A global MongoDb configuration helper

MongoDbContext.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MongoDB.Driver;

namespace SimpleMongoDb
{
    public class MongoDbContext
    {
        /// <summary>
        /// ** connection string **
        /// format example:
        /// 
        /// mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/[database][?options]]
        /// 
        /// ** OPTIONS **
        /// * w
        /// -1 : The driver will not acknowledge write operations and will suppress all network or socket errors.
        /// 0 : The driver will not acknowledge write operations, but will pass or handle any network and socket errors that it receives to the client.
        /// 1 : Provides basic acknowledgment of write operations, a standalone mongod instance, or the primary for replica sets, acknowledge all write operations
        /// majority
        /// n
        /// tags
        /// 
        /// * ssl
        /// true: Initiate the connection with SSL.
        /// false: Initiate the connection without SSL.
        /// The default value is false.
        /// 
        /// * connectTimeoutMS
        /// The time in milliseconds to attempt a connection before timing out. 
        /// The default is never to timeout, though different drivers might vary. See the driver documentation.
        /// 
        /// * socketTimeoutMS
        /// The time in milliseconds to attempt a send or receive on a socket before the attempt times out. 
        /// The default is never to timeout, though different drivers might vary. See the driver documentation.
        /// 
        /// * journal 
        /// true / false
        /// 
        /// * readPreference
        /// primaryPreferred - will try to read from primary (but if primary is offline, will read from the secondary nodes)
        /// secondaryPreferred - will try to read from a secondary node (but if offline, will read from the primary node)
        /// (OBS.: All writes go to the Primary)
        /// 
        /// </summary>

        static string m_baseConnectionString = String.Empty;
        static string m_login = null;
        static string m_password = null;
        static MongoServer m_server = null;

        /// <summary>
        /// Configures the specified login.
        /// </summary>
        /// <param name="login">The login.</param>
        /// <param name="password">The password.</param>
        /// <param name="addresses">List of addresses. Format: host1[:port1][,host2[:port2],...[,hostN[:portN]]]</param>
        /// <param name="safeMode">The safe mode. True to receive write confirmation from mongo.</param>
        /// <param name="readOnSecondary">The read on secondary. True to direct read operations to cluster secondary nodes (secondaryPreferred), else try to read from primary (primaryPreferred).</param>
        /// <param name="connectionTimeoutMilliseconds">The time to attempt a connection before timing out.</param>
        /// <param name="socketTimeoutMilliseconds">The time to attempt a send or receive on a socket before the attempt times out.</param>
        /// <param name="isReplicaSet">The is replica set hint.</param>
        /// <param name="readPreferenceTags">The read preference tags. List of a comma-separated list of colon-separated key-value pairs. Ex.: { {dc:ny,rack:1}, { dc:ny } } </param>
        public static void Configure (string login, string password, string addresses, bool safeMode = true, bool readOnSecondary = false, int connectionTimeoutMilliseconds = 1000, int socketTimeoutMilliseconds = 6000, /* bool isReplicaSet = true, */ IEnumerable<string> readPreferenceTags = null)
        {
            m_login = login;
            m_password = password;

            string connectionString = BuildConnectionString (login, password, safeMode, readOnSecondary, addresses, connectionTimeoutMilliseconds, socketTimeoutMilliseconds, /*isReplicaSet, */ readPreferenceTags);

            if (m_baseConnectionString != connectionString)
            {
                m_server = null;
                m_baseConnectionString = connectionString;
                m_docStore = new Lazy<MongoClient> (OpenConnection);
            }
        }

        /// <summary>
        /// Builds the connection string.
        /// </summary>
        /// <param name="login">The login.</param>
        /// <param name="password">The password.</param>
        /// <param name="safeMode">The safe mode. True to receive write confirmation from mongo.</param>
        /// <param name="readOnSecondary">The read on secondary. True to direct read operations to cluster secondary nodes (secondaryPreferred), else try to read from primary (primaryPreferred).</param>
        /// <param name="addresses">List of addresses. Format: host1[:port1][,host2[:port2],...[,hostN[:portN]]]</param>
        /// <param name="connectionTimeoutMilliseconds">The time to attempt a connection before timing out.</param>
        /// <param name="socketTimeoutMilliseconds">The time to attempt a send or receive on a socket before the attempt times out.</param>
        /// <param name="isReplicaSet">The is replica set hint.</param>
        /// <param name="readPreferenceTags">The read preference tags. List of a comma-separated list of colon-separated key-value pairs. Ex.: { {dc:ny,rack:1}, { dc:ny } } </param>
        public static string BuildConnectionString (string login, string password, bool safeMode, bool readOnSecondary, string addresses, int connectionTimeoutMilliseconds, int socketTimeoutMilliseconds, /* bool isReplicaSet = true, */ IEnumerable<string> readPreferenceTags = null)
        {
            StringBuilder sb = new StringBuilder ("mongodb://", 230);
            // check credentials
            if (!String.IsNullOrWhiteSpace (login) && !String.IsNullOrWhiteSpace (password))
            {
                sb.Append (login).Append (':').Append (password).Append ('@');
            }
            // address
            sb.Append (addresses).Append ("/?");
            // options
            //if (isReplicaSet)
            //    sb.Append ("connect=replicaset&");
            if (safeMode)
                sb.Append ("w=1&");
            else
                sb.Append ("w=0&");
            if (readOnSecondary)
            {
                sb.Append ("readPreference=secondaryPreferred&");
            }
            else
            {
                sb.Append ("readPreference=primaryPreferred&");
            }
            if (readPreferenceTags != null)
            {
                foreach (var tag in readPreferenceTags)
                {
                    if (String.IsNullOrWhiteSpace (tag))
                        continue;
                    sb.Append ("readPreferenceTags=").Append (tag.Trim ().Replace (' ', '_')).Append ('&');
                }
            }

            sb.Append ("connectTimeoutMS=").Append (connectionTimeoutMilliseconds).Append ("&socketTimeoutMS=").Append (socketTimeoutMilliseconds);

            // generate final connection string
            return sb.ToString ();
        }

        private static Lazy<MongoClient> m_docStore = new Lazy<MongoClient> (OpenConnection);

        private static MongoClient OpenConnection ()
        {
            // set serialization options (a design decision to use UtcNow or Local)
            var dateTimeSerializer = new MongoDB.Bson.Serialization.Serializers.DateTimeSerializer (MongoDB.Bson.Serialization.Options.DateTimeSerializationOptions.LocalInstance);
            MongoDB.Bson.Serialization.BsonSerializer.RegisterSerializer (typeof (DateTime), dateTimeSerializer);
            // create mongo client
            MongoClient client = new MongoClient (m_baseConnectionString);
            return client;
        }

        public static MongoClient Client
        {
            get { return m_docStore.Value; }
        }

        public static MongoServer Server
        {
            get
            {
                if (m_server == null)
                    m_server = Client.GetServer ();
                return m_server;
            }
        }

        public static MongoDatabase GetDatabase (string dbName)
        {
            return Server.GetDatabase (dbName);
        }

    }
}