Building .NET Apps using Couchbase Lite

Zack Gramana

About Me

Zack Gramana

Senior Software Engineer

Mobile

@zgramana

And, about me…

Wayne Carter

Architect

Mobile

@waynecarter

4

Couchbase LiteOn-device, lightweight, native

embedded JSON database

Sync GatewaySynchronize on-device

Couchbase Lite with Couchbase Server in the cloud

Couchbase ServerHigh performance, scalable, always-on JSON database in

the cloud

Couchbase Mobile

5

Couchbase Lite

Couchbase Lite

Full Featured

JSON

Native

Lightweight

Secure

Beta

6

Sync Gateway

Sync Gateway

Replication

Authentication

Data Partitioning

Data Access Control

7

Pluggable Authentication

JavaScript sync function runs on all mutations.

Data Partitioning– channel(…): Routes the document to the named channel

Data Access Control– Read

– access(…): Grants access to a channel to a specified user, list of users, or a role

– role(…): Grants a user a role

– Write

– throw(…): Prevents a document mutation from persisting

– requireUser/Role/Access(…): Validates the user, their role assignments, or their access privileges.

Authentication, Partitioning, Access Control

8

Couchbase Server

Couchbase Server

JSON

Highly Scalable

High Performance

Always On

Couchbase Lite In A Nutshell

Highlights

• Document Database• Map Reduce Queries• Sync• Small: Assembly is < 500KB

Document Database Overview

• Semi-structured• Key-value pairs• Schemaless• JSON-backed• Very low-friction

Map Reduce Queries Overview

• Functional queries, instead of set-theoretic• Write query logic in pure C#, not SQL• Can be one-off, or auto-updating as data

changes• You probably already know how to use it:–Map is like LINQ’s Select method– Reduce is like LINQ’s Aggregate method

Sync Overview

• Master-master replication• Uses HTTP + REST• Offline mode for free• Manual or continuous modes• Automatic retry on failure• Responds to network changes

Programming Model

• You: make your changes to docs• Queries: will reflect those changes• Replicators: sync changes for you

Getting Started with Documents

Opening a Database

var db = Manager.SharedInstance.GetDatabase("foo");Debug.Assert(db != null);

var db = Manager.SharedInstance.GetExistingDatabase("foo");Debug.Assert(db == null);

Getting a Document

var doc = db.GetDocument("foo-doc");Debug.Assert(doc != null);

var doc = db.GetExistingDocument("foo-doc");Debug.Assert(doc == null);

Creating a Document

var doc = db.CreateDocument();Debug.Assert(doc.Id != null);

Deleting a Document

doc.Delete();Debug.Assert(doc.Deleted);

Updating a New Document

var rev = doc.CreateRevision();var props = new Dictionary<string, object> { { "foo", "bar"}, { "fizz", "buzz"} };rev.SetUserProperties(props);rev.Save();

Updating an Existing Document

var props = doc.Properties;var newProps = new Dictionary<string, object>(props) { { "foo", "bar"} };doc.PutProperties(newProps); // Saves a new revision

Dealing with Changes

doc.Change += (sender, e) => { // e.g. if we get a conflict... if (e.Change.IsConflict) { // we can resolve it! }};

DocumentChange Members

StringBooleanBoolean

StringUri

RevisionInternal

DocumentId IsConflict IsCurrentRevision RevisionId SourceUrl WinningRevision

Handling Conflicts

var current = doc.CurrentRevision;foreach(var rev in doc.ConflictingRevisions){ var newRev = rev.CreateRevision(); if (rev.Equals(current)) { newRev.SetProperties(mergedProps); } else { newRev.IsDeletion = true; } newRev.Save();}

Auto-merging Properties using LINQ

Dictionary<string, object> mergedProps;try{ mergedProps = doc.ConflictingRevisions .SelectMany(rev => rev.UserProperties) .Distinct() .ToDictionary( kvp => kvp.Key, kvp => kvp.Value );} catch (ArgumentException ex) { // Merge conflict requires manual resolution.}

Getting Started with Queries

Create a View

var view = db.GetView("foo");Debug.Assert(view != null);

var view = db.GetExistingView("foo");Debug.Assert(view == null);

Add a Map Function

view.SetMap((doc, emit) => { var foo = (String)doc["foo"]; if (foo.Equals("bar")) { emit ("text", doc["text"]); }}, "1");

Using a Reduce Function

ReduceDelegate reducer = (keys, values, rereduce) => { var i = 0; var wordCount = 0; foreach(var key in keys) { if (key == "text") { var str = (String)values[i]; wordCount += str.Split(' ').Length; } } return wordCount;};view.SetMapReduce(mapper, reducer, "1");

Create a Query

var query = view.CreateQuery();

// Options, like...query.Completed += (sender, e) => { Log("Results: {0}", e.Rows);};query.Descending = true;

// Get records...var rows = await query.RunAsync();rows.Where(row => ...);

Create a LiveQuery

var liveQuery = query.ToLiveQuery();

// Respond to changes in the view.liveQuery.Changed += (sender, e) =>{ Log("Updates: {0}", e.Rows.Count);};

Getting Started with Replication

Pull Replicator

var uri = new Uri(syncGatewayUrl);var pull = db.CreatePullReplication(uri);pull.Continuous = true;pull.Changed += ReplicationChanged;pull.Start();

Push Replicator

var uri = new Uri(syncGatewayUrl);var push = db.CreatePushReplication(uri);push.Continuous = true;push.Changed += ReplicationChanged;push.Start();

Next Steps

Couchbase Developer Portal

developer.couchbase.com/mobile

Xamarin Component Store

components.xamarin.com/view/couchbase-lite-net

.:[coming soon]:.

nuget.org

Couchbase Connect

Questions and Answers

Additional Resources

Mailing List

groups.google.com/d/forum/mobile-couchbase

Contact Me

zack@couchbase.com (email)@zgramana (twitter)