Question

此地理编码代码在本地运行，但不在服务器中运行，它以self.request.get('address')的形式获取地址，并从ndb.GeoPt()函数返回get_lat_long(address)值。

那么，我怎么得到错误：

Traceback (most recent call last):
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1535, in __call__
    rv = self.handle_exception(request, response, e)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1529, in __call__
    rv = self.router.dispatch(request, response)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "/base/data/home/apps/s~map-jobs/2.371278632227250958/main.py", line 453, in post
    profile.geopoint = get_lat_long(self.request.get('address'))
  File "/base/data/home/apps/s~map-jobs/2.371278632227250958/main.py", line 17, in get_lat_long
    lat = data['results'][0]['geometry']['location']['lat']
IndexError: list index out of range

使用此代码：

def get_lat_long(address):
  address = cgi.escape(address.replace(" ","+"))
  sensor = "true"
  url = "http://maps.googleapis.com/maps/api/geocode/json?address=" + address + "&sensor="+ sensor
  result = urlfetch.fetch(url)
  data = json.loads(result.content)
  lat = data['results'][0]['geometry']['location']['lat']
  long = data['results'][0]['geometry']['location']['lng']
  return ndb.GeoPt(str(lat) +","+ str(long))

在google-app-engine服务器中写这个的正确方法是什么？

Answer 1

data['results'][0]实际上是空的。

当不是结果时会发生这种情况。通常，我只是将其放在try/catch块中，除了IndexError：

try:
    data['results'][0]....
except IndexError, e:
    print "No data found"  # You can use a logger here too

在您的情况下，在以下代码周围放置try/catch块，并找到处理错误的方法：

  lat = data['results'][0]['geometry']['location']['lat']
  long = data['results'][0]['geometry']['location']['lng']

当我使用谷歌驱动器时，这件事发生在我身上，因为很多doucments没有text/html作为输出格式，我总是得到KeyError。在您的情况下，您正在处理谷歌地图，如果结果应该 geometry和dict中的其他键，但是，您也可以选择将KeyError添加到您的except子句中，以便更加谨慎。

Answer 2

您可以使用len()检查索引是否存在。

在GAE中列出IndexError超出范围

2 个答案: