I use the following code to use webapp2
import webapp2
from webapp2_extras import i18n, jinja2
class Test(webapp2.RequestHandler):
#webapp2.cached_property
def jinja2(self):
# Returns a Jinja2 renderer cached in the app registry.
return jinja2.get_jinja2(app=self.app)
def render(self, _template, **context):
# Renders a template and writes the result to the response.
rv = self.jinja2.render_template(_template, **context)
self.response.write(rv)
def get(self):
self.render('index2.html')
app = webapp2.WSGIApplication([('/',Test)], debug=False)
app.run()
To be simple, we just make index2.html is full of 1000 test
If you run it, you will find that the Google App Engine Launcher log windows is full of test.
It's rather terrible when you are debugging a real website.
But I find that if index2.html contains just few words like 10 test. The test will not appear in logging window.
Any solution?
It looks like you are running two separate instances of your application.
The first is running through the development server, the second is actually running and outputting to the terminal. You can see this by adding a log output to your application. You can see that when you go to your site, the log is written two twice.
You can fix this by removing the line:
app.run()
This is not necessary when running on App Engine. Your app.yaml file references the app directly:
handlers:
- url: .*
script: guestbook.app # Notice the .app here.
Related
Could someone help me access Big Query from an App Engine application ?
I have completed the following steps -
Created an App Engine project.
Installed google-api-client, oauth2client dependencies (etc) into /lib.
Enabled the Big Query API for the App Engine project via the cloud console.
Created some 'Application Default Credentials' (a 'Service Account Key') [JSON] and saved it/them to the root of the App Engine application.
Created a 'Big Query Service Resource' as per the following -
def get_bigquery_service():
from googleapiclient.discovery import build
from oauth2client.client import GoogleCredentials
credentials=GoogleCredentials.get_application_default()
bigquery_service=build('bigquery', 'v2', credentials=credentials)
return bigquery_service
Verified that the resource exists -
<googleapiclient.discovery.Resource object at 0x7fe758496090>
Tried to query the resource with the following (ProjectId is the short name of the App Engine application) -
bigquery=get_bigquery_service()
bigquery.tables().list(projectId=#{ProjectId},
datasetId=#{DatasetId}).execute()
Returns the following -
<HttpError 401 when requesting https://www.googleapis.com/bigquery/v2/projects/#{ProjectId}/datasets/#{DatasetId}/tables?alt=json returned "Invalid Credentials">
Any ideas as to steps I might have wrong or be missing here ? The whole auth process seems a nightmare, quite at odds with the App Engine/PaaS ease-of-use ethos :-(
Thank you.
OK so despite being a Google Cloud fan in general, this is definitely the worst thing I have been unfortunate enough to have to work on in a while. Poor/inconsistent/nonexistent documentation, complexity, bugs etc. Avoid if you can!
1) Ensure your App Engine 'Default Service Account' exists
https://console.cloud.google.com/apis/dashboard?project=XXX&duration=PTH1
You get the option to create the Default Service Account only if it doesn't already exist. If you've deleted it by accident you will need a new project; you can't recreate it.
How to recover Google App Engine's "default service account"
You should probably create the default set of JSON credentials, but you won't need to include them as part of your project.
You shouldn't need to create any other Service Accounts, for Big Query or otherwise.
2) Install google-api-python-client and apply fix
pip install -t lib google-api-python-client
Assuming this installs oath2client 3.0.x, then on testing you'll get the following complaint:
File "~/oauth2client/client.py", line 1392, in _get_well_known_file
default_config_dir = os.path.join(os.path.expanduser('~'),
File "/usr/lib/python2.7/posixpath.py", line 268, in expanduser
import pwd
File "~/google_appengine-1.9.40/google/appengine/tools/devappserver2/python/sandbox.py", line 963, in load_module
raise ImportError('No module named %s' % fullname)
ImportError: No module named pwd
which you can fix by changing ~/oauth2client/client.py [line 1392] from:
os.path.expanduser('~')
to:
os.env("HOME")
and adding the following to app.yaml:
env_variables:
HOME: '/tmp'
Ugly but works.
3) Download GCloud SDK and login from console
https://cloud.google.com/sdk/
gcloud auth login
The issue here is that App Engine's dev_appserver.py doesn't include any Big Query replication (natch); so when you're interacting with Big Query tables it's the production data you're playing with; you need to login to get access.
Obvious in retrospect, but poorly documented.
4) Enable Big Query API in App Engine console; create a Big Query ProjectID
https://console.cloud.google.com/apis/dashboard?project=XXX&duration=PTH1
https://bigquery.cloud.google.com/welcome/XXX
5) Test
from oauth2client.client import GoogleCredentials
credentials=GoogleCredentials.get_application_default()
from googleapiclient.discovery import build
bigquery=build('bigquery', 'v2', credentials=credentials)
print bigquery.datasets().list(projectId=#{ProjectId}).execute()
[or similar]
Good luck!
I'm new to Google App Engine and Python. I've almost completed a project, but can't get the get_serving_url() function to work. I've stripped everything down to the most basic functionality, following the documentation. And yet I still get a 500 error from the server. Any thoughts? Here is the code:
from google.appengine.api import images
....
class Team(db.Model):
avatar = db.BlobProperty()
....
def to_dict(self):
....
image_url = images.get_serving_url(self.avatar.key())
The last line is the problem...commenting it out makes the app run fine. But it is copied almost directly from the documentation. I should note that I can download the avatar blob directly with:
class GetTeamAvatar(webapp2.RequestHandler):
def post(self):
team_id = self.request.get('team_id')
team = Team.get_by_id(long(team_id))
self.response.write(team.avatar)
So I know it is stored correctly. I do not have PIL on my machine...is that the issue? The datastore's image API says it has PIL locally so if I'm deploying my app it shouldn't matter, right? I have Python 3.3 and apparently PIL stopped at 2.6.
Python appengine run time is 2.7, (OK and 2.5) so don't even try to work with 3.x.
Secondly get_serving_URL is a method you call with a BlobStore entity key not a BlobProperty.
You are confusing two different things here.
I would concentrate on getting your code to run locally correctly under 2.7 first, and PIL is available for 2.7.
I'm very impressed if you're trying to deploy your app without even testing it locally.
One thing you'll need to do is make PIL available in your app.yaml via the libraries attribute.
I have used lxml on Google App Engine to scrape some basic data.
It works fine with the SDK. When I try to use it on the appengine servers I get.
IOError: Error reading file 'http://www.google.com': failed to load external entity "http://www.google.com"
My code looks like;
import lxml.html
url = "http://www.google.com"
t = lxml.html.parse(url)
pagetitle = t.find.(".//title").text
self.response.out.write(pagetitle)
edit:
I ended up having to make a small change to handle as is outlined in the answer below.
from google.appengine.api import urlfetch
result = urlfetch.fetch(url)
t = lxml.html.fromstring(result.content)
GAE does not support opening sockets, you should use urlfetch.fetch() to get the page contents, then feed it to the parser.
I'm learning developing in Google App Engine.
This is one of the code from the tutorial, http://code.google.com/appengine/docs/python/gettingstarted/usingwebapp.html
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
class MainPage(webapp.RequestHandler):
def get(self):
self.response.headers['Content-Type'] = 'text/plain'
self.response.out.write('Hello, webapp World!')
application = webapp.WSGIApplication(
[('/', MainPage)],
debug=True)
def main():
run_wsgi_app(application)
if __name__ == "__main__":
main()
I've almost identical code. I sometime get warning:
WARNING 2011-06-30 13:10:44,443 init.py:851] You are using the default Django version (0.96). The default Django version will change in an App Engine release in the near future. Please call use_library() to explicitly select a Django version. For more information see http://code.google.com/appengine/docs/python/tools/libraries.html#Django
Can anyone please re factor the above code with use_library(). I'm not sure how to start and where to use use_library and what to do with webapp.
Thanks in advance.
The above code should not require you to call use_library directly.
If you create a new file in the root directory of your application named appengine_config.py and add the following line to it:
# Make webapp.template use django 1.2
webapp_django_version = '1.2'
try putting this code on top of your module :
import os
from google.appengine.dist import use_library
use_library('django', '1.2')
In the current version this is even simpler as third-party libraries are now specified in app.yaml
libraries:
- name: django
version: "1.2"
You can also use webapp2 that includes Django’s templating engine.
import webapp2
from google.appengine.ext.webapp2 import template
This is my app.yaml:
- url: /about|/about/.*
script: about.py
This is my `about.py':
application = webapp.WSGIApplication([(r'^/about$', AboutPage),
(r'^/about/$', Redirect),
(r'.*', ErrorPage)],
debug = True)
I want to redirect all requests for /about/ to /about. I'd like all other requests to be sent to the error page.
It works in the development server on localhost, but I cannot access /about/ after I deployed the app on GAE - it just shows an empty page.
I adjusted the order of URL patterns in app.yaml.
It works now on GAE.
If you don't want trailing slashes for GET requests anywhere in your application, you can implement a global redirect at the top of your app.yaml. Note that POST requests will NOT redirect, but this is ok (for me anyway) because users don't generally hand-write POST URLs.
app.yaml:
application: whatever
version: 1
api_version: 1
runtime: python
handlers:
- url: .+/
script: slashmurderer.py
slashmurderer.py
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
class SlashMurdererApp(webapp.RequestHandler):
def get(self, url):
self.redirect(url)
application = webapp.WSGIApplication(
[('(.*)/$', SlashMurdererApp)]
)
def main():
run_wsgi_app(application)
I see that this question has already been answered, but I ran into the same problem and wanted to see if there was a "lazier" solution.
If you're using the Python 2.7 runtime, then the webapp2 library is available, and I believe the following will work:
import webapp2
from webapp2_extras.routes import Redirect Route
class MainHandler(webapp2.RequestHandler):
def get(self):
self.response.out.write("This is my first StackOverflow post")
app = webapp2.WSGIApplication([
RedirectRoute('/', MainHandler, name='main', strict_slash=True),
('/someurl', OtherHandler),
])
strict_slash=True means that if the client doesn't supply the slash it will be redirected to the url with the slash (to match the first argument).
You can combine the special Route classes from webapp2_extras with normal (regex, handler) tuples as shown above. The "name" parameter is required for the constructor for RedirectRoute. More details here: webapp2_extras documentation for RedirectRoute