TypeError:类型为“NoneType”的对象在应用程序部署中没有len（）Python

Question

我只是在学习python，并尝试运行我的应用程序，但得到以下结果：

Traceback (most recent call last):
  File "/Users/plugins/bluegreen.py", line 433, in <module>
    cnames = [bluegreen.get_cname(green), bluegreen.get_cname(blue)]
  File "/Users/plugins/bluegreen.py", line 66, in get_cname
    if len(data.get("cname")) == 0:
TypeError: object of type 'NoneType' has no len()

以下是第66行和第433行的内容：

66:

def get_cname(self, app):
    response = self.get("/apps/{}".format(app))
    data = json.loads(response.read())
    if len(data.get("cname")) == 0:
      return None
    return data.get("cname")

433：

cnames = [bluegreen.get_cname(green), bluegreen.get_cname(blue)]

编辑1:

如果我放置一个打印（数据），我会得到以下信息：

{u'entrypoints': [], u'routeropts': {}, u'description': u'', u'repository': u'git@10.10.1.1.nip.io:hello-green.git', u'tags': [], u'lock': {u'Owner': u'', u'Reason': u'', u'AcquireDate': u'0001-01-01T00:00:00Z', u'Locked': False}, u'routers': [{u'type': u'traefik', u'name': u'traefik', u'opts': {}, u'address': u'hello-green.10.10.1.1.nip.io'}], u'deploys': 0, u'routingsettings': None, u'teams': [u'admin'], u'platform': u'go', u'teamowner': u'admin', u'plan': {u'router': u'traefik', u'swap': 0, u'cpushare': 100, u'name': u'autogenerated', u'memory': 0}, u'ip': u'hello-green.10.10.1.1.nip.io', u'owner': u'admin@shipa.io', u'router': u'traefik', u'units': [], u'pool': u'gce', u'name': u'hello-green'}
Traceback (most recent call last):
  File "/Users/brunoandrade/.shipa/plugins/bluegreen.py", line 434, in <module>
    cnames = [bluegreen.get_cname(green), bluegreen.get_cname(blue)]
  File "/Users/brunoandrade/.shipa/plugins/bluegreen.py", line 67, in get_cname
    if len(data.get("cname")) == 0:
TypeError: object of type 'NoneType' has no len()

编辑2:

不知道为什么我没有得到cname密钥，因为我在这里得到它：

  config = Config.load('shipa-bluegreen.ini')

  app_name = config['name']
  blue = "%s-blue" % app_name
  green = "%s-green" % app_name

  bluegreen = BlueGreen(token, target, config)

  apps = [blue, green]
  cnames = [bluegreen.get_cname(green), bluegreen.get_cname(blue)]

这是从shipa-bluegreen.ini读取的，我在文件中有：

[Application]
name: hello

任何帮助都将不胜感激

谢谢

Answer 1

在data中没有cname键data.get("cname")如果找不到键，则返回None，但可以指定显式默认值。改为使用空字符串作为默认值

def get_cname(self, app):
    response = self.get("/apps/{}".format(app))
    data = json.loads(response.read())
    if len(data.get("cname", "")) == 0:
      return None
    return data.get("cname")