Add HTTP-based PID minter

- Add support for authenticated PID minter services - Makd master.xml spring config file to bundle config files and avoid wildcard include Resolves: https://www.pivotaltracker.com/story/show/70678050
fcrepo · May 15, 2014 · 4959897 · 4959897
1 parent 05a9522
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diff --git a/fcrepo-kernel/src/main/java/org/fcrepo/kernel/identifiers/HttpPidMinter.java b/fcrepo-kernel/src/main/java/org/fcrepo/kernel/identifiers/HttpPidMinter.java
@@ -0,0 +1,176 @@
+/**
+ * Copyright 2014 DuraSpace, Inc.
+ *
+ * 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.fcrepo.kernel.identifiers;
+
+import static org.slf4j.LoggerFactory.getLogger;
+import static org.apache.commons.lang.StringUtils.isBlank;
+import static com.google.common.base.Preconditions.checkArgument;
+
+import org.slf4j.Logger;
+import com.codahale.metrics.annotation.Timed;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.net.URI;
+
+import org.w3c.dom.Document;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.xpath.XPathException;
+import javax.xml.xpath.XPathExpression;
+import javax.xml.xpath.XPathFactory;
+
+import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.client.methods.HttpPut;
+import org.apache.http.client.methods.HttpUriRequest;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
+import org.apache.http.util.EntityUtils;
+
+import org.apache.http.auth.AuthScope;
+import org.apache.http.auth.UsernamePasswordCredentials;
+import org.apache.http.client.CredentialsProvider;
+import org.apache.http.impl.client.BasicCredentialsProvider;
+
+
+/**
+ * PID minter that uses an external REST service to mint PIDs.
+ *
+ * @author escowles
+ * @date 04/28/2014
+ */
+public class HttpPidMinter extends BasePidMinter {
+
+    private static final Logger log = getLogger(HttpPidMinter.class);
+    protected final String url;
+    protected final String method;
+    protected final String username;
+    protected final String password;
+    private final String regex;
+    private XPathExpression xpath;
+
+    protected HttpClient client;
+
+    /**
+     * Create a new HttpPidMinter.
+     * @param url The URL for the minter service.  This is the only required argument -- all
+     *    other parameters can be blank.
+     * @param method The HTTP method (POST, PUT or GET) used to generate a new PID (POST will
+     *    be used if the method is blank.
+     * @param username If not blank, use this username to connect to the minter service.
+     * @param password If not blank, use this password used to connect to the minter service.
+     * @param regex If not blank, use this regular expression used to remove unwanted text from the
+     *    minter service response.  For example, if the response text is "/foo/bar:baz" and the
+     *    desired identifier is "baz", then the regex would be ".*:".
+     * @param xpath If not blank, use this XPath expression used to extract the desired identifier
+     *    from an XML minter response.
+    **/
+    public HttpPidMinter( final String url, final String method, final String username,
+        final String password, final String regex, final String xpath ) {
+
+        checkArgument( !isBlank(url), "Minter URL must be specified!" );
+
+        this.url = url;
+        this.method = method;
+        this.username = username;
+        this.password = password;
+        this.regex = regex;
+        if ( xpath != null ) {
+            try {
+                this.xpath = XPathFactory.newInstance().newXPath().compile(xpath);
+            } catch ( XPathException ex ) {
+                log.warn("Error parsing xpath ({}): {}", xpath, ex );
+            }
+        }
+        this.client = buildClient();
+    }
+
+    /**
+     * Setup authentication in httpclient.
+    **/
+    protected HttpClient buildClient() {
+        HttpClientBuilder builder = HttpClientBuilder.create().useSystemProperties().setConnectionManager(
+            new PoolingHttpClientConnectionManager());
+        if (!isBlank(username) && !isBlank(password)) {
+            final URI uri = URI.create(url);
+            final CredentialsProvider credsProvider = new BasicCredentialsProvider();
+            credsProvider.setCredentials(new AuthScope(uri.getHost(), uri.getPort()),
+                new UsernamePasswordCredentials(username, password));
+            builder = builder.setDefaultCredentialsProvider(credsProvider);
+        }
+        return builder.build();
+    }
+
+    /**
+     * Instantiate a request object based on the method variable.
+    **/
+    private HttpUriRequest minterRequest() {
+        if ( method != null && method.equalsIgnoreCase("GET") ) {
+            return new HttpGet(url);
+        } else if ( method != null && method.equalsIgnoreCase("PUT") ) {
+            return new HttpPut(url);
+        } else {
+            return new HttpPost(url);
+        }
+    }
+
+    /**
+     * Remove unwanted text from the minter service response to produce the desired identifer.
+     * Override this method for processing more complex than a simple regex replacement.
+    **/
+    protected String responseToPid( final String responseText ) throws Exception {
+        log.debug("responseToPid({})", responseText);
+        if ( !isBlank(regex) ) {
+            return responseText.replaceFirst(regex,"");
+        } else if ( xpath != null ) {
+            return xpath( responseText, xpath );
+        } else {
+            return responseText;
+        }
+    }
+
+    /**
+     * Extract the desired identifier value from an XML response using XPath
+    **/
+    private static String xpath( String xml, XPathExpression xpath ) throws Exception {
+        final DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
+        final Document doc = builder.parse(new ByteArrayInputStream(xml.getBytes()));
+        return xpath.evaluate(doc);
+    }
+
+    /**
+     * Mint a unique identifier using an external HTTP API.
+     * @return The generated identifier.
+     */
+    @Timed
+    @Override
+    public String mintPid() {
+        try {
+            log.debug("mintPid()");
+            final HttpResponse resp = client.execute( minterRequest() );
+            return responseToPid( EntityUtils.toString(resp.getEntity()) );
+        } catch ( IOException ex ) {
+            log.warn("Error minting pid from {}: {}", url, ex);
+            throw new RuntimeException("Error minting pid", ex);
+        } catch ( Exception ex ) {
+            log.warn("Error processing minter response", ex);
+            throw new RuntimeException("Error processing minter response", ex);
+        }
+    }
+}
diff --git a/fcrepo-kernel/src/test/java/org/fcrepo/kernel/identifiers/HttpPidMinterTest.java b/fcrepo-kernel/src/test/java/org/fcrepo/kernel/identifiers/HttpPidMinterTest.java
@@ -0,0 +1,78 @@
+/**
+ * Copyright 2014 DuraSpace, Inc.
+ *
+ * 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.fcrepo.kernel.identifiers;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.mockito.Matchers.isA;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.verify;
+
+import org.junit.Test;
+
+import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
+import org.apache.http.entity.ByteArrayEntity;
+import org.apache.http.client.methods.HttpUriRequest;
+
+public class HttpPidMinterTest {
+
+    @Test
+    public void testMintPid() throws Exception {
+        final HttpPidMinter testMinter = new HttpPidMinter(
+            "http://localhost/minter","POST", "", "", ".*/", "");
+
+        final HttpClient mockClient = mock(HttpClient.class);
+        final HttpResponse mockResponse = mock(HttpResponse.class);
+        final ByteArrayEntity entity = new ByteArrayEntity("/foo/bar/baz".getBytes());
+        testMinter.client = mockClient;
+
+        when(mockClient.execute(isA(HttpUriRequest.class))).thenReturn(mockResponse);
+        when(mockResponse.getEntity()).thenReturn(entity);
+
+        final String pid = testMinter.mintPid();
+        verify(mockClient).execute(isA(HttpUriRequest.class));
+        assertEquals( pid, "baz" );
+    }
+
+    @Test
+    public void testMintPidXPath() throws Exception {
+        final HttpPidMinter testMinter = new HttpPidMinter(
+            "http://localhost/minter","POST", "", "", "", "/test/id");
+
+        final HttpClient mockClient = mock(HttpClient.class);
+        final HttpResponse mockResponse = mock(HttpResponse.class);
+        final ByteArrayEntity entity = new ByteArrayEntity("<test><id>baz</id></test>".getBytes());
+        testMinter.client = mockClient;
+
+        when(mockClient.execute(isA(HttpUriRequest.class))).thenReturn(mockResponse);
+        when(mockResponse.getEntity()).thenReturn(entity);
+
+        final String pid = testMinter.mintPid();
+        verify(mockClient).execute(isA(HttpUriRequest.class));
+        assertEquals( pid, "baz" );
+    }
+
+    @Test
+    public void testHttpClient() throws Exception {
+        final HttpPidMinter testMinter = new HttpPidMinter(
+            "http://localhost/minter","POST", "user", "pass", "", "");
+        final HttpClient client = testMinter.buildClient();
+        assertNotNull(client);
+    }
+
+}
diff --git a/fcrepo-webapp/src/main/resources/spring/master.xml b/fcrepo-webapp/src/main/resources/spring/master.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="
+    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
+
+    <!-- Master context for fcrepo4. -->
+
+    <import resource="classpath:/spring/repo.xml"/>
+    <import resource="classpath:/spring/rest.xml"/>
+    <import resource="${fcrepo.minter.config:classpath:/spring/minter.xml}"/>
+    <import resource="classpath:/spring/eventing.xml"/>
+    <import resource="classpath:/spring/jms.xml"/>
+    <import resource="classpath:/spring/generator.xml"/>
+    <import resource="classpath:/spring/transactions.xml"/>
+
+</beans>
diff --git a/fcrepo-webapp/src/main/resources/spring/minter.xml b/fcrepo-webapp/src/main/resources/spring/minter.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:c="http://www.springframework.org/schema/c"
+    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
+
+    <!-- Mints PIDs using random UUIDs -->
+    <bean class="org.fcrepo.kernel.identifiers.UUIDPathMinter"
+        c:length="${fcrepo.uuid.path.length:2}"
+        c:count="${fcrepo.uuid.path.count:4}"/>
+
+    <!-- Mints PIDs using external REST service
+    <bean class="org.fcrepo.kernel.identifiers.HttpPidMinter"
+        c:url="http://localhost/my/minter" c:method="POST"
+        c:username="${fcrepo.minter.username:minterUser}"
+        c:password="${fcrepo.minter.password:minterPass}"
+        c:regex="" c:xpath="/response/ids/value"/>
+    -->
+
+
+</beans>
diff --git a/fcrepo-webapp/src/main/resources/spring/rest.xml b/fcrepo-webapp/src/main/resources/spring/rest.xml
@@ -16,11 +16,6 @@
 
     <context:annotation-config/>
 
-    <!-- Mints PIDs-->
-    <bean class="org.fcrepo.kernel.identifiers.UUIDPathMinter"
-        c:length="${fcrepo.uuid.path.length:2}"
-        c:count="${fcrepo.uuid.path.count:4}"/>
-
     <bean class="org.fcrepo.http.commons.session.SessionFactory"/>
 
     <!-- Identifier translation chain -->

diff --git a/fcrepo-webapp/src/main/webapp/WEB-INF/web.xml b/fcrepo-webapp/src/main/webapp/WEB-INF/web.xml
@@ -9,7 +9,7 @@
 
 	<context-param>
 		<param-name>contextConfigLocation</param-name>
-		<param-value>WEB-INF/classes/spring/*.xml</param-value>
+		<param-value>WEB-INF/classes/spring/master.xml</param-value>
 	</context-param>
 
 	<listener>