Python 如何制作'；permalink'；在Google App Engine webapp2留言簿教程中显示两幅图像的详细信息页面
我正在关注（这是他们的）并希望：Python 如何制作'；permalink'；在Google App Engine webapp2留言簿教程中显示两幅图像的详细信息页面,python,google-app-engine,google-cloud-datastore,webapp2,blobstore,Python,Google App Engine,Google Cloud Datastore,Webapp2,Blobstore,我正在关注（这是他们的）并希望： 允许留言簿用户在发布问候语时除了“化身”之外，还可以上传额外的图像。这可以称为“其他” 发布问候语后，将用户重定向到带有类似/greeting/numeric id的URL的问候语详细页面，而不是列出所有问候语的主页 使用名为detail.html的Jinja2模板显示带有图像的详细信息页面 我无法理解： A）如何编写在发布问候语后调用的重定向代码，使其重定向到类似于/greeting/numeric id的URL B）如何编写用户重定向到的详细视图和模板页面，
import os
import urllib
from google.appengine.api import images
from google.appengine.api import users
from google.appengine.ext import ndb
from google.appengine.ext.webapp import blobstore_handlers
from google.appengine.ext import blobstore
import jinja2
import webapp2
JINJA_ENVIRONMENT = jinja2.Environment(
loader=jinja2.FileSystemLoader(os.path.dirname(__file__)),
extensions=['jinja2.ext.autoescape'],
autoescape=True)
DEFAULT_GUESTBOOK_NAME = 'default_guestbook'
def guestbook_key(guestbook_name=None):
"""Constructs a Datastore key for a Guestbook entity with name."""
return ndb.Key('Guestbook', guestbook_name or 'default_guestbook')
class Author(ndb.Model):
"""Sub model for representing an author."""
identity = ndb.StringProperty(indexed=False)
email = ndb.StringProperty(indexed=False)
class Greeting(ndb.Model):
"""A model for representing an individual Greeting entry."""
author = ndb.StructuredProperty(Author)
date = ndb.DateTimeProperty(auto_now_add=True)
avatar = ndb.BlobProperty(indexed=False, required=True)
other = ndb.BlobProperty(indexed=False, required=True)
class MainPage(webapp2.RequestHandler):
def get(self):
self.response.out.write('<html><body>')
guestbook_name = self.request.get('guestbook_name')
greetings = Greeting.query(
ancestor=guestbook_key(guestbook_name)) \
.order(-Greeting.date) \
.fetch(10)
self.response.out.write("""
<form action="/sign?%s"
enctype="multipart/form-data"
method="post">
<label>Avatar:</label>
<input type="file" name="avatar"/><br>
<label>Other Image:</label>
<input type="file" name="other"/><br>
<input type="submit" value="Submit">
</form>
</body>
</html>""" % (urllib.urlencode({'guestbook_name': guestbook_name})))
class Image(webapp2.RequestHandler):
""" Handle image stored as blobs of bytes.
No idea how the template knows to select a particular one. """
def get(self):
avatar_greeting_key = ndb.Key(urlsafe=self.request.get('avatar_id'))
other_greeting_key = ndb.Key(urlsafe=self.request.get('other_id'))
avatar_greeting = avatar_greeting_key.get()
other_greeting = other_greeting_key.get()
if avatar_greeting.avatar:
self.response.headers['Content-Type'] = 'image/png'
self.response.out.write(avatar_greeting.avatar)
elif other_greeting.other:
self.response.headers['Content-Type'] = 'image/png'
self.response.out.write(other_greeting.other)
else:
self.response.out.write('No image')
class Guestbook(webapp2.RequestHandler):
def post(self):
guestbook_name = self.request.get('guestbook_name',
DEFAULT_GUESTBOOK_NAME)
greeting = Greeting(parent=guestbook_key(guestbook_name))
if users.get_current_user():
greeting.author = Author(
identity=users.get_current_user().user_id(),
email=users.get_current_user().email())
avatar = self.request.get('avatar')
avatar = images.resize(avatar, 100, 100)
other = self.request.get('other')
other = images.resize(other, 400, 300)
greeting.avatar = avatar
greeting.other = other
greeting.put()
query_params = {'guestbook_name': guestbook_name}
self.redirect('/greeting/%d' % greeting.key.id())
class Detail(webapp2.RequestHandler):
""" Individual greeting. """
def get(self, *args, **kwargs):
guestbook_name = self.request.get('guestbook_name', DEFAULT_GUESTBOOK_NAME)
greeting = Greeting.get_by_id(args[0],
parent=guestbook_key(guestbook_name))
template_values = {
'greeting': greeting,
}
template = JINJA_ENVIRONMENT.get_template('detail.html')
self.response.write(template.render(template_values))
app = webapp2.WSGIApplication([
('/', MainPage),
('/img', Image),
('/sign', Guestbook),
('/greeting/(\d+)', Detail),
], debug=True)
Traceback (most recent call last):
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1535, in __call__
rv = self.handle_exception(request, response, e)
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1529, in __call__
rv = self.router.dispatch(request, response)
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1278, in default_dispatcher
return route.handler_adapter(request, response)
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1102, in __call__
return handler.dispatch()
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 572, in dispatch
return self.handle_exception(e, self.app.debug)
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 570, in dispatch
return method(*args, **kwargs)
File "/Users/simon/Projects/guestbook/guestbook.py", line 111, in get
self.response.write(template.render(template_values))
File "/Users/simon/Projects/google-cloud-sdk/platform/google_appengine/lib/jinja2-2.6/jinja2/environment.py", line 894, in render
return self.environment.handle_exception(exc_info, True)
File "/Users/simon/Projects/guestbook/detail.html", line 9, in top-level template code
Avatar: <img src="/img?avatar_id={{ greeting.key.urlsafe() }}">
UndefinedError: 'None' has no attribute 'key'
回溯（最近一次呼叫最后一次）：
文件“/Users/simon/Projects/google cloud sdk/platform/google\u appengine/lib/webapp2-2.5.2/webapp2.py”，第1535行，在__
rv=自身处理异常（请求、响应、e）
文件“/Users/simon/Projects/google cloud sdk/platform/google\u appengine/lib/webapp2-2.5.2/webapp2.py”，第1529行，在__
rv=自我路由器调度（请求、响应）
默认情况下，文件“/Users/simon/Projects/google cloud sdk/platform/google\u appengine/lib/webapp2-2.5.2/webapp2.py”第1278行
返回路由处理程序适配器（请求、响应）
文件“/Users/simon/Projects/google cloud sdk/platform/google\u appengine/lib/webapp2-2.5.2/webapp2.py”，第1102行，在__
返回处理程序.dispatch（）
文件“/Users/simon/Projects/google cloud sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py”，第572行，在调度中
返回self.handle_异常（e，self.app.debug）
文件“/Users/simon/Projects/google cloud sdk/platform/google_appengine/lib/webapp2-2.5.2/webapp2.py”，第570行，在调度中
返回方法（*args，**kwargs）
get中第111行的文件“/Users/simon/Projects/guestbook/guestbook.py”
self.response.write（template.render（template_值））
文件“/Users/simon/Projects/google cloud sdk/platform/google_appengine/lib/jinja2-2.6/jinja2/environment.py”，第894行，在render中
返回self.environment.handle\u异常（exc\u info，True）
顶级模板代码中的第9行文件“/Users/simon/Projects/guestbook/detail.html”
化身：
UndefinedError:“None”没有属性“key”
如果我在Dan的回答中添加python检查代码，我会得到一个500错误而不是堆栈跟踪，如果我尝试模板检查，我会得到一个空白的问候页面。我已经用我的完整代码和一个图表更新了这个问题，解释了我要做的事情。我将从
B问候语无{{greeting.key.urlsafe（）}问候语.key ...
greeting = Greeting.get_by_id(args[0])
if not greeting or not isinstance(greeting.key, ndb.Key):
# can't render that template, invalid greeting.key.urlsafe()
webapp2.abort(500)
return
template_values = {
'greeting': greeting,
}
template = JINJA_ENVIRONMENT.get_template('detail.html')
self.response.write(template.render(template_values))
...
{% if greeting and greeting.key %}<img src="/img?avatar_img_id={{ greeting.key.urlsafe() }}">{% endif %}
/guestbook/<guestbook_name>/greeting/<numeric-id>.
...
greeting = Greeting.get_by_id(args[0])
if not greeting or not isinstance(greeting.key, ndb.Key):
# can't render that template, invalid greeting.key.urlsafe()
webapp2.abort(500)
return
template_values = {
'greeting': greeting,
}
template = JINJA_ENVIRONMENT.get_template('detail.html')
self.response.write(template.render(template_values))
...
{% if greeting and greeting.key %}<img src="/img?avatar_img_id={{ greeting.key.urlsafe() }}">{% endif %}
/guestbook/<guestbook_name>/greeting/<numeric-id>.
greeting = Greeting.get_by_id(args[0],
parent=guestbook_key(guestbook_name))
留言簿名称 ...
greeting = Greeting.get_by_id(args[0])
if not greeting or not isinstance(greeting.key, ndb.Key):
# can't render that template, invalid greeting.key.urlsafe()
webapp2.abort(500)
return
template_values = {
'greeting': greeting,
}
template = JINJA_ENVIRONMENT.get_template('detail.html')
self.response.write(template.render(template_values))
...
{% if greeting and greeting.key %}<img src="/img?avatar_img_id={{ greeting.key.urlsafe() }}">{% endif %}
/guestbook/<guestbook_name>/greeting/<numeric-id>.
/guestbook//greeting/。
图像处理程序中，它们中的每一个都附加到单独的问候语。处理程序也根本不映射到图像的URL（这还需要对定位适当图像所需的数据进行额外编码，具体取决于体系结构决策）
恐怕你还有很多工作要做，直到你把整个事情都做好，远远超过一个简单的问题。退一步，重新思考您的架构，将其分成更小的部分，一次只关注一个部分，然后继续。在您熟悉了各种部件的技术之后，您会觉得立即解决整个问题更好。问题出在哪里？你有什么错误吗？代码不起作用？我在顶级模板代码UndefinedError中添加了错误-文件“/Users/simon/Projects/guestbook/detail.html”，第11行：“None”没有属性“key”
非常感谢，Dan。我会在有时间的时候尝试，如果我能让它工作，我会接受这个答案。如果我添加python检查代码，我会得到一个500错误而不是堆栈跟踪，如果我尝试模板检查，我会得到一个空白的问候页面。我已经用我的完整代码和一个图表更新了这个问题，解释了我要做的事情。你能提供一个在问候语“permalink”URL中编码留言簿名称的示例吗？我接受这个答案，因为它帮助我朝着正确的方向前进，即使我还不能让事情顺利进行。