Add ISBN data downloader

media/forms.py

@@ -2,6 +2,9 @@
 # Copyright (C) 2017-2019 by BDE ENS Paris-Saclay
 # SPDX-License-Identifier: GPL-3.0-or-later
 
+import json
+import urllib.request
+
 from django.forms import ModelForm
 
 from .models import Emprunt
@@ -11,3 +14,45 @@ class EmpruntForm(ModelForm):
     class Meta:
         model = Emprunt
         fields = ['media']
+
+
+class MediaAdminForm(ModelForm):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.fields['isbn'].widget.template_name = "media/isbn_button.html"
+
+    def download_data(self, isbn):
+        """
+        Download data from ISBN
+        """
+        api_url = "https://openlibrary.org/api/books?bibkeys=ISBN:{}" \
+                  "&format=json&jscmd=data".format(isbn)
+        with urllib.request.urlopen(api_url) as url:
+            data = json.loads(url.read().decode())
+        if data and data['ISBN:' + isbn]:
+            data = data['ISBN:' + isbn]
+
+            # Fill the data
+            # TODO implement authors
+            if data['title']:
+                self.cleaned_data['title'] = data['title']
+                self.cleaned_data['side_title'] = data['title']
+            if data['subtitle']:
+                self.cleaned_data['subtitle'] = data['subtitle']
+            if data['url']:
+                self.cleaned_data['external_url'] = data['url']
+            if data['number_of_pages']:
+                self.cleaned_data['number_of_pages'] = \
+                    data['number_of_pages']
+
+    def clean(self):
+        """
+        If user fetch ISBN data, then download data before validating the form
+        """
+        if "_continue" in self.request.POST:
+            isbn = self.cleaned_data.get('isbn')
+            if isbn:
+                # ISBN is present
+                self.download_data(isbn)
+
+        return super().clean()