Add @whereConstraints directive as an experimental, optional feature

composer.json

@@ -15,6 +15,11 @@
             "name": "Christopher Moore",
             "email": "chris@nuwavecommerce.com",
             "homepage": "https://www.nuwavecommerce.com"
+        },
+        {
+            "name": "Benedikt Franke",
+            "email": "benedikt@franke.tech",
+            "homepage": "https://franke.tech"
         }
     ],
     "support": {
@@ -35,12 +40,15 @@
     },
     "require-dev": {
         "laravel/scout": "^4.0",
+        "mll-lab/graphql-php-scalars": "^2.1",
         "mockery/mockery": "^1.0",
         "orchestra/database": "3.5.*|3.6.*|3.7.*|3.8.x-dev",
         "orchestra/testbench": "3.5.*|3.6.*|3.7.*|3.8.*",
         "pusher/pusher-php-server": "^3.2"
     },
     "suggest": {
+        "laravel/scout": "Required for the @search directive",
+        "mll-lab/graphql-php-scalars": "Useful scalar types, required for @whereConstraints",
         "mll-lab/laravel-graphql-playground": "GraphQL IDE for better development workflow - integrated with Laravel"
     },
     "autoload": {

docs/master/api-reference/directives.md

@@ -1366,6 +1366,81 @@ input DateRange {
 If the name of the argument does not match the database column,
 pass the actual column name as the `key`.
 
+## @whereConstraints
+
+Add a dynamically client-controlled where constraint to a fields query.
+
+### Setup
+
+**This is an experimental feature and not included in Lighthouse by default.**
+
+First, enable the service provider:
+
+```php
+'providers' => [
+    \Nuwave\Lighthouse\Defer\DeferServiceProvider::class,
+],
+```
+
+It depends upon [mll-lab/graphql-php-scalars](https://github.com/mll-lab/graphql-php-scalars):
+
+    composer require mll-lab/graphql-php-scalars
+
+### Usage
+
+The argument it is defined on may have any name but **must** be
+of the input type `WhereConstraints`.
+
+```graphql
+type Query {
+    people(where: WhereConstraints @whereConstraints): [Person!]!
+}
+```
+
+This is how you can use it to construct a complex query
+that gets actors over age 37 who either have red hair or are at least 150cm.
+
+```graphql
+{
+  people(
+    filter: {
+      where: [
+        {
+          AND: [
+            { column: "age", operator: ">" value: 37 }
+            { column: "type", value: "Actor" }
+            {
+              OR: [
+                { column: "haircolour", value: "red" }
+                { column: "height", operator: ">=", value: 150 }
+              ]
+            }
+          ]
+        }
+      ]
+    }
+  ) {
+    name
+  }
+}
+```
+
+The definition for the `WhereConstraints` input is automatically included
+within your schema.
+
+```graphql
+input WhereConstraints {
+    column: String
+    operator: String
+    value: Mixed
+    AND: [WhereConstraints!]
+    OR: [WhereConstraints!]
+    NOT: [WhereConstraints!]
+}
+
+scalar Mixed @scalar(class: "MLL\\GraphQLScalars\\Mixed")
+```
+
 ## @whereNotBetween
 
 Verify that a column's value lies outside of two values.

src/Schema/AST/ASTBuilder.php

@@ -288,9 +288,9 @@ interface Node @interface(resolveType: "Nuwave\\\Lighthouse\\\Schema\\\NodeRegis
                 )
             )
             ->addFieldToQueryType(
-                PartialParser::fieldDefinition(
-                    'node(id: ID! @globalId): Node @field(resolver: "Nuwave\\\Lighthouse\\\Schema\\\NodeRegistry@resolve")'
-                )
+                PartialParser::fieldDefinition('
+                    node(id: ID! @globalId): Node @field(resolver: "Nuwave\\\Lighthouse\\\Schema\\\NodeRegistry@resolve")
+                ')
             );
     }
 

src/WhereConstraints/WhereConstraintsDirective.php

@@ -0,0 +1,82 @@
+<?php
+
+namespace Nuwave\Lighthouse\WhereConstraints;
+
+use GraphQL\Error\Error;
+use Nuwave\Lighthouse\Schema\Directives\BaseDirective;
+use Nuwave\Lighthouse\Support\Contracts\ArgBuilderDirective;
+
+class WhereConstraintsDirective extends BaseDirective implements ArgBuilderDirective
+{
+    const NAME = 'whereConstraints';
+
+    /**
+     * Name of the directive.
+     *
+     * @return string
+     */
+    public function name(): string
+    {
+        return self::NAME;
+    }
+
+    /**
+     * @param  \Illuminate\Database\Query\Builder|\Illuminate\Database\Eloquent\Builder  $builder
+     * @param  mixed  $whereConstraints
+     * @param  bool  $nestedOr
+     * @return \Illuminate\Database\Query\Builder|\Illuminate\Database\Eloquent\Builder
+     */
+    public function handleBuilder($builder, $whereConstraints, bool $nestedOr = false)
+    {
+        if ($andConnectedConstraints = $whereConstraints['AND'] ?? null) {
+            $builder->whereNested(
+                function ($builder) use ($andConnectedConstraints): void {
+                    foreach ($andConnectedConstraints as $constraint) {
+                        $this->handleBuilder($builder, $constraint);
+                    }
+                }
+            );
+        }
+
+        if ($orConnectedConstraints = $whereConstraints['OR'] ?? null) {
+            $builder->whereNested(
+                function ($builder) use ($orConnectedConstraints): void {
+                    foreach ($orConnectedConstraints as $constraint) {
+                        $this->handleBuilder($builder, $constraint, true);
+                    }
+                }
+            );
+        }
+
+        if ($notConnectedConstraints = $whereConstraints['NOT'] ?? null) {
+            $builder->whereNested(
+                function ($builder) use ($notConnectedConstraints): void {
+                    foreach ($notConnectedConstraints as $constraint) {
+                        $this->handleBuilder($builder, $constraint);
+                    }
+                },
+                'not'
+            );
+        }
+
+        if ($column = $whereConstraints['column'] ?? null) {
+            if (! $value = $whereConstraints['value']) {
+                throw new Error(
+                    "Did not receive a value to match the WhereConstraints for column {$column}."
+                );
+            }
+
+            $where = $nestedOr
+                ? 'orWhere'
+                : 'where';
+
+            $builder->{$where}(
+                $column,
+                $whereConstraints['operator'],
+                $value
+            );
+        }
+
+        return $builder;
+    }
+}

src/WhereConstraints/WhereConstraintsServiceProvider.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Nuwave\Lighthouse\WhereConstraints;
+
+use Illuminate\Support\ServiceProvider;
+use Illuminate\Contracts\Events\Dispatcher;
+use Nuwave\Lighthouse\Events\ManipulateAST;
+use Nuwave\Lighthouse\Schema\AST\PartialParser;
+use Nuwave\Lighthouse\Schema\Factories\DirectiveFactory;
+
+class WhereConstraintsServiceProvider extends ServiceProvider
+{
+    /**
+     * Bootstrap any application services.
+     *
+     * @param  \Nuwave\Lighthouse\Schema\Factories\DirectiveFactory  $directiveFactory
+     * @param  \Illuminate\Contracts\Events\Dispatcher  $dispatcher
+     * @return void
+     */
+    public function boot(DirectiveFactory $directiveFactory, Dispatcher $dispatcher): void
+    {
+        $directiveFactory->addResolved(
+            WhereConstraintsDirective::NAME,
+            WhereConstraintsDirective::class
+        );
+
+        $dispatcher->listen(
+            ManipulateAST::class,
+            function(ManipulateAST $manipulateAST): void {
+                $manipulateAST->documentAST
+                    ->setDefinition(
+                        PartialParser::inputObjectTypeDefinition('
+                            input WhereConstraints {
+                                column: String
+                                operator: String
+                                value: Mixed
+                                AND: [WhereConstraints!]
+                                OR: [WhereConstraints!]
+                                NOT: [WhereConstraints!]
+                            }
+                        ')
+                    )
+                    ->setDefinition(
+                        PartialParser::scalarTypeDefinition('
+                            scalar Mixed @scalar(class: "MLL\\GraphQLScalars\\Mixed")
+                        ')
+                    );
+            }
+        );
+    }
+}