.gitignore

@@ -48,6 +48,9 @@ gradle-app.setting
 # JDT-specific (Eclipse Java Development Tools)
 .classpath
 
+# Gradle properties
+gradle.properties
+
 ## MacOS
 # General
 .DS_Store
@@ -122,4 +125,28 @@ $RECYCLE.BIN/
 
 ## bin
 bin/
-gradle.properties
+
+# LaTeX (TeX)
+## Core latex/pdflatex auxiliary files:
+*.aux
+*.lof
+*.log
+*.lot
+*.fls
+*.out
+*.toc
+*.fmt
+*.fot
+*.cb
+*.cb2
+.*.lb
+
+## Build tool auxiliary files:
+*.fdb_latexmk
+*.synctex
+*.synctex(busy)
+*.synctex.gz
+*.synctex.gz(busy)
+*.pdfsync
+*.rubbercache
+rubber.cache

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/ServerApp.java

@@ -3,6 +3,12 @@ package ch.unibas.dmi.dbis.cs108.casono.server;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick.CheckUsernameHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick.CheckUsernameParser;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick.CheckUsernameRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login.LoginHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login.LoginParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login.LoginRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout.LogoutHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout.LogoutParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout.LogoutRequest;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.ping.PingHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.ping.PingParser;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.ping.PingRequest;
@@ -91,5 +97,13 @@ public class ServerApp {
         commandRouter.register(
                 CheckUsernameRequest.class,
                 new CheckUsernameHandler(responseDispatcher, userRegistry));
+
+        parserDispatcher.register("LOGIN", new LoginParser());
+        commandRouter.register(
+                LoginRequest.class, new LoginHandler(responseDispatcher, userRegistry));
+
+        parserDispatcher.register("LOGOUT", new LogoutParser());
+        commandRouter.register(
+                LogoutRequest.class, new LogoutHandler(responseDispatcher, userRegistry));
     }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginHandler.java

@@ -0,0 +1,58 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserFactory;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+/**
+ * Handles {@link LoginRequest}s to create a user for a session, if the session has not assigned one
+ * already
+ */
+public class LoginHandler implements CommandHandler<LoginRequest> {
+    private final ResponseDispatcher responseDispatcher;
+    private final UserRegistry userRegistry;
+    private final UserFactory userFactory;
+
+    /**
+     * Creates a new handler for checking for existing user and creating a new one
+     *
+     * @param responseDispatcher the dispatcher used to send the response
+     * @param userRegistry the registry used to look up existing users and create the new one
+     */
+    public LoginHandler(ResponseDispatcher responseDispatcher, UserRegistry userRegistry) {
+        this.responseDispatcher = responseDispatcher;
+        this.userRegistry = userRegistry;
+        this.userFactory = new UserFactory(userRegistry);
+    }
+
+    /**
+     * Executes the login request
+     *
+     * <p>If no user is already assigned to the session, a new user is created and its name and
+     * {@link UserId} returned in the response. If the session has already a user assigned, a {@code
+     * ALREADY_LOGGED_IN} error is responded with.
+     *
+     * @param request the request to execute
+     */
+    @Override
+    public void execute(LoginRequest request) {
+        Optional<User> existingUser = userRegistry.getBySessionId(request.getSessionId());
+        if (existingUser.isPresent()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(),
+                            "ALREADY_LOGGED_IN",
+                            "This session is already associated with an active user."));
+            return;
+        }
+
+        User user = userFactory.create(request.getUsername(), request.getSessionId());
+        responseDispatcher.dispatch(
+                new LoginResponse(request.getContext(), user.getName(), user.getId()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginParser.java

@@ -0,0 +1,21 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/** Parses a primitive request into a {@link LoginRequest}. */
+public class LoginParser implements CommandParser<LoginRequest> {
+    /**
+     * Extracts the required {@code USERNAME} parameter from the incoming request.
+     *
+     * @param primitiveRequest the request to parse
+     * @return {@link LoginRequest} containing the username
+     */
+    @Override
+    public LoginRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+        return new LoginRequest(primitiveRequest.context(), accessor.require("USERNAME"));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginRequest.java

@@ -0,0 +1,30 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/** Request implementation used to create server-side user instance based on provided username */
+public class LoginRequest extends Request {
+    private final String username;
+
+    /**
+     * Constructs a new LoginRequest with the given context and desired username
+     *
+     * @param context the {@link RequestContext} containing information for responding to the
+     *     request
+     * @param username the desired username when creating the user
+     */
+    public LoginRequest(RequestContext context, String username) {
+        super(context);
+        this.username = username;
+    }
+
+    /**
+     * Returns the desired username requested for login
+     *
+     * @return the desired username
+     */
+    public String getUsername() {
+        return username;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginResponse.java

@@ -0,0 +1,23 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserId;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
+
+/** Response containing the assigned username and id of said user */
+public class LoginResponse extends SuccessResponse {
+    /**
+     * @param context the {@link RequestContext} associated with the request
+     * @param assignedUsername the assigned username to this user
+     * @param id of the created user
+     */
+    public LoginResponse(RequestContext context, String assignedUsername, UserId id) {
+        super(
+                context,
+                new ResponseBodyBuilder()
+                        .param("USERNAME", assignedUsername)
+                        .param("ID", id.value())
+                        .build());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/logout/LogoutHandler.java

@@ -0,0 +1,45 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+
+/** Handles {@link LogoutRequest} to logout connected user. */
+public class LogoutHandler implements CommandHandler<LogoutRequest> {
+    private final ResponseDispatcher responseDispatcher;
+    private final UserRegistry userRegistry;
+
+    /**
+     * Creates a new logout handler to logout user.
+     *
+     * @param responseDispatcher dispatcher used to send the logout result back to the client
+     * @param userRegistry registry responsible for tracking connected user sessions
+     */
+    public LogoutHandler(ResponseDispatcher responseDispatcher, UserRegistry userRegistry) {
+        this.responseDispatcher = responseDispatcher;
+        this.userRegistry = userRegistry;
+    }
+
+    /**
+     * Executes the logout request for the given request.
+     *
+     * <p>The user is removed from the {@link UserRegistry}.
+     *
+     * @param request the request to execute
+     */
+    @Override
+    public void execute(LogoutRequest request) {
+        boolean wasRemoved = userRegistry.removeBySessionId(request.getSessionId());
+        if (wasRemoved) {
+            responseDispatcher.dispatch(new OkResponse(request.getContext()));
+        } else {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(),
+                            "NO_USER_ASSOCIATED",
+                            "No user is associated with your session. Did you login before?"));
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/logout/LogoutParser.java

@@ -0,0 +1,19 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+
+/** Parses a primitive request into a {@link LogoutRequest}. */
+public class LogoutParser implements CommandParser<LogoutRequest> {
+
+    /**
+     * Parses a primitive request into a LogoutRequest.
+     *
+     * @param primitiveRequest the request to parse
+     * @return the created {@link LogoutRequest}
+     */
+    @Override
+    public LogoutRequest parse(PrimitiveRequest primitiveRequest) {
+        return new LogoutRequest(primitiveRequest.context());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/logout/LogoutRequest.java

@@ -0,0 +1,18 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/** Request implementation used to logout a currently logged in user */
+public class LogoutRequest extends Request {
+
+    /**
+     * Constructs a new LogoutRequest with the given context.
+     *
+     * @param context the {@link RequestContext} containing information for responding to the
+     *     request
+     */
+    public LogoutRequest(RequestContext context) {
+        super(context);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/domain/user/UserRegistry.java

@@ -31,6 +31,66 @@ public class UserRegistry {
         return Optional.of(user);
     }
 
+    /**
+     * Removes a user from the registry by user ID.
+     *
+     * @param userId the ID of the user to remove
+     * @return true if a user was removed, false if no user with that ID exists
+     */
+    public synchronized boolean removeByUserId(UserId userId) {
+        User user = byId.get(userId);
+        if (user == null) {
+            return false;
+        }
+
+        byName.remove(user.getName());
+        user.getSessionId().ifPresent(bySessionId::remove);
+        return true;
+    }
+
+    /**
+     * Removes a user from the registry by session ID.
+     *
+     * @param sessionId the session ID associated with the user to remove
+     * @return true if a user was removed, false if no user with that session exists
+     */
+    public synchronized boolean removeBySessionId(SessionId sessionId) {
+        User user = bySessionId.get(sessionId);
+        if (user == null) {
+            return false;
+        }
+
+        remove(user);
+        return true;
+    }
+
+    /**
+     * Removes a user from the registry by username.
+     *
+     * @param username the username associated with the user to remove
+     * @return true if a user was removed, false if no user with that session exists
+     */
+    public synchronized boolean removeByUsername(String username) {
+        User user = byName.get(username);
+        if (user == null) {
+            return false;
+        }
+
+        remove(user);
+        return true;
+    }
+
+    /**
+     * Removes a user from the internals of the registry.
+     *
+     * @param user the user to remove
+     */
+    private synchronized void remove(User user) {
+        byId.remove(user.getId());
+        byName.remove(user.getName());
+        user.getSessionId().ifPresent(bySessionId::remove);
+    }
+
     /**
      * Removes the user with the given ID, but only if they are still disconnected. This prevents
      * removing a user who has reconnected between the cleanup job's check and its removal call.
@@ -47,8 +107,7 @@ public class UserRegistry {
             return false;
         }
 
-        byId.remove(user.getId());
-        byName.remove(user.getName());
+        remove(user);
         return true;
     }