I am developing a data analytics app with Apache Flink and Neo4J (Community Edition).
In this application, the Flink sink must save/update relations in Neo4J.
Which is the best way for Neo4J session management, and why?
First implementation:
public class MySink extends RichSinkFunction<Link> {
private DbConfiguration dbconfig;
private Driver driver;
#Override
public void open(Configuration parameters) throws Exception {
this.driver = Neo4JManager.open(this.dbconfig);
}
#Override
public void close() throws Exception {
this.driver.close();
}
#Override
public void invoke(Link link) throws Exception {
Session session = this.driver.session();
Neo4JManager.saveLink(session, link);
session.close();
}
}
Second implementation:
public class MySink extends RichSinkFunction<Link> {
private DbConfiguration dbconfig;
private Driver driver;
private Session session;
#Override
public void open(Configuration parameters) throws Exception {
this.driver = Neo4JManager.open(this.dbconfig);
this.session = driver.session();
}
#Override
public void close() throws Exception {
this.session.close();
this.driver.close();
}
#Override
public void invoke(Link link) throws Exception {
Neo4JManager.saveLink(this.session, link);
}
}
In both implementations, the following functions have been used:
public class Neo4JManager {
public static Driver open(DbConfiguration dbconf) {
AuthToken auth = AuthTokens.basic(dbconf.getUsername(), dbconf.getPassword());
Config config = Config.build().withEncryptionLevel(Config.EncryptionLevel.NONE ).toConfig();
return GraphDatabase.driver(dbconf.getHostname(), auth, config);
}
public static void saveLink(Session session, Link link) {
Value params = parameters("x", link.x, "y", link.y);
session.run('CREATE (Person {id:{x}}-[FOLLOWS]->(Person {id:{y}}))'
}
}
Thank you.
Related
I am trying to connect to websocket server endpoint using below code but I am not able to resolve container.connectToServer(this, cec, uri); this. This method is not able to take my class as Endpoint class. It's a spring boot project. If I don't pass config then it accepts but then it fails to connect to server and return 401. I have tried many online links but failed to resolve this issue. Need help in how to fix it.
#ClientEndpoint
public class TestClassEndpoint {
private Session userSession = null;
public TestClassEndpoint(URI uri) {
try {
WebSocketContainer container = ContainerProvider.getWebSocketContainer();
ClientEndpointConfig cec = ClientEndpointConfig.Builder
.create().configurator(new ClientEndpointConfig.Configurator() {
public void beforeRequest(Map<String, List<String>> headers) {
System.out.println("Setting user cookie in beforeRequest ...");
headers.put("Authorization", Arrays.asList("Basic base64encodedString"));
}
}).build();
container.connectToServer(this, cec, uri);
} catch (Exception e) {
e.printStackTrace();
}
}
#OnOpen
public void onOpen(Session session) {
this.userSession = session;
System.out.println("New connection established");
}
#OnMessage
public void onMessage(String message, Session session) {
System.out.println(message);
}
#OnClose
public void onClose(Session userSession, CloseReason reason) {
this.userSession = null;
System.out.println("connection closed");
}
#OnError
public void onError(Throwable t) {
}
private void sendMessage(ByteBuffer buffer) {
this.userSession.getAsyncRemote().sendBinary(buffer);
}
}
Main class
#SpringBootApplication
public class MainApplication implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication.run(TwilioPocApplication.class, args);
}
#Override
public void run(String... args) throws Exception {
URI uri = UriComponentsBuilder.fromUriString("server_url").build().toUri();
new TestClassEndpoint(uri);
}
}
I am making a simple Social Media Website using Java Spring Boot. Now I want to add a profile edit page, where a logged in user can edit/update his profile data but other logged in users should not have access to it.
For example, there are two people John and Tom, John should be able to see only his profile edit page and Tom should see only his Profile edit page Only after login.
How to achieve this using Spring Security or by any other way ?
First of all you need to write BeanAccessor like following:
#Component
public class BeanAccessor implements ApplicationContextAware {
private static ApplicationContext context;
public static ObjectMapper getObjectMapper() {
return getBean(ObjectMapper.class);
}
public static <T> T getBean(Class<T> beanClass, Object... args) {
return context.getBean(beanClass, args);
}
private static <T> T getBean(Class<T> beanClass) {
return context.getBean(beanClass);
}
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
context = applicationContext;
}
}
then we need to write new class for method security like:
#Component
#Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class CustomMethodSecurityExpressionRoot extends SecurityExpressionRoot implements MethodSecurityExpressionOperations {
private Object filterObject;
private Object returnObject;
private Object target;
public CustomMethodSecurityExpressionRoot(Authentication authentication) {
super(authentication);
}
CustomMethodSecurityExpressionRoot setTarget(Object target) {
this.target = target;
return this;
}
#Override
public void setFilterObject(Object filterObject) {
this.filterObject = filterObject;
}
#Override
public Object getFilterObject() {
return filterObject;
}
#Override
public void setReturnObject(Object returnObject) {
this.returnObject = returnObject;
}
#Override
public Object getReturnObject() {
return returnObject;
}
#Override
public Object getThis() {
return target;
}
}
finally we need custom method security expressinon handler:
#Component
public class CustomMethodSecurityExpressionHandler extends DefaultMethodSecurityExpressionHandler {
#Autowired
private CustomPermissionEvaluator customPermissionEvaluator;
private AuthenticationTrustResolver trustResolver = new AuthenticationTrustResolverImpl();
#Override
protected MethodSecurityExpressionOperations createSecurityExpressionRoot(Authentication authentication, MethodInvocation invocation) {
final CustomMethodSecurityExpressionRoot root = BeanAccessor.getBean(CustomMethodSecurityExpressionRoot.class, authentication);
root.setPermissionEvaluator(customPermissionEvaluator);
root.setTrustResolver(this.trustResolver);
root.setRoleHierarchy(getRoleHierarchy());
root.setTarget(invocation.getThis());
return root;
}
}
now on your controller method yo can define #PreAuthorize("isProfileOwner(#id)") annotations your user profile show page method looks like :
#PreAuthorize("isProfileOwner(#id)")
#GetMapping("{id}")
public String show(#PathVariable("id") Long id, Model model) {
//omitted
}
everything okey but we need to write isProfileOwner() method to our CustomMethodSecurityExpressionRoot class like:
public boolean isProfileOwner(Long id) {
//add logic here and you are ready
}
also you can check this post
I have a very simple spring boot application that communicate with cassandra . In my sample When I run myApplication keySpace "myTestKeySpace" created but when i stop application that automatically dropped from database . what's wrong?
#Configuration
public class CassandraConfig extends AbstractCassandraConfiguration {
public static final String KEYSPACE = "myTestKeySpace";
#Override
public SchemaAction getSchemaAction() {
return SchemaAction.CREATE;
}
#Override
protected List<CreateKeyspaceSpecification> getKeyspaceCreations() {
CreateKeyspaceSpecification specification = CreateKeyspaceSpecification.createKeyspace(KEYSPACE);
return Arrays.asList(specification);
}
#Override
protected List<DropKeyspaceSpecification> getKeyspaceDrops() {
return Arrays.asList(DropKeyspaceSpecification.dropKeyspace(KEYSPACE));
}
#Override
protected String getKeyspaceName() {
return KEYSPACE;
}
#Override
public String[] getEntityBasePackages() {
return new String[]{"com.mySite"};
}
}
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class , args);
}
}
I have never use Springdata with Cassandra, but I guess the method getKeyspaceDrops will drop the keyspace in the same manner the getKeyspaceCreations will create it.
By default Togglz admin console runs on application port (configured by server.port property). I want to expose it on management.port. My question: is it possible?
If you use Togglz >= 2.4.0 then this feature is available out of the box.
For older releases solution is below:
I managed to expose a raw servlet on management.port by wrapping it with MvcEndpoint.
The easiest way to do it to use Spring Cloud module which does all the job for you (for example in the HystrixStreamEndpoint):
public class HystrixStreamEndpoint extends ServletWrappingEndpoint {
public HystrixStreamEndpoint() {
super(HystrixMetricsStreamServlet.class, "hystrixStream", "/hystrix.stream",
true, true);
}
}
In the case of TogglzConsoleServlet there is unfortunately one more hack to do with path's due to the way it extracts prefix from request URI, so the whole solution looks a little bit ugly:
#Component
class TogglzConsoleEndpoint implements MvcEndpoint {
private static final String ADMIN_CONSOLE_URL = "/togglz-console";
private final TogglzConsoleServlet togglzConsoleServlet;
#Autowired
TogglzConsoleEndpoint(final ServletContext servletContext) throws ServletException {
this.togglzConsoleServlet = new TogglzConsoleServlet();
togglzConsoleServlet.init(new DelegatingServletConfig(servletContext));
}
#Override
public String getPath() {
return ADMIN_CONSOLE_URL;
}
#Override
public boolean isSensitive() {
return true;
}
#Override
public Class<? extends Endpoint> getEndpointType() {
return null;
}
#RequestMapping("**")
public ModelAndView handle(HttpServletRequest request, HttpServletResponse response) throws Exception {
HttpServletRequestWrapper requestWrapper = new HttpServletRequestWrapper(request) {
#Override
public String getServletPath() {
return ADMIN_CONSOLE_URL;
}
};
togglzConsoleServlet.service(requestWrapper, response);
return null;
}
private class DelegatingServletConfig implements ServletConfig {
private final ServletContext servletContext;
DelegatingServletConfig(final ServletContext servletContext) {
this.servletContext = servletContext;
}
#Override
public String getServletName() {
return TogglzConsoleEndpoint.this.togglzConsoleServlet.getServletName();
}
#Override
public ServletContext getServletContext() {
return servletContext;
}
#Override
public String getInitParameter(final String name) {
return servletContext.getInitParameter(name);
}
#Override
public Enumeration<String> getInitParameterNames() {
return servletContext.getInitParameterNames();
}
}
}
I want check some external http service before my Spring Boot is ready.
The url to the external web service are stored in a property file with a #ConfigurationProperties class.
How do this check i tried using a springApplication.addListner() with a ping method. But the property class have not then been initialized.
public class ApplicationStartListener implements ApplicationListener<ApplicationPreparedEvent> {
#Override
public void onApplicationEvent(ApplicationPreparedEvent event) {
String url = AppProp.getURL();
inet = InetAddress.getByName(url );
inet.isReachable(5000)
...
application.yml
tops:
http://service.com
#Component
#ConfigurationProperties("tops")
public class AppProp{
private static String url;
public static String getUrl() {
The easiest way to accomplish this is to implement the ApplicationRunner interface.
From the Spring Boot documentation [1]
If you need to run some specific code once the SpringApplication has started, you can implement the ApplicationRunner or CommandLineRunner interfaces. Both interfaces work in the same way and offer a single run method which will be called just before SpringApplication.run(…) completes.
[1] https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-spring-application.html#boot-features-command-line-runner
Assuming you have url defined in application.properties:
#SpringBootApplication
public class MyApplication implements ApplicationRunner
{
#Inject
private AppConfig appConfig;
#Inject
private ConfigurableApplicationContext applicationContext;
public static void main(String[] args)
{
SpringApplication.run(MyApplication.class, args);
}
#Override
public void run(ApplicationArguments args) throws Exception
{
InetAddress inetAddress = InetAddress.getByName(appConfig.getUrl());
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Component
#ConfigurationProperties
public static class AppConfig
{
private String url;
public String getUrl()
{
return url;
}
public void setUrl(String url)
{
this.url = url;
}
}
}
If you need even more control than this, you can use SpringApplicationRunListener [2]
[2] http://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/SpringApplicationRunListener.html
#SpringBootApplication
public class MyApplication implements SpringApplicationRunListener
{
public MyApplication() { }
public MyApplication(SpringApplication springApplication, String[] args) { }
public static void main(String[] args)
{
SpringApplication.run(MyApplication.class, args);
}
#Override
public void started() { }
#Override
public void environmentPrepared(ConfigurableEnvironment environment)
{
// 1st opportunity
InetAddress inetAddress = InetAddress.getByName(environment.getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Override
public void contextPrepared(ConfigurableApplicationContext context)
{
// 2nd opportunity
InetAddress inetAddress = InetAddress.getByName(context.getEnvironment().getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Override
public void contextLoaded(ConfigurableApplicationContext context)
{
// 3rd opportunity
InetAddress inetAddress = InetAddress.getByName(context.getEnvironment().getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Override
public void finished(ConfigurableApplicationContext context, Throwable exception)
{
// 4th opportunity
InetAddress inetAddress = InetAddress.getByName(context.getEnvironment().getProperty("url"));
if (!inetAddress.isReachable(5000))
{
// Stop the application or do other things
}
}
#Component
#ConfigurationProperties
public static class AppConfig {
private String url;
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
}
}
then create META-INF\spring.factories and add
org.springframework.boot.SpringApplicationRunListener=com.foobar.MyApplication