Commit for merge

+import numpy as np
+import cv2
+import asyncio
+import websockets
+from io import BytesIO
+
+from PIL import Image, ImageDraw
+from IPython import display
+
+async def recv_image(websocket, path):
+    buf = await websocket.recv()
+    byte = BytesIO(buf)
+    image = Image.open(byte)
+    remote_ip = websocket.remote_address[0]
+    msg='[{ip}] receive face properly, image size={size}'.format(ip=remote_ip, size=image.size)
+    print(msg)
+    await websocket.send('100')
+    #for debug
+    #frame = np.array(image)
+    #frame = cv2.cvtColor(frame, cv2.COLOR_RGB2BGR)
+    #cv2.imshow('recv', frame)
+    #cv2.waitKey(2000)
+    #cv2.destroyAllWindows()
+
+print('run image server')
+start_image_server = websockets.serve(recv_image, '0.0.0.0', 8766)
+asyncio.get_event_loop().run_until_complete(start_image_server)
+asyncio.get_event_loop().run_forever()
\ No newline at end of file

+import torch
+import numpy as np
+import os
+import asyncio
+import json
+import websockets
+from io import BytesIO
+
+from PIL import Image, ImageDraw
+from IPython import display
+
+from models.mtcnn import MTCNN
+from models.inception_resnet_v1 import InceptionResnetV1
+
+device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
+print('Running on device: {}'.format(device))
+
+model = InceptionResnetV1().eval().to(device)
+
+async def get_embeddings(face_list):
+  global model
+  x = torch.Tensor(face_list).to(device)
+  yhat = model(x)
+  return yhat
+
+def get_distance(someone, database):
+  distance = [(someone - data).norm().item() for data in database]
+  return distance
+
+def get_argmin(someone, database):
+  distance = get_distance(someone, database)
+  for i in range(len(distance)):
+    return np.argmin(distance)
+  return -1
+
+async def recv_face(websocket, path):
+    buf = await websocket.recv()
+    face = np.frombuffer(buf, dtype = np.float32)
+    face = face.reshape((1,3,160,160))
+    remote_ip = websocket.remote_address[0]
+    msg='[{ip}] receive face properly, numpy shape={shape}'.format(ip=remote_ip, shape=face.shape)
+    print(msg)
+    embedding = await get_embeddings(face)
+    await websocket.send('100')
+    ##embedding DB서버에 넘기기##
+
+print('run verification server')
+start_server = websockets.serve(recv_face, '0.0.0.0', 8765)
+asyncio.get_event_loop().run_until_complete(start_server)
+asyncio.get_event_loop().run_forever()
\ No newline at end of file

+import torch
+from torch import nn
+from torch.nn import functional as F
+import os
+
+
+class BasicConv2d(nn.Module):
+
+    def __init__(self, in_planes, out_planes, kernel_size, stride, padding=0):
+        super().__init__()
+        self.conv = nn.Conv2d(
+            in_planes, out_planes,
+            kernel_size=kernel_size, stride=stride,
+            padding=padding, bias=False
+        ) # verify bias false
+        self.bn = nn.BatchNorm2d(
+            out_planes,
+            eps=0.001, # value found in tensorflow
+            momentum=0.1, # default pytorch value
+            affine=True
+        )
+        self.relu = nn.ReLU(inplace=False)
+
+    def forward(self, x):
+        x = self.conv(x)
+        x = self.bn(x)
+        x = self.relu(x)
+        return x
+
+
+class Block35(nn.Module):
+
+    def __init__(self, scale=1.0):
+        super().__init__()
+
+        self.scale = scale
+
+        self.branch0 = BasicConv2d(256, 32, kernel_size=1, stride=1)
+
+        self.branch1 = nn.Sequential(
+            BasicConv2d(256, 32, kernel_size=1, stride=1),
+            BasicConv2d(32, 32, kernel_size=3, stride=1, padding=1)
+        )
+
+        self.branch2 = nn.Sequential(
+            BasicConv2d(256, 32, kernel_size=1, stride=1),
+            BasicConv2d(32, 32, kernel_size=3, stride=1, padding=1),
+            BasicConv2d(32, 32, kernel_size=3, stride=1, padding=1)
+        )
+
+        self.conv2d = nn.Conv2d(96, 256, kernel_size=1, stride=1)
+        self.relu = nn.ReLU(inplace=False)
+
+    def forward(self, x):
+        x0 = self.branch0(x)
+        x1 = self.branch1(x)
+        x2 = self.branch2(x)
+        out = torch.cat((x0, x1, x2), 1)
+        out = self.conv2d(out)
+        out = out * self.scale + x
+        out = self.relu(out)
+        return out
+
+
+class Block17(nn.Module):
+
+    def __init__(self, scale=1.0):
+        super().__init__()
+
+        self.scale = scale
+
+        self.branch0 = BasicConv2d(896, 128, kernel_size=1, stride=1)
+
+        self.branch1 = nn.Sequential(
+            BasicConv2d(896, 128, kernel_size=1, stride=1),
+            BasicConv2d(128, 128, kernel_size=(1,7), stride=1, padding=(0,3)),
+            BasicConv2d(128, 128, kernel_size=(7,1), stride=1, padding=(3,0))
+        )
+
+        self.conv2d = nn.Conv2d(256, 896, kernel_size=1, stride=1)
+        self.relu = nn.ReLU(inplace=False)
+
+    def forward(self, x):
+        x0 = self.branch0(x)
+        x1 = self.branch1(x)
+        out = torch.cat((x0, x1), 1)
+        out = self.conv2d(out)
+        out = out * self.scale + x
+        out = self.relu(out)
+        return out
+
+
+class Block8(nn.Module):
+
+    def __init__(self, scale=1.0, noReLU=False):
+        super().__init__()
+
+        self.scale = scale
+        self.noReLU = noReLU
+
+        self.branch0 = BasicConv2d(1792, 192, kernel_size=1, stride=1)
+
+        self.branch1 = nn.Sequential(
+            BasicConv2d(1792, 192, kernel_size=1, stride=1),
+            BasicConv2d(192, 192, kernel_size=(1,3), stride=1, padding=(0,1)),
+            BasicConv2d(192, 192, kernel_size=(3,1), stride=1, padding=(1,0))
+        )
+
+        self.conv2d = nn.Conv2d(384, 1792, kernel_size=1, stride=1)
+        if not self.noReLU:
+            self.relu = nn.ReLU(inplace=False)
+
+    def forward(self, x):
+        x0 = self.branch0(x)
+        x1 = self.branch1(x)
+        out = torch.cat((x0, x1), 1)
+        out = self.conv2d(out)
+        out = out * self.scale + x
+        if not self.noReLU:
+            out = self.relu(out)
+        return out
+
+
+class Mixed_6a(nn.Module):
+
+    def __init__(self):
+        super().__init__()
+
+        self.branch0 = BasicConv2d(256, 384, kernel_size=3, stride=2)
+
+        self.branch1 = nn.Sequential(
+            BasicConv2d(256, 192, kernel_size=1, stride=1),
+            BasicConv2d(192, 192, kernel_size=3, stride=1, padding=1),
+            BasicConv2d(192, 256, kernel_size=3, stride=2)
+        )
+
+        self.branch2 = nn.MaxPool2d(3, stride=2)
+
+    def forward(self, x):
+        x0 = self.branch0(x)
+        x1 = self.branch1(x)
+        x2 = self.branch2(x)
+        out = torch.cat((x0, x1, x2), 1)
+        return out
+
+
+class Mixed_7a(nn.Module):
+
+    def __init__(self):
+        super().__init__()
+
+        self.branch0 = nn.Sequential(
+            BasicConv2d(896, 256, kernel_size=1, stride=1),
+            BasicConv2d(256, 384, kernel_size=3, stride=2)
+        )
+
+        self.branch1 = nn.Sequential(
+            BasicConv2d(896, 256, kernel_size=1, stride=1),
+            BasicConv2d(256, 256, kernel_size=3, stride=2)
+        )
+
+        self.branch2 = nn.Sequential(
+            BasicConv2d(896, 256, kernel_size=1, stride=1),
+            BasicConv2d(256, 256, kernel_size=3, stride=1, padding=1),
+            BasicConv2d(256, 256, kernel_size=3, stride=2)
+        )
+
+        self.branch3 = nn.MaxPool2d(3, stride=2)
+
+    def forward(self, x):
+        x0 = self.branch0(x)
+        x1 = self.branch1(x)
+        x2 = self.branch2(x)
+        x3 = self.branch3(x)
+        out = torch.cat((x0, x1, x2, x3), 1)
+        return out
+
+
+class InceptionResnetV1(nn.Module):
+    """Inception Resnet V1 model with optional loading of pretrained weights.
+
+    Model parameters can be loaded based on pretraining on the VGGFace2 or CASIA-Webface
+    datasets. Pretrained state_dicts are automatically downloaded on model instantiation if
+    requested and cached in the torch cache. Subsequent instantiations use the cache rather than
+    redownloading.
+
+    Keyword Arguments:
+        pretrained {str} -- Optional pretraining dataset. Either 'vggface2' or 'casia-webface'.
+            (default: {None})
+        classify {bool} -- Whether the model should output classification probabilities or feature
+            embeddings. (default: {False})
+        num_classes {int} -- Number of output classes. If 'pretrained' is set and num_classes not
+            equal to that used for the pretrained model, the final linear layer will be randomly
+            initialized. (default: {None})
+        dropout_prob {float} -- Dropout probability. (default: {0.6})
+    """
+    def __init__(self, classify=False, dropout_prob=0.6, device=None):
+        super().__init__()
+
+        # Set simple attributes
+        self.classify = classify
+        self.num_classes = 8631
+
+        # Define layers
+        self.conv2d_1a = BasicConv2d(3, 32, kernel_size=3, stride=2)
+        self.conv2d_2a = BasicConv2d(32, 32, kernel_size=3, stride=1)
+        self.conv2d_2b = BasicConv2d(32, 64, kernel_size=3, stride=1, padding=1)
+        self.maxpool_3a = nn.MaxPool2d(3, stride=2)
+        self.conv2d_3b = BasicConv2d(64, 80, kernel_size=1, stride=1)
+        self.conv2d_4a = BasicConv2d(80, 192, kernel_size=3, stride=1)
+        self.conv2d_4b = BasicConv2d(192, 256, kernel_size=3, stride=2)
+        self.repeat_1 = nn.Sequential(
+            Block35(scale=0.17),
+            Block35(scale=0.17),
+            Block35(scale=0.17),
+            Block35(scale=0.17),
+            Block35(scale=0.17),
+        )
+        self.mixed_6a = Mixed_6a()
+        self.repeat_2 = nn.Sequential(
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+            Block17(scale=0.10),
+        )
+        self.mixed_7a = Mixed_7a()
+        self.repeat_3 = nn.Sequential(
+            Block8(scale=0.20),
+            Block8(scale=0.20),
+            Block8(scale=0.20),
+            Block8(scale=0.20),
+            Block8(scale=0.20),
+        )
+        self.block8 = Block8(noReLU=True)
+        self.avgpool_1a = nn.AdaptiveAvgPool2d(1)
+        self.dropout = nn.Dropout(dropout_prob)
+        self.last_linear = nn.Linear(1792, 512, bias=False)
+        self.last_bn = nn.BatchNorm1d(512, eps=0.001, momentum=0.1, affine=True)
+        self.logits = nn.Linear(512, self.num_classes)
+        load_weights(self)
+
+        self.device = torch.device('cpu')
+        if device is not None:
+            self.device = device
+            self.to(device)
+
+    def forward(self, x):
+        """Calculate embeddings or logits given a batch of input image tensors.
+
+        Arguments:
+            x {torch.tensor} -- Batch of image tensors representing faces.
+
+        Returns:
+            torch.tensor -- Batch of embedding vectors or multinomial logits.
+        """
+        x = self.conv2d_1a(x)
+        x = self.conv2d_2a(x)
+        x = self.conv2d_2b(x)
+        x = self.maxpool_3a(x)
+        x = self.conv2d_3b(x)
+        x = self.conv2d_4a(x)
+        x = self.conv2d_4b(x)
+        x = self.repeat_1(x)
+        x = self.mixed_6a(x)
+        x = self.repeat_2(x)
+        x = self.mixed_7a(x)
+        x = self.repeat_3(x)
+        x = self.block8(x)
+        x = self.avgpool_1a(x)
+        x = self.dropout(x)
+        x = self.last_linear(x.view(x.shape[0], -1))
+        x = self.last_bn(x)
+        if self.classify:
+            x = self.logits(x)
+        else:
+            x = F.normalize(x, p=2, dim=1)
+        return x
+
+
+def load_weights(mdl):
+    features_path = state_dict_path = os.path.join(os.path.dirname(__file__), 'vggface2-dict/20180402-114759-vggface2-features.pt')
+    logits_path = state_dict_path = os.path.join(os.path.dirname(__file__), 'vggface2-dict/20180402-114759-vggface2-logits.pt')
+    state_dict = {}
+    for i, path in enumerate([features_path, logits_path]):
+        state_dict.update(torch.load(path))
+    mdl.load_state_dict(state_dict)
+
+
+def get_torch_home():
+    torch_home = os.path.expanduser(
+        os.getenv(
+            'TORCH_HOME',
+            os.path.join(os.getenv('XDG_CACHE_HOME', '~/.cache'), 'torch')
+        )
+    )
+    return torch_home

+import torch
+import numpy as np
+import time
+
+
+class Logger(object):
+
+    def __init__(self, mode, length, calculate_mean=False):
+        self.mode = mode
+        self.length = length
+        self.calculate_mean = calculate_mean
+        if self.calculate_mean:
+            self.fn = lambda x, i: x / (i + 1)
+        else:
+            self.fn = lambda x, i: x
+
+    def __call__(self, loss, metrics, i):
+        track_str = '\r{} | {:5d}/{:<5d}| '.format(self.mode, i + 1, self.length)
+        loss_str = 'loss: {:9.4f} | '.format(self.fn(loss, i))
+        metric_str = ' | '.join('{}: {:9.4f}'.format(k, self.fn(v, i)) for k, v in metrics.items())
+        print(track_str + loss_str + metric_str + '   ', end='')
+        if i + 1 == self.length:
+            print('')
+
+
+class BatchTimer(object):
+    """Batch timing class.
+    Use this class for tracking training and testing time/rate per batch or per sample.
+    
+    Keyword Arguments:
+        rate {bool} -- Whether to report a rate (batches or samples per second) or a time (seconds
+            per batch or sample). (default: {True})
+        per_sample {bool} -- Whether to report times or rates per sample or per batch.
+            (default: {True})
+    """
+
+    def __init__(self, rate=True, per_sample=True):
+        self.start = time.time()
+        self.end = None
+        self.rate = rate
+        self.per_sample = per_sample
+
+    def __call__(self, y_pred, y):
+        self.end = time.time()
+        elapsed = self.end - self.start
+        self.start = self.end
+        self.end = None
+
+        if self.per_sample:
+            elapsed /= len(y_pred)
+        if self.rate:
+            elapsed = 1 / elapsed
+
+        return torch.tensor(elapsed)
+
+
+def accuracy(logits, y):
+    _, preds = torch.max(logits, 1)
+    return (preds == y).float().mean()
+
+
+def pass_epoch(
+    model, loss_fn, loader, optimizer=None, scheduler=None,
+    batch_metrics={'time': BatchTimer()}, show_running=True,
+    device='cpu', writer=None
+):
+    """Train or evaluate over a data epoch.
+    
+    Arguments:
+        model {torch.nn.Module} -- Pytorch model.
+        loss_fn {callable} -- A function to compute (scalar) loss.
+        loader {torch.utils.data.DataLoader} -- A pytorch data loader.
+    
+    Keyword Arguments:
+        optimizer {torch.optim.Optimizer} -- A pytorch optimizer.
+        scheduler {torch.optim.lr_scheduler._LRScheduler} -- LR scheduler (default: {None})
+        batch_metrics {dict} -- Dictionary of metric functions to call on each batch. The default
+            is a simple timer. A progressive average of these metrics, along with the average
+            loss, is printed every batch. (default: {{'time': iter_timer()}})
+        show_running {bool} -- Whether or not to print losses and metrics for the current batch
+            or rolling averages. (default: {False})
+        device {str or torch.device} -- Device for pytorch to use. (default: {'cpu'})
+        writer {torch.utils.tensorboard.SummaryWriter} -- Tensorboard SummaryWriter. (default: {None})
+    
+    Returns:
+        tuple(torch.Tensor, dict) -- A tuple of the average loss and a dictionary of average
+            metric values across the epoch.
+    """
+    
+    mode = 'Train' if model.training else 'Valid'
+    logger = Logger(mode, length=len(loader), calculate_mean=show_running)
+    loss = 0
+    metrics = {}
+
+    for i_batch, (x, y) in enumerate(loader):
+        x = x.to(device)
+        y = y.to(device)
+        y_pred = model(x)
+        loss_batch = loss_fn(y_pred, y)
+
+        if model.training:
+            loss_batch.backward()
+            optimizer.step()
+            optimizer.zero_grad()
+
+        metrics_batch = {}
+        for metric_name, metric_fn in batch_metrics.items():
+            metrics_batch[metric_name] = metric_fn(y_pred, y).detach().cpu()
+            metrics[metric_name] = metrics.get(metric_name, 0) + metrics_batch[metric_name]
+            
+        if writer is not None and model.training:
+            if writer.iteration % writer.interval == 0:
+                writer.add_scalars('loss', {mode: loss_batch.detach().cpu()}, writer.iteration)
+                for metric_name, metric_batch in metrics_batch.items():
+                    writer.add_scalars(metric_name, {mode: metric_batch}, writer.iteration)
+            writer.iteration += 1
+        
+        loss_batch = loss_batch.detach().cpu()
+        loss += loss_batch
+        if show_running:
+            logger(loss, metrics, i_batch)
+        else:
+            logger(loss_batch, metrics_batch, i_batch)
+    
+    if model.training and scheduler is not None:
+        scheduler.step()
+
+    loss = loss / (i_batch + 1)
+    metrics = {k: v / (i_batch + 1) for k, v in metrics.items()}
+            
+    if writer is not None and not model.training:
+        writer.add_scalars('loss', {mode: loss.detach()}, writer.iteration)
+        for metric_name, metric in metrics.items():
+            writer.add_scalars(metric_name, {mode: metric})
+
+    return loss, metrics
+
+
+def collate_pil(x): 
+    out_x, out_y = [], [] 
+    for xx, yy in x: 
+        out_x.append(xx) 
+        out_y.append(yy) 
+    return out_x, out_y 

+import os
+import torch
+import numpy as np
+import asyncio
+import json
+import base64
+import websockets
+from io import BytesIO
+
+import pymysql
+from datetime import datetime
+
+from PIL import Image, ImageDraw
+from IPython import display
+
+from models.mtcnn import MTCNN
+from models.inception_resnet_v1 import InceptionResnetV1
+
+device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
+print('Running on device: {}'.format(device))
+
+model = InceptionResnetV1().eval().to(device)
+attendance_db = pymysql.connect(
+    user='root', 
+    passwd='1234', 
+    host='localhost', 
+    db='attendance', 
+    charset='utf8'
+)
+
+lock = asyncio.Lock()
+clients = set()
+#processes = []
+
+async def get_embeddings(face_list):
+  global model
+  x = torch.Tensor(face_list).to(device)
+  yhat = model(x)
+  return yhat
+
+async def get_distance(arr1, arr2):
+    distance = np.linalg.norm(arr1 - arr2)
+    return distance
+
+async def get_cosine_similarity(arr1, arr2):
+    similarity = np.inner(arr1, arr2) / (np.linalg.norm(arr1) * np.linalg.norm(arr2))
+    return similarity
+
+async def register(websocket):
+    global lock
+    global clients
+    async with lock:
+        clients.add(websocket)
+        remote_ip = websocket.remote_address[0]
+        msg='[{ip}] connected'.format(ip=remote_ip)
+        print(msg)
+
+async def unregister(websocket):
+    global lock
+    global clients
+    async with lock:
+        clients.remove(websocket)
+        remote_ip = websocket.remote_address[0]
+        msg='[{ip}] disconnected'.format(ip=remote_ip)
+        print(msg)
+
+async def thread(websocket, path):
+    await register(websocket)
+    try:
+        async for message in websocket:
+            data = json.loads(message)
+            remote_ip = websocket.remote_address[0]
+            if data['action'] == 'register':
+                # log
+                msg='[{ip}] register face'.format(ip=remote_ip)
+                print(msg)
+
+                # load json
+                student_id = data['student_id']
+                student_name = data['student_name']
+                face = np.asarray(data['MTCNN'], dtype = np.float32)
+                face = face.reshape((1,3,160,160))
+
+                # DB에 연결
+                cursor = attendance_db.cursor(pymysql.cursors.DictCursor)
+
+                # 학생을 찾음
+                sql = "SELECT student_id FROM student WHERE student_id = %s;"
+                cursor.execute(sql, (student_id))
+
+                # DB에 학생이 없으면 등록
+                if not cursor.fetchone():
+                    sql = "INSERT INTO student(student_id, student_name) VALUES (%s, %s)"
+                    cursor.execute(sql, (student_id, student_name))
+                    sql = "INSERT INTO lecture_students(lecture_id, student_id) VALUES (%s, %s)"
+                    cursor.execute(sql, ('0', student_id))
+                    msg='[{ip}] {id} is registered'.format(ip=remote_ip, id=student_id)
+                    print(msg)
+
+                # student_embedding Table에 등록
+                embedding = await get_embeddings(face)
+                embedding = embedding.detach().numpy().tobytes()
+                embedding_date = datetime.now().strftime('%Y-%m-%d')
+                sql = "insert into student_embedding(student_id, embedding_date, embedding) values (%s, %s, _binary %s)"
+                cursor.execute(sql, (student_id, embedding_date, embedding))
+                attendance_db.commit()
+                send = json.dumps({'status': 'success', 'student_id': student_id})
+                await websocket.send(send)
+
+            elif data['action'] == 'verify':
+                # log
+                msg='[{ip}] verify face'.format(ip=remote_ip)
+                print(msg)
+
+                # load json
+                face = np.asarray(data['MTCNN'], dtype = np.float32)
+                face = face.reshape((1,3,160,160))
+
+                embedding = await get_embeddings(face)
+                embedding = embedding.detach().numpy()
+
+                # 가장 비슷한 Embedding을 찾는 SQL
+                cursor = attendance_db.cursor(pymysql.cursors.DictCursor)
+                sql = "SELECT student_id, embedding FROM student_embedding;"
+                cursor.execute(sql)
+                result = cursor.fetchall()
+                verified_id = '0'
+                distance_min = 99
+                for row_data in result:
+                    db_embedding = np.frombuffer(row_data['embedding'], dtype=np.float32)
+                    db_embedding = db_embedding.reshape((1,512))
+                    distance = await get_distance(embedding, db_embedding)
+                    if (distance < distance_min):
+                        verified_id = row_data['student_id']
+                        distance_min = distance
+
+                # 출석 데이터 전송
+                print('[debug] distance:', distance_min)
+                send = ''
+                if distance_min < 0.4:
+                    # 인증 성공
+                    # 오늘 이미 출석 됐는지 확인
+                    sql = "SELECT DATE(timestamp) FROM student_attendance WHERE (lecture_id=%s) AND (student_id=%s) AND (DATE(timestamp) = CURDATE());"
+                    cursor.execute(sql, ('0', verified_id))
+                    
+                    # 출석 기록이 없는 경우에만
+                    if not cursor.fetchone():
+                        # 테이블 맨 뒤에 datetime attribute가 있음. 서버 시간 가져오게 default로 설정해둠.
+                        sql = "INSERT INTO student_attendance(lecture_id, student_id, status) VALUES (%s, %s, %s)"
+                        # TODO: attend / late 처리
+                        cursor.execute(sql, ('0', verified_id, 'attend'))
+                        attendance_db.commit()
+                        # log 작성
+                        msg='[{ip}] verification success {id}'.format(ip=remote_ip, id=verified_id)
+                        print(msg)
+                        send = json.dumps({'status': 'success', 'student_id': verified_id})
+                    else:
+                        msg='[{ip}] verification failed: {id} is already verified'.format(ip=remote_ip, id=verified_id)
+                        print(msg)
+                        send = json.dumps({'status': 'already', 'student_id': verified_id})
+                else:
+                    # 인증 실패
+                    msg='[{ip}] verification failed'.format(ip=remote_ip)
+                    print(msg)
+                    send = json.dumps({'status': 'fail'})                    
+                await websocket.send(send)
+            elif data['action'] == "save_image":
+                # 출석이 제대로 이뤄지지 않으면 이미지를 저장하여
+                # 나중에 교강사가 출석을 확인할 수 있도록 한다
+                msg='[{ip}] save image'.format(ip=remote_ip)
+                print(msg)
+                arr = np.asarray(data['image'], dtype = np.uint8)
+                blob = arr.tobytes()
+                # TODO: lecture DB에 tuple 삽입해야 아래 코드가 돌아감
+                # 테이블 맨 뒤에 datetime attribute가 있음. 서버 시간 가져오게 default로 설정해둠.
+                cursor = attendance_db.cursor(pymysql.cursors.DictCursor)
+                sql = "INSERT INTO undefined_image(lecture_id, image, width, height) VALUES (%s, _binary %s, %s, %s)"
+                cursor.execute(sql, ('0', blob, arr.shape[0], arr.shape[1]))
+                attendance_db.commit()
+            else:
+                print("unsupported event: {}", data)
+    finally:
+        await unregister(websocket)
+
+print('run verification server')
+start_server = websockets.serve(thread, '0.0.0.0', 8765)
+asyncio.get_event_loop().run_until_complete(start_server)
+asyncio.get_event_loop().run_forever()