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

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Couchbase  Lite  On-­‐device,  lightweight,  na1ve  embedded  JSON  database  

Sync  Gateway  Synchronize  on-­‐device  

Couchbase  Lite  with  Couchbase  Server  in  the  cloud  

Couchbase  Server  High  performance,  scalable,  always-­‐on  JSON  database  in  

the  cloud  

Couchbase Mobile

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Couchbase  Lite  

Couchbase Lite

Full Featured

JSON

Native

Lightweight

Secure

Beta

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Sync  Gateway  

Sync Gateway

Replication

Authentication

Data Partitioning

Data Access Control

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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

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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

String "Boolean "Boolean "String "

Uri "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)