worked on updating html elements and fixing some bugs with switching charts

1 files changed, 30 insertions, 6 deletions

diff --git a/api.py b/api.py
index 0625f1a..00c2733 100644
--- a/api.py
+++ b/api.py
@@ -1,10 +1,9 @@
 import requests
 import json
-
 """
 Given the parameters, 
 fetches the data for the corresponding chart using yahoo finance.
-Expect it to raise an error on bad params!
+If bad request, returns the previous chart.
 """
 def fetch_chart_data(ticker, period='1y', interval='1d'):
     params = {
@@ -19,20 +18,45 @@ def fetch_chart_data(ticker, period='1y', interval='1d'):
     print("status_code:\t", r.status_code)
 
     # decode the JSON response data into a Python object
-    r.raise_for_status() # raises if error before parsing
+    try:
+        r.raise_for_status() # raises if error before parsing
+    except:
+        last_data = pull_last_from_file()
+        last_data['error'] = True
+        return last_data
+    
     data_obj = r.json()
 
     # get the specific data we want
     timestamps = data_obj['chart']['result'][0]['timestamp']
     close_prices = data_obj['chart']['result'][0]['indicators']['quote'][0]['close']
-    print('close_price len: ', len(close_prices), 'timestamps len: ', len(timestamps))
+    
     # clean out null's and 0s from the data
-    for i in range(len(timestamps)):
+    i = 0
+    while i < len(timestamps):
         if close_prices[i] == None or close_prices[i] == 0:
             del close_prices[i]
             del timestamps[i]
             i -= 1
+        i += 1
     
     name = data_obj['chart']['result'][0]['meta']['longName']
 
-    return {'timestamps': timestamps, 'prices': close_prices, 'name': name}
\ No newline at end of file
+    data = {'timestamps': timestamps, 'prices': close_prices, 'name': name, 'error': False}
+
+    update_last_file(data)
+    # save data to file in case necessary
+    return data
+
+# helper function to pull most recent chart data on failure
+def pull_last_from_file():
+    fd = open('last_chart_data.json', 'r')
+    d = json.loads(fd.read())
+    fd.close()
+    return d
+    
+def update_last_file(data):
+    fd = open('last_chart_data.json', 'w')
+    fd.truncate(0)
+    fd.write(json.dumps(data))
+    fd.close()
\ No newline at end of file