ParameterCollection.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;

namespace HttpServer
{
    /// <summary>
    /// Collection of parameters.
    /// </summary>
    /// <remarks>
    /// <see cref="Dictionary{TKey,TValue}"/> or <see cref="NameValueCollection"/> is not used since each parameter can
    /// have multiple values.
    /// </remarks>
    public class ParameterCollection : IParameterCollection
    {
        private readonly Dictionary<string, IParameter> _items = new Dictionary<string, IParameter>(StringComparer.OrdinalIgnoreCase);

        /// <summary>
        /// Initializes a new instance of the <see cref="ParameterCollection"/> class.
        /// </summary>
        /// <param name="collections">Collections to merge.</param>
        /// <remarks>
        /// Later collections will overwrite parameters from earlier collections.
        /// </remarks>
        public ParameterCollection(params IParameterCollection[] collections)
        {
            foreach (IParameterCollection collection in collections)
            {
                if (collection == null)
                    continue;
                foreach (IParameter p in collection)
                {
                    foreach (string value in p)
                        Add(p.Name, value);
                }
            }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ParameterCollection"/> class.
        /// </summary>
        public ParameterCollection()
        {
        }

        /// <summary>
        /// Get a list of string arrays.
        /// </summary>
        /// <returns></returns>
        public string[] GetArrayNames()
        {
            var names = new List<string>();
            foreach (var item in _items)
            {
                int pos = item.Key.IndexOf("[");
                if (pos == -1)
                    continue;

                names.Add(item.Key.Substring(0, pos));
            }

            return names.ToArray();
        }

        /// <summary>
        /// Get parameters 
        /// </summary>
        /// <param name="arrayName">Sub array (text array)</param>
        /// <returns></returns>
        public IParameterCollection GetParameters(string arrayName)
        {
            var collection = new ParameterCollection();
            arrayName = arrayName + "[";
            foreach (var item in _items)
            {
                if (!item.Key.StartsWith(arrayName)) continue;
                int pos = arrayName.IndexOf("]");
                if (pos == -1) continue;

                string name = arrayName.Substring(arrayName.Length, pos - arrayName.Length);
                foreach (string value in item.Value)
                    collection.Add(name, value);
            }

            return collection;
        }

        #region IParameterCollection Members

        /// <summary>
        /// Gets number of parameters.
        /// </summary>
        public int Count
        {
            get { return _items.Count; }
        }

        /// <summary>
        /// Gets last value of an parameter.
        /// </summary>
        /// <param name="name">Parameter name</param>
        /// <returns>String if found; otherwise <c>null</c>.</returns>
        public string this[string name]
        {
            get
            {
                IParameter param = Get(name);
                return param != null ? param.Value : null;
            }
        }


        /// <summary>
        /// Returns an enumerator that iterates through the collection.
        /// </summary>
        /// <returns>
        /// A <see cref="T:System.Collections.Generic.IEnumerator`1"/> that can be used to iterate through the collection.
        /// </returns>
        /// <filterpriority>1</filterpriority>
        public IEnumerator<IParameter> GetEnumerator()
        {
            return _items.Values.GetEnumerator();
        }

        /// <summary>
        /// Returns an enumerator that iterates through a collection.
        /// </summary>
        /// <returns>
        /// An <see cref="T:System.Collections.IEnumerator"/> object that can be used to iterate through the collection.
        /// </returns>
        /// <filterpriority>2</filterpriority>
        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        /// <summary>
        /// Get a parameter.
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        public IParameter Get(string name)
        {
            IParameter parameter;
            return _items.TryGetValue(name, out parameter) ? parameter : null;
        }

        /// <summary>
        /// Add a query string parameter.
        /// </summary>
        /// <param name="name">Parameter name</param>
        /// <param name="value">Value</param>
        public void Add(string name, string value)
        {
            IParameter parameter;
            if (!_items.TryGetValue(name, out parameter))
            {
                parameter = new Parameter(name, value);
                _items.Add(name, parameter);
            }
            else
                parameter.Values.Add(value);

        }

        /// <summary>
        /// Checks if the specified parameter exists
        /// </summary>
        /// <param name="name">Parameter name.</param>
        /// <returns><c>true</c> if found; otherwise <c>false</c>;</returns>
        public bool Exists(string name)
        {
            return _items.ContainsKey(name);
        }

        #endregion
    }
}