我得到了这个回溯；
--- Trimmed parts ---
File "C:\Users\muhammed\Desktop\gifdatabase\gifdatabase.py", line 76, in maketransaction
gif.tags = list(set(gif.tags + tags))
File "C:\Program Files (x86)\Google\google_appengine\google\appengine\ext\ndb\model.py", line 2893, in __hash__
raise TypeError('Model is not immutable')
TypeError: Model is not immutable
这是我的代码的相关部分；
class Gif(ndb.Model):
author = ndb.UserProperty()
#tags = ndb.StringProperty(repeated=True)
tags = ndb.KeyProperty(repeated=True)
@classmethod
def get_by_tag(cls,tag_name):
return cls.query(cls.tags == ndb.Key(Tag, tag_name)).fetch()
class Tag(ndb.Model):
gif_count = ndb.IntegerProperty()
class PostGif(webapp2.RequestHandler):
def post(self):
user = users.get_current_user()
if user is None:
self.redirect(users.create_login_url("/static/submit.html"))
return
link = self.request.get('gif_link')
tag_names = shlex.split(self.request.get('tags').lower())
@ndb.transactional(xg=True)
def maketransaction():
tags = [Tag.get_or_insert(tag_name) for tag_name in tag_names]
gif = Gif.get_or_insert(link)
if not gif.author: # first time submission
gif.author = user
gif.tags = list(set(gif.tags + tags))
gif.put()
for tag in tags:
tag.gif_count += 1
tag.put()
if validate_link(link) and tag_names:
maketransaction()
self.redirect('/static/submit_successful.html')
else:
self.redirect('/static/submit_fail.html')
gif.tags = list(set(gif.tags + tags)) 行有什么问题？
最佳答案
您正在插入标签而不是 key ，您需要访问
tags = [Tag.get_or_insert(tag_name).key .....]
但您也可以像这样将其设为单个网络跃点
futures = [Tag.get_or_insert_async(tag_name) for tag_name in tag_names]
futures.append(Gif.get_or_insert_async(link))
ndb.Future.wait_all(futures)
gif = futures.pop().get_result()
tags = [future.get_result() for future in futures]
但这并不是真正的问题，只是一个建议^，为了使用 .key 得到更清晰的答案，
gif.tags = gif.tags + [tag.key for tag in tags]
# or
gif.tags.extend([tag.key for tag in tags])
关于google-app-engine - “模型不是一成不变的”类型错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18793956/