I am currently work on a web app using webapp2, that deals with restaurant in several cities. Some of the url would look like
1. www.example.com/newyork
2. www.example.com/newyork/fastfood
3. www.example.com/newyork/fastfood/tacobell
To handle the first url, I used the following
CITY_RE = r'(/(?:[a-zA-Z0-9]+/?)*)'
app = webapp2.WSGIApplication([(CITY_RE, CityHandler)], debug = True)
How would I handle the url with multiple parameters such as 2 and 3.
I have a similar approach to match urls like /<country>/<region>/<city>/<category>e.g. /usa/california/losangeles/restaurants where I use this regex:
app = webapp2.WSGIApplication([('/([^/]+)/?([^/]*)/?([^/]*)', RegionSearch)], config=settings.w2config, debug=True)
The declare the relevant parameters in the handler class.
class RegionSearch(SearchBaseHandler):
"""Handles regional search requests."""
def get(
self,
region=None,
city=None,
category=None,
subcategory='For sale',
PAGESIZE=50, # items on page
limit=60, # number of days
year=2012,
month=1,
day=1,
next_page=None,
):
I think that you could even do it this way
webapp2.Route('/passwdresetcomplete/<city>/<category>/<name>', handler=RegionSearch, name='regionsearch')
Related
I've got a Django app with Tastypie, and mainly BackBone client side. One of my models has a few ImageFields. Here is a similar setup to help me explain the issue.
settings.py
MEDIA_URL = "/media/"
models.py
class Foo(models.model):
bar = models.ImageField()
baz = models.CharField()
api.py
class FooResource(ModelResource):
class Meta:
queryset=models.Foo.objects.all()
resource_name = "foo"
authorization = Authorization()
When I make a GET request to the API, it appends the MEDIA_URL to the file names to return the URI where a bar can be accessed. However, when I change the value of baz on a row, and then make a PUT request with that, it also changes the value for a bar to the URI. This means that the next time I GET the row, it appends the MEDIA_URL again, breaking the system and appending it for each successive GET and PUT. I end up with values for bar in the DB that look like.
/media/media/media/bar.jpg
I think I should fix this by overriding a method in my ModelResource, so that when there is a PUT request, it recognizes that it's getting either a URI or a real file, and alters its behavior in some way.
Is this the correct fix? Could you provide some implementation details of a fix?
I found the answer. Tastypie is well designed, similarly to Django. Unfortunately I was not familiar with the terminology so when I read the docs I didn't understand. You can easily modify behavior of the API at many levels. Here is my new API definition, which fixed the issue.
api.py
class FooResource(ModelResource):
class Meta:
queryset=models.Foo.objects.all()
resource_name = "foo"
authorization = Authorization()
def hydrate_bar(bundle):
bundle["bar"] = bundle["bar"].strip(MEDIA_URL)
return bundle
I should add that this only works for me because I exclusively POST my image files individually with a post_detail method which doesn't call this method. If I was to POST or PUT image files as part of the entire row, I expect this might raise an error if that isn't considered.
I found this post from Amir in regards to redirecting request from google.appspot domain to the custom domain. My question is where do you put something like this using Web2py?
**To just add a custom domain, just follow the instructions here: http://code.google.com/appengine/articles/domains.html
And once that works, you can put a check in your code to forward anyone landing on the appspot.com domain to your domain: (example in python)
def get(self):
if self.request.host.endswith('appspot.com'):
return self.redirect('www.jaavuu.com', True)
# ... your code ...**
At the beginning of your first model file, you can do:
if request.env.http_host.endswith('appspot.com'):
redirect(URL(host='www.yourdomain.com', args=request.args, vars=request.vars))
This will preserve the entire original URL, except for replacing yourdomain.appspot.com with www.yourdomain.com. Note, URL() will automatically fill in the current controller and function, but you have to explicitly pass the current request.args and request.vars to make sure they get preserved.
That goes into your request handler.
Using example from web2py documentation:
Example 8
In controller: simple_examples.py
def redirectme():
redirect(URL('hello3'))
You'd want to do something like this:
def some_function():
if request.env.http_host.endswith('appspot.com'):
redirect(URL('www.yourdomain.com'))
With webapp2 here is something like what I did, where BaseHandler is the type of all my handlers:
class BaseHandler(webapp2.RequestHandler):
def __init__(self, request, response):
self.initialize(request, response)
if request.host.endswith('appspot.com'):
query_string = self.request.query_string
redirect_to = 'https://www.example.com' + self.request.path + ("?" + query_string if query_string else "")
self.redirect(redirect_to, permanent=True, abort=True)
I am learning the webapp2 framework with its powerful Route mechanism.
My application is supposed to accept URIs like these:
/poll/abc-123
/poll/abc-123/
/poll/abc-123/vote/ # post new vote
/poll/abc-123/vote/456 # view/update a vote
Polls may optionally be organized into categories, so all the above should work also like this:
/mycategory/poll/abc-123
/mycategory/poll/abc-123/
/mycategory/poll/abc-123/vote/
/mycategory/poll/abc-123/vote/456
My incorrect configuration:
app = webapp2.WSGIApplication([
webapp2.Route('/<category>/poll/<poll_id><:/?>', PollHandler),
webapp2.Route('/<category>/poll/<poll_id>/vote/<vote_id>', VoteHandler),
], debug=True)
Question: How could I fix my configuration?
If possible it should be optimized for GAE CPU-time/hosting fee. For example, it may be faster if I add two lines for each entry: one line with category and another one without category...
webapp2 has a mechanism to reuse common prefixes, but in this case they vary, so you can't avoid duplicating those routes, as in:
app = webapp2.WSGIApplication([
webapp2.Route('/poll/<poll_id><:/?>', PollHandler),
webapp2.Route('/poll/<poll_id>/vote/<vote_id>', VoteHandler),
webapp2.Route('/<category>/poll/<poll_id><:/?>', PollHandler),
webapp2.Route('/<category>/poll/<poll_id>/vote/<vote_id>', VoteHandler),
], debug=True)
You should not worry about adding many routes. They are really cheap to build and match. Unless you have tens of thousands, reducing the number of routes won't matter.
A small note: the first route accepts an optional end slash. You could instead use the RedirectRoute to accept only one and redirect if the other is accessed, using the option strict_slash=True. This is not well documented but has been around for a while. See the explanation in the docstring.
I am going to add my solution to this as a complimentary answer on top of #moraes.
So other people having problems like below can get a more complete answer.
Trailing Slash Problem
Optional Parameter Problem
In addition, I figured out how to route both /entity/create and /entity/edit/{id} in one regex.
Below are my routes that supports the following url patterns.
/
/myentities
/myentities/
/myentities/create
/myentities/create/
/myentities/edit/{entity_id}
SITE_URLS = [
webapp2.Route(r'/', handler=HomePageHandler, name='route-home'),
webapp2.Route(r'/myentities/<:(create/?)|edit/><entity_id:(\d*)>',
handler=MyEntityHandler,
name='route-entity-create-or-edit'),
webapp2.SimpleRoute(r'/myentities/?',
handler=MyEntityListHandler,
name='route-entity-list'),
]
app = webapp2.WSGIApplication(SITE_URLS, debug=True)
Below is my BaseHandler that all my handlers inherit from.
class BaseHandler(webapp2.RequestHandler):
#webapp2.cached_property
def jinja2(self):
# Sets the defaulte templates folder to the './app/templates' instead of 'templates'
jinja2.default_config['template_path'] = s.path.join(
os.path.dirname(__file__),
'app',
'templates'
)
# Returns a Jinja2 renderer cached in the app registry.
return jinja2.get_jinja2(app=self.app)
def render_response(self, _template, **context):
# Renders a template and writes the result to the response.
rv = self.jinja2.render_template(_template, **context)
self.response.write(rv)
Below is my MyEntityHandler python class with the get() method signature for the Google App Engine Datastore API.
class MyEntityHandler(BaseHandler):
def get(self, entity_id, **kwargs):
if entity_id:
entity = MyEntity.get_by_id(int(entity_id))
template_values = {
'field1': entity.field1,
'field2': entity.field2
}
else:
template_values = {
'field1': '',
'field2': ''
}
self.render_response('my_entity_create_edit_view_.html', **template_values)
def post(self, entity_id, **kwargs):
# Code to save to datastore. I am lazy to write this code.
self.redirect('/myentities')
I am having problems getting the logout link work in GAE (Python).
This is the page I am looking at.
In my template, I create a link
<p>Logout</p>
But when I click on it I get "broken link" message from Chrome. The url for the link looks like this:
http://localhost:8085/users.create_logout_url(
My questions:
Can anybody explain how this works in general?
What is the correct url for the dev server?
What is the correct url for the app server?
What is the ("/") in the logout url?
Thanks.
EDIT
This link works; but I don't know why:
<p>Logout</p>
What sort of templates are you using? It's clear from the output that you're not escaping your code correctly.
Seems to me that you want to do this instead:
self.response.out.write("This is the url: %s", users.create_logout_url("/"))
You could also pass it to your template, using GAEs implemented django templates.
from google.appengine.ext.webapp import template
...
...
(inside your request handler)
class Empty: pass
data = Empty()
data.logout = users.create_logout_url("/")
self.response.out.write(template.render(my_tmpl, {'data': data})
A useful approach is to add all sorts of info to a BaseRequestHandler and then use this as base class for all of your other request handler classes.
from google.appengine.ext import webapp
...
class BaseRequestHandler(webapp.RequestHandler):
def __init__(self):
webapp.RequestHandler.__init__(self) # extend the base class
class Empty: pass
data = Empty()
data.foo = "bar"
Then your new classes will have access to all the data you provided in the base class.
class OtherHandler(BaseRequestHandler):
def get(self):
self.response.out.write("This is foo: %s" % self.data.foo) # passes str "bar"
Hope it helps.
A.
Hi following more or less what this article is showing for the user account stuff. In gwt I store server side the logout/login url and I pass them to the client
http://www.dev-articles.com/article/App-Engine-User-Services-in-JSP-3002
I need to scrape a simple webpage which has the following text:
Value=29
Time=128769
The values change frequently.
I want to extract the Value (29 in this case) and store it in a database. I want to scrape this page every 6 hours. I am not interested in displaying the value anywhere, I just am interested in the cron. Hope I made sense.
Please advise me if I can accomplish this using Google's App Engine.
Thank you!
Please advise me if I can accomplish
this using Google's App Engine.
Sure! E.g., in Python, urlfetch (with the URL as argument) to get the contents, then a simple re.search(r'Value=(\d+)').group(1) (if the contents are as simple as you're showing) to get the value, and a db.put to store it. Do you want the Python details spelled out, or do you prefer Java?
Edit: urllib / urllib2 would also be feasible (GAE does support them now).
So cron.yaml should be something like:
cron:
- description: refresh "value"
url: /refvalue
schedule: every 6 hours
and app.yaml something like:
application: valueref
version: 1
runtime: python
api_version: 1
handlers:
- url: /refvalue
script: refvalue.py
login: admin
You may have other entries in either or both, of course, but this is the subset needed to "refresh the value". A possible refvalue.py might be:
import re
import wsgiref.handlers
from google.appengine.ext import db
from google.appengine.ext import webapp
from google.appengine.api import urlfetch
class Value(db.Model):
thevalue = db.IntegerProperty()
when = db.DateTimeProperty(auto_now_add=True)
class RefValueHandler(webapp.RequestHandler):
def get(self):
resp = urlfetch.fetch('http://whatever.example.com')
mo = re.match(r'Value=(\d+)', resp.content)
if mo:
val = int(mo.group(1))
else:
val = None
valobj = Value(thevalue=val)
valobj.put()
def main():
application = webapp.WSGIApplication(
[('/refvalue', RefValueHandler),], debug=True)
wsgiref.handlers.CGIHandler().run(application)
if __name__ == '__main__':
main()
Depending on what else your web app is doing, you'll probably want to move the class Value to a separate file (e.g. models.py with other models) which of course you'll then have to import (from this .py file and from others which do something interesting with all of your saved values). Here I've taken some possible anomalies into account (no Value= found on the target page) but not others (the target page's server does not respond or gives an error); it's hard to know exactly what anomalies you need to consider and what you want to do if they occur (what I'm doing here is very simply recording None as the value at the anomaly's time, but you may want to do more... or less -- I'll leave that up to you!-)