allow for loading one set only

scripts/update_cards.py

-from urllib.request import Request, urlopen
+from urllib.request import Request, urlopen, HTTPError
 import json
+import sys
+import shutil
+from pathlib import Path
 
 def save(name, data):
     with open(name, 'w', encoding = 'utf8') as file:
         json.dump(data, file, ensure_ascii = False, indent = 4, sort_keys = True)
 
-def download():
+def download(url):
     cards = list()
     page = 1
     nonEmpty = True
     while nonEmpty:
-        request_url = 'https://api.magicthegathering.io/v1/cards?page={}'.format(page)
+        request_url = '{}page={}'.format(url, page)
         print('Loading page {}...'.format(page))
         try:
             req = Request(request_url, headers={'User-Agent': 'Mozilla/5.0'})
             if nonEmpty:
                 cards.extend(cardsPage)
                 page += 1
-        except HTTPError:
-            print ('Failed at page {}'.format(page))
+        except HTTPError as e:
+            print ('Failed at page {}: {}'.format(page, e.reason))
     return cards
 
-# Can load or download and save card info
+names = {}
+oracle = {}
+oracle_file_name = 'data/oracle.json'
+names_file_name = 'data/names.json'
 
-# Load
-#with open('data/cards.json') as file:
-#    cards = json.load(file)
 
-# Download and save for the future
-cards = download()
-#save('data/cards.json', cards)
+def download_all():
+    print ("downloading the whole card set")
+    return download('https://api.magicthegathering.io/v1/cards?')
 
-languages = ['Russian']
-ignore = [
-    {'language': 'Russian', 'name': 'Plunder'},
-    {'language': 'Russian', 'name': 'Goblin Spelunkers'},
-    {'language': 'Russian', 'name': 'Raise Dead'},
-]
-copy = ['name', 'flavor', 'power', 'toughness', 'colors', 'printings', 'legality', 'manaCost', 'subtypes', 'text', 'layout', 'colorIdentity', 'type', 'types', 'cmc', 'loyalty', 'rulings']
 
-names = {}
-oracle = {}
+def download_set(set_name):
+    print ("downloading set {}".format(set_name))
+    return download('https://api.magicthegathering.io/v1/cards?set={}&'.format(set_name))
+
+
+def process_cards(cards):
+    languages = ['Russian']
+    ignore = [
+        {'language': 'Russian', 'name': 'Plunder'},
+        {'language': 'Russian', 'name': 'Goblin Spelunkers'},
+        {'language': 'Russian', 'name': 'Raise Dead'},
+    ]
+    copy = ['name', 'flavor', 'power', 'toughness', 'colors', 'printings', 'legality', 'manaCost', 'subtypes', 'text', 'layout', 'colorIdentity', 'type', 'types', 'cmc', 'loyalty', 'rulings']
+    for card in cards:
+        if card['name'] in names:
+            if not card['name'] in names[card['name']]:
+                names[card['name']].append(card['name'])
+            else:
+                names[card['name']] = [card['name']]
+
+        if 'foreignNames' in card:
+            for translation in card['foreignNames']:
+                if translation['name'] and translation['language'] in languages and not {'language': translation['language'], 'name': card['name']} in ignore:
+                    if translation['name'] in names:
+                        if not card['name'] in names[translation['name']]:
+                            print('{} version of "{}": "{}" is named as another card "{}"'.format(translation['language'], card['name'], translation['name'], names[translation['name']]))
+                            names[translation['name']].append(card['name'])
 
-for card in cards:
-    if card['name'] in names:
-        if not card['name'] in names[card['name']]:
-            names[card['name']].append(card['name'])
-    else:
-        names[card['name']] = [card['name']]
+                    else:
+                        names[translation['name']] = [card['name']]
 
-    if 'foreignNames' in card:
-        for translation in card['foreignNames']:
-            if translation['name'] and translation['language'] in languages and not {'language': translation['language'], 'name': card['name']} in ignore:
-                if translation['name'] in names:
-                    if not card['name'] in names[translation['name']]:
-                        print('{} version of "{}": "{}" is named as another card "{}"'.format(translation['language'], card['name'], translation['name'], names[translation['name']]))
-                        names[translation['name']].append(card['name'])
+        if not card['name'] in oracle:
+            oracle[card['name']] = {k: card[k] for k in card if k in copy}
 
-                else:
-                  names[translation['name']] = [card['name']]
 
-    if not card['name'] in oracle:
-        oracle[card['name']] = {k: card[k] for k in card if k in copy}
+def backup_data_files():
+    try:
+        shutil.copyfile(oracle_file_name, oracle_file_name + ".bak")
+        shutil.copyfile(names_file_name, names_file_name + '.bak')
+        return True
+    except shutil.Error:
+        return False
 
+
+if len(sys.argv) == 2:
+    if not Path(oracle_file_name).is_file() or not Path(names_file_name).is_file():
+        print("oracle of name files don't exist. Exiting")
+        exit()
+
+    if not backup_data_files():
+        print("failed to create backup files. Exiting")
+        exit()
+
+    with open(names_file_name) as file:
+        names = json.load(file)
+    with open(oracle_file_name) as file:
+        oracle = json.load(file)
+
+    cards = download_set(sys.argv[1])
+else:
+    cards = download_all()
+
+process_cards(cards)
 save('data/names.json', names)
 save('data/oracle.json', oracle)
-