Servlet session is not persistent - java

I have a servlet like the following
public class Ticket extends HttpServlet {
private static final long serialVersionUID = 1L;
public Ticket() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// check cookies
Cookie[] receivedCookies = request.getCookies();
if(receivedCookies != null){
Cookie user = receivedCookies[0];
response.getWriter().println("user: " + user.getValue());
response.addCookie(user);
// check session
HttpSession session = request.getSession(true);
Object atribVal = session.getAttribute(user.getValue()); // get a current state
if(atribVal == null){
response.getWriter().println("current state: null");
}
else{
response.getWriter().println("current state: " + atribVal.toString());
}
String newState = TicketMachine.getNextState(atribVal); // get a new state based on the current one
response.getWriter().println("new state: " + newState);
if(newState == "COMPLETED"){ // ticket completed, destroy session
session.invalidate();
return;
}
else{ // move to the next state
session.setAttribute(user.getValue(), newState);
}
}
}
}
I am trying to store a state of a ticket machine for each user who requests a ticket. I'm running this on Oracle WebLogic Server and testing it using cURL get requests that looks like the following
curl --cookie "user=John" 127.0.0.1:7001/myApp/Ticket
I would expect it to move through states as they are defined in the state machine, but it always returns the same lines
user: John
current state: null
new state: NEW
The ticket machine is quite simple
public class TicketMachine {
public static String getNextState(Object currentState){
if(currentState == null)
return "NEW";
switch(currentState.toString()){
case "NEW":
return "PAYMENT";
case "PAYMENT":
return "COMPLETED";
}
return null;
}
}
What am I doing wrong here?

When session is created it adds to response cookies session parameters such as session id. Your command to cURL does not stores cookies from server. You have to store cookies as follows curl --cookie oldcookies.txt --cookie-jar newcookies.txt http://www.example.com.
Also read section about cookies at http://curl.haxx.se/docs/httpscripting.html

Related

Finding why an Angular 5 service subscription is returning a null observable

I have the following service subscription in my component:
this.userService.loginUser(this.user).subscribe(users => {
if (users == null) {
console.log('users is null');
this.isValid = !this.isValid;
} else {
this.userService.subscribers.next(users);
localStorage.setItem('user', JSON.stringify(users));
console.log(`User, ${this.user.username}, successfully logged in!`);
console.log(localStorage.getItem('user'));
this.router.navigate(['dashboard']);
}
});
The service method looks like this:
public loginUser(user: User) {
console.log(`Attempting to login user: ${user.username}`);
const json = JSON.stringify(user);
this.currentUser = user;
return this.http.post<User>(API_URL + 'login', json, HTTP_OPTIONS);
}
The post request goes to this java servlet method:
#Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("login attempt");
if (req.getInputStream() != null) {
ObjectMapper mapper = new ObjectMapper();
User user = mapper.readValue(req.getInputStream(), User.class);
user = userService.loginUser(user);
if (user != null) {
user.setPassword("");
HttpSession session = req.getSession();
session.setAttribute("user", user);
}
}
}
On the java end, a username and password match is found and the session attribute is correctly set. However, on the Angular end, 'users' is null, as evidenced by the console.log('users is null') in the first code block. So my question is, why is this null? Can someone please help me understand the mechanics of this? I'm having a very hard time grasping how certain aspects of Angular even work...
So the problem was that in the servlet I didn't have a response. At the end I needed
PrintWriter out = resp.getWriter();
out.write(mapper.writeValueAsString(user));

Fetching old session value even if session is destroyed

#Override
public void sessionDestroyed(HttpSessionEvent arg0)
{
boolean isRemoved = sessionIdSet.remove(arg0.getSession().getId());
if (isRemoved)
{
arg0.getSession().invalidate();
System.out.println(arg0.getSession().getAttribute("userName"));
System.out.println("session destroyed");
}
}
Suppose the attribute userName was testUser at the time of login. So after timeout in my java console I get null and session destroyed printed. So if it is null that means when I do following in my jsp I should get null but instead still I get testUser
$("body").click(function(event){
var property="<%=session.getAttribute("userName")%>";
//Here I expect property to be null as session is destroyed
//and it prints null in java so it should also here.
alert(property);
//But what i get here is testUser
}
Using Spring interceptor
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws ServletException {
boolean allowRequest = true;
String requestUri = request.getRequestURI().toString();
HttpSession session = request.getSession(false);
logger.info("Pre-intercepting request URI: " + requestUri);
try {
if(null != session) {
String sessionBelongsTo = (String) session.getAttribute("CUR_TYPE");
String user = (String) session.getAttribute("userName");
System.out.println(user);
if(!requestUri.endsWith("/login") && !requestUri.endsWith("/loginauth") && !requestUri.endsWith("sap-ui-core.js") && !requestUri.endsWith("/main")) {
if(null == user) {
logger.info(""
+ "Login required, redirecting to LOGIN page");
response.sendRedirect(request.getContextPath() + "/login");
allowRequest = false;
}
else {
logger.info("Login not required");
}
}
}
else{
logger.debug("session is null.redirecting to login");
session = request.getSession();
response.sendRedirect(request.getContextPath() + "/login");
allowRequest = false;
}
}catch(IOException ioe) {
logger.info(ioe.getMessage());
allowRequest = false;
}
return allowRequest;
}
Using interceptor makes an redirect call GET http://localhost:9090/app/login which is successfull but redirect never really happens.
You are mixing two different codes. You have to realize, where and when each code is executed - JSP on the server when the page is requested and rendered (i.e. before the response is send to the browser) and Javascript in the browser, after the browser receives the already generated response.
I.e. <%=session.getAttribute("userName")%> is processed on the server, and your browser receives e.g. var property="johndoe"; - the JSP code is NOT executed again when your onclick handler is executed.

HTPPSession with Google Cloud Endpoints new session every time

I am successfully using Google Cloud Endpoints. Now for custom user auth, I want to use HTTPSession. The problem is, the initial session is not being reused in future calls, and new session are created (I can see from datastore admin that the session all exists, _AH_SESSION entity). As instructed in the docs, i have enabled it in appengine-web.xml:
<sessions-enabled>true</sessions-enabled>
I made some sample code to narrow it down:
#Api(name = "loginService", version = "v0.1.5")
public class LoginService {
private static final Logger log = Logger.getLogger(LoginService.class.getName());
#ApiMethod(name = "login", path= "login")
public LoginResponse login(HttpServletRequest req)
{
HttpSession session = req.getSession(false);
if(session == null){
log.warning("creating new session");
session = req.getSession(true);
}
LoginResponse resp = new LoginResponse();
resp.statusCode = 200;
resp.statusMessage = "SessionId:" + session.getId();
return resp;
}
#ApiMethod(name = "show", path= "show")
public LoginResponse show(HttpServletRequest req)
{
//session should exist when calling LOGIN first
HttpSession session = req.getSession(false); //NULLPOINTER since session from login is not being reused/found!
LoginResponse resp = new LoginResponse();
resp.statusCode = 200;
resp.statusMessage = "SessionId:" + session.getId();
return resp;
}
public class LoginResponse implements Serializable{
public int statusCode;
public String statusMessage;
}
}`
So first, I call the login method, this creates a new session and prints me the session id. Then in the next request (both using Postman - which should track sessions - in Chrome as the API explorer) i call the 'show' endpoint, and there the previous session does not exist anymore, hence the nullpointer exception.
In the comments on this post, user mikO says endpoints don't keep the session. Is this the reason? I don't really understand the reason behind it. When I just deploy a 'regular' servlet on appengine, it DOES work using Postman or just browsing.. (testing by calling the getter twice, i see that the previous session is being picked up), so it seems that the comment in that post could be right, but i really don't understand why. Working code without endpoints:
public class LoginServlet extends HttpServlet {
private static final Logger log = Logger.getLogger(LoginServlet.class.getName());
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
HttpSession s = request.getSession(false);
if (s == null) {
log.warning("creating new session");
s = request.getSession(true);
}
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<h1>" + s.getId() + "</h1>");
}
}
Thanks!

Getting sessionId without accessing the session using cookies API

I need to get current session Id without hitting the session (to give it a chance to expire).
I've used Cookies from Servlet code in order keep the session not-touched and then make the session expires after its timeout time.
I am using the following code:
public static String getSessionId(HttpServletRequest request)
{
String sessionId = "";
String logMsg = "";
if (request != null)
{
String sessionTimeout = PropertiesReader.SESSION_TIMEOUT_SCHEMA;
if (sessionTimeout != null && SessionHelper.SESSION_TIMEOUT_FIXED.equalsIgnoreCase(sessionTimeout))
{
logMsg = "FIXED: Getting SessionId from Cookies with activating the session";
Cookie[] cookies = request.getCookies();
if (cookies != null)
{
for (Cookie cook : cookies)
{
if ("JSESSIONID".equalsIgnoreCase(cook.getName()))
{
sessionId = cook.getValue();
break;
}
}
}
} else
{
logMsg = "PER_USAGE: Getting SessionId from Session";
sessionId = request.getSession(false) != null ? request.getSession(false).getId() : "";
}
}else
{
logMsg = "Request object is null";
}
logger.info(logMsg + ", sessionId=" + sessionId);
return sessionId;
}
One one OC4J app server, it works fine. although on another oc4j server, the code of accessing cookies makes the session keep active and don't timeout!
EDIT:
I really stucked!, I've trying to place afilter to remove the JSESSIONID cookie and remove all cookies from the HttpServletRequest, but when I call getSession(false) on the request passed to the servlet, I got a valid Session!
class CookieRemovalHttpServletRequestWrapper extends HttpServletRequestWrapper
{
public static final String COOKIE_HEADER = "cookie";
public static final String JSESSIONID = "JSESSIONID";
public CookieRemovalHttpServletRequestWrapper(HttpServletRequest request)
{
super(request);
}
#Override
public String getHeader(String name)
{
if (COOKIE_HEADER.equalsIgnoreCase(name))
{
return "";
}
return super.getHeader(name);
}
#Override
public Enumeration getHeaderNames()
{
Enumeration e = super.getHeaderNames();
List l = new ArrayList();
while (e.hasMoreElements())
{
String headerName = (String) e.nextElement();
if (!COOKIE_HEADER.equalsIgnoreCase(headerName))
{
l.add(headerName);
}
}
return Collections.enumeration(l);
}
#Override
public Enumeration getHeaders(String name)
{
if (COOKIE_HEADER.equalsIgnoreCase(name))
{
return new Enumeration()
{
public boolean hasMoreElements()
{
return false;
}
public Object nextElement()
{
return null;
}
};
}
return super.getHeaders(name);
}
#Override
public Cookie[] getCookies()
{
Cookie[] cs = super.getCookies();
List<Cookie> cokRet = new ArrayList<Cookie>(cs.length);
for (Cookie c : cs)
{
if (c.getName().equalsIgnoreCase(JSESSIONID)) continue;
cokRet.add(c);
}
return cokRet.toArray(new Cookie[] {});
}
}
And really think to forget all about Session and just use the session Id as just a unique identifier to the user, and do it myself the hard way.
As to your code, don't do it the hard way, use HttpServletRequest#getRequestedSessionId() and HttpServletRequest#isRequestedSessionIdValid() instead to check the requested session ID and if it is valid.
if (request.getRequestedSessionId() != null && !request.isRequestedSessionIdValid()) {
// The session has been expired (or a hacker supplied a fake cookie).
}
As to your concrete problem:
the code of accessing cookies makes the session keep active and don't timeout!
No, the code doesn't do that. It's the HTTP request itself which does that. It is not true that whenever you don't call getSession() or something, the session timeout won't be postponed. It will be postponed on every single HTTP request fired by the client, regardless of whether you need the session in the code.
To learn about how sessions work, you may find this answer helpful: How do servlets work? Instantiation, sessions, shared variables and multithreading
The session expiring isn't dependent on your code accessing the session, it depends on the user making a request with that session. Every time the user makes a request, the session's timeout will reset itself.
If you want to not have the user's request re-set the timeout (ie. have a fixed-length session), then you will need to do additional things for configuring the session, including possibly using a different filter to handle sessions.
The session is not timeout, that is correct behavior, because request was accepted and session expiration is updated in any case.

HtmlUnit's WebClient fails on second identical loadWebResponse() call

I'm attempting to write tests for a very long and kludgy "getPost" method in a webapp I'm working on for my job. I'm using JUnit, HtmlUnit, and Jetty's ServletTester to approximate sending a request to a servlet and receiving a response. I've managed to get it mostly working, but I'm having a problem. I'm trying to test the login functionality. If the user logs in successfully, the server should send some JSON back to the client with the user's information. If the user is already logged in, the server should send back "result": "failure" and an error message.
My problem comes when I try to test the second requirement. I can log in successfully, and get the correct data back. However, when I try to send the request again, it returns 404: not found. I tried breaking the code up into different tests, but I have to be able to call login twice in order to test the second requirement. Later tests in the JUnit file run just fine, and the servlet is staying connected the same time. I tried making a second, identical request, but that also failed. I've searched the internet to no avail. In short, I'm stumped.
Here's what I'm working with (unnecessary code has been edited out):
//In MyFunServlet class:
private final static String USERID_ATTRIBUTENAME = "userid";
void doPost(HttpServletRequest request, HttpServletResponse response) {
String action = request.getParameter("opt");
final HttpSession session = request.getSession();
if(action != null){
Long userId = (Long)session.getAttribute(USERID_ATTRIBUTENAME);
if(userId != null){
//do stuffz
} else {
if(action.equals("login")) {
User user = LoginUser(request, response);
try{
JSONObject json = new JSONObject();
if(request.getAttribute("result") == "success"){
json.put("result", "success");
json.put("id", user.getId());
json.put("name", user.getName());
} else {
json.put("result", "failure");
json.put("message", request.getAttribute("message"));
}
SendJSONResponse(json, request, response);
}catch(Exception e){
}
} else {
System.out.print("Unknown opt: " + action);
response.setStatus(HttpServletResponse.SC_NOT_FOUND);
}
}
}
}
private void LoginUser(HttpServletRequest request, HttpServletResponse response){
final HttpSession session = request.getSession();
User user = null;
Long userId = (Long)session.getAttribute(USERID_ATTRIBUTENAME);
if(userId != null){
request.setAttribute("result", "failure");
request.setAttribute("message", "The user is already logged in.");
} else {
final String email = request.getParameter("accountEmail");
final String password = request.getParameter("accountPassword");
if(email != null) {
user = helperClass.magicallyGetUserByEmail(email);
if(user != null){
if(user.getPassword().equals(password)){
session.setAttribute(USERID_ATTRIBUTENAME, user.getId();
request.setAttribute("result", "success");
}
}
} else {
request.setAttribute("result", "failure");
}
}
return user;
}
private void SendJSONResponse(JSONObject json, HttpServletRequest request,
HttpServletResponse response) {
String contentStr = json.toString();
response.setContentType("application/json");
response.setStatus( HttpServletResponse.SC_OK);
response.setContentLength(contentStr.length());
response.getWriter().print(contentStr);
response.flushBuffer();
}
For reference purposes, this file is 1084 lines long. The doPost method is about 900 of those. Disclaimer: this is not my code. I did not write it. I only have to test it.
Now for the test:
//In MyFunServletTest.java:
//using JUnit 4
public class MyFunServletTest {
static ServletTester tester;
static String baseUrl;
WebClient webClient = new WebClient();
User user;
WebRequest loginRequest;
#BeforeClass
public static void initClass(){
tester = new ServletTester;
tester.setContextPath("/");
tester.addServlet(MyFunServlet.class, "/fun.service");
baseUrl = tester.createSocketConnector(true);
tester.start();
}
#AfterClass
public static void cleanClass() {
tester.stop();
}
#Before
public void preTest(){
//taking values from our magical test user
user = new User();
user.setEmail("blah#blah.com");
user.setPassword("secure");
loginRequest = new WebRequest(baseUrl + "/fun.service", HttpMethod.POST);
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new NameValuePair("opt","login"));
params.add(new NameValuePair("accountEmail", user.getEmail());
params.add(new NameValuePair("accountPassword", user.getPassword());
loginRequest.setRequestParameters(params);
}
#Test
public void testLogin() {
WebResponse response = webClient.loadWebResponse(loginRequest);
JSONObject responseJSON = new JSONObject(response.getContentAsString());
//this test passes
assertEquals("success", responseJSON.getString("result"));
response = webClient.loadWebResponse(loginRequest);
//this test fails
assertTrue(404 != response.getStatusCode());
//this then causes an error, as response.getContentAsString() is null.
esponseJSON = new JSONObject(response.getContentAsString());
}
}
Help? Where am I missing something?
Thanks.
Without the ability to run the test myself, I can only offer some approaches:
Try creating two JSONObject objects to store the two responses separately, and compare the two (either print them or using the debugger), see if anything looks odd there.
If that doesn't tell you anything, create two separate identical request instances and use each.
Then try tracing through the call to loadWebResponse to see exactly what URL is being requested (cranking up the log level might tell you this, too).
If the 404 is correct, then the second request is somehow being mangled, but the question would be WHERE.

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