Split off implementation that allows supplying arbitrary QueryDSL pre…

…dicates

This is a focussed, reusable piece of code that is not tightly bound to the Thunx ABAC system, and that is reusable for other purposes without having to use all of thunx.

README.md

@@ -69,7 +69,8 @@ that fulfill the conditional authorization predicate.
 ![overview](./resources/diagrams/container-diagram-overview.png)
 
 [C4 model]: https://c4model.com/
-[QueryDSL support in Spring Data]: https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#core.extensions.querydsl]
+
+[Spring Data QueryDSL Extension]: https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#core.extensions.querydsl]
 
 ### Solution mechanics
 
@@ -86,32 +87,33 @@ This repository has several modules:
 * `thunx-encoding-json` is a JSON-serialization library for thunk-expressions
 * `thunx-predicates-querydsl` is a library to convert thunk-expressions into QueryDSL predicates
 * `thunx-spring` provides an integration with Spring Cloud Gateway and Spring Data REST
+* `thunx-spring-querydsl-predicate-resolver` is a library to inject additional [QueryDSL] predicates to be processed
+  together with the predicates from the [Spring Data QueryDSL Extension]
 
 ## Getting Started
 
 ### Installation
 
 Requirements:
-* Java 11+
+
+* Java 17+
 
 #### Spring Cloud Gateway
+
 Using Gradle:
 
 ```groovy
-implementation "com.contentgrid.thunx:thunx-spring:${thunxVersion}"
-implementation "com.contentgrid.thunx:thunx-pdp-opa:${thunxVersion}"
+implementation "com.contentgrid.thunx:thunx-gateway-spring-boot-starter:${thunxVersion}"
 ```
 
 #### Spring Data REST Service
 
 Using Gradle:
 
 ```groovy
-implementation "com.contentgrid.thunx:thunx-spring:${thunxVersion}"
-runtimeOnly "com.contentgrid.thunx:thunx-predicates-querydsl:${thunxVersion}"
+implementation "com.contentgrid.thunx:thunx-gateway-spring-boot-starter:${thunxVersion}"
 
-implementation "com.querydsl:querydsl-core"
-implementation "com.querydsl:querydsl-jpa"
+implementation "com.querydsl:querydsl-jpa" // Or another QueryDSL implementation, dependent on the spring data flavor you're using
 ```
 
 

build.gradle

@@ -9,8 +9,10 @@ allprojects {
                 canBeConsumed = false
                 canBeResolved = false
             }
+            annotationProcessor.extendsFrom(internalPlatform)
             compileClasspath.extendsFrom(internalPlatform)
             runtimeClasspath.extendsFrom(internalPlatform)
+            testAnnotationProcessor.extendsFrom(internalPlatform)
             testCompileClasspath.extendsFrom(internalPlatform)
             testRuntimeClasspath.extendsFrom(internalPlatform)
         }

settings.gradle

@@ -19,6 +19,7 @@ include 'thunx-model'
 include 'thunx-pdp'
 include 'thunx-pdp-opa'
 include 'thunx-spring'
+include 'spring-data-querydsl-predicate-injector'
 include 'thunx-autoconfigure'
 include 'thunx-api-spring-boot-starter'
 include 'thunx-gateway-spring-boot-starter'

spring-data-querydsl-predicate-injector/build.gradle

@@ -0,0 +1,42 @@
+plugins {
+    id 'java-library'
+    id 'maven-publish'
+}
+
+dependencies {
+    internalPlatform platform(project(':thunx-dependencies'))
+
+    compileOnly 'org.projectlombok:lombok'
+    annotationProcessor 'org.projectlombok:lombok'
+
+    api 'com.querydsl:querydsl-core'
+    api 'org.springframework:spring-core'
+
+    implementation 'org.springframework.data:spring-data-rest-webmvc'
+
+    compileOnly "org.springframework.boot:spring-boot-autoconfigure" // for autoconfiguration annotations
+
+    testCompileOnly 'org.projectlombok:lombok'
+    testAnnotationProcessor 'org.projectlombok:lombok'
+
+    testAnnotationProcessor 'jakarta.persistence:jakarta.persistence-api'
+    testAnnotationProcessor 'com.querydsl:querydsl-apt::jakarta'
+
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    testImplementation 'org.springframework.boot:spring-boot-testcontainers'
+    testImplementation 'org.springframework.boot:spring-boot-starter-data-rest'
+    testImplementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+    testImplementation 'com.querydsl:querydsl-jpa::jakarta'
+
+    testImplementation "org.assertj:assertj-core"
+    testImplementation "org.junit.jupiter:junit-jupiter-api"
+
+    testImplementation 'org.testcontainers:testcontainers'
+    testImplementation 'org.testcontainers:junit-jupiter'
+    testImplementation 'org.testcontainers:postgresql'
+    testRuntimeOnly 'org.postgresql:postgresql'
+}
+
+test {
+    useJUnitPlatform()
+}

spring-data-querydsl-predicate-injector/gradle.properties

@@ -0,0 +1 @@
+description=Inject additional QueryDSL predicates in Spring Data REST repositories

spring-data-querydsl-predicate-injector/src/main/java/com/contentgrid/thunx/spring/data/querydsl/predicate/injector/repository/RepositoryInvokerAdapterFactory.java

@@ -0,0 +1,22 @@
+package com.contentgrid.thunx.spring.data.querydsl.predicate.injector.repository;
+
+import com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver.OperationPredicates;
+import com.querydsl.core.types.Predicate;
+import org.springframework.data.repository.support.RepositoryInvoker;
+
+/**
+ * Adapts a {@link RepositoryInvoker} with one applies the {@link Predicate} to results
+ */
+@FunctionalInterface
+public interface RepositoryInvokerAdapterFactory {
+
+    /**
+     * Adapt a repository invoker to apply the supplied QueryDSL predicate
+     *
+     * @param repositoryInvoker Original invoker
+     * @param domainType Domain class for which the invoker is requested
+     * @param predicate Predicate to apply to the invoker
+     * @return An invoker that applies the predicate
+     */
+    RepositoryInvoker adaptRepositoryInvoker(RepositoryInvoker repositoryInvoker, Class<?> domainType, OperationPredicates predicate);
+}

spring-data-querydsl-predicate-injector/src/main/java/com/contentgrid/thunx/spring/data/querydsl/predicate/injector/resolver/CollectionFilteringOnlyOperationPredicates.java

@@ -0,0 +1,54 @@
+package com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver;
+
+import com.contentgrid.thunx.spring.data.querydsl.predicate.injector.repository.RepositoryInvokerAdapterFactory;
+import com.querydsl.core.types.ExpressionUtils;
+import com.querydsl.core.types.Predicate;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * Only applies predicates on the collection of entities
+ * <p>
+ * This implementation of {@link OperationPredicates} is the only implementation that can be used with the out-of-the
+ * box {@link RepositoryInvokerAdapterFactory}
+ */
+@RequiredArgsConstructor
+public class CollectionFilteringOnlyOperationPredicates implements OperationPredicates {
+
+    private final Predicate predicate;
+
+    @Override
+    public OperationPredicates and(OperationPredicates predicate) {
+        if (predicate instanceof CollectionFilteringOnlyOperationPredicates) {
+            return new CollectionFilteringOnlyOperationPredicates(ExpressionUtils.and(
+                    this.readPredicate(),
+                    predicate.readPredicate()
+            ));
+        }
+        return OperationPredicates.super.and(predicate);
+    }
+
+    @Override
+    public Predicate readPredicate() {
+        return predicate;
+    }
+
+    @Override
+    public Predicate afterCreatePredicate() {
+        return null;
+    }
+
+    @Override
+    public Predicate beforeUpdatePredicate() {
+        return null;
+    }
+
+    @Override
+    public Predicate afterUpdatePredicate() {
+        return null;
+    }
+
+    @Override
+    public Predicate beforeDeletePredicate() {
+        return null;
+    }
+}

spring-data-querydsl-predicate-injector/src/main/java/com/contentgrid/thunx/spring/data/querydsl/predicate/injector/resolver/CompositeOperationPredicates.java

@@ -0,0 +1,54 @@
+package com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver;
+
+import com.querydsl.core.types.ExpressionUtils;
+import com.querydsl.core.types.Predicate;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Function;
+import lombok.RequiredArgsConstructor;
+import org.springframework.lang.Nullable;
+
+@RequiredArgsConstructor
+class CompositeOperationPredicates implements OperationPredicates {
+    private final List<OperationPredicates> predicates;
+
+    @Override
+    public OperationPredicates and(OperationPredicates predicate) {
+        var copy = new ArrayList<>(predicates);
+        copy.add(predicate);
+        return new CompositeOperationPredicates(copy);
+    }
+
+    @Nullable
+    private Predicate combine(Function<OperationPredicates, Predicate> extractor) {
+        return predicates.stream()
+                .map(extractor)
+                .reduce(ExpressionUtils::and)
+                .orElse(null);
+    }
+
+    @Override
+    public Predicate readPredicate() {
+        return combine(OperationPredicates::readPredicate);
+    }
+
+    @Override
+    public Predicate afterCreatePredicate() {
+        return combine(OperationPredicates::afterCreatePredicate);
+    }
+
+    @Override
+    public Predicate beforeUpdatePredicate() {
+        return combine(OperationPredicates::beforeUpdatePredicate);
+    }
+
+    @Override
+    public Predicate afterUpdatePredicate() {
+        return combine(OperationPredicates::afterUpdatePredicate);
+    }
+
+    @Override
+    public Predicate beforeDeletePredicate() {
+        return combine(OperationPredicates::beforeDeletePredicate);
+    }
+}

spring-data-querydsl-predicate-injector/src/main/java/com/contentgrid/thunx/spring/data/querydsl/predicate/injector/resolver/OperationPredicates.java

@@ -0,0 +1,51 @@
+package com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver;
+
+import com.querydsl.core.types.Predicate;
+import java.util.List;
+import org.springframework.lang.Nullable;
+
+/**
+ * A set of QueryDSL predicates that apply to different operations that can be executed on an entity
+ */
+public interface OperationPredicates {
+
+    /**
+     * Combines this predicate with a different predicate
+     *
+     * @param predicate The predicate to AND together with
+     * @return The combined predicate
+     */
+    default OperationPredicates and(OperationPredicates predicate) {
+        return new CompositeOperationPredicates(List.of(this, predicate));
+    }
+
+    /**
+     * @return Predicate used for reading an entity
+     */
+    @Nullable
+    Predicate readPredicate();
+
+    /**
+     * @return Predicate used to check permissions for creating an entity with certain values
+     */
+    @Nullable
+    Predicate afterCreatePredicate();
+
+    /**
+     * @return Predicate used to check permission before updating an entity
+     */
+    @Nullable
+    Predicate beforeUpdatePredicate();
+
+    /**
+     * @return Predicate used to check permissions for updating an entity with certain values
+     */
+    @Nullable
+    Predicate afterUpdatePredicate();
+
+    /**
+     * @return Predicate used for deleting an entity
+     */
+    @Nullable
+    Predicate beforeDeletePredicate();
+}

thunx-spring/src/main/java/com/contentgrid/thunx/spring/data/querydsl/QuerydslPredicateResolver.java → spring-data-querydsl-predicate-injector/src/main/java/com/contentgrid/thunx/spring/data/querydsl/predicate/injector/resolver/QuerydslPredicateResolver.java

@@ -1,13 +1,12 @@
-package com.contentgrid.thunx.spring.data.querydsl;
+package com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver;
 
 import com.querydsl.core.types.Predicate;
 import java.util.Map;
 import java.util.Optional;
 import org.springframework.core.MethodParameter;
 
 /**
- * Resolves a QueryDSL {@link Predicate}  that will be applied to requests by the
- * {@link org.springframework.data.rest.webmvc.config.RootResourceInformationHandlerMethodArgumentResolver}
+ * Resolves a QueryDSL {@link Predicate} for injection into a method parameter of a Spring controller
  */
 public interface QuerydslPredicateResolver {
 
@@ -19,5 +18,5 @@ public interface QuerydslPredicateResolver {
      * @param parameters All parameters parsed from the requests's query string
      * @return The predicate to apply to the request
      */
-    Optional<Predicate> resolve(MethodParameter methodParameter, Class<?> domainType, Map<String, String[]> parameters);
+    Optional<OperationPredicates> resolve(MethodParameter methodParameter, Class<?> domainType, Map<String, String[]> parameters);
 }

spring-data-querydsl-predicate-injector/src/main/java/com/contentgrid/thunx/spring/data/querydsl/predicate/injector/rest/webmvc/PredicateInjectingRootResourceInformationHandlerMethodArgumentResolver.java

@@ -0,0 +1,58 @@
+package com.contentgrid.thunx.spring.data.querydsl.predicate.injector.rest.webmvc;
+
+import com.contentgrid.thunx.spring.data.querydsl.predicate.injector.repository.RepositoryInvokerAdapterFactory;
+import com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver.QuerydslPredicateResolver;
+import com.contentgrid.thunx.spring.data.querydsl.predicate.injector.resolver.OperationPredicates;
+import java.util.Map;
+import java.util.Optional;
+import lombok.NonNull;
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.core.MethodParameter;
+import org.springframework.data.repository.support.Repositories;
+import org.springframework.data.repository.support.RepositoryInvoker;
+import org.springframework.data.repository.support.RepositoryInvokerFactory;
+import org.springframework.data.rest.webmvc.RootResourceInformation;
+import org.springframework.data.rest.webmvc.config.ResourceMetadataHandlerMethodArgumentResolver;
+import org.springframework.data.rest.webmvc.config.RootResourceInformationHandlerMethodArgumentResolver;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+
+/**
+ * {@link HandlerMethodArgumentResolver} to create {@link RootResourceInformation} for injection into Spring MVC
+ * controller methods.
+ * <p>
+ * This variant injects a custom {@link RepositoryInvoker} that filters its output based on QueryDSL predicates resolved
+ * by {@link QuerydslPredicateResolver}
+ */
+class PredicateInjectingRootResourceInformationHandlerMethodArgumentResolver extends
+        RootResourceInformationHandlerMethodArgumentResolver {
+
+    private final RepositoryInvokerAdapterFactory repositoryInvokerAdapterFactory;
+    private final ObjectProvider<QuerydslPredicateResolver> predicateResolvers;
+
+    public PredicateInjectingRootResourceInformationHandlerMethodArgumentResolver(
+            Repositories repositories,
+            RepositoryInvokerFactory invokerFactory,
+            ResourceMetadataHandlerMethodArgumentResolver resourceMetadataResolver,
+            @NonNull RepositoryInvokerAdapterFactory repositoryInvokerAdapterFactory,
+            @NonNull ObjectProvider<QuerydslPredicateResolver> predicateResolvers
+    ) {
+        super(repositories, invokerFactory, resourceMetadataResolver);
+
+        this.repositoryInvokerAdapterFactory = repositoryInvokerAdapterFactory;
+        this.predicateResolvers = predicateResolvers;
+    }
+
+    @Override
+    protected RepositoryInvoker postProcess(MethodParameter parameter, RepositoryInvoker invoker, Class<?> domainType, Map<String, String[]> parameters) {
+        return getPredicate(parameter, domainType, parameters)
+                .map(predicate -> repositoryInvokerAdapterFactory.adaptRepositoryInvoker(invoker, domainType, predicate))
+                .orElse(invoker);
+    }
+
+    private Optional<OperationPredicates> getPredicate(MethodParameter parameter, Class<?> domainType, Map<String, String[]> parameters) {
+        return predicateResolvers.stream()
+                .map(resolver -> resolver.resolve(parameter, domainType, parameters))
+                .flatMap(Optional::stream)
+                .reduce(OperationPredicates::and);
+    }
+}