webapp2: regex in routing - python

I have such a problem: I want one method of the class to handle different URIs (for URI "/solution/add" and "solution/edit"). So I wrote such routing:
app = webapp2.WSGIApplication([webapp2.Route(r'/solutions/(add|edit)', handler='solution.SolutionPage:add_edit_solution'), ], debug=True)
And webapp2 gives 404 error. Could you please suggest the solution of this problem?
Ofcourse I can write different routes for every URI, but it's not so interesting.)

As the webapp2 docs indicate, you have to put the regex in angle brackets, with a colon separating name and expression. The name is optional, but
everything outside of <> is not interpreted as a regular expression to be matched
So something like this: '/blog/<:\d{4}>/<:\d{2}>' Or in your case, this:
webapp2.Route(r'/solutions/<:(add|edit)>',
handler='solution.SolutionPage:add_edit_solution')

If I can add something.
For my own purpose, I've try to create a handler which perform a little bit similar operation, but the point is that I've used self.request.host or self.request.route instead of arguments.
Doing this, and parsing the result with a switch case or if/elif/else loop, allow me to create a class named URIHandler which is use to route any kind of request to the correct ressources (even 404/500/yyy error pages) dynamicly whithout having to rewrite or add route for each new ressources.
So I'll be interested in comparing the two method to bench them a little bit.

Related

Eve framework: modify query_string

I'm writing API using Python EVE framework.
In my on_post_GET hook I want to extend request.query_string with some additional condition for some reason.
This request.query_string looks like a raw encoded string and it's not useful to add some new condition into existing.
My string looks like:
embedded=%7B%22some_key%22%3A1%2C%22another_key%22%3A1%2C%22one_more_key%22%3A1%2C%22and_more_key%22%3A1%2C%22and_more%22%3A1%2C%22some_specific_key%22%3A1%2C%22the_last_key%22%3A1%7D&where=%7B%22some_statement%22%3A%22in%28%5B%5C%22value1%5C%22%2C%5C%22value2%5C%22%5D%29%22%7D&max_results=10&page=1&sort=%5B%28%22date%22%2C0%29%5D
So, I want to add one additional condition into WHERE statement. I may parse it somehow, but there are a few things:
1) I may have another conditions and hardcoding related to condition looks terrible for me.
2) I hope, there is some better way to extend it somehow.
Thoughts?
You should be able to make your filter by handling the lookup inside a pre_GET event hook, as in this example from pyeve's documentation:
def pre_GET(resource, request, lookup):
# only return documents that have a 'username' field.
lookup["username"] = {'$exists': True}
app = Eve()
app.on_pre_GET += pre_GET
app.run()

Is it a good practise to use underscore to ignore a value that is being passed to a function, which we don't need?

I am working on Django rest framework which specifies a set format for function prototype for detail_route in ModelViewSet. Some background: -
The function takes in request object and lookup_field which can be the primary key for a particular table.
#detail_route(methods=["get"], url_path="get-some-data")
def get_some_data(self, request, id=None):
return Response(get_some_data(id))
Now as you can see, I do not need request object here, So should I keep it like this? or change it to
#detail_route(methods=["get"], url_path="get-some-data")
def get_some_data(self, _, id=None):
return Response(get_some_data(id))
Here I changed request to _ to indicate that I do not need this value.
which approach should be followed? Should I let it remain as a request, or change it to an underscore?
For the method arguments I would always use the proper variable name so that in future whether I work on it or my peers if I provide this code to someone else they don't have to struggle to understand what it is.
For now you might think to ignore it but since it is a method argument it would be better to have a name it stands for.
Or, let's say you are adding a docstring where you are including and defining which parameter is what. You would yourself appreciate it if some one had:
#param request: HTTP request object
instead of:
#param _: HTTP request object
If you leave the parameter exist, then give it a meaningful name always do good, even you do not use it.
In addition, _ has special use in python, check it in the following url.
What is the purpose of the single underscore "_" variable in Python?
I'd leave it with a descriptive name. Changing it to underscore or any other non-descriptive name is not beneficial.

Django reverse routes - two optional parameters

I have a question about Django and it's routing system. I believe that it can be powerfull, but right now I am struggling with one issue I don't experience when working in other frameworks and I can't seem to get a grip on it. Worth to mention that I don't have much experience with Django at this point.
The issue is simple - I have a view which takes two optional parameters, defined like this
def test_view(id=None, grid=None):
Both parameters are optional and frequently are not passed. Id can only be an integer and grid will never be an integer (it is a special string to control datagrid when I don't want to use sessions). I have a route defined like this:
url(a(r'^test_view (\/(?P<id>\d+))? (\/(?P<grid>[^\/]+))? \/?$'), views.test_view, name='test_view'),
This works great and I am not having trouble with using one-way routes. But when I try to use the reverse function or url template tag, following error occurs:
Reverse for 'test_view' with arguments '('20~id~desc~1',)' and keyword arguments '{}' not found.
In this example I tried to find reverse without the id, just with the grid parameter. I have tried various methods of passing parameters to the reverse function:
(grid, )
(None, grid)
('', grid)
{id=None, grid=grid}
All of them result in same error or similliar one.
Is there a way to implement this in django? Maybe just disable the cool URL for the grid parameter. That is how I do it in for example Nette framework for PHP, isntead of having an url like this: 'localhost/test_view/1/20~id~desc~1' I have url like this: 'localhost/test_view/1?grid=20~id~desc~1'. This would be completely sufficient, but I have no idea how to achive this in Django.
As you note in your question, the best way to achieve this is to use standard GET query parameters, rather than doing it in the path itself. In Django you do that exclusively in the view; the URL itself is then just
url(r'^test_view$', views.test_view, name='test_view'),
and you request it via localhost/test_view?id=1&grid=20~id~desc~1. You get the params from request.GET, which is a dictionary-like object; you can use .get so that it does not raise a KeyError when the key is not provided.
def test_view(request):
id = request.GET.get('id')
grid = request.GET.get('grid')

How does the get_list tastypie function work?

I'm trying to use the get_list tastypie function but I can't make it work. I've looked for documentation about that but I can't find it.
Whatever, I've a list of item ids and an ItemResource. I'm trying to return a list of serialized objects.
So I just want to do something like that :
item_resource = ItemResource()
item_ids = my_item_id_list
return item_resource.get_list(request, id=item_ids)
But of course it's not working.
What would be the correct syntax to do that ?
Thx !
Unless your ItemResource accepts filters (more here), you have to copy-paste all the stuff from here, lines #1306 - #1313.
The point is that get_list results get filtered only by obj_get_list (initial filters), and apply_filters (request-specific filters) so you have to skip directly to the serialization part (you can include the pagination part, if needed).
This is one of the cases where django-restframework appears to be better than django-tastypie - it refactores serialization out into a separate class, avoiding the code duplication.

pyramid_handlers not working

I'm currently moving a project from Pylons 1.0 to Pyramid.
My problem so far is how to use restful routes in Pyramid. I'm currently using pyramid_handlers since it seemed like a good start. I'm using Akhet.
So here is the two important lines in my route:
config.add_handler("new_account", "/accounts/new", "sproci2.handlers.accounts:Accounts")
# or
config.add_handler("new_account", "/accounts/new", "sproci2.handlers.accounts:Accounts", action="new")
My action:
#action(name="new_account", renderer='accounts/new.mako', request_method='GET')
The errors:
TypeError: 'Accounts' object is not callable
or
ValueError: Could not convert view return value "{}" into a response Object.
Accounts... so far so good, it is easy to understand that pyramid_handlers doesn't seem to register normally or handle name as it should... that said in request.matched_route, I do have "new_account".
If I add "action='new'" in the route definition, it will find the function but it will not listen to the action definition. In other words, it will fail to find a renderer and expect a response object. The request_method parameter doesn't actually do anything yet, so removing it doesn't change any results.
In short, the #action(name="..." doesn't work. Pyramid fails to find the function by itself and if the function name is defined it fails to execute the action statement.
No idea what I'm doing wrong.
Correct way to do it.
config.add_handler("new_account", "/accounts/new", "sproci2.handlers.accounts:Accounts", action="new_account")
EDIT
route_name is probably going to get used by url generator functions. While action is the actual name in #action. As I understood, #action name was the route_name and not the action name. That makes more sense now.
Well a call to add_handler needs an action pattern. So that's either adding {action} to the url pattern, or setting action= as an argument. Those actions must match the names defined in #action decorators. In your example, you named the action new_account, yet you called add_handler with an action of new. Thus they aren't properly connected.

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