Added a REST URI to retrieve the number of checked-in visitors...

src/main/java/de/hs_mannheim/informatik/ct/controller/ErrorController.java

@@ -21,18 +21,23 @@
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.io.UnsupportedEncodingException;
+import java.util.Date;
 
 import javax.servlet.RequestDispatcher;
 import javax.servlet.http.HttpServletRequest;
 
 import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseStatus;
 
 import de.hs_mannheim.informatik.ct.controller.exception.InvalidRoomPinException;
+import de.hs_mannheim.informatik.ct.controller.rest.InvalidPinRestException;
+import de.hs_mannheim.informatik.ct.controller.rest.RestErrorMessage;
+import de.hs_mannheim.informatik.ct.controller.rest.RoomNotFoundRestException;
 import de.hs_mannheim.informatik.ct.persistence.EventNotFoundException;
 import de.hs_mannheim.informatik.ct.persistence.InvalidEmailException;
 import de.hs_mannheim.informatik.ct.persistence.InvalidExternalUserdataException;
@@ -42,6 +47,21 @@
 @ControllerAdvice
 @Slf4j
 public class ErrorController {
+
+    @ExceptionHandler(value = {RoomNotFoundRestException.class})
+    public ResponseEntity<RestErrorMessage> handleRoomNotFoundRestException() {
+        RestErrorMessage rem = new RestErrorMessage(404, new Date(), "Room not found.");
+
+        return new ResponseEntity<RestErrorMessage>(rem, HttpStatus.NOT_FOUND);
+    }
+
+    @ExceptionHandler(value = {InvalidPinRestException.class})
+    public ResponseEntity<RestErrorMessage> handleRoomPinException() {
+        RestErrorMessage rem = new RestErrorMessage(400, new Date(), "Room Pin not valid or not submitted.");
+
+        return new ResponseEntity<RestErrorMessage>(rem, HttpStatus.BAD_REQUEST);
+    }
+
     @ExceptionHandler({RoomController.RoomNotFoundException.class})
     @ResponseStatus(value = HttpStatus.NOT_FOUND)
 //    @ResponseStatus(value = HttpStatus.NOT_FOUND, reason = "Room not found")

src/main/java/de/hs_mannheim/informatik/ct/controller/rest/InvalidPinRestException.java

@@ -0,0 +1,8 @@
+package de.hs_mannheim.informatik.ct.controller.rest;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(code = HttpStatus.NOT_FOUND, reason = "Room not found")
+public class InvalidPinRestException extends RuntimeException {
+}

src/main/java/de/hs_mannheim/informatik/ct/controller/rest/RestErrorMessage.java

@@ -0,0 +1,29 @@
+package de.hs_mannheim.informatik.ct.controller.rest;
+
+import java.util.Date;
+
+public class RestErrorMessage {
+    private int statusCode;
+    private Date timestamp;
+    private String message;
+
+    public RestErrorMessage(int statusCode, Date timestamp, String message) {
+        super();
+        this.statusCode = statusCode;
+        this.timestamp = timestamp;
+        this.message = message;
+    }
+
+    public int getStatusCode() {
+        return statusCode;
+    }
+
+    public Date getTimestamp() {
+        return timestamp;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+}

src/main/java/de/hs_mannheim/informatik/ct/controller/rest/RestRoomController.java

@@ -0,0 +1,61 @@
+/*
+ * Corona Tracking Tool der Hochschule Mannheim
+ * Copyright (c) 2021 Hochschule Mannheim
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.hs_mannheim.informatik.ct.controller.rest;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import de.hs_mannheim.informatik.ct.controller.RoomController.RoomNotFoundException;
+import de.hs_mannheim.informatik.ct.controller.exception.InvalidRoomPinException;
+import de.hs_mannheim.informatik.ct.persistence.services.RoomService;
+import de.hs_mannheim.informatik.ct.persistence.services.RoomVisitService;
+import lombok.val;
+
+@RestController
+@RequestMapping("/api")
+public class RestRoomController {   // couldn't resist using this name ;-)
+    @Autowired
+    private RoomVisitService rvs;
+
+    @Autowired
+    private RoomService roomService;
+
+    @RequestMapping(value="/rooms/{roomId}/visitors", method=RequestMethod.GET)
+    public String getNumberOfCheckedInVisitors(@PathVariable(value = "roomId") String id, 
+                                               @RequestParam(value = "pin", required=false) String pin) 
+                                                       throws InvalidRoomPinException, RoomNotFoundRestException {
+
+        try {
+            val room = roomService.getRoomOrThrow(id);
+
+            if (pin == null || !room.getRoomPin().equals(pin))
+                throw new InvalidPinRestException();
+
+            return "" + rvs.getVisitorCount(room);
+        } catch(RoomNotFoundException rnfe) {
+            throw new RoomNotFoundRestException();
+        }
+
+    }
+
+}

src/main/java/de/hs_mannheim/informatik/ct/controller/rest/RoomNotFoundRestException.java

@@ -0,0 +1,8 @@
+package de.hs_mannheim.informatik.ct.controller.rest;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(code = HttpStatus.NOT_FOUND, reason = "Room not found")
+public class RoomNotFoundRestException extends RuntimeException {
+}

src/test/java/de/hs_mannheim/informatik/ct/end_to_end/RoomControllerTest.java

@@ -19,6 +19,7 @@
 package de.hs_mannheim.informatik.ct.end_to_end;
 
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
 import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.csrf;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
@@ -293,6 +294,44 @@ public void roomNotFoundException() throws Exception {
                 .andExpect(status().is(404))  // checking for response status code 404
                 .andExpect(content().string(containsString("Raum nicht gefunden")));// checking if error message is displayed for user
     }
+
+    @Test
+    public void testRoomVisitorsViaRest() throws Exception {
+        Room testRoom = roomService.findByName(TEST_ROOM_NAME).get();
+
+        // /{roomId}
+        this.mockMvc.perform(
+                get("/api/rooms/" + TEST_ROOM_NAME + "/visitors?pin=" + TEST_ROOM_PIN).with(csrf()))
+                .andExpect(status().isOk())
+                .andExpect(content().string(is("0"))
+        );
+
+
+        fillRoom(testRoom, 2);
+        this.mockMvc.perform(
+                get("/api/rooms/" + TEST_ROOM_NAME + "/visitors?pin=" + TEST_ROOM_PIN).with(csrf()))
+                .andExpect(status().isOk())
+                .andExpect(content().string(is("2"))
+        );
+
+        fillRoom(testRoom, 5);
+        this.mockMvc.perform(
+                get("/api/rooms/" + TEST_ROOM_NAME + "/visitors?pin=" + TEST_ROOM_PIN).with(csrf()))
+                .andExpect(status().isOk())
+                .andExpect(content().string(is("7"))
+        );
+
+
+        this.mockMvc.perform(
+                get("/api/rooms/" + TEST_ROOM_NAME + "/visitors").with(csrf()))
+                .andExpect(status().isBadRequest()
+        );
+
+        this.mockMvc.perform(
+                get("/api/rooms/notExistingName/visitors").with(csrf()))
+                .andExpect(status().isNotFound()
+        );
+    }
 
     /**
      * Helper method that creates users to fill room.

src/test/java/de/hs_mannheim/informatik/ct/persistence/services/RoomServiceTest.java

@@ -2,7 +2,6 @@
 
 import static org.junit.jupiter.api.Assertions.assertAll;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 import java.util.Collections;