// Inspired by SharpCouch and tweaked for our specific needs

using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System.Net.Http;

namespace SharpRepository.CouchDbRepository

{

/// <summary>

/// Used to return metadata about a document.

/// </summary>

public class DocInfo

{

public string Id;

public string Revision;

}

/// <summary>

/// A simple wrapper class for the CouchDB HTTP API. No

/// initialisation is necessary, just create an instance and

/// call the appropriate methods to interact with CouchDB.

/// All methods throw exceptions when things go wrong.

/// </summary>

public class CouchDbClient<T> where T : class, new()

{

private readonly string _server;

private readonly string _database;

public CouchDbClient()

{

}

public CouchDbClient(string server, string database)

{

_server = server;

_database = database;

}

public string Server

{

get { return _server; }

}

public string Database

{

get { return _database; }

}

public string DatabaseUrl

{

get { return _server + "/" + _database; }

}

/// <summary>

/// Get the document count for the given database.

/// </summary>

/// <returns>The number of documents in the database</returns>

public int CountDocuments()

{

// Get information about the database...

var result = CouchDbRequest.Execute(_server, _database, HttpMethod.Get);

var dictionary = JsonConvert.DeserializeObject<IDictionary<string, string>>(result);

// The document count is a field within...

return Int32.Parse(dictionary["doc_count"]);

}

/// <summary>

/// Get information on all the documents in the given database.

/// </summary>

/// <returns>An array of entitiy instances</returns>

public IList<T> GetAllDocuments()

{

var json = ExecMapReduce(_server, _database + "/_temp_view", "function (doc) {emit(doc._id, doc);}", null);

var res = JObject.Parse(json);

var rows = res["rows"];

return rows.Select(row => row["value"].ToObject<T>()).ToList();

}

public string ExecMapReduce(string url, string uri, string map, string reduce)

{

var viewdef = "{ \"map\":\"" + map + "\"";

if (reduce != null)

viewdef += ",\"reduce\":\"" + reduce + "\"";

viewdef += "}";

return CouchDbRequest.Execute(url, uri, HttpMethod.Post, viewdef, "application/json");

}

/// <summary>

/// Execute a temporary view and return the results.

/// </summary>

/// <param name="map">The javascript map function</param>

/// <param name="reduce">The javascript reduce function or

/// null if not required</param>

/// <param name="startkey">The startkey or null not to use</param>

/// <param name="endkey">The endkey or null not to use</param>

/// <returns>The result (JSON format)</returns>

public string ExecTempView(string map, string reduce ,string startkey, string endkey)

{

// Generate the JSON view definition from the supplied

// map and optional reduce functions...

var viewdef = "{ \"map\":\"" + map + "\"";

if (reduce != null)

viewdef += ",\"reduce\":\"" + reduce + "\"";

viewdef += "}";

var uri = _database + "/_temp_view";

if(startkey != null)

{

uri += "?startkey=" + Uri.EscapeDataString(startkey);

}

if(endkey != null)

{

if (startkey == null)

uri += "?";

else

uri += "&";

uri += "endkey=" + Uri.EscapeDataString(endkey);

}

return CouchDbRequest.Execute(_server, uri, HttpMethod.Post, viewdef, "application/json");

}

/// <summary>

/// Create a new document. If the document has no ID field,

/// it will be assigned one by the server.

/// </summary>

/// <param name="entity">The item to store in the database.</param>

public void CreateDocument(T entity, string id)

{

var item = JsonConvert.SerializeObject(entity);

// add the _id so that it is the same as the PK of the entity

// this is a crappy way of doing it I think, but just trying to get it to work for now

if (!String.IsNullOrEmpty(id))

{

item = "{\"_id\":\"" + id + "\"," + item.Substring(1);

}

CouchDbRequest.Execute(_server, _database, HttpMethod.Post, item, "application/json");

}

public string GetLatestRevision(string id)

{

var json = Get(id);

var obj = JObject.Parse(json);

return obj.Value<string>("_rev");

}

/// <summary>

/// Updates a document.

/// </summary>

/// <param name="entity">The item to store in the database.</param>

/// <param name="id">The document ID.</param>

public void UpdateDocument(T entity, string id)

{

var item = JsonConvert.SerializeObject(entity);

//needs the revision for updates and deletes, this isn't a great way because it's an extra API call, but it is what it is for now, just want to get it working then refactor

var rev = GetLatestRevision(id);

// add the _id so that it is the same as the PK of the entity

// this is a crappy way of doing it I think, but just trying to get it to work for now

item = "{\"_id\":\"" + id + "\",\"_rev\":\"" + rev + "\"," + item.Substring(1);

CouchDbRequest.Execute(_server, _database + "/" + id, HttpMethod.Put, item, "application/json");

}

/// <summary>

/// Get a document.

/// </summary>

/// <param name="id">The document ID.</param>

/// <returns>The document contents (JSON)</returns>

public T GetDocument(string id)

{

var json = Get(id);

if (String.IsNullOrEmpty(json))

{

return null;

}

return JsonConvert.DeserializeObject<T>(json);

}

private string Get(string id)

{

var uri = _database + "/" + id;

return CouchDbRequest.Execute(_server, uri, HttpMethod.Get);

}

/// <summary>

/// Delete a document.

/// </summary>

/// <param name="id">The document ID.</param>

public void DeleteDocument(string id)

{

//needs the revision for updates and deletes, this isn't a great way because it's an extra API call, but it is what it is for now, just want to get it working then refactor

var rev = GetLatestRevision(id);

CouchDbRequest.Execute(_server, _database + "/" + id + "?rev=" + rev, HttpMethod.Delete);

}

}

}