1nameserv::auto(n) Name service facility nameserv::auto(n)
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6
8 nameserv::auto - Name service facility, Client Extension
9
11 package require Tcl 8.4
12 package require nameserv::auto ?0.3?
14 package require nameserv
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18
20 Please read the document Name service facility, introduction first.
21 This package provides the exact same API as is provided by package
23 nameserv, i.e. the regular name service client. It differs from the
24 former by taking measures to ensure that longer-lived data, i.e. bound
25 names, continuous and unfullfilled async searches, survive the loss of
26 the connection to the name server as much as is possible.
27 This means that the bound names and continuous and unfullfilled async
29 searches are remembered client-side and automatically re-entered into
30 the server when the connection comes back after its loss. For bound
31 names there is one important limitation to such restoration: It is pos‐
32 sible that a name of this client was bound by a different client while
33 the connection was gone. Such names are fully lost, and the best the
34 package can and will do is to inform the user of this.
35
37 The user-visible API is mainly identical to the API of nameserv and is
38 therefore not described here. Please read the documentation of name‐
39 serv.
40 The differences are explained below, in the sections OPTIONS and
42 EVENTS.
43
45 This package supports all the options of package nameserv, plus one
46 more. The additional option allows the user to specify the time inter‐
47 val between attempts to restore a lost connection.
48 -delay milliseconds
50 The value of this option is an integer value > 0 which specifies
51 the interval to wait between attempts to restore a lost connec‐
52 tion, in milliseconds. The default value is 1000, i.e. one sec‐
53 ond.
54
56 This package generates all of the events of package nameserv, plus two
57 more. Both events are generated for the tag nameserv.
58 lost-name
60 This event is generated when a bound name is truly lost, i.e.
61 could not be restored after the temporary loss of the connection
62 to the name server. It indicates that a different client took
63 ownership of the name while this client was out of contact.
64 The detail information of the event will be a Tcl dictionary
66 containing two keys, name, and data. Their values hold all the
67 information about the lost name.
68 re-connection
70 This event is generated when the connection to the server is re‐
71 stored. The remembered data has been restored when the event is
72 posted.
73 The event has no detail information.
75
77 The package is implemented on top of the regular nameservice client,
78 i.e. package nameserv. It detects the loss of the connection by listen‐
79 ing for lost-connection events, on the tag nameserv.
80 It reacts to such events by starting a periodic timer and trying to re‐
82 connect to the server whenver this timer triggers. On success the timer
83 is canceled, a re-connection event generated, and the package proceeds
84 to re-enter the remembered bound names and continuous searches.
85 Another loss of the connection, be it during or after re-entering the
87 remembered information simply restarts the timer and subsequent recon‐
88 nection attempts.
89
91 This document, and the package it describes, will undoubtedly contain
92 bugs and other problems. Please report such in the category nameserv
93 of the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please
94 also report any ideas for enhancements you may have for either package
95 and/or documentation.
96 When proposing code changes, please provide unified diffs, i.e the out‐
98 put of diff -u.
99 Note further that attachments are strongly preferred over inlined
101 patches. Attachments can be made by going to the Edit form of the
102 ticket immediately after its creation, and then using the left-most
103 button in the secondary navigation bar.
104
106 nameserv(n)
107
109 automatic, client, name service, reconnect, restore
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112 Networking
113
115 Copyright (c) 2007-2008 Andreas Kupries <andreas_kupries@users.sourceforge.net>
116tcllib 0.3 nameserv::auto(n)