDAP source) that can provide the FBURL property.
26 Unfortunately, the built-in address books do not seem to support the FBURL
27 property. Moreover, when vCard information is imported, properties such as
28 FBURL that are not part of the traditional set of vCard properties are
29 discarded.
30
31 Although not directly related to FBURL and over-the-Web free/busy resource
32 retrieval, such information may also be exchanged using iMIP and normal e-mail
33 communications:
34
35 https://tools.ietf.org/html/rfc6047
36
37 Thunderbird supports iMIP for VEVENT and VTODO components but not for
38 VFREEBUSY components. Support for VFREEBUSY would require received components
39 to be recorded in a suitable repository so that they may then be consulted by
40 a specific free/busy provider when scheduling events. The sending of VFREEBUSY
41 components would involve access to the user's schedule and the construction of
42 iCalendar output from such information. Control over free/busy sharing would
43 need to be exercised, probably requiring configuration settings to indicate
44 whether such information is sent along with other iMIP payloads and with whom
45 such information may be shared.
46
47 With iMIP, the effective "FBURL" of a contact would in fact be the e-mail
48 address of that contact or, more accurately, the address expressed using the
49 mailto URI scheme. Thus, wider support for FBURL in vCard-handling and in
50 Thunderbird address books would let users indicate that they can expect
51 free/busy information via iMIP from certain contacts and, in their own vCard
52 details, that they will publish their own availability details via iMIP.
53
54 Contact, Copyright and Licence Information
55 ==========================================
56
57 See the following Web pages for more information about this work:
58
59 http://hgweb.boddie.org.uk/fburl
60
61 The author can be contacted at the following e-mail address:
62
63 paul@boddie.org.uk
64
65 Copyright and licence information can be found in the docs directory - see
66 docs/COPYING.txt for more information.