Hotchocolate query generation demo

.gitignore

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-Cosmos.GraphQL.Service/Cosmos.GraphQL.Service/bin/*
-Cosmos.GraphQL.Service/Cosmos.GraphQL.Service/obj/*
-Cosmos.GraphQL.Service/Cosmos.GraphQL.Service/.idea/*
-Cosmos.GraphQL.Service/Cosmos.GraphQL.Service.Tests/bin/*
-Cosmos.GraphQL.Service/Cosmos.GraphQL.Service.Tests/obj/*
-Cosmos.GraphQL.Service/Cosmos.GraphQL.Service.Tests/.idea/*
+bin/
+obj/
+system-commandline-sentinel-files/
 
-
-*/.idea/*
+.idea/
+.vscode/

Demo/Demo.csproj

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+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="HotChocolate" Version="12.0.0-rc.4" />
+    <PackageReference Include="HotChocolate.AspNetCore" Version="12.0.0-rc.4" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+  </ItemGroup>
+
+</Project>

Demo/Program.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace Demo
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateHostBuilder(args).Build().Run();
+        }
+
+        public static IHostBuilder CreateHostBuilder(string[] args) =>
+            Host.CreateDefaultBuilder(args)
+                .ConfigureWebHostDefaults(webBuilder =>
+                {
+                    webBuilder.UseStartup<Startup>();
+                });
+    }
+}

Demo/Properties/launchSettings.json

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+{
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:15115",
+      "sslPort": 44328
+    }
+  },
+  "profiles": {
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "Demo": {
+      "commandName": "Project",
+      "dotnetRunMessages": "true",
+      "launchBrowser": true,
+      "applicationUrl": "https://localhost:5001;http://localhost:5002",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

Demo/Startup.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using System.ComponentModel;
+using HotChocolate.Language;
+using HotChocolate.Resolvers;
+using HotChocolate.Types;
+
+using Newtonsoft.Json.Linq;
+
+namespace Demo
+{
+    public class QueryMetadata
+    {
+        Dictionary<string, string> columns;
+        public List<string> conditions;
+        Dictionary<string, QueryMetadata> joinQueries;
+        string tableName;
+        string tableAlias;
+        // public List<string> conditions;
+        public QueryMetadata(string tableName, IResolverContext ctx) : this(
+            tableName,
+            "0",
+            ctx.Selection.SyntaxNode.SelectionSet.Selections
+        )
+        {
+            // TODO: hopefully useful for later
+            ObjectField schema = ctx.Schema.QueryType.Fields.FirstOrDefault((field) => field.Name == "book");
+        }
+
+        public QueryMetadata(string tableName, string tableAlias, IReadOnlyList<ISelectionNode> selections)
+        {
+            columns = new();
+            joinQueries = new();
+            conditions = new();
+
+            this.tableName = tableName;
+            this.tableAlias = tableAlias;
+            AddFields(selections);
+        }
+        static string Table(string name, string alias)
+        {
+            return $"{escapeIdentifier(name)} AS {escapeIdentifier(alias)}";
+        }
+
+        static string QualifiedColumn(string tableAlias, string columnName)
+        {
+            return $"{escapeIdentifier(tableAlias)}.{escapeIdentifier(columnName)}";
+        }
+
+        void AddFields(IReadOnlyList<ISelectionNode> Selections)
+        {
+            int subselectionCount = 0;
+            foreach (var node in Selections)
+            {
+                FieldNode field = node as FieldNode;
+                string fieldName = field.Name.Value;
+
+                if (field.SelectionSet == null)
+                {
+                    // TODO: Get column name from JSON config
+                    string columnName = field.Name.Value;
+                    string column = QualifiedColumn(tableAlias, columnName);
+                    columns.Add(fieldName, column);
+                }
+                else
+                {
+                    string subtableName = "authors";
+                    string subtableAlias = $"{tableAlias}.{subselectionCount}";
+                    // TODO: Get find fieldtype in schema and use JSON config to determine join column(s)
+                    string leftColumnName = "author_id";
+                    string rightColumnName = "id";
+                    string leftColumn = QualifiedColumn(tableAlias, leftColumnName);
+                    string rightColumn = QualifiedColumn(subtableAlias, rightColumnName);
+
+                    QueryMetadata subquery = new(subtableName, subtableAlias, field.SelectionSet.Selections);
+                    subquery.conditions.Add($"{leftColumn} = {rightColumn}");
+                    string subqueryAlias = $"q{subtableAlias}";
+                    joinQueries.Add(subqueryAlias, subquery);
+                    columns.Add(fieldName, $"{escapeIdentifier(subqueryAlias)}.data");
+                }
+            }
+        }
+
+        static string escapeIdentifier(string ident)
+        {
+            // TODO: Make this safe by using SQL/PG library provided versions
+            return $"\"{ident}\"";
+        }
+
+        static string escapeString(string str)
+        {
+            // TODO: Make this safe by using SQL/PG library provided versions
+            return $"'{str}'";
+        }
+
+        public override string ToString()
+        {
+            var buildObjectArgs = String.Join(", ", columns.Select(x => $"{escapeString(x.Key)}, ({x.Value})"));
+            string fromPart = Table(tableName, tableAlias);
+            fromPart += String.Join("", joinQueries.Select(x => $"LEFT OUTER JOIN LATERAL ({x.Value.ToString()}) AS {escapeIdentifier(x.Key)} ON TRUE"));
+            string query = $"SELECT json_build_object({buildObjectArgs}) AS data FROM {fromPart}";
+            if (conditions.Count() > 0)
+            {
+                query += $" WHERE {String.Join(" AND ", conditions)}";
+            }
+            return query;
+        }
+
+    }
+
+    public class Startup
+    {
+        // This method gets called by the runtime. Use this method to add services to the container.
+        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services
+                .AddGraphQLServer()
+                .AddDocumentFromString(@"
+                    type Query {
+                      books: [Book]
+                    }
+
+                    type Book {
+                      id: ID
+                      title: String
+                      author: Author
+                      author_id: ID
+                    }
+
+                    type Author {
+                        id: ID
+                        name: String
+                        birthdate: String
+                    }
+                ")
+
+                .AddResolver("Query", "books", (ctx) =>
+                {
+                    // Replace below with query
+                    var metadata = new QueryMetadata("books", ctx);
+                    JArray result = new();
+                    result.Add(JObject.FromObject(new
+                    {
+                        id = 1,
+                        title = metadata.ToString(),
+                        author_id = 123,
+                        author = new
+                        {
+                            id = 123,
+                            name = "Jelte",
+                            birtdate = "2001-01-01"
+                        }
+                    }));
+                    result.Add(JObject.FromObject(new
+                    {
+                        id = 2,
+                        title = metadata.ToString(),
+                        author_id = 124,
+                        author = new
+                        {
+                            id = 124,
+                            name = "Aniruddh",
+                            birtdate = "2002-01-01"
+                        }
+                    }));
+
+                    return result;
+                })
+                .AddResolver("Book", "id", (ctx) =>
+                {
+                    return (string)ctx.Parent<JObject>()["id"];
+                })
+                .AddResolver("Book", "author", (ctx) =>
+                {
+                    return ctx.Parent<JObject>()["author"];
+                })
+                .AddResolver("Book", "author_id", (ctx) =>
+                {
+                    return (int)ctx.Parent<JObject>()["author_id"];
+                })
+                .AddResolver("Author", "id", (ctx) =>
+                {
+                    return (int)ctx.Parent<JObject>()["id"];
+                })
+                .AddResolver("Author", "name", (ctx) =>
+                {
+                    return (string)ctx.Parent<JObject>()["name"];
+                })
+                .AddResolver("Author", "birthdate", (ctx) =>
+                {
+                    return (string)ctx.Parent<JObject>()["birtdate"];
+                })
+            ;
+        }
+
+        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
+        {
+            app
+                .UseRouting()
+                .UseEndpoints(endpoints =>
+                {
+                    endpoints.MapGraphQL();
+                });
+        }
+    }
+}

Demo/appsettings.Development.json

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+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}

Demo/appsettings.json

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+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  },
+  "AllowedHosts": "*"
+}