Massive.PostgreSQL.cs

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Configuration;
using System.Data;
using System.Data.Common;
using System.Dynamic;
using System.Linq;
using System.Text;

namespace Massive.PostgreSQL {
    public static class ObjectExtensions {
        /// <summary>
        /// Extension method for adding in a bunch of parameters
        /// </summary>
        public static void AddParams(this DbCommand cmd, params object[] args) {
            foreach (var item in args) {
                AddParam(cmd, item);
            }
        }
        /// <summary>
        /// Extension for adding single parameter
        /// </summary>
        public static void AddParam(this DbCommand cmd, object item) {
            var p = cmd.CreateParameter();
            p.ParameterName = string.Format("@{0}", cmd.Parameters.Count);
            if (item == null) {
                p.Value = DBNull.Value;
            } else {
                if (item.GetType() == typeof(Guid)) {
                    p.Value = item.ToString();
                    p.DbType = DbType.String;
                    p.Size = 4000;
                } else if (item.GetType() == typeof(ExpandoObject)) {
                    var d = (IDictionary<string, object>)item;
                    p.Value = d.Values.FirstOrDefault();
                } else {
                    p.Value = item;
                }
                if (item.GetType() == typeof(string))
                    p.Size = ((string)item).Length > 4000 ? -1 : 4000;
            }
            cmd.Parameters.Add(p);
        }
        /// <summary>
        /// Turns an IDataReader to a Dynamic list of things
        /// </summary>
        public static List<dynamic> ToExpandoList(this IDataReader rdr) {
            var result = new List<dynamic>();
            while (rdr.Read()) {
                result.Add(rdr.RecordToExpando());
            }
            return result;
        }
        public static dynamic RecordToExpando(this IDataReader rdr) {
            dynamic e = new ExpandoObject();
            var d = e as IDictionary<string, object>;
            for (int i = 0; i < rdr.FieldCount; i++)
                d.Add(rdr.GetName(i), DBNull.Value.Equals(rdr[i]) ? null : rdr[i]);
            return e;
        }
        /// <summary>
        /// Turns the object into an ExpandoObject
        /// </summary>
        public static dynamic ToExpando(this object o) {
            var result = new ExpandoObject();
            var d = result as IDictionary<string, object>; //work with the Expando as a Dictionary
            if (o.GetType() == typeof(ExpandoObject)) return o; //shouldn't have to... but just in case
            if (o.GetType() == typeof(NameValueCollection) || o.GetType().IsSubclassOf(typeof(NameValueCollection))) {
                var nv = (NameValueCollection)o;
                nv.Cast<string>().Select(key => new KeyValuePair<string, object>(key, nv[key])).ToList().ForEach(i => d.Add(i));
            } else {
                var props = o.GetType().GetProperties();
                foreach (var item in props) {
                    d.Add(item.Name, item.GetValue(o, null));
                }
            }
            return result;
        }
        /// <summary>
        /// Turns the object into a Dictionary
        /// </summary>
        public static IDictionary<string, object> ToDictionary(this object thingy) {
            return (IDictionary<string, object>)thingy.ToExpando();
        }
    }
    /// <summary>
    /// A class that wraps your database table in Dynamic Funtime
    /// </summary>
    public class DynamicModel : DynamicObject {
        DbProviderFactory _factory;
        string ConnectionString;
        public static DynamicModel Open(string connectionStringName) {
            dynamic dm = new DynamicModel(connectionStringName);
            return dm;
        }
        public DynamicModel(string connectionStringName, string tableName = "", string primaryKeyField = "") {
            TableName = tableName == "" ? this.GetType().Name : tableName;
            PrimaryKeyField = string.IsNullOrEmpty(primaryKeyField) ? "id" : primaryKeyField;
            var _providerName = "Npgsql";
            _factory = DbProviderFactories.GetFactory(_providerName);
            ConnectionString = ConfigurationManager.ConnectionStrings[connectionStringName].ConnectionString;
        }

        /// <summary>
        /// Creates a new Expando from a Form POST - white listed against the columns in the DB
        /// </summary>
        public dynamic CreateFrom(NameValueCollection coll) {
            dynamic result = new ExpandoObject();
            var dc = (IDictionary<string, object>)result;
            var schema = Schema;
            //loop the collection, setting only what's in the Schema
            foreach (var item in coll.Keys) {
                var exists = schema.Any(x => x.COLUMN_NAME.ToLower() == item.ToString().ToLower());
                if (exists) {
                    var key = item.ToString();
                    var val = coll[key];
                    if (!String.IsNullOrEmpty(val)) {
                        //what to do here? If it's empty... set it to NULL?
                        //if it's a string value - let it go through if it's NULLABLE?
                        //Empty? WTF?
                        dc.Add(key, val);
                    }
                }
            }
            return result;
        }
        /// <summary>
        /// Gets a default value for the column
        /// </summary>
        public dynamic DefaultValue(dynamic column) {
            dynamic result = null;
            string def = column.COLUMN_DEFAULT;
            if (String.IsNullOrEmpty(def)) {
                result = null;
            } else if (def == "getdate()" || def == "(getdate())") {
                result = DateTime.Now.ToShortDateString();
            } else if (def == "newid()") {
                result = Guid.NewGuid().ToString();
            } else {
                result = def.Replace("(", "").Replace(")", "");
            }
            return result;
        }
        /// <summary>
        /// Creates an empty Expando set with defaults from the DB
        /// </summary>
        public dynamic Prototype {
            get {
                dynamic result = new ExpandoObject();
                var schema = Schema;
                foreach (dynamic column in schema) {
                    var dc = (IDictionary<string, object>)result;
                    dc.Add(column.COLUMN_NAME, DefaultValue(column));
                }
                result._Table = this;
                return result;
            }
        }
        /// <summary>
        /// List out all the schema bits for use with ... whatever
        /// </summary>
        IEnumerable<dynamic> _schema;
        public IEnumerable<dynamic> Schema {
            get {
                if(_schema == null)
                    _schema= Query("SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = @0", TableName);
                return _schema;
            }
        }

        /// <summary>
        /// Enumerates the reader yielding the result - thanks to Jeroen Haegebaert
        /// </summary>
        public virtual IEnumerable<dynamic> Query(string sql, params object[] args) {
            using (var conn = OpenConnection()) {
                var rdr = CreateCommand(sql, conn, args).ExecuteReader();
                while (rdr.Read()) {
                    yield return rdr.RecordToExpando(); ;
                }
            }
        }


        public virtual IEnumerable<dynamic> Query(string sql, DbConnection connection, params object[] args) {
            using (var rdr = CreateCommand(sql, connection, args).ExecuteReader()) {
                while (rdr.Read()) {
                    yield return rdr.RecordToExpando(); ;
                }
            }
        }
        /// <summary>
        /// Returns a single result
        /// </summary>
        public virtual object Scalar(string sql, params object[] args) {
            object result = null;
            using (var conn = OpenConnection()) {
                result = CreateCommand(sql, conn, args).ExecuteScalar();
            }
            return result;
        }
        /// <summary>
        /// Creates a DBCommand that you can use for loving your database.
        /// </summary>
        DbCommand CreateCommand(string sql, DbConnection conn, params object[] args) {
            var result = _factory.CreateCommand();
            result.Connection = conn;
            result.CommandText = sql;
            if (args.Length > 0)
                result.AddParams(args);
            return result;
        }
        /// <summary>
        /// Returns and OpenConnection
        /// </summary>
        public virtual DbConnection OpenConnection() {
            var result = _factory.CreateConnection();
            result.ConnectionString = ConnectionString;
            result.Open();
            return result;
        }
        /// <summary>
        /// Builds a set of Insert and Update commands based on the passed-on objects.
        /// These objects can be POCOs, Anonymous, NameValueCollections, or Expandos. Objects
        /// With a PK property (whatever PrimaryKeyField is set to) will be created at UPDATEs
        /// </summary>
        public virtual List<DbCommand> BuildCommands(params object[] things) {
            var commands = new List<DbCommand>();
            foreach (var item in things) {
                if (HasPrimaryKey(item)) {
                    commands.Add(CreateUpdateCommand(item, GetPrimaryKey(item)));
                } else {
                    commands.Add(CreateInsertCommand(item));
                }
            }
            return commands;
        }
        /// <summary>
        /// Executes a set of objects as Insert or Update commands based on their property settings, within a transaction.
        /// These objects can be POCOs, Anonymous, NameValueCollections, or Expandos. Objects
        /// With a PK property (whatever PrimaryKeyField is set to) will be created at UPDATEs
        /// </summary>
        public virtual int Save(params object[] things) {
            var commands = BuildCommands(things);
            return Execute(commands);
        }

        public virtual int Execute(DbCommand command) {
            return Execute(new DbCommand[] { command });
        }

        public virtual int Execute(string sql, params object[] args) {
            return Execute(CreateCommand(sql, null, args));
        }
        /// <summary>
        /// Executes a series of DBCommands in a transaction
        /// </summary>
        public virtual int Execute(IEnumerable<DbCommand> commands) {
            var result = 0;
            using (var conn = OpenConnection()) {
                using (var tx = conn.BeginTransaction()) {
                    foreach (var cmd in commands) {
                        cmd.Connection = conn;
                        cmd.Transaction = tx;
                        result += cmd.ExecuteNonQuery();
                    }
                    tx.Commit();
                }
            }
            return result;
        }
        public virtual string PrimaryKeyField { get; set; }
        /// <summary>
        /// Conventionally introspects the object passed in for a field that 
        /// looks like a PK. If you've named your PrimaryKeyField, this becomes easy
        /// </summary>
        public virtual bool HasPrimaryKey(object o) {
            return o.ToDictionary().ContainsKey(PrimaryKeyField);
        }
        /// <summary>
        /// If the object passed in has a property with the same name as your PrimaryKeyField
        /// it is returned here.
        /// </summary>
        public virtual object GetPrimaryKey(object o) {
            object result = null;
            o.ToDictionary().TryGetValue(PrimaryKeyField, out result);
            return result;
        }
        public virtual string TableName { get; set; }
        /// <summary>
        /// Creates a command for use with transactions - internal stuff mostly, but here for you to play with
        /// </summary>
        public virtual DbCommand CreateInsertCommand(object o) {
            DbCommand result = null;
            var expando = o.ToExpando();
            var settings = (IDictionary<string, object>)expando;
            var sbKeys = new StringBuilder();
            var sbVals = new StringBuilder();
            var stub = "INSERT INTO {0} ({1}) \r\n VALUES ({2}) RETURNING {3}";
            result = CreateCommand(stub, null);
            int counter = 0;
            foreach (var item in settings) {
                sbKeys.AppendFormat("{0},", item.Key);
                sbVals.AppendFormat("@{0},", counter.ToString());
                result.AddParam(item.Value);
                counter++;
            }
            if (counter > 0) {
                var keys = sbKeys.ToString().Substring(0, sbKeys.Length - 1);
                var vals = sbVals.ToString().Substring(0, sbVals.Length - 1);
                var sql = string.Format(stub, TableName, keys, vals,PrimaryKeyField);
                result.CommandText = sql;
            } else throw new InvalidOperationException("Can't parse this object to the database - there are no properties set");
            return result;
        }
        /// <summary>
        /// Creates a command for use with transactions - internal stuff mostly, but here for you to play with
        /// </summary>
        public virtual DbCommand CreateUpdateCommand(object o, object key) {
            var expando = o.ToExpando();
            var settings = (IDictionary<string, object>)expando;
            var sbKeys = new StringBuilder();
            var stub = "UPDATE {0} SET {1} WHERE {2} = @{3}";

            var result = CreateCommand(stub, null);
            int counter = 0;
            foreach (var item in settings) {
                var val = item.Value;
                if (!item.Key.Equals(PrimaryKeyField, StringComparison.CurrentCultureIgnoreCase) && item.Value != null) {
                    result.AddParam(val);
                    sbKeys.AppendFormat("{0} = @{1}, \r\n", item.Key, counter.ToString());
                    counter++;
                }
            }
            if (counter > 0) {
                //add the key
                result.AddParam(key);
                //strip the last commas
                var keys = sbKeys.ToString().Substring(0, sbKeys.Length - 4);
                result.CommandText = string.Format(stub, TableName, keys, PrimaryKeyField, counter);
            } else throw new InvalidOperationException("No parsable object was sent in - could not divine any name/value pairs");
            return result;
        }
        /// <summary>
        /// Removes one or more records from the DB according to the passed-in WHERE
        /// </summary>
        public virtual DbCommand CreateDeleteCommand(string where = "", object key = null, params object[] args) {
            var sql = string.Format("DELETE FROM {0} ", TableName);
            if (key != null) {
                sql += string.Format("WHERE {0}=@0", PrimaryKeyField);
                args = new object[] { key };
            } else if (!string.IsNullOrEmpty(where)) {
                sql += where.Trim().StartsWith("where", StringComparison.CurrentCultureIgnoreCase) ? where : "WHERE " + where;
            }
            return CreateCommand(sql, null, args);
        }
        /// <summary>
        /// Adds a record to the database. You can pass in an Anonymous object, an ExpandoObject,
        /// A regular old POCO, or a NameValueColletion from a Request.Form or Request.QueryString
        /// </summary>
        public virtual object Insert(object o) {
            dynamic result = 0;
            using (var conn = OpenConnection()) {
                var cmd = CreateInsertCommand(o);    			 
                cmd.Connection = conn;
                result = cmd.ExecuteScalar();
            }
            return result;
        }
        /// <summary>
        /// Updates a record in the database. You can pass in an Anonymous object, an ExpandoObject,
        /// A regular old POCO, or a NameValueCollection from a Request.Form or Request.QueryString
        /// </summary>
        public virtual int Update(object o, object key) {
            return Execute(CreateUpdateCommand(o, key));
        }
        /// <summary>
        /// Removes one or more records from the DB according to the passed-in WHERE
        /// </summary>
        public int Delete(object key = null, string where = "", params object[] args) {
            return Execute(CreateDeleteCommand(where: where, key: key, args: args));
        }
        /// <summary>
        /// Returns all records complying with the passed-in WHERE clause and arguments, 
        /// ordered as specified, limited (TOP) by limit.
        /// </summary>
        public virtual IEnumerable<dynamic> All(string where = "", string orderBy = "", int limit = 0, string columns = "*", params object[] args) {
            string sql = BuildSelect(where, orderBy, limit);
            return Query(string.Format(sql, columns, TableName), args);
        }
        private static string BuildSelect(string where, string orderBy, int limit) {
            string sql = "SELECT {0} FROM {1} ";
			if (!string.IsNullOrEmpty(where))
				sql += where.Trim().StartsWith("where", StringComparison.OrdinalIgnoreCase) ? where : "WHERE " + where;
			if (!String.IsNullOrEmpty(orderBy))
				sql += orderBy.Trim().StartsWith("order by", StringComparison.OrdinalIgnoreCase) ? orderBy : " ORDER BY " + orderBy;
			if (limit > 0)
				sql += " LIMIT " + limit; 
			
            return sql;
        }

        /// <summary>
        /// Returns a single row from the database
        /// </summary>
        public virtual dynamic Single(string where, params object[] args) {
            var sql = string.Format("SELECT * FROM {0} WHERE {1}", TableName, where);
            return Query(sql, args).FirstOrDefault();
        }
        /// <summary>
        /// Returns a single row from the database
        /// </summary>
        public virtual dynamic Single(object key, string columns = "*") {
            var sql = string.Format("SELECT {0} FROM {1} WHERE {2} = @0", columns, TableName, PrimaryKeyField);
            return Query(sql, key).FirstOrDefault();
        }
        /// <summary>
        /// A helpful query tool
        /// </summary>
        public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) {
            //parse the method
            var constraints = new List<string>();
            var counter = 0;
            var info = binder.CallInfo;
            // accepting named args only... SKEET!
            if (info.ArgumentNames.Count != args.Length) {
                throw new InvalidOperationException("Please use named arguments for this type of query - the column name, orderby, columns, etc");
            }


            //first should be "FindBy, Last, Single, First"
            var op = binder.Name;
            var columns = " * ";
            string orderBy = string.Format(" ORDER BY {0}", PrimaryKeyField);
            string where = "";
            var whereArgs = new List<object>();

            //loop the named args - see if we have order, columns and constraints
            if (info.ArgumentNames.Count > 0) {

                for (int i = 0; i < args.Length; i++) {
                    var name = info.ArgumentNames[i].ToLower();
                    switch (name) {
                        case "orderby":
                            orderBy = " ORDER BY " + args[i];
                            break;
                        case "columns":
                            columns = args[i].ToString();
                            break;
                        default:
                            constraints.Add(string.Format(" {0} = @{1}", name, counter));
                            whereArgs.Add(args[i]);
                            counter++;
                            break;
                    }
                }
            }
            //Build the WHERE bits
            if (constraints.Count > 0) {
                where = " WHERE " + string.Join(" AND ", constraints.ToArray());
            }
            //build the SQL
            string sql = "SELECT TOP 1 " + columns + " FROM " + TableName + where;
            var justOne = op.StartsWith("First") || op.StartsWith("Last") || op.StartsWith("Get");

            //Be sure to sort by DESC on the PK (PK Sort is the default)
            if (op.StartsWith("Last")) {
                orderBy = orderBy + " DESC ";
            } else {
                //default to multiple
                sql = "SELECT " + columns + " FROM " + TableName + where;
            }

            if (justOne) {
                //return a single record
                result = Query(sql + orderBy, whereArgs.ToArray()).FirstOrDefault();
            } else {
                //return lots
                result = Query(sql + orderBy, whereArgs.ToArray());
            }

            return true;
        }
    }
}