Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
The Science of Etherpad
Search
Tim Cameron Ryan
May 14, 2012
Programming
2
62
The Science of Etherpad
How does Operational Transform work?
Tim Cameron Ryan
May 14, 2012
Tweet
Share
More Decks by Tim Cameron Ryan
See All by Tim Cameron Ryan
BayNode Meetup June 2014
tcr
1
79
Elevator redesign: Team Unibros Final Presentation
tcr
0
430
Other Decks in Programming
See All in Programming
Node-RED を(HTTP で)つなげる MCP サーバーを作ってみた
highu
0
120
20250704_教育事業におけるアジャイルなデータ基盤構築
hanon52_
5
840
AIと”コードの評価関数”を共有する / Share the "code evaluation function" with AI
euglena1215
1
170
MCPを使ってイベントソーシングのAIコーディングを効率化する / Streamlining Event Sourcing AI Coding with MCP
tomohisa
0
110
A full stack side project webapp all in Kotlin (KotlinConf 2025)
dankim
0
120
チームのテスト力を総合的に鍛えて品質、スピード、レジリエンスを共立させる/Testing approach that improves quality, speed, and resilience
goyoki
5
940
『自分のデータだけ見せたい!』を叶える──Laravel × Casbin で複雑権限をスッキリ解きほぐす 25 分
akitotsukahara
2
640
XP, Testing and ninja testing
m_seki
3
250
PicoRuby on Rails
makicamel
2
130
なぜ「共通化」を考え、失敗を繰り返すのか
rinchoku
1
660
VS Code Update for GitHub Copilot
74th
2
660
効率的な開発手段として VRTを活用する
ishkawa
0
150
Featured
See All Featured
Stop Working from a Prison Cell
hatefulcrawdad
271
21k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
367
26k
Sharpening the Axe: The Primacy of Toolmaking
bcantrill
44
2.4k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
331
22k
The Web Performance Landscape in 2024 [PerfNow 2024]
tammyeverts
8
700
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
PRO
181
54k
Agile that works and the tools we love
rasmusluckow
329
21k
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
danielanewman
229
22k
XXLCSS - How to scale CSS and keep your sanity
sugarenia
248
1.3M
Adopting Sorbet at Scale
ufuk
77
9.5k
Templates, Plugins, & Blocks: Oh My! Creating the theme that thinks of everything
marktimemedia
31
2.4k
Faster Mobile Websites
deanohume
307
31k
Transcript
THE SCIENCE OF ETHERPAD MAKING ANY DOCUMENT COLLABORATIVE, ANYWHERE
Operations
app
apple
“app” + ”le”
app Operation 1 1. insertCharacter “a” 2. insertCharacter “p” 3.
insertCharacter “p“
apple Operation 2 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. insertCharacter “l” 5. insertCharacter “e“
applecore Operation 2 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. retain (skip character) 5. retain (skip character) 6. insertCharacter “c” 7. insertCharacter “o“ 8. insertCharacter “r“ 9. insertCharacter “e“
Composition
appl Operation 1 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. insertCharacter “l” apple Operation 2 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. retain (skip character) 5. insertCharacter “e”
Operation 1+2 1. retain (skip character) 2. retain (skip character)
3. retain (skip character) 4. insertCharacter “l” 5. insertCharacter “e“ appl apple
Concurrency
app app CLIENT A CLIENT B
appl appe CLIENT A CLIENT B
appl Operation A 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. insertCharacter “l” appe Operation B 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “e” CLIENT A CLIENT B
appl Operation B 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. insertCharacter “e” appe Operation A 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “l” CLIENT A CLIENT B
appel Operation B 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. insertCharacter “e” apple Operation A 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “l” CLIENT A CLIENT B
appel apple CLIENT A CLIENT B
Operational Transform
“A theoretical framework of concurrency control” that “provides a mechanism
for sanely resolving [editing] conflicts so that neither user intervention or locking become necessary.” A mechanism to “transform” two operations in conflict, resulting in two new operations which bring both clients into a common state.
app app CLIENT A CLIENT B SERVER
appl Operation A 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. insertCharacter “l” CLIENT A SERVER 1 appe Operation B 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “e” CLIENT B 2
Operation A 1. retain (skip character) 2. retain (skip character)
3. retain (skip character) 4. insertCharacter “l” SERVER TRANSFORM Operation B 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “e” Operation B` 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. retain (skip character) 5. insertCharacter “e” Operation A` 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “l” 5. retain (skip character)
appl Operation B` 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. retain (skip character) 5. insertCharacter “e” CLIENT A SERVER appe Operation A` 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “l” 5. retain (skip character) CLIENT B B` A`
apple Operation B` 1. retain (skip character) 2. retain (skip
character) 3. retain (skip character) 4. retain (skip character) 5. insertCharacter “e” CLIENT A SERVER apple Operation A` 1. retain (skip character) 2. retain (skip character) 3. retain (skip character) 4. insertCharacter “l” 5. retain (skip character) CLIENT B B` A`
apple apple CLIENT A CLIENT B
CLIENT A CLIENT B A1: retain 3, insert “l” Broadcast
A1 Apply A1` SERVER
CLIENT A CLIENT B SERVER A1: retain 3, insert “l”
B1: retain 3, insert “e” Transform A1 x B1 Apply A1` Apply B1`
CLIENT A CLIENT B SERVER A1: retain 3, insert “l”
B1: retain 3, insert “e” A2: retain 4, insert “core” Transform A1 x B1 Apply A1` Transform A2 x B1` Apply B1`` Broadcast A2 Apply A2`
CLIENT A CLIENT B SERVER A1: retain 3, insert “l”
B1: retain 3, insert “e” A2: retain 4, insert “core” Transform A1 x B1 B2: retain 4, insert “sauce” Transform B2 x A1` Apply A1`` Transform A2 x B1` Apply B1`` Transform A2` x B2` Apply A2`` Apply B2``
CLIENT A CLIENT B SERVER A1: retain 3, insert “l”
B1: retain 3, insert “e” A2: retain 4, insert “core” Transform A1 x B1 B2: retain 4, insert “sauce” Transform B2 x A1` Apply A1`` Transform A2 x B1` Apply B1`` Transform A2` x B2` Apply A2`` Apply B2``
Markup
big apple
big apple
<i>big</i> <b>apple</b>
<i>big</i> <b>apple</b>
<i>big</i> <b>apple</b> Operation 1. insertStartTag “i” 2. insertCharacter “b” 3.
insertCharacter “i” 4. insertCharacter “g” 5. insertEndTag “i” 6. insertCharacter “ ” 7. insertStartTag “b” 8. insertCharacter “a” 9. insertCharacter “p” 10. insertCharacter “p” 11. insertCharacter “l” 12. insertCharacter “e” 13. insertEndTag “b”
a big word a big word CLIENT A CLIENT B
a <b>big</b> word Operation A 1. retain 2 2. insertStartTag
“b” 3. retain 3 4. insertEndTag “b” a biiiiig word Operation B 1. retain 3 2. insertCharacters “iiii” CLIENT A CLIENT B
a <b>big</b> word Operation B` 1. retain 4 2. insertCharacters
“iiii” a biiiiig word Operation A` 1. retain 2 2. insertStartTag “b” 3. retain 5 4. insertEndTag “b” CLIENT A CLIENT B
a <b>biiiiig</b> word Operation B` 1. retain 4 2. insertCharacters
“iiii” a <b>biiiiig</b> word Operation A` 1. retain 2 2. insertStartTag “b” 3. retain 5 4. insertEndTag “b” CLIENT A CLIENT B
Preserving Intent
CLIENT A CLIENT B Desired Word1 Word2 Word3 <ol> <li>
Word4 Word5 Word6 </li> </ol> <ol> <li> Word1 Word2 Word3 Word4 </li> </ol> Word5 Word6 <ol> <li> Word1 Word2 Word3 Word4 Word5 Word6 </li> </ol>
CLIENT A CLIENT B Desired Word1 Word2 <p> Word3 Word4
Word5 Word6 </p> <h1> Word1 Word2 Word3 Word4 </h1> Word5 Word6 <h1> Word1 Word2 </h1> <p> Word3 Word4 </p> <p> Word5 Word6 </p>
CLIENT A CLIENT B Desired Word1 Word2 Word3 <i> Word4
Word5 Word6 Word7 Word8 </i> <b> Word1 Word2 Word3 Word4 Word5 </b> Word6 Word7 Word8 <b> Word1 Word2 Word3 </b> <bi> Word4 Word5 </bi> <i> Word6 Word7 Word8 </i>
• retain • deleteCharacter • deleteStartTag(tag, attrs) • deleteEndTag() •
deleteEmptyTag() • insertCharacter • insertStartTag(tag, attrs) • insertEndTag() • insertEmptyTag() • modifyAttrs(attrs) Deletion Phase Insertion Phase OPERATION ATOMS
Containers like: preserve unlike: priority Blocks like: priority unlike: priority
Styles like: preserve unlike: merge Inline <ul> <li> <ol> <blockquote> <p> <div> <h1> <h2> <h3> <pre> <b> <i> <span> <u> <s> “text” <br> DOCUMENT SCHEMA