P2P Dictionary is a distributed key-value store for multiple nodes on a local area network. Each node will subscribe to a subset of key-value pairs. Key-value pairs are replicated as necessary between nodes to reach to another node. Similar to most NoSQL implementations, it does not provide an SQL interface or guarantee ACID (atomicity, consistency, isolation, durability).

P2P dictionary will run on a local area network discovered using LAN discovery technologies (e.g., Apple Bonjour, Zeroconf, UDP broadcast) or any reachable IP address in a public network. Peer links can be discovered or connected by the client.

P2P dictionary provides a server written in .NET Framework, .NET Core, and Java JVM. A REST interface is provided by the P2P server for read-only access to key-value pairs. A web interface is provided for web browser access to key-value pairs stored on each node. A redistributable package is provided using Docker containers with both .NET and Java implementations.

Copyright (C) 2011-2018, Richard H Fung

You agree to the LICENSE before using this Software.

All platforms:

• Microsoft .NET Core 2.x on Linux, Mac, or Windows

For redistributable:

• Docker 17.05 or higher

For Mac:

• Visual Studio Code, or
• Visual Studio for Mac

For Windows:

• Microsoft Visual Studio 2017
• Microsoft .NET Framework 4.6.1 on Windows
• Requires Apple Bonjour Print Services for Windows: http://support.apple.com/kb/DL999

Several example projects using P2P Dictionary are in the ''examples'' directory.

• Fastest response time for dictionary updates is 8 ms.

P2PDictionary methods conform to IDictionary interface. Additional methods are:

Additional dictionary methods:

• Clear() removes all dictionary entries owned by this dictionary
• GetValue(key,msTimeout) blocking call to read from the dictionary, waits for msTimeout, throws IndexOutOfRangeException
• TryGetValue(key) blocking call to read from the dictionary, returns false if cannot get the value
• TryGetValue(key,msTimeOut) blocking call to read from the dictionary, waits for msTimeout, returns false if cannot get the value
• AddSubscription("pattern") adds a subscription that matches the pattern. Pattern matching is Visual Basic patterns (* for many characters, ? for a single character)

Control methods:

• Abort() force close all incoming and outgoing connections
• Close() safely close all incoming and outgoing connections
• ConstructNetwork() searches for peers on the network using Apple Bonjour -- must be enabled ahead of time??
• GetSubscriptions() returns a list of subscriptions (subscribed patterns)
• OpenClient() opens a client connection to a known remote peer
• OpenServer() opens a server instance if not already specified on constructor
• RemoveSubscription() removes a previously added subscription '''not tested'''

Static methods:

• P2PDictionary.GetFreePort(port) returns the next open free port at or above the specified value. Throws ApplicationException if the port cannot be found.

• DebugBuffer sets/gets the buffer for debug messages
• Description returns the friendly name for the dictionary, assigned on constructor
• LocalEndPoint returns the IP address of the server
• LocalID returns a unique ID number for the dictionary, should be unique to all peers
• Namespace returns the namespace provided on constructor, must be the same to all peers on the network
• RemotePeersCount returns the number of remotely connected peers

• Connected when a peer joins
• ConnectionFailure when a peer fails to join
• Disconnected when a peer departs
• Notified when a subscribed dictionary key is added, changed, or removed
• SubscriptionChanged when a subscription changes

Build on Linux/Mac using Docker. Example commands:

cd <SOURCEDIR>
docker build -t p2pd-csharp .
docker run -p 8800:8800 -it p2pd-csharp -s test -p 8800

And open http://localhost:8800 to see the running server.

Get additional commands using (see next section for detail):

docker run -p 8800:8800 -it p2pd-csharp --help

The CLI p2pd and p2pwin support the following arguments:

  -m, --description    (Default: ) Description for the server
  -p, --port           (Default: 8765) Bind to port
  -s, --namespace      Required. Namespace for the server
  -t, --timespan       (Default: 1500) Search interval for clients
  -d, --discovery      Specify a backend discovery mechanism, defaults to none
  --nopattern          Monitors no patterns
  --pattern            Monitors a specific pattern using wildcard (*), single character (?), and number (#) placeholders; default to *
  -n                   Provide clients in the form host:port
  --debug
  --fulldebug

• 2.1

  • added supported for .NET Core 2.0
  • upgraded to .NET Framework 4.6.1 and Visual Studio 2017
  • added in required constructor argument for IPeerInterface and default discovery module NoDiscovery
  • added CLI for Windows p2pwin and Linux p2pd
  • new discovery module P2PDictionary.Peers.Zeroconf for ZeroconfDiscovery module that was previously enabled by default

• 2.0

  • new REST API
  • Bonjour registration
  • support for any MIME type
  • not compatible with 1.6.3