Refactored post request handler

src/main/java/de/igslandstuhl/database/Application.java

@@ -10,6 +10,7 @@
 import de.igslandstuhl.database.holidays.Holiday;
 import de.igslandstuhl.database.server.Server;
 import de.igslandstuhl.database.server.commands.Command;
+import de.igslandstuhl.database.server.webserver.PostRequestHandler;
 import de.igslandstuhl.database.utils.CommandLineUtils;
 
 /**
@@ -94,6 +95,7 @@ public static void main(String[] args) throws Exception {
         Server.getInstance().getConnection().createTables();
 
         Holiday.setupCurrentSchoolYear();
+        PostRequestHandler.registerHandlers();
 
         if (getInstance().runsWebServer()) {
             Server.getInstance().getWebServer().start();

src/main/java/de/igslandstuhl/database/Registry.java

@@ -6,12 +6,23 @@
 import java.util.stream.Stream;
 
 import de.igslandstuhl.database.server.commands.Command;
+import de.igslandstuhl.database.server.webserver.requests.APIPostRequest;
+import de.igslandstuhl.database.server.webserver.requests.GetRequest;
+import de.igslandstuhl.database.server.webserver.requests.HttpHandler;
 
 public class Registry<K, V> implements Closeable {
     private static final Registry<String,Command> COMMAND_REGISTRY = new Registry<>();
+    private static final Registry<String,HttpHandler<APIPostRequest>> POST_HANDLER_REGISTRY = new Registry<>();
+    private static final Registry<String,HttpHandler<GetRequest>> GET_HANDLER_REGISTRY = new Registry<>();
     public static Registry<String,Command> commandRegistry() {
         return COMMAND_REGISTRY;
     }
+    public static Registry<String, HttpHandler<APIPostRequest>> postRequestHandlerRegistry() {
+        return POST_HANDLER_REGISTRY;
+    }
+    public static Registry<String, HttpHandler<GetRequest>> getRequestHandlerRegistry() {
+        return GET_HANDLER_REGISTRY;
+    }
 
     private final Map<K,V> objects = new HashMap<>();
 

src/main/java/de/igslandstuhl/database/api/APIObject.java

@@ -0,0 +1,5 @@
+package de.igslandstuhl.database.api;
+
+public interface APIObject {
+    public String toJSON();
+}

src/main/java/de/igslandstuhl/database/api/GraduationLevel.java

@@ -1,6 +1,6 @@
 package de.igslandstuhl.database.api;
 
-public enum GraduationLevel {
+public enum GraduationLevel implements APIObject {
     LEVEL0 (0, "Neustarter"),
     LEVEL1 (1, "Starter"),
     LEVEL2 (2, "Durchstarter"),
@@ -46,4 +46,9 @@ public static GraduationLevel of(int level) {
     public static GraduationLevel initialValue() {
         return LEVEL1;
     }
+
+    @Override
+    public String toJSON() {
+        return String.valueOf(level);
+    }
 }

src/main/java/de/igslandstuhl/database/api/Room.java

@@ -13,7 +13,7 @@
  * Represents a room in the system.
  * Each room has a label and a minimum level required for students to access it.
  */
-public class Room {
+public class Room implements APIObject {
     private static final String[] SQL_FIELDS = {"label", "minimum_level"};
     /**
      * A map to store all rooms, keyed by their label.
@@ -229,5 +229,9 @@ public boolean equals(Object obj) {
             return false;
         return true;
     }
+    @Override
+    public String toJSON() {
+        return "{\"label\": \""+label+ "\", \"minimumLevel\": \"" + minimumLevel + "\"}";
+    }
 
 }

src/main/java/de/igslandstuhl/database/api/SchoolClass.java

@@ -13,7 +13,7 @@
  * Represents a school class with its associated subjects and students.
  * Provides methods to fetch subjects and students from the database.
  */
-public class SchoolClass {
+public class SchoolClass implements APIObject {
     /**
      * SQL fields for the SchoolClass table.
      * Used for database queries to retrieve class information.
@@ -321,5 +321,10 @@ public boolean equals(Object obj) {
             return false;
         return true;
     }
+
+    @Override
+    public String toJSON() {
+        return "{\"id\": " + id + ", \"label\": \"" + label + "\", \"grade\": " + grade + "}";
+    }
 
 }

src/main/java/de/igslandstuhl/database/api/SchoolYear.java

@@ -9,7 +9,7 @@
  * Represents a school year with its associated properties and methods to manage it.
  * Provides functionality to retrieve, add, and update school years in the database.
  */
-public class SchoolYear {
+public class SchoolYear implements APIObject {
     /**
      * SQL fields for the SchoolYear table.
      * Used for database queries to retrieve school year information.
@@ -240,4 +240,9 @@ public boolean equals(Object obj) {
             return false;
         return true;
     }
+
+    @Override
+    public String toJSON() {
+        return "{\"id\":" + id + ",\"label\":\"" + label + "\",\"weekCount\":" + weekCount + ",\"currentWeek\":" + currentWeek + "}";
+    }
 }

src/main/java/de/igslandstuhl/database/api/SpecialTask.java

@@ -50,6 +50,16 @@ public String toString() {
                 '}';
     }
 
+    @Override
+    public String toJSON() {
+        return "{" +
+                "\"id\":" + getId() +
+                ", \"name\": \"" + getName() + '"' +
+                ", \"ratio\":" + ratio +
+                ", \"subject\": \"" + subject.getName() + '"' +
+                '}';
+    }
+
     /**
      * Creates a SpecialTask object from SQL query result fields.
      * This method is used to convert the result of a database query into a SpecialTask object.

src/main/java/de/igslandstuhl/database/api/Student.java

@@ -389,6 +389,7 @@ public Set<SubjectRequest> getCurrentRequests(Subject subject) {
      * Adds a subject request for this student.
      * @param subjectId the subject ID
      * @param type the request type
+     * @deprecated Use addSubjectRequest(Subject, SubjectRequest) instead
      */
     public void addSubjectRequest(int subjectId, String type) {
         currentRequests.computeIfPresent(subjectId, (key, value) -> {
@@ -397,17 +398,34 @@ public void addSubjectRequest(int subjectId, String type) {
         });
         currentRequests.computeIfAbsent(subjectId, key -> new HashSet<>()).add(SubjectRequest.fromGermanTranslation(type));
     }
+    /**
+     * Adds a subject request for this student.
+     * @param subject the corresponding subject
+     * @param subjectRequest the request
+     */
+    public void addSubjectRequest(Subject subject, SubjectRequest subjectRequest) {
+        addSubjectRequest(subject.getId(), subjectRequest.getGermanTranslation());
+    }
     /**
      * Removes a subject request for this student.
      * @param subjectId the subject ID
      * @param type the request type to remove
+     * @deprecated Use removeSubjectRequest(Subject, SubjectRequest) instead
      */
     public void removeSubjectRequest(int subjectId, String type) {
         currentRequests.computeIfPresent(subjectId, (key, value) -> {
             value.remove(SubjectRequest.fromGermanTranslation(type));
             return value;
         });
     }
+    /**
+     * Removes a subject request from this student.
+     * @param subject the corresponding subject
+     * @param subjectRequest the request
+     */
+    public void removeSubjectRequest(Subject subject, SubjectRequest subjectRequest) {
+        removeSubjectRequest(subject.getId(), subjectRequest.getGermanTranslation());
+    }
 
     public void beginTask(Task task) throws SQLException {
         if (task == null) {

src/main/java/de/igslandstuhl/database/api/Subject.java

@@ -16,7 +16,7 @@
  * Represents a subject in the student database.
  * Subjects can be added to grades and have associated topics.
  */
-public class Subject {
+public class Subject implements APIObject {
     /**
      * A map to cache subjects by their unique identifier.
      * This helps avoid repeated database queries for the same subject.
@@ -282,5 +282,10 @@ public boolean equals(Object obj) {
             return false;
         return true;
     }
+
+    @Override
+    public String toJSON() {
+        return "{\"id\": " + id + ", \"name\": \"" + name + "\"}";
+    }
 
 }

src/main/java/de/igslandstuhl/database/api/SubjectRequest.java

@@ -1,6 +1,6 @@
 package de.igslandstuhl.database.api;
 
-public enum SubjectRequest {
+public enum SubjectRequest implements APIObject {
     HELP ("hilfe"),
     PARTNER ("partner"),
     EXPERIMENT ("betreuung"),
@@ -23,4 +23,9 @@ public static SubjectRequest fromGermanTranslation(String translation) {
         }
         throw new IllegalArgumentException("No matching SubjectRequest for translation: " + translation);
     }
+
+    @Override
+    public String toJSON() {
+        return '"' + germanTranslation + '"';
+    }
 }

src/main/java/de/igslandstuhl/database/api/Task.java

@@ -16,7 +16,7 @@
  * Represents a task in the student database.
  * Tasks are associated with topics and have different levels of difficulty.
  */
-public class Task {
+public class Task implements APIObject {
     public static final int STATUS_NOT_STARTED = 0;
     public static final int STATUS_IN_PROGRESS = 1;
     public static final int STATUS_COMPLETED = 2;
@@ -285,5 +285,10 @@ public static Task fromSerialized(Topic topic, String serialized) throws SQLExce
         TaskLevel level = TaskLevel.get(Integer.parseInt(parts[1]));
         return addTask(topic, name, level);
     }
+
+    @Override
+    public String toJSON() {
+        return "{\"id\": " + id + ", \"topic\": " + topic + ", \"name\": \"" + name + "\", \"niveau\": " + niveau + ", \"number\": \"" + getNumber() + "\", \"ratio\": " + getRatio() + "}";
+    }
 
 }

src/main/java/de/igslandstuhl/database/api/TaskLevel.java

@@ -5,7 +5,7 @@
  * Each level has a specific ratio that indicates the proportion of the progress
  * that can be achieved at that level.
  */
-public enum TaskLevel {
+public enum TaskLevel implements APIObject {
     LEVEL1 (1, "Niveau 1"),
     LEVEL2 (2, "Niveau 2"),
     LEVEL3 (3, "Niveau 3"),
@@ -73,4 +73,9 @@ public double getRatio() {
     public String toString() {
         return this == SPECIAL ? "Special" : String.valueOf(number);
     }
+
+    @Override
+    public String toJSON() {
+        return this == SPECIAL ? "\"Special\"" : String.valueOf(number);
+    }
 }

src/main/java/de/igslandstuhl/database/api/Topic.java

@@ -15,7 +15,7 @@
  * Represents a topic in the student database.
  * Topics are associated with subjects and contain tasks of varying difficulty levels.
  */
-public class Topic {
+public class Topic implements APIObject {
     /**
      * SQL fields for the Topic table.
      * Used for database queries to retrieve topic information.
@@ -300,6 +300,11 @@ public String toString() {
         return "{\"id\":" + id + ", \"name\": \"" + name + "\", \"subject\": " + subject + ", \"ratio\": " + ratio + ", \"grade\": " + grade
                 + ", \"tasks\": " + getTaskIds() + ", \"number\": " + number + "}";
     }
+    @Override
+    public String toJSON() {
+        return "{\"id\":" + id + ", \"name\": \"" + name + "\", \"subject\": " + subject + ", \"ratio\": " + ratio + ", \"grade\": " + grade
+                + ", \"tasks\": " + getTaskIds() + ", \"number\": " + number + "}";
+    }
     /**
      * Adds a new topic to the database.
      * This method executes a secure SQL process to insert a new topic with the provided parameters.

src/main/java/de/igslandstuhl/database/api/User.java

@@ -11,7 +11,7 @@
  * Abstract class representing a user in the system.
  * This class provides methods to check user roles, retrieve password hashes, and convert user data to JSON format.
  */
-public abstract class User {
+public abstract class User implements APIObject {
     public static final User ANONYMOUS = new User() {
         @Override
         public boolean isTeacher() {

src/main/java/de/igslandstuhl/database/api/results/GenerationResult.java

@@ -1,6 +1,6 @@
 package de.igslandstuhl.database.api.results;
 
-public class GenerationResult<T> {
+public abstract class GenerationResult<T> {
     private final T entity;
     private final String password;
 
@@ -16,4 +16,6 @@ public T getEntity() {
     public String getPassword() {
         return password;
     }
+
+    public abstract String toCSVRow();
 }

src/main/java/de/igslandstuhl/database/api/results/StudentGenerationResult.java

@@ -9,4 +9,12 @@ public StudentGenerationResult(Student student, String password) {
     public Student getStudent() {
         return getEntity();
     }
+    @Override
+    public String toCSVRow() {
+        return new StringBuilder().append(this.getStudent().getId()).append(",")
+            .append(this.getStudent().getFirstName()).append(",")
+            .append(this.getStudent().getLastName()).append(",")
+            .append(this.getStudent().getEmail()).append(",")
+            .append(this.getPassword()).toString();
+    }
 }

src/main/java/de/igslandstuhl/database/api/results/TeacherGenerationResult.java

@@ -23,4 +23,13 @@ public String getLastName() {
     public String getEmail() {
         return getTeacher().getEmail();
     }
+
+    @Override
+    public String toCSVRow() {
+        return new StringBuilder().append(this.getId()).append(",")
+                .append(this.getFirstName()).append(",")
+                .append(this.getLastName()).append(",")
+                .append(this.getEmail()).append(",")
+                .append(this.getPassword()).toString();
+    }
 }

src/main/java/de/igslandstuhl/database/server/WebServer.java

@@ -22,13 +22,14 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
-import de.igslandstuhl.database.server.webserver.GetRequest;
-import de.igslandstuhl.database.server.webserver.GetResponse;
 import de.igslandstuhl.database.server.webserver.HttpHeader;
-import de.igslandstuhl.database.server.webserver.PostRequest;
 import de.igslandstuhl.database.server.webserver.PostRequestHandler;
-import de.igslandstuhl.database.server.webserver.PostResponse;
 import de.igslandstuhl.database.server.webserver.SessionManager;
+import de.igslandstuhl.database.server.webserver.requests.GetRequest;
+import de.igslandstuhl.database.server.webserver.requests.PostRequest;
+import de.igslandstuhl.database.server.webserver.responses.GetResponse;
+import de.igslandstuhl.database.server.webserver.responses.HttpResponse;
+import de.igslandstuhl.database.server.webserver.responses.PostResponse;
 
 /**
  * A simple HTTPS web server that handles various requests related to student data.
@@ -152,7 +153,7 @@ void handlePost(String headerString, InputStream in, PrintStream out) throws IOE
                 body = URLDecoder.decode(raw, bodyCharset.name());
             }
             PostRequest parsedRequest = new PostRequest(postHeader, body, clientIp, secure);
-            PostResponse response = Server.getInstance().getWebServer().getSessionManager().validateSession(parsedRequest) ? PostRequestHandler.getInstance().handlePostRequest(parsedRequest) : PostResponse.forbidden("Forbidden: session manipulation or ratelimit", parsedRequest);
+            HttpResponse response = Server.getInstance().getWebServer().getSessionManager().validateSession(parsedRequest) ? PostRequestHandler.getInstance().handlePostRequest(parsedRequest) : PostResponse.forbidden("Forbidden: session manipulation or ratelimit", parsedRequest);
             response.respond(out);
         }
 

src/main/java/de/igslandstuhl/database/server/webserver/AccessLevel.java

@@ -0,0 +1,17 @@
+package de.igslandstuhl.database.server.webserver;
+
+import de.igslandstuhl.database.api.User;
+
+public enum AccessLevel {
+    PUBLIC, USER, STUDENT, TEACHER, ADMIN, NONE;
+
+    public boolean hasAccess(User user) {
+        if (this == PUBLIC) return true;
+        else if (user == null || user == User.ANONYMOUS) return false;
+        else if (this == USER || this == STUDENT) return true;
+        else if (user.isStudent()) return false;
+        else if (this == TEACHER) return true;
+        else if (user.isTeacher()) return false;
+        else return this == ADMIN;
+    }
+}

src/main/java/de/igslandstuhl/database/server/webserver/ContentType.java

@@ -11,7 +11,8 @@ public enum ContentType {
     JAVASCRIPT ("text/javascript"),
     CSS ("text/css"),
     PNG ("image/png"),
-    JSON ("text/json")
+    JSON ("text/json"),
+    CSV ("text/csv")
     ;
     /**
      * The name of the content type, used in HTTP headers.