#8 integrated with paging

src/modules/crm/CRMCore.Module.GraphQL/CRMCore.Module.GraphQL.csproj

@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="GraphQL" Version="0.17.3" />
+    <PackageReference Include="System.Linq.Dynamic.Core" Version="1.0.8.1" />
   </ItemGroup>
 
   <ItemGroup>

src/modules/crm/CRMCore.Module.GraphQL/DbContextExtensions.cs

@@ -0,0 +1,18 @@
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Linq;
+using System.Reflection;
+
+namespace CRMCore.Module.GraphQL
+{
+    public static class DbContextExtensions
+    {
+        public static IQueryable Query(this DbContext context, string entityName) =>
+            context.Query(context.Model.FindEntityType(entityName).ClrType);
+
+        static readonly MethodInfo SetMethod = typeof(DbContext).GetMethod(nameof(DbContext.Set));
+
+        public static IQueryable Query(this DbContext context, Type entityType) =>
+            (IQueryable)SetMethod.MakeGenericMethod(entityType).Invoke(context, null);
+    }
+}

src/modules/crm/CRMCore.Module.GraphQL/GraphQLController.cs

@@ -17,8 +17,16 @@ public GraphQLController(Schema schema)
             graphQLSchema = schema;
         }
 
-        [HttpPost("")]
-        public async Task<string> Get([FromQuery] string query = "{ crm_Tasks_list { id } }")
+        /// <summary>
+        /// Try as following
+        /// { crm_Tasks_list(offset:1, first:10) { name } }
+        /// { crm_Tasks_list { name } }
+        /// { crm_Tasks(id: "5BEF390D-5B71-4DBA-853A-00E164D4EA93") { name } }
+        /// </summary>
+        /// <param name="query"></param>
+        /// <returns></returns>
+        [HttpPost]
+        public async Task<string> Get([FromQuery] string query = "{ crm_Tasks_list(offset:1, first:10) { id, name } }")
         {
             var result = await new DocumentExecuter().ExecuteAsync(
                 new ExecutionOptions()
@@ -28,6 +36,11 @@ public async Task<string> Get([FromQuery] string query = "{ crm_Tasks_list { id
                 }
             ).ConfigureAwait(false);
 
+            if (result.Errors?.Count > 0)
+            {
+                return result.Errors.ToString();
+            }
+
             var json = new DocumentWriter(indent: true).Write(result.Data);
             return json;
         }

src/modules/crm/CRMCore.Module.GraphQL/GraphQLQuery.cs

@@ -1,19 +1,16 @@
-using CRMCore.Module.Data;
-using CRMCore.Module.GraphQL.Models;
-using GraphQL.Resolvers;
+using CRMCore.Module.GraphQL.Models;
+using CRMCore.Module.GraphQL.Resolvers;
 using GraphQL.Types;
 using Microsoft.EntityFrameworkCore;
-using System;
-using System.Collections.Generic;
 
 namespace CRMCore.Module.GraphQL
 {
     public class GraphQLQuery : ObjectGraphType<object>
     {
         private IDatabaseMetadata _dbMetadata;
-        private ApplicationDbContext _dbContext;
+        private DbContext _dbContext;
 
-        public GraphQLQuery(ApplicationDbContext dbContext, IDatabaseMetadata dbMetadata)
+        public GraphQLQuery(DbContext dbContext, IDatabaseMetadata dbMetadata)
         {
             _dbMetadata = dbMetadata;
             _dbContext = dbContext;
@@ -23,7 +20,7 @@ public GraphQLQuery(ApplicationDbContext dbContext, IDatabaseMetadata dbMetadata
             foreach (var metaTable in _dbMetadata.GetMetadataTables())
             {
                 var tableType = new TableType(metaTable);
-                /*AddField(new FieldType()
+                AddField(new FieldType
                 {
                     Name = metaTable.TableName,
                     Type = tableType.GetType(),
@@ -32,71 +29,21 @@ public GraphQLQuery(ApplicationDbContext dbContext, IDatabaseMetadata dbMetadata
                     Arguments = new QueryArguments(
                         tableType.TableArgs
                     )
-                });*/
+                });
 
-                //lets add key to get list of current table
+                // lets add key to get list of current table
                 var listType = new ListGraphType(tableType);
                 AddField(new FieldType
                 {
                     Name = $"{metaTable.TableName}_list",
                     Type = listType.GetType(),
                     ResolvedType = listType,
                     Resolver = new MyFieldResolver(metaTable, _dbContext),
-                    /*Arguments = new QueryArguments(
-                        tableType.TableArgs
-                    ) */
+                    Arguments = new QueryArguments(
+                        tableType.TableArgs                        
+                    )
                 });
             }
         }
     }
-
-    public class MyFieldResolver : IFieldResolver
-    {
-        private TableMetadata _tableMetadata;
-        private ApplicationDbContext _dbContext;
-
-        public MyFieldResolver(TableMetadata tableMetadata, ApplicationDbContext dbContext)
-        {
-            _tableMetadata = tableMetadata;
-            _dbContext = dbContext;
-        }
-
-        public object Resolve(ResolveFieldContext context)
-        {
-            var source = context.Source;
-
-            List<Dictionary<string, object>> finalResult = new List<Dictionary<string, object>>();
-            if (context.FieldName.Contains("_list"))
-            {
-
-                using (var command = _dbContext.Database.GetDbConnection().CreateCommand())
-                {
-                    command.CommandText = "SELECT * FROM " + _tableMetadata.TableName;
-                    _dbContext.Database.OpenConnection();
-                    using (var result = command.ExecuteReader())
-                    {
-                        while (result.Read())
-                        {
-                            var temp = new Dictionary<string, object>();
-
-                            for (var index = 0; index < result.FieldCount; index++)
-                            {
-                                var lowerCase = Char.ToLowerInvariant(result.GetName(index)[0]) + result.GetName(index).Substring(1);
-                                temp.Add(lowerCase, result[result.GetName(index)]);
-                            }
-
-                            finalResult.Add(temp);
-                        }
-                    }
-
-                    if (_dbContext.Database.GetDbConnection().State == System.Data.ConnectionState.Open)
-                    {
-                        _dbContext.Database.CloseConnection();
-                    }
-                }
-            }
-
-            return finalResult;
-        }
-    }
 }

src/modules/crm/CRMCore.Module.GraphQL/Models/ColumnMetadata.cs

@@ -1,25 +1,15 @@
-using System.ComponentModel.DataAnnotations.Schema;
-
-namespace CRMCore.Module.GraphQL.Models
+namespace CRMCore.Module.GraphQL.Models
 {
     public class ColumnMetadata
     {
-        [Column("name")]
         public string ColumnName
         {
             get; set;
         }
 
-        [Column("type")]
         public string DataType
         {
             get; set;
         }
-
-        [Column("notnull")]
-        public string IsNullable
-        {
-            get; set;
-        }
     }
 }

src/modules/crm/CRMCore.Module.GraphQL/Models/DatabaseMetadata.cs

@@ -1,5 +1,4 @@
-using CRMCore.Module.Data;
-using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Metadata;
 using System.Collections.Generic;
 using System.Linq;
@@ -8,9 +7,9 @@ namespace CRMCore.Module.GraphQL.Models
 {
     public class DatabaseMetadata : IDatabaseMetadata
     {
-        protected ApplicationDbContext _dbContext;
+        protected DbContext _dbContext;
 
-        public DatabaseMetadata(ApplicationDbContext dbContext)
+        public DatabaseMetadata(DbContext dbContext)
         {
             _dbContext = dbContext;
             DatabaseName = _dbContext.Database.GetDbConnection().Database;
@@ -37,22 +36,9 @@ public IEnumerable<TableMetadata> GetMetadataTables()
 
         private void LoadMetaData()
         {
-            // var res = new List<TableMetadata>();
-            /*res.Add(
-                FetchTableMetaData("Customers")
-            );*/
-
             Tables = FetchTableMetaData();
         }
 
-        /*public List<TableMetadata> GetMetadataTables()
-        {
-            if (Tables == null)
-                return new List<TableMetadata>();
-
-            return Tables;
-        } */
-
         private List<TableMetadata> FetchTableMetaData()
         {
             var metaTables = new List<TableMetadata>();
@@ -63,6 +49,7 @@ private List<TableMetadata> FetchTableMetaData()
                 var tableName = relational.TableName;
 
                 metaTable.TableName = tableName;
+                metaTable.AssemblyFullName = entityType.ClrType.FullName;
                 metaTable.Columns = GetColumnsMetadata(entityType).ToList();
 
                 metaTables.Add(metaTable);

src/modules/crm/CRMCore.Module.GraphQL/Models/TableMetadata.cs

@@ -1,14 +1,13 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
+using System.Collections.Generic;
 
 namespace CRMCore.Module.GraphQL.Models
 {
     public class TableMetadata
     {
-        [Column("table_name")]
         public string TableName { get; set; }
 
+        public string AssemblyFullName { get; set; }
+
         public List<ColumnMetadata> Columns { get; set; }
     }
 }

src/modules/crm/CRMCore.Module.GraphQL/Resolvers/MyFieldResolver.cs

@@ -0,0 +1,48 @@
+using CRMCore.Module.GraphQL.Models;
+using GraphQL.Resolvers;
+using GraphQL.Types;
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Linq;
+using System.Linq.Dynamic.Core;
+
+namespace CRMCore.Module.GraphQL.Resolvers
+{
+    public class MyFieldResolver : IFieldResolver
+    {
+        private TableMetadata _tableMetadata;
+        private DbContext _dbContext;
+
+        public MyFieldResolver(TableMetadata tableMetadata, DbContext dbContext)
+        {
+            _tableMetadata = tableMetadata;
+            _dbContext = dbContext;
+        }
+
+        public object Resolve(ResolveFieldContext context)
+        {
+            var queryable = _dbContext.Query(_tableMetadata.FullQualifiedName);
+            if (context.FieldName.Contains("_list"))
+            {
+
+                var first = context.Arguments["first"] != null ? 
+                    context.GetArgument("first", int.MaxValue) :
+                    int.MaxValue;
+
+                var offset = context.Arguments["offset"] != null ? 
+                    context.GetArgument("offset", 0) : 
+                    0;
+
+                return queryable
+                    .Skip(offset)
+                    .Take(first)
+                    .ToDynamicList<object>();
+            }
+            else
+            {
+                var id = context.GetArgument<Guid>("id");
+                return queryable.FirstOrDefault($"Id == @0", id);
+            }
+        }
+    }
+}

src/modules/crm/CRMCore.Module.GraphQL/Resolvers/NameFieldResolver.cs

@@ -0,0 +1,34 @@
+using GraphQL.Resolvers;
+using GraphQL.Types;
+using System;
+
+namespace CRMCore.Module.GraphQL.Resolvers
+{
+    public class NameFieldResolver : IFieldResolver
+    {
+        public object Resolve(ResolveFieldContext context)
+        {
+            var source = context.Source;
+
+            if (source == null)
+            {
+                return null;
+            }
+
+            var name = Char.ToUpperInvariant(context.FieldAst.Name[0]) + context.FieldAst.Name.Substring(1);
+            var value = GetPropValue(source, name);
+
+            if (value == null)
+            {
+                throw new InvalidOperationException($"Expected to find property {context.FieldAst.Name} on {context.Source.GetType().Name} but it does not exist.");
+            }
+
+            return value;
+        }
+
+        private static object GetPropValue(object src, string propName)
+        {
+            return src.GetType().GetProperty(propName).GetValue(src, null);
+        }
+    }
+}