Implemented picking method in Client and refactored picking in server

client-impl/src/main/java/ru/dragonestia/picker/api/impl/repository/NodeRepositoryImpl.java

@@ -76,6 +76,10 @@ public class NodeRepositoryImpl implements NodeRepository {
 
     @Override
     public @NotNull PickedRoomResponse pickRoom(@NotNull NodeIdentifier identifier, @NotNull Set<UserIdentifier> users) {
-        throw new UnsupportedOperationException("Not implemented");
+        return rest.queryPostWithBody(
+                "/nodes/" + identifier.getValue() + "/pick",
+                PickedRoomResponse.class,
+                params -> {}, String.join(",", users.stream().map(user -> user.getValue()).toList())
+        );
     }
 }

client-impl/src/main/java/ru/dragonestia/picker/api/impl/util/RestTemplate.java

@@ -3,9 +3,7 @@ package ru.dragonestia.picker.api.impl.util;
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import okhttp3.FormBody;
+import okhttp3.*;
-import okhttp3.OkHttpClient;
-import okhttp3.Response;
 import org.jetbrains.annotations.ApiStatus.Internal;
 import ru.dragonestia.picker.api.exception.ExceptionFactory;
 import ru.dragonestia.picker.api.impl.RoomPickerClient;
@@ -78,6 +76,22 @@ public class RestTemplate {
         }
     }
 
+    public <T> T queryPostWithBody(String uri, Class<T> clazz, ParamsConsumer paramsConsumer, String body) {
+        var request = client.prepareRequestBuilder(uri + queryEncode(paramsConsumer))
+                .post(RequestBody.create(body, MediaType.get("text/plain")))
+                .build();
+
+        try (var response = httpClient.newCall(request).execute()) {
+            checkResponseForErrors(response);
+
+            return json.readValue(new String(Objects.requireNonNull(response.body()).bytes(), StandardCharsets.UTF_8), clazz);
+        } catch (JsonProcessingException ex) {
+            throw new RuntimeException("Json processing error", ex);
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
     private String queryEncode(ParamsConsumer paramsConsumer) {
         var params = new HashMap<String, String>();
         paramsConsumer.accept(params);

server/src/main/java/ru/dragonestia/picker/controller/NodeController.java

@@ -77,7 +77,7 @@ public class NodeController {
     @PostMapping("/{nodeId}/pick")
     ResponseEntity<PickedRoomResponse> pickRoom(
             @Parameter(description = "Node identifier") @PathVariable("nodeId") String nodeId,
-            @Parameter(description = "Users to add", example = "user1,user3,user3") @RequestParam(name = "userIds") String userIds
+            @RequestBody String userIds
     ) {
         namingValidator.validateNodeId(nodeId);
 

server/src/main/java/ru/dragonestia/picker/service/impl/RoomServiceImpl.java

@@ -80,7 +80,7 @@ public class RoomServiceImpl implements RoomService {
     @Override
     public PickedRoomResponse pickAvailable(Node node, List<User> users) {
         var room = roomRepository.pickFree(node, users)
-                .orElseThrow(() -> new RuntimeException("There are no rooms available"));
+                .orElseThrow(() -> new RuntimeException("There are no rooms available. Given users count: " + users.size()));
         var roomUsers = userRepository.usersOf(room);
 
         return new PickedRoomResponse(