Karl Kleinpaste
2014-06-02 03:56:16 UTC
When I released Xiphos 3.2.0, I mentioned that it had a new feature,
BibleSync, to provide for multicast co-navigation of Bible programs.
I've now separated BibleSync into a distinct library outside Xiphos,
able to be built and linked separately.
I would be interested to hear from any of the other Sword apps' authors
who would be interested in experimenting with integrating BibleSync
capability.
Short summary: BibleSync is a single C++ class library that provides a
minimal public interface with the essentials needed to configure,
transmit, and receive through the metaphorical conduit through which
navigation packets travel. The requirements to use it well are
straightforward, involving mode selection, polled call of the receiver,
calling the transmitter as needed, and identifying which other potential
transmitters should be heard according to user request and with regard
to default listen policy. Options exist to specify total privacy if
only the current system's apps should hear nav transmit, and whether the
overall operational mode should be pure Speaker, pure Audience, or mixed
Personal mode which both transmits and receives among cooperating apps
(e.g. small team).
BibleSync has a github repository you can clone:
https://github.com/karlkleinpaste/biblesync.git
If you care to see it operate in Xiphos, you can build both BibleSync
and Xiphos, or if you use Windows or Wine, you can just try out the
3.2.1pre Win32 installer found in
http://ftp.xiphos.org/sword/biblesync/1.0.1/. (It's visually poor under
Wine but fully functional.) See the screenshots in the same directory
for the Prefs page showing BibleSync configuration. Obviously you'll
have to run multiple instances; I've run as many as 9 simultaneously, on
an assortment of real hardware and VMs. The manual needs an update.
I've attached the man page in both regular format and post-processed
text format.
Be aware that the current implementation takes a few liberties with the
original spec (compare .hh against spec, mentioned in man page) that are
well-received so far by the group of people working on this, plus the
addition of transmitter beacons which is waiting for critique and
consensus. Beacons, or something similar, were deemed necessary to deal
with the problem of interloper transmitters, whether maliciously or
inadvertently. Note that BibleSync in Xiphos 3.2.0 and 3.2.1pre will
not interoperate because of the new beacon aspect: 3.2.0 will not
understand or generate them and 3.2.1 will not recognize Speakers
without them.
It's new, it's weird, it's cool, it's exactly the kind of thing people
like us should find interesting. :-)
--karl
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BIBLESYNC(7) Linux Programmer's Manual BIBLESYNC(7)
NAME
biblesync - multicast navigation synchronization in Bible programs
SYNOPSIS
#include <biblesync.hh>
typedef enum_BibleSync_mode {
BSP_MODE_DISABLE,
BSP_MODE_PERSONAL,
BSP_MODE_SPEAKER,
BSP_MODE_AUDIENCE,
N_BSP_MODE
} BibleSync_mode;
typedef enum_BibleSync_xmit_status {
BSP_XMIT_OK,
BSP_XMIT_FAILED,
BSP_XMIT_NO_SOCKET,
BSP_XMIT_BAD_TYPE,
BSP_XMIT_NO_AUDIENCE_XMIT,
BSP_XMIT_RECEIVING,
N_BSP_XMIT
} BibleSync_xmit_status;
#define BSP_ANNOUNCE 1
#define BSP_SYNC 2
#define BSP_BEACON 3
typedef void (*BibleSync_navigate)(char cmd,
string bible, string ref, string alt,
string group, string domain,
string info, string dump);
Public interface:
BibleSync *object = new BibleSync(string application,
string version,
string user);
BibleSync_mode BibleSync::setMode(BibleSync_mode mode,
BibleSync_navigate *nav_func,
string passPhrase);
BibleSync_mode BibleSync::getMode(void);
string BibleSync::getVersion(void);
string BibleSync::getPassphrase(void);
BibleSync_xmit_status BibleSync::Transmit(char type,
string bible, string ref, string alt,
string group, string domain);
static int BibleSync::Receive(void *object);
bool BibleSync::setPrivate(bool privacy);
void BibleSync::listenToSpeaker(bool listen, string speakerkey);
DESCRIPTION
BibleSync is a published protocol specification by which cooperating
Bible programs navigate together. It is implemented as a C++ class
providing a small, clean interface including basic setup, take-down,
transmit, polled receive, and a bare few utility methods.
The value of BibleSync is found in several examples:
A single user may have multiple programs, or multiple comput-
ers/devices, all of which he wishes to follow along together.
Similarly, a group of people working closely together, such as transla-
tors, can stay together as they work.
In an instructional motif, BibleSync takes either the active or passive
mode, providing for a unidirectional navigation control.
BIBLESYNC ESSENTIALS
BibleSync communicates using local multicast. Three operational modes
are provided: Personal, Speaker, or Audience.
In Personal mode, BibleSync operates as a peer among peers, both send-
ing and receiving navigation synchronization on the shared local multi-
cast network. Applications are expected to respond appropriately to
navigation, and to send synchronization events of their own as the user
moves about his Bible.
In Speaker or Audience mode, BibleSync either transmits only (Speaker)
or receives only (Audience) navigation. The Audience is expected to
follow along with the Speaker's direction. The Speaker ignores incom-
ing navigation; the Audience transmits no navigation.
The difference between Personal and Speaker/Audience is thus strictly
as to whether both sides of the conversation are active for each par-
ticipant.
On startup of the protocol, BibleSync transmits a presence announce-
ment, informing other communication partners of the application's par-
ticipation. BibleSync makes this announcement available to the appli-
cation; whether the application shows these announcements to the user
is the application designer's choice.
Thereafter, as appropriate to the operational mode selected, BibleSync
is tasked with polled reception of incoming navigation event packets
and transmission of navigation event packets on the user's part.
Transmitters (Personal and Speaker modes) issue availability beacons
every 10 seconds. Received beacons for previously-unknown Speakers are
handed up to the application. These beacons provide for receivers
(Personal and Audience modes) to maintain a managed list of available
Speakers. Furthermore, when a transmitter ceases to issue beacons, its
presence in the list of available Speakers is aged out until being
removed after 30 seconds of beacon silence. The application is again
informed when a Speaker goes dead.
Default listening behavior is that the first Speaker heard via beacon
is marked for listening. Other transmitters claiming Speaker status
via beacon are initially ignored, but their presence is made known to
the application. This provides for the application to maintain a list
from which the user can select Speakers he wishes to synchronize his
application. It is useful for the application to provide blanket "lis-
ten to all" and "listen to none" functions, as well as per-Speaker
selections, informing BibleSync of these choices. In any case, this
default "first Speaker only" policy can be overridden by the applica-
tion with any other policy desired, through the use of listenToS-
peaker() as the application designer requires.
Synchronization events include 5 data elements: The Bible abbreviation;
the verse reference; an alternate reference (if desired; not required)
which may allow the application to interpret better based on variant
versification; a synchronization group identifier; and the domain.
The group identifier is a single digit between 1 and 9. The specifica-
tion is imprecise as to this parameter's use. The initial implementa-
tion of BibleSync in Xiphos uses the synchronization group as an indi-
cator of the tab number in its tabbed interface: Not only is the Bible
navigated, but the tab in which to navigate is selected.
The domain parameter is currently fixed as "BIBLE-VERSE". This will be
put to greater use in future revisions of the protocol.
BibleSync transmits no packet when the application leaves the conversa-
tion.
Only the 3 packet types BSP_ANNOUNCE, BSP_SYNC, and BSP_BEACON are
defined in the protocol.
PUBLIC INTERFACE
Object creation
The application must create a single BibleSync object, identifying the
application's name, its version, and the user.
setMode
setMode identifies how BibleSync should behave. The application must
provide as well the navigation callback function by which BibleSync
will inform the application of incoming events; the callback makes all
the navigation parameters provided in event packets available to the
application. setMode returns the resulting mode. The application pro-
vides the passphrase to be used as well; this argument defaults to ""
(empty string), indicating that the existing passphrase should be left
in place.
getMode
The application may request the current mode.
getVersion
The version string of the library itself is returned.
getPassphrase
Intended for use when preparing to enter any active mode, the applica-
tion may request the current passphrase, so as to provide a default.
Transmit
The application must provide the message type, which in the normal case
should be BSP_SYNC. The protocol requires all the indicated parame-
ters, but all have defaults in Transmit: KJV, Gen.1.1, empty alternate,
1, and BIBLE-VERSE.
Receive
This is a static method accessible from either C or C++. It must be
called with the object pointer so as to re-enter object context for the
private internal receiver. Receive() must be called regularly (i.e.
polled) as long as it continues to return TRUE. When it returns FALSE,
it means that the mode has changed to BSP_MODE_DISABLE, and the sched-
uled polling should stop. See also the note below on polled reception.
setPrivate
In the circumstance where the user has multiple programs running on a
single computer and does not want his navigation broadcast outside that
single system, when in Personal mode, the application may also request
privacy. The effect is to set multicast TTL to zero, meaning that
packets will not go out on the wire.
listenToSpeaker
Aside from default listen behavior detailed above, the application
specifically asks to listen or not to listen to specific Speakers. The
key is as provided during the notification of a new Speaker.
RECEIVE USE CASES
There are 6 values for the cmd parameter of the nav_func. In all
cases, the dump parameter provides the raw content of an arriving
packet.
'A'
Announce. A general presence message is in alt, and the individual
elements are also available, as overloaded use of the parameters: bible
contains the user; ref contains the IP address; group contains the
application name and version; and domain contains the device identifi-
cation.
'N'
Navigation. The bible, ref, alt, group, and domain parameters are pre-
sented as they arrived. info and dump are also available.
'S'
Speaker's initial recognition from beacon receipt. alt holds a UUID
key identifying the particular application. Overloaded parameters are
available as for presence announcements.
'D'
Dead Speaker. alt holds the UUID key of a previously-identified appli-
cation which is no longer a candidate for listening.
'M'
Mismatch. The incoming event packet is mismatched, either against the
current passphrase or for a navigation synchronization packet when
BibleSync is in Speaker mode. The info parameter begins with either
"announce" or "sync", plus the user and IP address from whom the packet
came. As well, in the sync case, the regular bible, ref, alt, group,
and domain parameters are available. In the announce case, the pres-
ence message is in alt, with overloaded individual parameters as previ-
ously described.
'E'
Error. This indicates network errors and malformed packets. The
application's nav_func is provided only the info and dump parameters.
NOTES
Polled reception
The application must provide a means by which to poll regularly for
incoming packets. In Xiphos, which is built on GTK and GLib, this is
readily provided by mechanisms like g_timeout_add(), which sets a regu-
lar interval call of the indicated function. GLib will re-schedule the
call as long as the called function returns TRUE. When it returns
FALSE, GLib un-schedules the call. Receive() adheres to this straight-
forward convention. Therefore, it is imperative that every time the
application moves from disabled to any non-disabled mode, Receive is
again scheduled for polled use.
A 1-second poll interval is suggested. Brief experience during
development has shown that longer intervals lead to a perception of
lag.
During every Receive() call, all waiting packets are processed.
No datalink security
BibleSync is a protocol defined for a friendly environment. It offers
no security in its current specification, and any packet sniffer such
as wireshark(1) or tcpdump(8) can see the entire conversation. The
specification makes passing reference to future encryption, but at this
time none is implemented.
Managed Speaker lists
The addition of transmitter beacons was a result of initial experience
showing that it can be too easy for a user to mis-start BibleSync, or
for a malicious user to interject himself into serious work. The goal
of beacons is to provide a means by which, on the one hand, the user
can be made aware of who is attempting to be a Speaker and, on the
other hand, confine the set of Speakers whom the user will permit to
make synchronization changes in the application. The simplest use of
'S' new Speaker notification events is to respond with listenToS-
peaker(true, speakerkey) which in effect makes BibleSync behave as
though there are no beacons. More serious use of 'S'/'D' is for the
application to manage its own sense of available Speakers, providing a
means by which the user can make sensible selections about how to react
to each Speaker's presence. BibleSync can be told to listen to legiti-
mate Speakers, and to ignore interlopers, whether intended maliciously
or merely due to other users' inadvertent behavior.
Protocol extensions
This implementation takes certain liberties with the specification. In
light of this being the first functioning, published implementation of
BibleSync, these changes are intended to be reflected in a near-future
specification update.
Conformity checks
This implementation does not guarantee conformity of incoming packets
in 2 areas:
The names in the "name=value" pairs are expected to be composed from a
particular character subset. This implementation does not verify this.
At this time, any non-NUL characters left of '=' are acceptable.
Continuation lines in "name=value" pairs are defined by the specifica-
tion, but this implementation does not support them.
Sending verse lists
One of the better uses of BibleSync is in sharing verse lists. Con-
sider a relatively weak application, perhaps on a mobile device, and a
desktop-based application with strong search capability. Run searches
on the desktop, and send the result via BibleSync to the mobile app.
The ref parameter is not confined to a single reference. In normal
citation syntax, the verse reference may consist of semicolon-separated
references, comma-separated verses, and hyphen-separated ranges. Be
aware that the specification has a relatively short limit on packet
size, so that at most a few dozen references will be sent.
Standard reference syntax
It is the responsibility of the application to transmit references in
standard format. BibleSync neither validates nor converts the applica-
tion's incoming bible, ref, and alt parameters. The specification ref-
erences the BibleRef and OSIS specifications.
SEE ALSO
http://biblesyncprotocol.wikispaces.com (user "General_Public", pass-
word "password"), http://semanticbible.com/bibleref/bibleref-specifica-
tion.html, socket(2), setsockopt(2), select(2), recvfrom(2), sendto(2),
and ip(7), especially sections on IP_ADD_MEMBERSHIP, IP_MULTICAST_IF,
IP_MULTICAST_LOOP, and IP_MULTICAST_TTL.
Linux 2014-06-01 BIBLESYNC(7)
BibleSync, to provide for multicast co-navigation of Bible programs.
I've now separated BibleSync into a distinct library outside Xiphos,
able to be built and linked separately.
I would be interested to hear from any of the other Sword apps' authors
who would be interested in experimenting with integrating BibleSync
capability.
Short summary: BibleSync is a single C++ class library that provides a
minimal public interface with the essentials needed to configure,
transmit, and receive through the metaphorical conduit through which
navigation packets travel. The requirements to use it well are
straightforward, involving mode selection, polled call of the receiver,
calling the transmitter as needed, and identifying which other potential
transmitters should be heard according to user request and with regard
to default listen policy. Options exist to specify total privacy if
only the current system's apps should hear nav transmit, and whether the
overall operational mode should be pure Speaker, pure Audience, or mixed
Personal mode which both transmits and receives among cooperating apps
(e.g. small team).
BibleSync has a github repository you can clone:
https://github.com/karlkleinpaste/biblesync.git
If you care to see it operate in Xiphos, you can build both BibleSync
and Xiphos, or if you use Windows or Wine, you can just try out the
3.2.1pre Win32 installer found in
http://ftp.xiphos.org/sword/biblesync/1.0.1/. (It's visually poor under
Wine but fully functional.) See the screenshots in the same directory
for the Prefs page showing BibleSync configuration. Obviously you'll
have to run multiple instances; I've run as many as 9 simultaneously, on
an assortment of real hardware and VMs. The manual needs an update.
I've attached the man page in both regular format and post-processed
text format.
Be aware that the current implementation takes a few liberties with the
original spec (compare .hh against spec, mentioned in man page) that are
well-received so far by the group of people working on this, plus the
addition of transmitter beacons which is waiting for critique and
consensus. Beacons, or something similar, were deemed necessary to deal
with the problem of interloper transmitters, whether maliciously or
inadvertently. Note that BibleSync in Xiphos 3.2.0 and 3.2.1pre will
not interoperate because of the new beacon aspect: 3.2.0 will not
understand or generate them and 3.2.1 will not recognize Speakers
without them.
It's new, it's weird, it's cool, it's exactly the kind of thing people
like us should find interesting. :-)
--karl
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BIBLESYNC(7) Linux Programmer's Manual BIBLESYNC(7)
NAME
biblesync - multicast navigation synchronization in Bible programs
SYNOPSIS
#include <biblesync.hh>
typedef enum_BibleSync_mode {
BSP_MODE_DISABLE,
BSP_MODE_PERSONAL,
BSP_MODE_SPEAKER,
BSP_MODE_AUDIENCE,
N_BSP_MODE
} BibleSync_mode;
typedef enum_BibleSync_xmit_status {
BSP_XMIT_OK,
BSP_XMIT_FAILED,
BSP_XMIT_NO_SOCKET,
BSP_XMIT_BAD_TYPE,
BSP_XMIT_NO_AUDIENCE_XMIT,
BSP_XMIT_RECEIVING,
N_BSP_XMIT
} BibleSync_xmit_status;
#define BSP_ANNOUNCE 1
#define BSP_SYNC 2
#define BSP_BEACON 3
typedef void (*BibleSync_navigate)(char cmd,
string bible, string ref, string alt,
string group, string domain,
string info, string dump);
Public interface:
BibleSync *object = new BibleSync(string application,
string version,
string user);
BibleSync_mode BibleSync::setMode(BibleSync_mode mode,
BibleSync_navigate *nav_func,
string passPhrase);
BibleSync_mode BibleSync::getMode(void);
string BibleSync::getVersion(void);
string BibleSync::getPassphrase(void);
BibleSync_xmit_status BibleSync::Transmit(char type,
string bible, string ref, string alt,
string group, string domain);
static int BibleSync::Receive(void *object);
bool BibleSync::setPrivate(bool privacy);
void BibleSync::listenToSpeaker(bool listen, string speakerkey);
DESCRIPTION
BibleSync is a published protocol specification by which cooperating
Bible programs navigate together. It is implemented as a C++ class
providing a small, clean interface including basic setup, take-down,
transmit, polled receive, and a bare few utility methods.
The value of BibleSync is found in several examples:
A single user may have multiple programs, or multiple comput-
ers/devices, all of which he wishes to follow along together.
Similarly, a group of people working closely together, such as transla-
tors, can stay together as they work.
In an instructional motif, BibleSync takes either the active or passive
mode, providing for a unidirectional navigation control.
BIBLESYNC ESSENTIALS
BibleSync communicates using local multicast. Three operational modes
are provided: Personal, Speaker, or Audience.
In Personal mode, BibleSync operates as a peer among peers, both send-
ing and receiving navigation synchronization on the shared local multi-
cast network. Applications are expected to respond appropriately to
navigation, and to send synchronization events of their own as the user
moves about his Bible.
In Speaker or Audience mode, BibleSync either transmits only (Speaker)
or receives only (Audience) navigation. The Audience is expected to
follow along with the Speaker's direction. The Speaker ignores incom-
ing navigation; the Audience transmits no navigation.
The difference between Personal and Speaker/Audience is thus strictly
as to whether both sides of the conversation are active for each par-
ticipant.
On startup of the protocol, BibleSync transmits a presence announce-
ment, informing other communication partners of the application's par-
ticipation. BibleSync makes this announcement available to the appli-
cation; whether the application shows these announcements to the user
is the application designer's choice.
Thereafter, as appropriate to the operational mode selected, BibleSync
is tasked with polled reception of incoming navigation event packets
and transmission of navigation event packets on the user's part.
Transmitters (Personal and Speaker modes) issue availability beacons
every 10 seconds. Received beacons for previously-unknown Speakers are
handed up to the application. These beacons provide for receivers
(Personal and Audience modes) to maintain a managed list of available
Speakers. Furthermore, when a transmitter ceases to issue beacons, its
presence in the list of available Speakers is aged out until being
removed after 30 seconds of beacon silence. The application is again
informed when a Speaker goes dead.
Default listening behavior is that the first Speaker heard via beacon
is marked for listening. Other transmitters claiming Speaker status
via beacon are initially ignored, but their presence is made known to
the application. This provides for the application to maintain a list
from which the user can select Speakers he wishes to synchronize his
application. It is useful for the application to provide blanket "lis-
ten to all" and "listen to none" functions, as well as per-Speaker
selections, informing BibleSync of these choices. In any case, this
default "first Speaker only" policy can be overridden by the applica-
tion with any other policy desired, through the use of listenToS-
peaker() as the application designer requires.
Synchronization events include 5 data elements: The Bible abbreviation;
the verse reference; an alternate reference (if desired; not required)
which may allow the application to interpret better based on variant
versification; a synchronization group identifier; and the domain.
The group identifier is a single digit between 1 and 9. The specifica-
tion is imprecise as to this parameter's use. The initial implementa-
tion of BibleSync in Xiphos uses the synchronization group as an indi-
cator of the tab number in its tabbed interface: Not only is the Bible
navigated, but the tab in which to navigate is selected.
The domain parameter is currently fixed as "BIBLE-VERSE". This will be
put to greater use in future revisions of the protocol.
BibleSync transmits no packet when the application leaves the conversa-
tion.
Only the 3 packet types BSP_ANNOUNCE, BSP_SYNC, and BSP_BEACON are
defined in the protocol.
PUBLIC INTERFACE
Object creation
The application must create a single BibleSync object, identifying the
application's name, its version, and the user.
setMode
setMode identifies how BibleSync should behave. The application must
provide as well the navigation callback function by which BibleSync
will inform the application of incoming events; the callback makes all
the navigation parameters provided in event packets available to the
application. setMode returns the resulting mode. The application pro-
vides the passphrase to be used as well; this argument defaults to ""
(empty string), indicating that the existing passphrase should be left
in place.
getMode
The application may request the current mode.
getVersion
The version string of the library itself is returned.
getPassphrase
Intended for use when preparing to enter any active mode, the applica-
tion may request the current passphrase, so as to provide a default.
Transmit
The application must provide the message type, which in the normal case
should be BSP_SYNC. The protocol requires all the indicated parame-
ters, but all have defaults in Transmit: KJV, Gen.1.1, empty alternate,
1, and BIBLE-VERSE.
Receive
This is a static method accessible from either C or C++. It must be
called with the object pointer so as to re-enter object context for the
private internal receiver. Receive() must be called regularly (i.e.
polled) as long as it continues to return TRUE. When it returns FALSE,
it means that the mode has changed to BSP_MODE_DISABLE, and the sched-
uled polling should stop. See also the note below on polled reception.
setPrivate
In the circumstance where the user has multiple programs running on a
single computer and does not want his navigation broadcast outside that
single system, when in Personal mode, the application may also request
privacy. The effect is to set multicast TTL to zero, meaning that
packets will not go out on the wire.
listenToSpeaker
Aside from default listen behavior detailed above, the application
specifically asks to listen or not to listen to specific Speakers. The
key is as provided during the notification of a new Speaker.
RECEIVE USE CASES
There are 6 values for the cmd parameter of the nav_func. In all
cases, the dump parameter provides the raw content of an arriving
packet.
'A'
Announce. A general presence message is in alt, and the individual
elements are also available, as overloaded use of the parameters: bible
contains the user; ref contains the IP address; group contains the
application name and version; and domain contains the device identifi-
cation.
'N'
Navigation. The bible, ref, alt, group, and domain parameters are pre-
sented as they arrived. info and dump are also available.
'S'
Speaker's initial recognition from beacon receipt. alt holds a UUID
key identifying the particular application. Overloaded parameters are
available as for presence announcements.
'D'
Dead Speaker. alt holds the UUID key of a previously-identified appli-
cation which is no longer a candidate for listening.
'M'
Mismatch. The incoming event packet is mismatched, either against the
current passphrase or for a navigation synchronization packet when
BibleSync is in Speaker mode. The info parameter begins with either
"announce" or "sync", plus the user and IP address from whom the packet
came. As well, in the sync case, the regular bible, ref, alt, group,
and domain parameters are available. In the announce case, the pres-
ence message is in alt, with overloaded individual parameters as previ-
ously described.
'E'
Error. This indicates network errors and malformed packets. The
application's nav_func is provided only the info and dump parameters.
NOTES
Polled reception
The application must provide a means by which to poll regularly for
incoming packets. In Xiphos, which is built on GTK and GLib, this is
readily provided by mechanisms like g_timeout_add(), which sets a regu-
lar interval call of the indicated function. GLib will re-schedule the
call as long as the called function returns TRUE. When it returns
FALSE, GLib un-schedules the call. Receive() adheres to this straight-
forward convention. Therefore, it is imperative that every time the
application moves from disabled to any non-disabled mode, Receive is
again scheduled for polled use.
A 1-second poll interval is suggested. Brief experience during
development has shown that longer intervals lead to a perception of
lag.
During every Receive() call, all waiting packets are processed.
No datalink security
BibleSync is a protocol defined for a friendly environment. It offers
no security in its current specification, and any packet sniffer such
as wireshark(1) or tcpdump(8) can see the entire conversation. The
specification makes passing reference to future encryption, but at this
time none is implemented.
Managed Speaker lists
The addition of transmitter beacons was a result of initial experience
showing that it can be too easy for a user to mis-start BibleSync, or
for a malicious user to interject himself into serious work. The goal
of beacons is to provide a means by which, on the one hand, the user
can be made aware of who is attempting to be a Speaker and, on the
other hand, confine the set of Speakers whom the user will permit to
make synchronization changes in the application. The simplest use of
'S' new Speaker notification events is to respond with listenToS-
peaker(true, speakerkey) which in effect makes BibleSync behave as
though there are no beacons. More serious use of 'S'/'D' is for the
application to manage its own sense of available Speakers, providing a
means by which the user can make sensible selections about how to react
to each Speaker's presence. BibleSync can be told to listen to legiti-
mate Speakers, and to ignore interlopers, whether intended maliciously
or merely due to other users' inadvertent behavior.
Protocol extensions
This implementation takes certain liberties with the specification. In
light of this being the first functioning, published implementation of
BibleSync, these changes are intended to be reflected in a near-future
specification update.
Conformity checks
This implementation does not guarantee conformity of incoming packets
in 2 areas:
The names in the "name=value" pairs are expected to be composed from a
particular character subset. This implementation does not verify this.
At this time, any non-NUL characters left of '=' are acceptable.
Continuation lines in "name=value" pairs are defined by the specifica-
tion, but this implementation does not support them.
Sending verse lists
One of the better uses of BibleSync is in sharing verse lists. Con-
sider a relatively weak application, perhaps on a mobile device, and a
desktop-based application with strong search capability. Run searches
on the desktop, and send the result via BibleSync to the mobile app.
The ref parameter is not confined to a single reference. In normal
citation syntax, the verse reference may consist of semicolon-separated
references, comma-separated verses, and hyphen-separated ranges. Be
aware that the specification has a relatively short limit on packet
size, so that at most a few dozen references will be sent.
Standard reference syntax
It is the responsibility of the application to transmit references in
standard format. BibleSync neither validates nor converts the applica-
tion's incoming bible, ref, and alt parameters. The specification ref-
erences the BibleRef and OSIS specifications.
SEE ALSO
http://biblesyncprotocol.wikispaces.com (user "General_Public", pass-
word "password"), http://semanticbible.com/bibleref/bibleref-specifica-
tion.html, socket(2), setsockopt(2), select(2), recvfrom(2), sendto(2),
and ip(7), especially sections on IP_ADD_MEMBERSHIP, IP_MULTICAST_IF,
IP_MULTICAST_LOOP, and IP_MULTICAST_TTL.
Linux 2014-06-01 BIBLESYNC(7)