RFC9457 implementation

maven-resolver-transport-http/pom.xml

@@ -48,6 +48,11 @@
       <groupId>org.apache.maven.resolver</groupId>
       <artifactId>maven-resolver-util</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <version>2.13.1</version>
+    </dependency>
     <dependency>
       <groupId>org.apache.httpcomponents</groupId>
       <artifactId>httpclient</artifactId>

maven-resolver-transport-http/src/main/java/org/eclipse/aether/transport/http/HttpTransporter.java

@@ -95,6 +95,8 @@
 import org.eclipse.aether.spi.connector.transport.TransportTask;
 import org.eclipse.aether.transfer.NoTransporterException;
 import org.eclipse.aether.transfer.TransferCancelledException;
+import org.eclipse.aether.transport.http.RFC9457.HttpRFC9457Exception;
+import org.eclipse.aether.transport.http.RFC9457.RFC9457Reporter;
 import org.eclipse.aether.util.ConfigUtils;
 import org.eclipse.aether.util.FileUtils;
 import org.slf4j.Logger;
@@ -624,9 +626,12 @@ private <T extends HttpUriRequest> void resume(T request, GetTask task) {
         }
     }
 
-    private void handleStatus(CloseableHttpResponse response) throws HttpResponseException {
+    private void handleStatus(CloseableHttpResponse response) throws HttpResponseException, HttpRFC9457Exception {
         int status = response.getStatusLine().getStatusCode();
         if (status >= 300) {
+            if (RFC9457Reporter.INSTANCE.isRFC9457Message(response)) {
+                RFC9457Reporter.INSTANCE.generateException(response);
+            }
             throw new HttpResponseException(status, response.getStatusLine().getReasonPhrase() + " (" + status + ")");
         }
     }

maven-resolver-transport-http/src/main/java/org/eclipse/aether/transport/http/RFC9457/HttpRFC9457Exception.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.eclipse.aether.transport.http.RFC9457;
+
+import java.io.IOException;
+
+/**
+ * Exception thrown by {@link HttpTransporter} in case of errors.
+ *
+ * @since 1.9.24
+ */
+public class HttpRFC9457Exception extends IOException {
+    private final int statusCode;
+
+    private final String reasonPhrase;
+
+    private final RFC9457Payload payload;
+
+    public HttpRFC9457Exception(int statusCode, String reasonPhrase, RFC9457Payload payload) {
+        super(payload.toString());
+        this.statusCode = statusCode;
+        this.reasonPhrase = reasonPhrase;
+        this.payload = payload;
+    }
+
+    public int getStatusCode() {
+        return statusCode;
+    }
+
+    public String getReasonPhrase() {
+        return reasonPhrase;
+    }
+
+    public RFC9457Payload getPayload() {
+        return payload;
+    }
+}

maven-resolver-transport-http/src/main/java/org/eclipse/aether/transport/http/RFC9457/RFC9457Parser.java

@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.eclipse.aether.transport.http.RFC9457;
+
+import java.lang.reflect.Type;
+import java.net.URI;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+
+public class RFC9457Parser {
+    private static final Gson GSON = new GsonBuilder()
+            .registerTypeAdapter(RFC9457Payload.class, new RFC9457PayloadAdapter())
+            .create();
+
+    public static RFC9457Payload parse(String data) {
+        return GSON.fromJson(data, RFC9457Payload.class);
+    }
+
+    private static class RFC9457PayloadAdapter implements JsonDeserializer<RFC9457Payload> {
+        @Override
+        public RFC9457Payload deserialize(
+                final JsonElement json, final Type typeOfT, final JsonDeserializationContext context)
+                throws JsonParseException {
+            JsonObject asJsonObject = json.getAsJsonObject();
+            URI type = parseNullableURI(asJsonObject, "type", "about:blank");
+            Integer status = parseStatus(asJsonObject);
+            String title = parseNullableString(asJsonObject, "title");
+            String detail = parseNullableString(asJsonObject, "detail");
+            URI instance = parseNullableURI(asJsonObject, "instance", null);
+            return new RFC9457Payload(type, status, title, detail, instance);
+        }
+    }
+
+    private static Integer parseStatus(JsonObject jsonObject) {
+        return jsonObject.get("status") == null || jsonObject.get("status").isJsonNull()
+                ? null
+                : jsonObject.get("status").getAsInt();
+    }
+
+    private static String parseNullableString(JsonObject jsonObject, String key) {
+        return jsonObject.get(key) == null || jsonObject.get(key).isJsonNull()
+                ? null
+                : jsonObject.get(key).getAsString();
+    }
+
+    private static URI parseNullableURI(JsonObject jsonObject, String key, String defaultValue) {
+        return !jsonObject.has(key) || jsonObject.get(key).isJsonNull()
+                ? defaultValue != null ? URI.create(defaultValue) : null
+                : URI.create(jsonObject.get(key).getAsString());
+    }
+}

maven-resolver-transport-http/src/main/java/org/eclipse/aether/transport/http/RFC9457/RFC9457Payload.java

@@ -0,0 +1,78 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.eclipse.aether.transport.http.RFC9457;
+
+import java.net.URI;
+
+public class RFC9457Payload {
+    public static final RFC9457Payload INSTANCE = new RFC9457Payload();
+
+    private final URI type;
+
+    private final Integer status;
+
+    private final String title;
+
+    private final String detail;
+
+    private final URI instance;
+
+    private RFC9457Payload() {
+        this(null, null, null, null, null);
+    }
+
+    public RFC9457Payload(
+            final URI type, final Integer status, final String title, final String detail, final URI instance) {
+        this.type = type;
+        this.status = status;
+        this.title = title;
+        this.detail = detail;
+        this.instance = instance;
+    }
+
+    public URI getType() {
+        return type;
+    }
+
+    public Integer getStatus() {
+        return status;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public String getDetail() {
+        return detail;
+    }
+
+    public URI getInstance() {
+        return instance;
+    }
+
+    @Override
+    public String toString() {
+        return "RFC9457Payload {" + "type="
+                + type + ", status="
+                + status + ", title='"
+                + title + ", detail='"
+                + detail + ", instance="
+                + instance + '}';
+    }
+}

maven-resolver-transport-http/src/main/java/org/eclipse/aether/transport/http/RFC9457/RFC9457Reporter.java

@@ -0,0 +1,80 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.eclipse.aether.transport.http.RFC9457;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import org.apache.http.Header;
+import org.apache.http.HttpHeaders;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.util.EntityUtils;
+
+public class RFC9457Reporter {
+    public static final RFC9457Reporter INSTANCE = new RFC9457Reporter();
+
+    public boolean isRFC9457Message(CloseableHttpResponse response) {
+        Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE);
+        if (headers.length > 0) {
+            String contentType = headers[0].getValue();
+            return hasRFC9457ContentType(contentType);
+        }
+        return false;
+    }
+
+    public void generateException(CloseableHttpResponse response) throws HttpRFC9457Exception {
+        int statusCode = getStatusCode(response);
+        String reasonPhrase = getReasonPhrase(response);
+
+        String body;
+        try {
+            body = getBody(response);
+        } catch (IOException ignore) {
+            // No body found but it is representing a RFC 9457 message due to the content type.
+            throw new HttpRFC9457Exception(statusCode, reasonPhrase, RFC9457Payload.INSTANCE);
+        }
+
+        if (body != null && !body.isEmpty()) {
+            RFC9457Payload rfc9457Payload = RFC9457Parser.parse(body);
+            throw new HttpRFC9457Exception(statusCode, reasonPhrase, rfc9457Payload);
+        }
+        throw new HttpRFC9457Exception(statusCode, reasonPhrase, RFC9457Payload.INSTANCE);
+    }
+
+    private String getBody(final CloseableHttpResponse response) throws IOException {
+        return EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
+    }
+
+    private int getStatusCode(final CloseableHttpResponse response) {
+        return response.getStatusLine().getStatusCode();
+    }
+
+    private String getReasonPhrase(final CloseableHttpResponse response) {
+        String reasonPhrase = response.getStatusLine().getReasonPhrase();
+        if (reasonPhrase == null || reasonPhrase.isEmpty()) {
+            return "";
+        }
+        int statusCode = getStatusCode(response);
+        return reasonPhrase + " (" + statusCode + ")";
+    }
+
+    private boolean hasRFC9457ContentType(String contentType) {
+        return "application/problem+json".equals(contentType);
+    }
+}

maven-resolver-transport-http/src/test/java/org/eclipse/aether/transport/http/HttpServer.java

@@ -25,6 +25,9 @@
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Enumeration;
@@ -35,6 +38,8 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import com.google.gson.Gson;
+import org.eclipse.aether.transport.http.RFC9457.RFC9457Payload;
 import org.eclipse.aether.util.ChecksumUtils;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpMethod;
@@ -229,6 +234,7 @@ public HttpServer start() throws Exception {
         handlers.addHandler(new AuthHandler());
         handlers.addHandler(new RedirectHandler());
         handlers.addHandler(new RepoHandler());
+        handlers.addHandler(new RFC9457Handler());
 
         server = new Server();
         httpConnector = new ServerConnector(server);
@@ -478,6 +484,46 @@ public void handle(String target, Request req, HttpServletRequest request, HttpS
         }
     }
 
+    private class RFC9457Handler extends AbstractHandler {
+        @Override
+        public void handle(
+                final String target,
+                final Request req,
+                final HttpServletRequest request,
+                final HttpServletResponse response)
+                throws IOException {
+            String path = req.getPathInfo().substring(1);
+
+            if (!path.startsWith("rfc9457/")) {
+                return;
+            }
+            req.setHandled(true);
+
+            if (HttpMethod.GET.is(req.getMethod())) {
+                response.setStatus(HttpServletResponse.SC_FORBIDDEN);
+                response.setHeader(HttpHeader.CONTENT_TYPE.asString(), "application/problem+json");
+                RFC9457Payload rfc9457Payload;
+                if (path.endsWith("missing_fields.txt")) {
+                    rfc9457Payload = new RFC9457Payload(null, null, null, null, null);
+                } else {
+                    rfc9457Payload = new RFC9457Payload(
+                            URI.create("https://example.com/probs/out-of-credit"),
+                            HttpServletResponse.SC_FORBIDDEN,
+                            "You do not have enough credit.",
+                            "Your current balance is 30, but that costs 50.",
+                            URI.create("/account/12345/msgs/abc"));
+                }
+                try (OutputStream outputStream = response.getOutputStream()) {
+                    outputStream.write(buildRFC9457Message(rfc9457Payload).getBytes(StandardCharsets.UTF_8));
+                }
+            }
+        }
+    }
+
+    private String buildRFC9457Message(RFC9457Payload payload) {
+        return new Gson().toJson(payload, RFC9457Payload.class);
+    }
+
     static boolean checkBasicAuth(String credentials, String username, String password) {
         if (credentials != null) {
             int space = credentials.indexOf(' ');