Add read-only BlobStore middleware

Implement as a proof-of-concept JavaScript middleware.  Requires JDK
8.

.travis.yml

@@ -2,7 +2,7 @@ dist: trusty
 sudo: required
 language: java
 jdk:
-  - openjdk7
+  - openjdk8
 env:
   global:
     - secure: "aY2WMlIMs7qiKJ6ZH4CgC4JpkXHUgZm9VyrBUPNa7E5vDVRK8+fQpZx2xSlUOIl/DG6OhtPyFGydXiYNjSdBldjEN6mqCo85bzZfRnl0E/fp2lBYarMvAcNrN8+8CSme077Hs/wV7XSdsEhBpm/LAWd7Enql9x3Vwuj4NxAN04c="  # DOCKER_EMAIL

src/main/java/org/gaul/s3proxy/Main.java

@@ -19,6 +19,7 @@ package org.gaul.s3proxy;
 import java.io.Console;
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.PrintStream;
@@ -29,9 +30,14 @@ import java.util.Properties;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
+import javax.script.Invocable;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
+
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.io.Files;
+import com.google.common.io.Resources;
 import com.google.inject.Module;
 
 import org.jclouds.Constants;
@@ -61,6 +67,9 @@ public final class Main {
 
         @Option(name = "--version", usage = "display version")
         private boolean version;
+
+        @Option(name = "--middleware", usage = "JavaScript file")
+        private String middleware;
     }
 
     public static void main(String[] args) throws Exception {
@@ -196,6 +205,22 @@ public final class Main {
             blobStore = ReadOnlyBlobStore.newReadOnlyBlobStore(blobStore);
         }
 
+        if (options.middleware != null) {
+            ScriptEngineManager factory = new ScriptEngineManager();
+            ScriptEngine engine = factory.getEngineByName("nashorn");
+            String script;
+            try {
+                script = Files.toString(new File(options.middleware),
+                        StandardCharsets.UTF_8);
+            } catch (FileNotFoundException fnfe) {
+                script = Resources.toString(Resources.getResource(
+                        options.middleware), StandardCharsets.UTF_8);
+            }
+            engine.eval(script);
+            blobStore = (BlobStore) ((Invocable) engine).invokeFunction(
+                    "newBlobStore", blobStore, properties);
+        }
+
         S3Proxy s3Proxy;
         try {
             S3Proxy.Builder s3ProxyBuilder = S3Proxy.builder()

src/main/java/org/gaul/s3proxy/S3ProxyHandlerJetty.java

@@ -23,6 +23,8 @@ import java.util.concurrent.TimeoutException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import jdk.nashorn.api.scripting.NashornException;
+
 import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableMap;
 
@@ -67,7 +69,11 @@ final class S3ProxyHandlerJetty extends AbstractHandler {
             baseRequest.setAttribute(S3ProxyConstants.ATTRIBUTE_QUERY_ENCODING,
                     baseRequest.getQueryEncoding());
 
-            handler.doHandle(baseRequest, request, response, is);
+            try {
+                handler.doHandle(baseRequest, request, response, is);
+            } catch (NashornException ne) {
+                throw ne.getCause();
+            }
             baseRequest.setHandled(true);
         } catch (ContainerNotFoundException cnfe) {
             S3ErrorCode code = S3ErrorCode.NO_SUCH_BUCKET;
@@ -96,6 +102,8 @@ final class S3ProxyHandlerJetty extends AbstractHandler {
             }
             baseRequest.setHandled(true);
             return;
+        } catch (IOException ioe) {
+            throw ioe;
         } catch (IllegalArgumentException iae) {
             response.sendError(HttpServletResponse.SC_BAD_REQUEST);
             baseRequest.setHandled(true);
@@ -130,7 +138,7 @@ final class S3ProxyHandlerJetty extends AbstractHandler {
                 baseRequest.setHandled(true);
                 return;
             } else {
-                throw throwable;
+                throw new RuntimeException(throwable);
             }
         }
     }

src/main/resources/checkstyle.xml

@@ -55,7 +55,7 @@
       <property name="classes" value="java.lang.Boolean,java.lang.Short,java.lang.Integer,java.lang.Long"/>
     </module>
     <module name="ImportOrder">
-      <property name="groups" value="java,javax,com,org"/>
+      <property name="groups" value="java,javax,jdk,com,org"/>
       <property name="separated" value="true"/>
       <property name="option" value="top"/>
     </module>

src/test/java/org/gaul/s3proxy/ReadOnlyBlobStoreTest.java

@@ -18,9 +18,18 @@ package org.gaul.s3proxy;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import java.nio.charset.StandardCharsets;
+import java.util.Properties;
 import java.util.Random;
 
+import javax.script.Invocable;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
+
+import jdk.nashorn.api.scripting.NashornException;
+
 import com.google.common.collect.ImmutableList;
+import com.google.common.io.Resources;
 import com.google.inject.Module;
 
 import org.assertj.core.api.Fail;
@@ -50,7 +59,13 @@ public final class ReadOnlyBlobStoreTest {
                 .build(BlobStoreContext.class);
         blobStore = context.getBlobStore();
         blobStore.createContainerInLocation(null, containerName);
-        readOnlyBlobStore = ReadOnlyBlobStore.newReadOnlyBlobStore(blobStore);
+
+        ScriptEngineManager factory = new ScriptEngineManager();
+        ScriptEngine engine = factory.getEngineByName("nashorn");
+        engine.eval(Resources.toString(Resources.getResource(
+                "readonly_blobstore.js"), StandardCharsets.UTF_8));
+        readOnlyBlobStore = (BlobStore) ((Invocable) engine).invokeFunction(
+                "newBlobStore", blobStore, new Properties());
     }
 
     @After
@@ -73,9 +88,10 @@ public final class ReadOnlyBlobStoreTest {
         try {
             readOnlyBlobStore.putBlob(containerName, null);
             Fail.failBecauseExceptionWasNotThrown(
+                    NashornException.class);
+        } catch (NashornException ne) {
+            assertThat(ne.getCause().getClass()).isEqualTo(
                     UnsupportedOperationException.class);
-        } catch (UnsupportedOperationException ne) {
-            // expected
         }
     }
 
@@ -84,9 +100,10 @@ public final class ReadOnlyBlobStoreTest {
         try {
             readOnlyBlobStore.putBlob(containerName, null, new PutOptions());
             Fail.failBecauseExceptionWasNotThrown(
+                    NashornException.class);
+        } catch (NashornException ne) {
+            assertThat(ne.getCause().getClass()).isEqualTo(
                     UnsupportedOperationException.class);
-        } catch (UnsupportedOperationException ne) {
-            // expected
         }
     }
 

src/test/resources/readonly_blobstore.js

@@ -0,0 +1,64 @@
+/*
+ * 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.
+ */
+
+var newBlobStore = function(blobStore) {
+    var readOnlyBlobStore = Java.extend(Java.type("org.jclouds.blobstore.util.ForwardingBlobStore"));
+    return new readOnlyBlobStore(blobStore) {
+        // container operations
+        createContainerInLocation: function(location, container) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        deleteContainer: function(container) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        deleteContainerIfEmpty: function(container) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        clearContainer: function(container) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        setContainerAccess: function(container, access) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+
+        // object operations
+        putBlob: function(containerName, blob) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        removeBlob: function(containerName, blobName) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        removeBlobs: function(containerName, iterable) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        initiateMultipartUpload: function(containerName, blobMetadata, options) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        abortMultipartUpload: function(mpu) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        completeMultipartUpload: function(mpu, parts) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        uploadMultipartPart: function(mpu, partNumber, payload) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+        setBlobAccess: function(container, blob, access) {
+            throw new java.lang.UnsupportedOperationException();
+        },
+    }
+}