Can get a user id included in a POST request

src/helpers/database.rs

@@ -107,6 +107,11 @@ impl QueryInfo {
                                                              -> Result<Vec<E>, Box<dyn Error>> {
         query(self, process_function)
     }
+
+    /// Execute count query
+    pub fn exec_count(self) -> ResultBoxError<usize> {
+        count(self)
+    }
 }
 
 /// Struct used to read the result of a request

src/helpers/user_helper.rs

@@ -52,4 +52,11 @@ fn exec_get_user_query(query: database::QueryInfo) -> ResultBoxError<User> {
             account_image_visibility,
         })
     })
+}
+
+/// Check out whether a given id maps to a user or not
+pub fn exists(id: UserID) -> ResultBoxError<bool> {
+    Ok(database::QueryInfo::new(USERS_TABLE)
+        .cond_i64("ID", id)
+        .exec_count()? > 0)
 }