How to Create and Delete edge properties (Titan 1.

Question

I was using Titan 1.0 with gremlin server to create and delete vertex. I want to implement this logic in my .net project. I wonder if there is any pre build plugin for titan and gremlin server in asp.net?

Currently i'm directly using command prompt to create and delete the required vertices and edges. how can I implement it in my .net MVC project?

Answer 1

I've created one class in my project for interacting with Gremlin server using REST API. you can make small changes to make it work for you.

Source: https://askgif.com/blog/145/how-to-create-and-delete-edge-properties-titan-1-0-using-c-in-net-mvc/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using Newtonsoft.Json;
using RestSharp;
using urNotice.Common.Infrastructure.Common.Config;
using urNotice.Common.Infrastructure.Common.Constants;
using urNotice.Common.Infrastructure.Common.Enum;
using urNotice.Common.Infrastructure.commonMethods;
using urNotice.Common.Infrastructure.Model.urNoticeModel.DynamoDb;
using urNotice.Services.NoSqlDb.DynamoDb;

namespace urNotice.Services.GraphDb
{
    public class GremlinServerGraphEdgeDb : IGraphEdgeDb
    {
        private delegate Dictionary<string, string> AddEdgeAsyncDelegate(string userName, string graphName, Dictionary<string, string> properties);

    public Dictionary<string, string> AddEdge(string userName, string graphName, Dictionary<string, string> properties)
    {
        string url = TitanGraphConfig.Server;
        var response = CreateEdge(graphName, properties, url);

        // add edge to dynamodb.
        var edgeDetail = new OrbitPageEdgeDetail
        {
            url = url,
            edgeId = response[TitanGraphConstants.Id],
            graphName = graphName,
            properties = properties
        };

        IDynamoDb dynamoDbModel = new DynamoDb();
        dynamoDbModel.UpsertOrbitPageEdgeDetail(edgeDetail, userName, properties[EdgePropertyEnum._inV.ToString()], properties[EdgePropertyEnum._outV.ToString()]);

        //Adding edgeDetail for faster query.
        //dynamoDbModel.UpsertOrbitPageEdgeForQueryDetail(edgeDetail, userName, properties[EdgePropertyEnum._inV.ToString()], properties[EdgePropertyEnum._outV.ToString()]);

        return response;
    }

    public Dictionary<string, string> DeleteEdge(string inV, string outV, string label)
    {
        string url = TitanGraphConfig.Server;

        IDynamoDb dynamoDbModel = new DynamoDb();
        string uniqueKey = OrbitPageUtil.GenerateUniqueKeyForEdgeQuery(inV, label, outV);
        var edgeInfo = dynamoDbModel.GetOrbitPageCompanyUserWorkgraphyTable(
                   DynamoDbHashKeyDataType.EdgeDetail.ToString(),
                   uniqueKey,
                   null);

        if (edgeInfo == null)
            return null;

        var response = DeleteEdgeNative(TitanGraphConfig.Graph, edgeInfo.CompareId, url);
        dynamoDbModel.DeleteOrbitPageCompanyUserWorkgraphyTable(edgeInfo);

        //Deleting Edge detail creating for only query purpose.
        //string uniqueKey = OrbitPageUtil.GenerateUniqueKeyForEdgeQuery(inV, label, outV);
        //edgeInfo = dynamoDbModel.GetOrbitPageCompanyUserWorkgraphyTable(
        //            DynamoDbHashKeyDataType.EdgeDetail.ToString(),
        //            uniqueKey,
        //            null);

        //if(edgeInfo!=null)
        //    dynamoDbModel.DeleteOrbitPageCompanyUserWorkgraphyTable(edgeInfo);

        return response;
    }

    public Dictionary<string, string> AddEdgeAsync(string userName, string graphName, Dictionary<string, string> properties)
    {
        var addEdgeAsyncDelegate = new GremlinServerGraphEdgeDb.AddEdgeAsyncDelegate(AddEdge);
        addEdgeAsyncDelegate.BeginInvoke(userName, graphName, properties, null, null);
        return null;
    }

    private Dictionary<String, String> CreateEdge(string graphName, Dictionary<string, string> properties, string url)
    {
        var uri = new StringBuilder(url + "/?gremlin=");

        //http://localhost:8182/?gremlin=g.V(8320).next().addEdge("Using",g.V(12416).next(),"Desc","Item used by Person","time",12345)

        string graphProperties = string.Empty;

        //_outV must be the first parameter
        graphProperties += "'" + properties[EdgePropertyEnum._label.ToString()] + "', g.V(" + properties[EdgePropertyEnum._inV.ToString()] + ").next() ,";
        foreach (KeyValuePair<string, string> property in properties)
        {
            if (property.Key == EdgePropertyEnum._inV.ToString() || property.Key == EdgePropertyEnum._outV.ToString() || property.Key == EdgePropertyEnum._label.ToString())
            {
                //do nothing.. May be in future we will write logic here.                    
            }
            else
            {
                if (property.Key == EdgePropertyEnum.PostedDateLong.ToString() || property.Key == EdgePropertyEnum.SalaryAmount.ToString())
                    graphProperties += "'" + property.Key + "', " + property.Value + " ,";
                else
                    graphProperties += "'" + property.Key + "', '" + property.Value + "' ,";
            }
        }

        if (!string.IsNullOrEmpty(graphProperties))
        {
            graphProperties = graphProperties.Substring(0, graphProperties.Length - 2);
        }

        uri.Append("g.V(" + properties[EdgePropertyEnum._outV.ToString()] + ").next().addEdge(" + graphProperties + ");");
        var client = new RestClient(uri.ToString());
        var request = new RestRequest();

        request.Method = Method.GET;
        request.AddHeader("Accept", "application/json");
        request.Parameters.Clear();
        request.AddParameter("application/json", "", ParameterType.RequestBody);

        var res = client.Execute(request);
        var content = res.Content; // raw content as string 

        dynamic jsonResponse = JsonConvert.DeserializeObject(content);
        var response = new Dictionary<String, String>();
        response["status"] = "200";
        response["CreateEdgeStatus"] = "200";
        response[TitanGraphConstants.Id] = jsonResponse.result.data[0].id;
        response[TitanGraphConstants.RexsterUri] = url;
        return response;
    }

    private Dictionary<String, String> DeleteEdgeNative(string graphName, string edgeId, string url)
    {
        var uri = new StringBuilder(url + "/?gremlin=");
        //var uri = new StringBuilder(url + "/graphs/" + graphName + "/edges/" + edgeId);

        //http://localhost:8182/?gremlin=g.E('odxqo-6f4-2hat-9kw').drop()

        uri.Append("g.E('" + edgeId + "').drop();");

        var client = new RestClient(uri.ToString());
        var request = new RestRequest();

        request.Method = Method.GET;
        request.AddHeader("Accept", "application/json");
        request.Parameters.Clear();
        request.AddParameter("application/json", "", ParameterType.RequestBody);

        var res = client.Execute(request);
        var content = res.Content; // raw content as string 

        dynamic jsonResponse = JsonConvert.DeserializeObject(content);
        var response = new Dictionary<String, String>();
        response["status"] = "200";
        response["DeleteEdgeStatus"] = "200";
        //response[TitanGraphConstants.Id] = jsonResponse.result.data[0].id;
        //response[TitanGraphConstants.RexsterUri] = url;
        return response;
    }
}
}

comment if you face any issue in the class.