Add JSON schema validator

metafacture-json/build.gradle

@@ -22,7 +22,9 @@ dependencies {
   implementation 'com.fasterxml.jackson.core:jackson-core:2.13.0'
   implementation 'com.fasterxml.jackson.core:jackson-databind:2.13.0'
   implementation 'com.jayway.jsonpath:json-path:2.6.0'
+  implementation 'com.github.erosb:everit-json-schema:1.14.1'
   testImplementation 'junit:junit:4.12'
   testImplementation 'org.mockito:mockito-core:2.5.5'
+  testImplementation 'com.github.tomakehurst:wiremock-jre8:2.33.2'
   testRuntimeOnly 'org.slf4j:slf4j-simple:1.7.21'
 }

metafacture-json/src/main/java/org/metafacture/json/JsonValidator.java

@@ -0,0 +1,194 @@
+/*
+ * Copyright 2021, 2023 Fabian Steeg, hbz
+ *
+ * Licensed under the Apache License, Version 2.0 the "License";
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.metafacture.json;
+
+import org.metafacture.framework.FluxCommand;
+import org.metafacture.framework.MetafactureException;
+import org.metafacture.framework.ObjectReceiver;
+import org.metafacture.framework.annotations.Description;
+import org.metafacture.framework.annotations.In;
+import org.metafacture.framework.annotations.Out;
+import org.metafacture.framework.helpers.DefaultObjectPipe;
+
+import org.everit.json.schema.Schema;
+import org.everit.json.schema.ValidationException;
+import org.everit.json.schema.loader.SchemaClient;
+import org.everit.json.schema.loader.SchemaLoader;
+import org.everit.json.schema.loader.SchemaLoader.SchemaLoaderBuilder;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.json.JSONTokener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+
+/**
+ * Validate JSON against a given schema, pass only valid input to the receiver.
+ *
+ * @author Fabian Steeg (fsteeg)
+ */
+@Description("Validate JSON against a given schema, send only valid input to the receiver. Pass the schema location to validate against. " +
+        "Write valid and/or invalid output to locations specified with `writeValid` and `writeInvalid`. " +
+        "Set the JSON key for the record ID value with `idKey` (for logging output, defaults to `id`).")
+@In(String.class)
+@Out(String.class)
+@FluxCommand("validate-json")
+public final class JsonValidator extends DefaultObjectPipe<String, ObjectReceiver<String>> {
+
+    private static final Logger LOG = LoggerFactory.getLogger(JsonValidator.class);
+    private static final String DEFAULT_ID_KEY = "id";
+    private Schema schema;
+    private long fail;
+    private long success;
+    private FileWriter writeInvalid;
+    private FileWriter writeValid;
+    private String idKey = DEFAULT_ID_KEY;
+
+    /**
+     * @param url The URL of the schema to validate against.
+     */
+    public JsonValidator(final String url) {
+        initSchema(url);
+    }
+
+    /**
+     * @param writeValid The location to write valid data to.
+     */
+    public void setWriteValid(final String writeValid) {
+        this.writeValid = fileWriter(writeValid);
+    }
+
+    /**
+     * @param writeInvalid The location to write invalid data to.
+     */
+    public void setWriteInvalid(final String writeInvalid) {
+        this.writeInvalid = fileWriter(writeInvalid);
+    }
+
+    /**
+     * @param idKey The JSON key for the record ID value.
+     */
+    public void setIdKey(final String idKey) {
+        this.idKey = idKey;
+    }
+
+    @Override
+    public void process(final String json) {
+        try {
+            validate(json, new JSONObject(json) /* throws JSONException on syntax error */);
+        }
+        catch (final JSONException e) {
+            handleInvalid(json, null, e.getMessage());
+        }
+    }
+
+    private void validate(final String json, final JSONObject object) {
+        try {
+            schema.validate(object); // throws ValidationException if invalid
+            getReceiver().process(json);
+            ++success;
+            write(json, writeValid);
+        }
+        catch (final ValidationException e) {
+            handleInvalid(json, object, e.getAllMessages().toString());
+        }
+    }
+
+    @Override
+    protected void onCloseStream() {
+        close(writeInvalid);
+        close(writeValid);
+        LOG.debug("Success: {}, Fail: {}", success, fail);
+        super.onCloseStream();
+    }
+
+    private void initSchema(final String schemaUrl) {
+        if (schema != null) {
+            return;
+        }
+        SchemaLoaderBuilder schemaLoader = SchemaLoader.builder();
+        try {
+            final URL url = new URL(schemaUrl);
+            schemaLoader = schemaLoader.schemaJson(jsonFrom(url.openStream()))
+                    .resolutionScope(baseFor(url.toString()));
+        }
+        catch (final IOException e) {
+            LOG.info("Could not read as URL: {}, trying to load from class path", schemaUrl);
+            schemaLoader = schemaLoader.schemaClient(SchemaClient.classPathAwareClient())
+                    .schemaJson(jsonFrom(getClass().getResourceAsStream(schemaUrl)))
+                    .resolutionScope("classpath://" + baseFor(schemaUrl));
+        }
+        schema = schemaLoader.build().load().build();
+    }
+
+    private JSONObject jsonFrom(final InputStream inputStream) {
+        try {
+            return new JSONObject(new JSONTokener(inputStream));
+        }
+        catch (final JSONException e) {
+            throw new MetafactureException(e.getMessage(), e);
+        }
+    }
+
+    private String baseFor(final String path) {
+        return path.substring(0, path.lastIndexOf('/') + 1);
+    }
+
+    private FileWriter fileWriter(final String fileLocation) {
+        try {
+            return new FileWriter(fileLocation);
+        }
+        catch (final IOException e) {
+            throw new MetafactureException(e.getMessage(), e);
+        }
+    }
+
+    private void handleInvalid(final String json, final JSONObject object,
+            final String errorMessage) {
+        LOG.info("Invalid JSON: {} in {}", errorMessage, object != null ? object.opt(idKey) : json);
+        ++fail;
+        write(json, writeInvalid);
+    }
+
+    private void write(final String json, final FileWriter fileWriter) {
+        if (fileWriter != null) {
+            try {
+                fileWriter.append(json);
+                fileWriter.append("\n");
+            }
+            catch (final IOException e) {
+                throw new MetafactureException(e.getMessage(), e);
+            }
+        }
+    }
+
+    private void close(final FileWriter fileWriter) {
+        if (fileWriter != null) {
+            try {
+                fileWriter.close();
+            }
+            catch (final IOException e) {
+                throw new MetafactureException(e.getMessage(), e);
+            }
+        }
+    }
+
+}

metafacture-json/src/main/resources/flux-commands.properties

@@ -15,3 +15,4 @@
 #
 encode-json org.metafacture.json.JsonEncoder
 decode-json org.metafacture.json.JsonDecoder
+validate-json org.metafacture.json.JsonValidator

metafacture-json/src/test/java/org/metafacture/json/JsonValidatorTest.java

@@ -0,0 +1,175 @@
+/*
+ * Copyright 2021, 2023 Fabian Steeg, hbz
+ *
+ * Licensed under the Apache License, Version 2.0 the "License";
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.metafacture.json;
+
+import static org.hamcrest.CoreMatchers.both;
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertThat;
+import static com.github.tomakehurst.wiremock.client.WireMock.stubFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.request;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.metafacture.framework.MetafactureException;
+import org.metafacture.framework.ObjectReceiver;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+
+import com.github.tomakehurst.wiremock.client.WireMock;
+import com.github.tomakehurst.wiremock.core.WireMockConfiguration;
+import com.github.tomakehurst.wiremock.junit.WireMockRule;
+
+
+/**
+ * Tests for {@link JsonValidator}.
+ *
+ * @author Fabian Steeg
+ *
+ */
+@RunWith(Parameterized.class)
+public final class JsonValidatorTest {
+
+    private static final String MAIN_SCHEMA = "/schemas/schema.json";
+    private static final String ID_SCHEMA = "/schemas/id.json";
+    private static final String JSON_VALID = "{\"id\":\"http://example.org/\"}";
+    private static final String JSON_INVALID_MISSING_REQUIRED = "{}";
+    private static final String JSON_INVALID_URI_FORMAT= "{\"id\":\"example.org/\"}";
+    private static final String JSON_INVALID_DUPLICATE_KEY = "{\"id\":\"val\",\"id\":\"val\"}";
+    private static final String JSON_INVALID_SYNTAX_ERROR = "{\"id1\":\"val\",\"id2\":\"val\"";
+
+    private JsonValidator validator;
+
+    @Mock
+    private ObjectReceiver<String> receiver;
+    private InOrder inOrder;
+    private Function<Object, String> schemaLocationGetter;
+
+    @Rule
+    public WireMockRule wireMockRule = new WireMockRule(WireMockConfiguration.wireMockConfig()
+            .jettyAcceptors(Runtime.getRuntime().availableProcessors()).dynamicPort());
+
+    @Parameterized.Parameters(name = "{index}")
+    public static Collection<Object[]> siteMaps() {
+        return Arrays.asList((Object[][]) (new Function[][] { //
+                // Pass the schema to each test as path on classpath, file url, and http url:
+                { (Object rule) -> MAIN_SCHEMA },
+                { (Object rule) -> JsonValidatorTest.class.getResource(MAIN_SCHEMA).toString() },
+                { (Object rule) -> ((WireMockRule) rule).baseUrl() + MAIN_SCHEMA } }));
+    }
+
+    public JsonValidatorTest(Function<Object, String> schemaLocationGetter) {
+        this.schemaLocationGetter = schemaLocationGetter;
+    }
+
+    @Before
+    public void setup() throws IOException {
+        MockitoAnnotations.initMocks(this);
+        wireMock(MAIN_SCHEMA, ID_SCHEMA);
+        String schemaLocation = schemaLocationGetter.apply(wireMockRule);
+        validator = new JsonValidator(schemaLocation);
+        validator.setReceiver(receiver);
+        inOrder = Mockito.inOrder(receiver);
+    }
+
+    private void wireMock(final String... schemaLocations) throws IOException {
+        for (String schemaLocation : schemaLocations) {
+            stubFor(request("GET", WireMock.urlEqualTo(schemaLocation)).willReturn(
+                    WireMock.ok().withBody(readToString(getClass().getResource(schemaLocation)))
+                            .withHeader("Content-type", "application/json")));
+        }
+    }
+
+    private String readToString(final URL url) throws IOException {
+        return new BufferedReader(new InputStreamReader(url.openStream(), StandardCharsets.UTF_8))
+                .lines().collect(Collectors.joining("\n"));
+    }
+
+    @Test
+    public void callWireMockSchema() throws MalformedURLException, IOException {
+        final String schemaContent = readToString(new URL(wireMockRule.baseUrl() + MAIN_SCHEMA));
+        assertThat(schemaContent, both(containsString("$schema")).and(containsString("$ref")));
+    }
+
+    @Test
+    public void testShouldValidate() {
+        validator.process(JSON_VALID);
+        inOrder.verify(receiver, Mockito.calls(1)).process(JSON_VALID);
+    }
+
+    @Test
+    public void testShouldInvalidateMissingRequired() {
+        validator.process(JSON_INVALID_MISSING_REQUIRED);
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testShouldInvalidateUriFormat() {
+        validator.process(JSON_INVALID_URI_FORMAT);
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testShouldInvalidateDuplicateKey() {
+        validator.process(JSON_INVALID_DUPLICATE_KEY);
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testShouldInvalidateSyntaxError() {
+        validator.process(JSON_INVALID_SYNTAX_ERROR);
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test(expected = MetafactureException.class)
+    public void testShouldCatchMissingSchemaFile() {
+        new JsonValidator("").process("{}");
+    }
+
+    @Test(expected = MetafactureException.class)
+    public void testShouldCatchMissingValidOutputFile() {
+        validator.setWriteValid("");
+        validator.process(JSON_INVALID_MISSING_REQUIRED);
+    }
+
+    @Test(expected = MetafactureException.class)
+    public void testShouldCatchMissingInvalidOutputFile() {
+        validator.setWriteInvalid("");
+        validator.process(JSON_INVALID_MISSING_REQUIRED);
+    }
+
+    @After
+    public void cleanup() {
+        validator.closeStream();
+    }
+
+}

metafacture-json/src/test/resources/schemas/id.json

@@ -0,0 +1,8 @@
+{
+  "$id": "id.json",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "URL",
+  "description": "The URL/URI of the resource",
+  "type": "string",
+  "format": "uri"
+}