Major refactoring of views.py and other files thanks to pylint use and google python development guide

Author: marcogdepinto

App/__pycache__/models.cpython-36.pyc

@@ -1,8 +1,19 @@
 from django.db import models
 from django.conf import settings
+from django.dispatch import receiver
+from django.db.models.signals import post_delete
 
 
 class FileModel(models.Model):
     file = models.FileField(null=True, blank=True)
     timestamp = models.DateTimeField(auto_now_add=True)
     path = models.FilePathField(path=settings.MEDIA_ROOT, default=settings.MEDIA_ROOT)
+
+
+@receiver(post_delete, sender=FileModel)
+def submission_delete(sender, instance, **kwargs):
+    """
+    This function is used to delete attachments when a file object is deleted.
+    Django does not do this automatically.
+    """
+    instance.file.delete(False)

App/__pycache__/tests.cpython-36.pyc

@@ -19,10 +19,13 @@ <h2>Deep Learning to predict human emotions.</h2>
         </div>
         <div class="container" id="Container1">
           <div class="row">
-            <div class="col-sm-6 text-center" id="FileUpload">
+            <div class="col-sm-4 text-center" id="FileUpload">
               <a href="{% url 'upload_file' %}" class="btn btn-primary">Upload your audio file</a>
             </div>
-            <div class="col-sm-6 text-center" id="makePredictions">
+            <div class="col-sm-4 text-center" id="FileDelete">
+              <a href="{% url 'file_delete' %}" class="btn btn-primary">Delete a file from the server</a>
+            </div>
+            <div class="col-sm-4 text-center" id="makePredictions">
               <a href="{% url 'file_select' %}" class="btn btn-primary">Make your prediction</a>
             </div>
           </div>

App/__pycache__/urls.cpython-36.pyc

@@ -0,0 +1,15 @@
+{% extends "index.html" %}
+
+{% block content %}
+    <form action="/App/delete/" method="post" enctype="multipart/form-data">
+        {% csrf_token %}
+        {{ form.as_p }}
+        <p>Please select one file at a time from the list below to delete it from the server.</p>
+        <p>The list includes the files already available on the server.</p>
+        {% for myfile in filename %}
+          <input type="checkbox" name="file_name" value="{{ myfile }}">{{ myfile }}<br>
+        {% endfor %}
+        <br>
+        <button type="submit" class="btn btn-primary">Delete</button>
+    </form>
+{% endblock %}

App/__pycache__/views.cpython-36.pyc

@@ -1,11 +1,16 @@
+"""
+tests.py includes all the test of the application.
+"""
+
 import os
-from App.views import Predict
+
 from django.test import TestCase
 from rest_framework.request import Request
 from rest_framework.test import APIRequestFactory
 from rest_framework.parsers import MultiPartParser, FormParser
 from django.core.files.uploadedfile import SimpleUploadedFile
 
+from App.views import Predict
 from App.forms import FileForm
 
 
@@ -90,6 +95,13 @@ def testselectfile(self):
         file_name_dir = 'App/templates/select_file_predictions.html'
         assert os.path.isfile(file_name_dir)
 
+    def testdeletefile(self):
+        """
+        Ensure a select_file_predictions template exists
+        """
+        file_name_dir = 'App/templates/select_file_deletion.html'
+        assert os.path.isfile(file_name_dir)
+
 
 class TestForm(TestCase):
 

App/models.py

@@ -1,11 +1,12 @@
-from App.views import Predict, FileView
+from App.views import Predict, FileView, FileDeleteView
 from django.conf.urls import url
 
 app_name = 'App'
 
 urlpatterns = [
     url(r'^predict/$', Predict.as_view(), name="APIpredict"),
     url(r'^upload/$', FileView.as_view(), name='APIupload'),
+    url(r'^delete/$', FileDeleteView.as_view(), name='APIupload'),
 ]
 
 

App/templates/index.html

@@ -1,20 +1,30 @@
+"""
+views.py includes the main business logic of the application.
+Its role is to manage file upload, deletion and predictions.
+"""
+
 import os
+from os import listdir
+from os.path import join
+from os.path import isfile
+
 import keras
 import librosa
 import numpy as np
-from os import listdir
 import tensorflow as tf
-from App.models import FileModel
-from rest_framework import views
 from django.conf import settings
-from os.path import isfile, join
-from rest_framework import status
-from App.serialize import FileSerializer
-from rest_framework.response import Response
 from django.views.generic import TemplateView
 from django.views.generic.edit import CreateView
+from rest_framework import views
+from rest_framework import status
+from rest_framework import generics
+from rest_framework.parsers import FormParser
+from rest_framework.parsers import MultiPartParser
+from rest_framework.response import Response
 from rest_framework.renderers import TemplateHTMLRenderer
-from rest_framework.parsers import MultiPartParser, FormParser
+
+from App.models import FileModel
+from App.serialize import FileSerializer
 
 
 class IndexView(TemplateView):
@@ -48,7 +58,29 @@ class SelectPredFileView(TemplateView):
     The server will return the predictions.
     """
 
-    template_name = "select_file_predictions.html"
+    template_name = 'select_file_predictions.html'
+    parser_classes = FormParser
+    queryset = FileModel.objects.all()
+
+    def get_context_data(self, **kwargs):
+        """
+        This function is used to render the list of file in the MEDIA_ROOT in the html template.
+        """
+        context = super().get_context_data(**kwargs)
+        media_path = settings.MEDIA_ROOT
+        myfiles = [f for f in listdir(media_path) if isfile(join(media_path, f))]
+        context['filename'] = myfiles
+        return context
+
+
+class SelectFileDelView(TemplateView):
+    """
+    This view is used to select a file from the list of files in the server.
+    After the selection, it will send the file to the server.
+    The server will delete the file.
+    """
+    template_name = 'select_file_deletion.html'
+
     parser_classes = FormParser
     queryset = FileModel.objects.all()
 
@@ -65,8 +97,8 @@ def get_context_data(self, **kwargs):
 
 class FileView(views.APIView):
     """
-    This class contains the method to upload and delete a file interacting directly with the API.
-    POST and DELETE request are accepted.
+    This class contains the method to upload a file interacting directly with the API.
+    POST requests are accepted.
     """
     parser_classes = (MultiPartParser, FormParser)
     queryset = FileModel.objects.all()
@@ -79,34 +111,52 @@ def upload(self, request):
         if file_serializer.is_valid():
             # TODO: implement a check to see if the file is already on the server
             file_serializer.save()
-            return Response(file_serializer.data, status=status.HTTP_201_CREATED)
+            response = Response(file_serializer.data, status=status.HTTP_201_CREATED)
         else:
-            return Response(file_serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+            response = Response(file_serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
-    def delete(self, request):
-        # TODO: Implement
-        raise NotImplementedError
+        return response
+
+
+class FileDeleteView(generics.RetrieveDestroyAPIView):
+    """
+    This class contains the method to delete a file interacting directly with the API.
+    DELETE requests are accepted.
+    """
+
+    parser_classes = FormParser
+    queryset = FileModel.objects.all()
+
+    def post(self, request):
+        """
+        This method will be used to delete files from the server.
+        """
+        # TODO: complete, not working (error: type "object" is not iterable)
+        filename = request.POST.getlist('file_name').pop()
+        getfile = FileModel.objects.filter(name__in=filename)
+        getfile.file.delete()
+        return getfile
 
 
 class Predict(views.APIView):
     """
     This class is used to making predictions.
 
     Example of input:
-    {"filename": "01-01-01-01-01-01-01.wav"}
+    {'filename': '01-01-01-01-01-01-01.wav'}
 
     Example of output:
-    [["neutral"]]
+    [['neutral']]
     """
 
     template_name = 'index.html'
+    # Removing this shows the API view to the user instead of the template.
     renderer_classes = [TemplateHTMLRenderer]
 
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
         modelname = 'Emotion_Voice_Detection_Model.h5'
-        global graph
-        graph = tf.get_default_graph()
+        self.graph = tf.get_default_graph()
         self.loaded_model = keras.models.load_model(os.path.join(settings.MODEL_ROOT, modelname))
         self.predictions = []
 
@@ -118,26 +168,28 @@ def file_elaboration(self, filepath):
         """
         data, sampling_rate = librosa.load(filepath)
         try:
-            mfccs = np.mean(librosa.feature.mfcc(y=data, sr=sampling_rate, n_mfcc=40).T, axis=0)
-            x = np.expand_dims(mfccs, axis=2)
-            x = np.expand_dims(x, axis=0)
-            numpred = self.loaded_model.predict_classes(x)
+            mfccs = np.mean(librosa.feature.mfcc(y=data, sr=sampling_rate,
+                                                 n_mfcc=40).T, axis=0)
+            training_data = np.expand_dims(mfccs, axis=2)
+            training_data_expanded = np.expand_dims(training_data, axis=0)
+            numpred = self.loaded_model.predict_classes(training_data_expanded)
             self.predictions.append([self.classtoemotion(numpred)])
             return self.predictions
-        except Exception as err:
+        except ValueError as err:
             return Response(str(err), status=status.HTTP_400_BAD_REQUEST)
 
     def post(self, request):
         """
-        This method is used to making predictions on audio files previously loaded with FileView.post
+        This method is used to making predictions on audio files
+        loaded with FileView.post
         """
-        with graph.as_default():
+        with self.graph.as_default():
             filename = request.POST.getlist('file_name').pop()
             filepath = str(os.path.join(settings.MEDIA_ROOT, filename))
             predictions = self.file_elaboration(filepath)
             try:
                 return Response({'predictions': predictions.pop()})
-            except Exception as err:
+            except ValueError as err:
                 return Response(str(err), status=status.HTTP_400_BAD_REQUEST)
 
         return Response(predictions, status=status.HTTP_200_OK)
@@ -150,20 +202,20 @@ def classtoemotion(pred):
         ::output:: A string label
 
         Example:
-        >>> classtoemotion(0) == neutral
+        classtoemotion(0) == neutral
         """
 
-        label_conversion = {"0": "neutral",
-                            "1": "calm",
-                            "2": "happy",
-                            "3": "sad",
-                            "4": "angry",
-                            "5": "fearful",
-                            "6": "disgust",
-                            "7": "surprised"}
+        label_conversion = {'0': 'neutral',
+                            '1': 'calm',
+                            '2': 'happy',
+                            '3': 'sad',
+                            '4': 'angry',
+                            '5': 'fearful',
+                            '6': 'disgust',
+                            '7': 'surprised'}
 
-        for key in label_conversion.keys():
+        for key, value in label_conversion.items():
             if int(key) == pred:
-                return label_conversion[key]
-            else:
-                continue
+                label = value
+
+        return label