A simple Nancy Module that uses DataStax drivers to read data from Cassandra

DocumentModule.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Xml.Linq;
using Nancy;
using Nancy.ModelBinding;
using Cassandra.Data.Linq;
using Cassandra.Data;
using Cassandra;


namespace AP.ECRNextGen
{
    [Table("latest_documents")]
    public class APPLDocVersion
    {
        [PartitionKey(0)]
        [Column("item_id")]
        public Guid ItemId { get; set; }

        [ClusteringKey(0, "DESC")]
        [Column("record_seqno")]
        public int RecordSequenceNumber { get; set; }

    }

    [Table("document_versions")]
    public class LatestAPPLDocVersion
    {

        [PartitionKey(0)]
        [Column("item_id")]
        public Guid ItemId { get; set; }

        [ClusteringKey(0)]
        [Column("record_seqno")]
        public int RecordSequenceNumber { get; set; }

    }

    [Table("documents")]
    public class APPLDoc
    {
        [PartitionKey(0)]
        [Column("item_id_rsn")]
        public string ItemIdRSN { get; set; }

        [ClusteringKey(0)]
        [Column("record_seqno")]
        public int RecordSequenceNumber { get; set; }

        [Column("status")]
        public string Status { get; set; }

        [Column("appl")]
        public string APPL { get; set; }

        [Column("update_time")]
        public DateTime UpdateTime { get; set; }

        [Column("arrival_time")]
        public DateTime ArrivalTime { get; set; }

    }

    public class DocumentModule : NancyModule
    {
        public DocumentModule()
        {
            var cluster = Cluster.Builder()
               .AddContactPoint("127.0.0.1")
               .Build();

            var s = cluster.Connect("ci_appl");

            Table<APPLDoc> docs_table = s.GetTable<APPLDoc>();
            Table<APPLDocVersion> docs_versions_table = s.GetTable<APPLDocVersion>();

            Get["/documents/{itemid}"] = _ =>
            {
                string item_id = _.itemid;
                var latest_item = (from d in docs_versions_table 
                                   where d.ItemId == Guid.Parse(item_id) 
                                   orderby d.RecordSequenceNumber descending 
                                   select d).FirstOrDefault().Execute();

                var iid_rsn = latest_item.ItemId.ToString("n") + "_" + latest_item.RecordSequenceNumber;

                var appl_doc = (from d in docs_table 
                                where d.ItemIdRSN == iid_rsn 
                                select d.APPL).FirstOrDefault().Execute();

                var response = (Response)appl_doc;
                response.ContentType = "application/xml";

                return response;
            };

            Get["/documents/{itemid}/versions/{rsn}"] = _ =>
            {
                string item_id = _.itemid;
                string rsn = _.rsn;

                var iid_rsn = item_id + "_" + rsn;

                var appl_doc = (from d in docs_table
                                where d.ItemIdRSN == iid_rsn
                                select d.APPL).FirstOrDefault().Execute();

                var response = (Response)appl_doc;
                response.ContentType = "application/xml";

                return response;
            };
        }
    }
}