Add UserDetailsResourceFactoryBean

Add the ability to create a Collection<UserDetails> from a Properties
Resource using the standard Spring Security user format.

Fixes gh-4380

config/src/main/java/org/springframework/security/config/core/userdetails/UserDetailsResourceFactoryBean.java

@@ -0,0 +1,132 @@
+/*
+ *
+ *  * Copyright 2002-2017 the original author or authors.
+ *  *
+ *  * 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.springframework.security.config.core.userdetails;
+
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.context.ResourceLoaderAware;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.memory.UserAttribute;
+import org.springframework.security.core.userdetails.memory.UserAttributeEditor;
+import org.springframework.util.Assert;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.Properties;
+
+/**
+ * Parses a Resource that is a Properties file in the format of:
+ *
+ * <code>
+ * username=password[,enabled|disabled],roles...
+ * </code>
+ *
+ * The enabled and disabled properties are optional with enabled being the default. For example:
+ *
+ * <code>
+ * user=password,ROLE_USER
+ * admin=secret,ROLE_USER,ROLE_ADMIN
+ * disabled_user=does_not_matter,disabled,ROLE_USER
+ * </code>
+ *
+ * @author Rob Winch
+ * @since 5.0
+ */
+public class UserDetailsResourceFactoryBean implements ResourceLoaderAware, FactoryBean<Collection<UserDetails>> {
+	private ResourceLoader resourceLoader;
+
+	private String propertiesResourceLocation;
+
+	private Resource propertiesResource;
+
+	@Override
+	public void setResourceLoader(ResourceLoader resourceLoader) {
+		this.resourceLoader = resourceLoader;
+	}
+
+	@Override
+	public Collection<UserDetails> getObject() throws Exception {
+		Properties userProperties = new Properties();
+		Resource resource = getProperitesResource();
+		try(InputStream in = resource.getInputStream()){
+			userProperties.load(in);
+		}
+
+		Collection<UserDetails> users = new ArrayList<>(userProperties.size());
+		Enumeration<?> names = userProperties.propertyNames();
+		UserAttributeEditor editor = new UserAttributeEditor();
+
+		while (names.hasMoreElements()) {
+			String name = (String) names.nextElement();
+			String property = userProperties.getProperty(name);
+			editor.setAsText(property);
+			UserAttribute attr = (UserAttribute) editor.getValue();
+			if(attr == null) {
+				throw new IllegalStateException("The entry with username '" + name + "' and value '" + property + "' could not be converted to a UserDetails.");
+			}
+			UserDetails user = User.withUsername(name)
+				.password(attr.getPassword())
+				.disabled(!attr.isEnabled())
+				.authorities(attr.getAuthorities())
+				.build();
+			users.add(user);
+		}
+		return users;
+	}
+
+	@Override
+	public Class<?> getObjectType() {
+		return Collection.class;
+	}
+
+	/**
+	 * Sets a the location of a Resource that is a Properties file in the format defined in {@link UserDetailsResourceFactoryBean}
+	 *
+	 * @param propertiesResourceLocation the location of the properties file that contains the users (i.e. "classpath:users.properties")
+	 */
+	public void setPropertiesResourceLocation(String propertiesResourceLocation) {
+		this.propertiesResourceLocation = propertiesResourceLocation;
+	}
+
+	/**
+	 * Sets a a Resource that is a Properties file in the format defined in {@link UserDetailsResourceFactoryBean}
+	 *
+	 * @param propertiesResource the Resource to use
+	 */
+	public void setPropertiesResource(Resource propertiesResource) {
+		this.propertiesResource = propertiesResource;
+	}
+
+	private Resource getProperitesResource() {
+		if(propertiesResource != null) {
+			return propertiesResource;
+		}
+		if(propertiesResourceLocation != null) {
+			Assert.notNull(resourceLoader, "resourceLoader cannot be null if propertiesResource is null");
+			return resourceLoader.getResource(propertiesResourceLocation);
+		}
+		throw new IllegalStateException("Either propertiesResource cannot be null or both resourceLoader and propertiesResourceLocation cannot be null");
+	}
+}