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\o/
WOOT
for Lift
Richard Dallaway @d6y
Jono Ferguson @jonoabroad
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Richard Dallaway @d6y
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Collaborative Editing
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Don’t Do This
A B C A B C
Site A Site B
1 2 3 1 2 3
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Don’t Do This
A B C A B C
Site A Site B
1 2 3 1 2 3
A x B C
1 2 3 4
insert x @ 2
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Don’t Do This
A B C A B C
Site A Site B
1 2 3 1 2 3
A x B C
1 2 3 4
insert x @ 2
A B
1 2
delete 3
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Don’t Do This
A B C A B C
Site A Site B
1 2 3 1 2 3
A x B C
1 2 3 4
insert x @ 2
A B
1 2
delete 3
A x B
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Don’t Do This
A B C A B C
Site A Site B
1 2 3 1 2 3
A x B C
1 2 3 4
insert x @ 2
A B
1 2
delete 3
A x B
A x C
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What do we want?
‣Intention Preservation
‣Causal Consistency
‣Convergence
When do we want it?
Eventually
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The WOOT Algorithm
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WOOT
A B C A B C
Site A Site B
1 2 3 1 2 3
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WOOT
A B C A B C
Site A Site B
1 2 3 1 2 3
1 2 3 4
A x B C
A ≺ x ≺ B
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WOOT
A B C A B C
Site A Site B
1 2 3 1 2 3
1 2 3 4
A x B C
A ≺ x ≺ B
1 2
A B
delete C
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WOOT
A B C A B C
Site A Site B
1 2 3 1 2 3
1 2 3 4
A x B C
A ≺ x ≺ B
1 2
A B
delete C
A x B
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WOOT
A B C A B C
Site A Site B
1 2 3 1 2 3
1 2 3 4
A x B C
A ≺ x ≺ B
1 2
A B
delete C
A x B
A x B
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WChar
ID Prev Next Alpha Visible?
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WChar
ID Prev Next Alpha Visible?
Site Clock
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WChar
ID Prev Next Alpha Visible?
Site Clock
ID ID
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WOOT Algorithm
Local Integration
Remote Integration
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WOOT Algorithm
(WString, Char, Pos) =>
(WString, WChar)
Local Integration
Remote Integration
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WOOT Algorithm
(WString, Char, Pos) =>
(WString, WChar)
Local Integration
(WString, WChar) => WString
Remote Integration
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WOOT Algorithm
a b c d a b c d a b c d
a b c x d a c d a b y c d
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WOOT Algorithm
a b c d a b c d a b c d
a b c x d a c d a b y c d
a b c d
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WOOT Algorithm
a b c d a b c d a b c d
a b c x d a c d a b y c d
a b c d
x
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WOOT Algorithm
a b c d a b c d a b c d
a b c x d a c d a b y c d
a b c d
x
／
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WOOT Algorithm
a b c d a b c d a b c d
a b c x d a c d a b y c d
a b c d
x
y
／
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Example using Ace
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Scala, JavaScript, Lift
WOOT
Local WOOT Model
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Scala, JavaScript, Lift
WOOT
x
Local WOOT Model
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Scala, JavaScript, Lift
WOOT
x
Local WOOT Model
A ≺ x ≺ B
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Scala, JavaScript, Lift
WOOT
WOOT WOOT
x
Local WOOT Model
A ≺ x ≺ B
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Scala, JavaScript, Lift
WOOT
WOOT WOOT
x
Local WOOT Model
A ≺ x ≺ B
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Scala, JavaScript, Lift
WOOT
WOOT WOOT
x
x x
Local WOOT Model
A ≺ x ≺ B
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Fork It
bitbucket.org/d6y/woot
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Fork It
bitbucket.org/d6y/woot
$ git clone https://[email protected]/d6y/woot.git
$ ./sbt
> container:start
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Fork It
bitbucket.org/d6y/woot
$ git clone https://[email protected]/d6y/woot.git
$ ./sbt
> container:start
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JavaScript
jQuery(document).ready(function() {
wootServer.init({doc:1}).then(messageHandler);
});
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JavaScript
jQuery(document).ready(function() {
wootServer.init({doc:1}).then(messageHandler);
});
var wootServer = {
init: function(config) {
return $.Deferred().promise();
},
send: function(wchar) {}
};
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JavaScript
jQuery(document).ready(function() {
wootServer.init({doc:1}).then(messageHandler);
});
var wootServer = {
init: function(config) {
return $.Deferred().promise();
},
send: function(wchar) {}
};
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Scala
def services = List[RoundTripInfo](
"send" -> receive _,
"init" -> init _)
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Scala
def services = List[RoundTripInfo](
"send" -> receive _,
"init" -> init _)
def init(config: JValue) : Stream[JValue] = {
!
!
}
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Scala
def services = List[RoundTripInfo](
"send" -> receive _,
"init" -> init _)
def init(config: JValue) : Stream[JValue] = {
!
!
}
val doc = toJson(wootModel)
val q = LinkedBlockingQueue[JValue]()
doc #:: Stream.continually(q.take())
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Pros
‣No vector clocks
‣Simple
LoC Scala JavaScript
Model 100 200
Glue 100 100
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Cons
‣Bulk operations
‣Space
‣No GC
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You Have Options
OT
Many options
(since 1998)
•Wave
•Google Docs
•Etherpad
Post-OT
Tombstones Tombstones
WOOT
2005
RGA
2011
CT
2010
Treedoc
2007
Logoot
2009
LSEQ
2013
×
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References
Oster et al (2006)
Data Consistency for P2P Collaborative Editing
http://www.loria.fr/~oster/pmwiki/pub/papers/OsterCSCW06.pdf
Ahmed-Nacer et al (2011)
Evaluating CRDTs for Real-time Document Editing
http://hal.archives-ouvertes.fr/docs/00/62/95/03/PDF/doce63-ahmednacer.pdf
Nédelec, Molli, Mostefaoui & Desmontils (2013)
LSEQ: an Adaptive Structure for Sequences in
Distributed Collaborative Editing
http://dl.acm.org/citation.cfm?id=2494278
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Summary
‣WOOT pretty neat
‣Lift is pretty neat
‣Put effort into the editor
‣Fun area, go explore
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Thank
you
Richard Dallaway
Jono Ferguson
@d6y
@jonoabroad
bitbucket.org/d6y/woot