James Nocentini Mobile Developer Advocate, UK Couchbase Sync is hard: building offline-first Android apps from the ground up www.droidcon.ae @droidconae

1. Let’s
build
offline-­‐first
apps!
James
Nocentini
|
Developer
Advocate,
Couchbase

2. ©2014
Couchbase
Inc.
Use
case
2
• Clean
UI
• The
user
shouldn’t
have
to
be
online
@jamiltz

3. No
loading,
no
waiting,
nothing.

4. ©2014
Couchbase
Inc.
Options
4
@jamiltz

5. ©2014
Couchbase
Inc.
Options
5
@jamiltz

6. 6
Sync
Gateway Couchbase
Server

7. ©2014
Couchbase
Inc.
Couchbase
Lite
7
Today
I’d
like
to
talk
about
some
of
the
internals
of
Couchbase
Lite
Android
@jamiltz

8. ©2014
Couchbase
Inc.
Saving
a
document
8
Map<String, Object> properties = new HashMap<String, Object>();
properties.put("type", "list");
properties.put("title", title);
properties.put("created_at", currentTimeString);
properties.put("owner", "profile:" + userId);
properties.put("members", new ArrayList<String>());
// save to database
Document document = database.createDocument();
document.putProperties(properties);
@jamiltz

9. ©2014
Couchbase
Inc.
Saving
a
document
9
Document document = database.getDocument(myDocId);
String title = document.getProperty("title");
Map<String, Object> properties = doc.getProperties();
String owner = (String) properties.get("owner");
@jamiltz

10. ©2014
Couchbase
Inc.
Saving
a
document
10
Document document = database.getDocument(myDocId);
String title = document.getProperty("title");
Map<String, Object> properties = doc.getProperties();
String owner = (String) properties.get("owner");
@jamiltz

11. Plain
Old
Java
Objects

12. Plain
Old
JSON
Objects

13. ©2014
Couchbase
Inc.
It’s
JSON
{
"_id": "123",
"type": "list",
"title": "TodoMVC list",
"owner": "1234567890",
"members": [
"0987654321",
"0192837465"
]
}
13
@jamiltz

14. ©2014
Couchbase
Inc.
Content
Types
JSON ❤ HTTP
14
@jamiltz

15. ©2014
Couchbase
Inc.
What
else?
15
Replicators
@jamiltz

16. ©2014
Couchbase
Inc.
Two
Verbs
Push
→
Pull
←
16
@jamiltz

17. ©2014
Couchbase
Inc.
Two
Verbs
Push
→
Server
Pull
←
Server
17
@jamiltz

18. ©2014
Couchbase
Inc.
Two
Verbs
Push
→
Couchbase
Sync
Gateway
Pull
←
Couchbase
Sync
Gateway
18
@jamiltz

19. ©2014
Couchbase
Inc.
Push
19
facebookAuthenticator = AuthenticatorFactory.createFacebookAuthenticator(accessToken);
Replication push = database.createPushReplication(SYNC_URL);
push.setAuthenticator(facebookAuthenticator);
push.setContinuous(true);
push.start();

20. ©2014
Couchbase
Inc.
If
you
were
to
build
your
own
▪ Create
a
job
object
that
has
an
action
▪ Write
data
to
a
durable
queue
▪ Run
a
service
to
process
the
queue
▪ The
service
retries
if
the
network
hiccups
or
app
crashes
▪ Remove
from
the
queue
once
the
job
is
complete
20
@jamiltz

21. ©2014
Couchbase
Inc.
Replicators
21
Source Target
Android
App Sync
Gateway
@jamiltz

22. ©2014
Couchbase
Inc.
Replicators
Get
the
sequence
ID
of
the
source
database
22
@jamiltz

23. ©2014
Couchbase
Inc.
Replicators
23
Source Target
Android
App Sync
Gateway
@jamiltz
seq:
15 seq:
5

24. ©2014
Couchbase
Inc.
Pull
Pull
==
24
Push
@jamiltz

25. ©2014
Couchbase
Inc.
Replicators
25
Source
Android
App Sync
Gateway
@jamiltz
Target

26. ©2014
Couchbase
Inc.
Replicators
26
Source
Android
App Sync
Gateway
@jamiltz
Target
seq:
15seq:
5

27. ©2014
Couchbase
Inc.
Pull
27
facebookAuthenticator = AuthenticatorFactory.createFacebookAuthenticator(accessToken);
Replication pull = database.createPullReplication(SYNC_URL);
pull.setAuthenticator(facebookAuthenticator);
pull.setContinuous(true);
pull.start();

28. Demo

29. Don’t
drain
all
my
battery!

30. ©2014
Couchbase
Inc.
Pull
30
facebookAuthenticator = AuthenticatorFactory.createFacebookAuthenticator(accessToken);
Replication pull = database.createPullReplication(SYNC_URL);
pull.setAuthenticator(facebookAuthenticator);
pull.setContinuous(true);
pull.start();

31. ©2014
Couchbase
Inc.
Solution
GCM
is
your
friend
🎉
31
@jamiltz

32. ©2014
Couchbase
Inc.
Data
Flow
Techniques
32
Sync
Gateway
changes
feed
Push
notifications
worker
Continuous
push
@jamiltz

33. ©2014
Couchbase
Inc.
Data
Flow
Techniques
33
Sync
Gateway
changes
feed
Push
notifications
worker
Continuous
push
GCM
notification
GCM
notification
@jamiltz

34. ©2014
Couchbase
Inc.
Data
Flow
Techniques
34
Sync
Gateway
changes
feed
Push
notifications
worker
Continuous
push
One
shot
pull
One
shot
pull
@jamiltz

35. Demo

36. ©2014
Couchbase
Inc.
Conflict
resolution
36
rev-­‐1
rev-­‐2
rev-­‐1
rev-­‐2’
@jamiltz

37. ©2014
Couchbase
Inc.
Conflict
resolution
37
rev-­‐1
rev-­‐2 rev-­‐2’

38. ©2014
Couchbase
Inc.
Conflict
resolution
38
rev-­‐1
rev-­‐2 rev-­‐2’
current
revision

39. ©2014
Couchbase
Inc.
Conflict
resolution
39
rev-­‐1
rev-­‐2 rev-­‐2’

40. ©2014
Couchbase
Inc.
Conflict
resolution
40
rev-­‐1
rev-­‐2
current
revision

41. P2P Demo

42. ©2014
Couchbase
Inc.
CouchbaseLite
Listener
42
Embedded
lightweight
HTTP
server

43. ©2014
Couchbase
Inc.
Replications
43
Same
Replication
Interface
as
Sync
Gateway

44. ©2014
Couchbase
Inc.
Mesh
Networks
44

45. Workshops
• Push
/
Pull
• Basic
config
for
Sync
Gateway
• And
more…

46. ©2014
Couchbase
Inc.
Summary
▪ Performance
▪ Ease
of
development
▪ Live
Queries
▪ Robustness
46

47. ©2014
Couchbase
Inc.
More
Information
47
James
Nocentini
Developer
Advocate
@jamiltz
ToDoLite
Android
https://github.com/couchbaselabs/ToDoLite-­‐Android
Couchbase
Developer
Forums
http://forums.couchbase.com