I am new in web development in django i don't know when to use slug field and when to use query string parameters in the url.Can anyone suggest me practical differences between them.
Using slugs keep urls simple and clean, thereby easy to remember. Consider the following example:
example.com/post/hello-world/
v/s
example.com/?post=hello-world
Obviously, first one is cleaner.
But query string parameters have their uses too. For example, when you search for an object.
example.com/search/?q=hello-world
or when you need to pass multiple parameters
example.com/search/?q=hello+world&lang=en&something=else
In slug related django urls you have a url associated to a view. But you cannot pass querystring parameters to your views.
Ex -example.com/post/hello-world/ does not pass any parameter to your view function.
But if you want to pass additional parameters to your views, ex,
example.com/search/?q=hello-world
here q=hello-world is a query string parameter passed to your views.
And inside your views function you can get these parameters in request.GET
So your views function goes something like this
def helloworld():
qParams = request.GET.get('q', '')
....
....
Hope this helps.
Related
How can I pass parameters via URL as query parameters to avoid multiple and complicated url patterns?
For example, instead of making a complicated url like
example.com/page/12/red/dog/japan/spot
or something like that, and then a corresponding entry in urls.py that will parse that url and direct it to a view, I want to simply get a url where I can freely add or remove parameters as needed similar to the ugly way
example.com/page?id=12&color=red&animal=dog&country=Japan&name=spot
Then in urls.py simply have something like
path('page/<parameter_dictionary>', views.page, name='page' parameters='parameter_dictionary)
If I have to use url patterns, how can I account for urls that have parameters that may or may not fit the pattern, such as sometimes
"/page/12/red/dog/Japan/spot" -> path('page/<int:id>/<str:color>/<str:animal>/<str:country>/<str:name>', views.page, name='page'),
"/page/12/dog/red/Japan/"-> path('page/<int:id>/<str:animal>/<str:color>/<str:country>', views.page, name='page')
"/page/dog/red/Japan/"-> path('page/<str:animal>/<str:color>/<str:country>', views.page, name='page')
I would like to just have anything sent to http://example.com/page/
go to views.page(), and then be accessible by something like
animal = request.GET['animal']
color = request.GET['color']
id = request.GET['id']
etc. so examples below would all work via one entry in urls.py
example.com/page?id=12&animal=dog&country=Japan&name=spot
example.com/page?id=12&color=red&animal=dog&name=spot
example.com/page?id=12&country=Japan&color=red&animal=dog&name=spot
You are looking for queryparameters and you are almost done with it. The following code is untested but should kinda work:
def page(request):
animal = request.GET.get("animal",None) # default None if not present
color = request.GET.get("color",None)
return render(request,'some_html.html')
# urls.py:
path('page/', views.page, name='page')
You access the queryparameters via the passed request object request.GET. This is a dict like object. The main difference is that this object handles multi keys.
For example if you pass the these params ?a=1&a=2 to your url, it converts request.GET.getlist("a") # Returns ["1","2"] to a list.
request.GET.get("a") returns the last passed value "2" as #Kbeen mentioned in comments,. Read more about QueryDict here.
Also be sure to know the difference and best practice for url parameters and queryparameters. Example Stackoverflow post
Edit: Added request.GET.getlist()
I am currently defining regular expressions in order to capture parameters in a URL, as described in the tutorial. How do I access parameters from the URL as part the HttpRequest object?
My HttpRequest.GET currently returns an empty QueryDict object.
I'd like to learn how to do this without a library, so I can get to know Django better.
When a URL is like domain/search/?q=haha, you would use request.GET.get('q', '').
q is the parameter you want, and '' is the default value if q isn't found.
However, if you are instead just configuring your URLconf**, then your captures from the regex are passed to the function as arguments (or named arguments).
Such as:
(r'^user/(?P<username>\w{0,50})/$', views.profile_page,),
Then in your views.py you would have
def profile_page(request, username):
# Rest of the method
To clarify camflan's explanation, let's suppose you have
the rule url(regex=r'^user/(?P<username>\w{1,50})/$', view='views.profile_page')
an incoming request for http://domain/user/thaiyoshi/?message=Hi
The URL dispatcher rule will catch parts of the URL path (here "user/thaiyoshi/") and pass them to the view function along with the request object.
The query string (here message=Hi) is parsed and parameters are stored as a QueryDict in request.GET. No further matching or processing for HTTP GET parameters is done.
This view function would use both parts extracted from the URL path and a query parameter:
def profile_page(request, username=None):
user = User.objects.get(username=username)
message = request.GET.get('message')
As a side note, you'll find the request method (in this case "GET", and for submitted forms usually "POST") in request.method. In some cases, it's useful to check that it matches what you're expecting.
Update: When deciding whether to use the URL path or the query parameters for passing information, the following may help:
use the URL path for uniquely identifying resources, e.g. /blog/post/15/ (not /blog/posts/?id=15)
use query parameters for changing the way the resource is displayed, e.g. /blog/post/15/?show_comments=1 or /blog/posts/2008/?sort_by=date&direction=desc
to make human-friendly URLs, avoid using ID numbers and use e.g. dates, categories, and/or slugs: /blog/post/2008/09/30/django-urls/
Using GET
request.GET["id"]
Using POST
request.POST["id"]
Someone would wonder how to set path in file urls.py, such as
domain/search/?q=CA
so that we could invoke query.
The fact is that it is not necessary to set such a route in file urls.py. You need to set just the route in urls.py:
urlpatterns = [
path('domain/search/', views.CityListView.as_view()),
]
And when you input http://servername:port/domain/search/?q=CA. The query part '?q=CA' will be automatically reserved in the hash table which you can reference though
request.GET.get('q', None).
Here is an example (file views.py)
class CityListView(generics.ListAPIView):
serializer_class = CityNameSerializer
def get_queryset(self):
if self.request.method == 'GET':
queryset = City.objects.all()
state_name = self.request.GET.get('q', None)
if state_name is not None:
queryset = queryset.filter(state__name=state_name)
return queryset
In addition, when you write query string in the URL:
http://servername:port/domain/search/?q=CA
Do not wrap query string in quotes. For example,
http://servername:port/domain/search/?q="CA"
def some_view(request, *args, **kwargs):
if kwargs.get('q', None):
# Do something here ..
For situations where you only have the request object you can use request.parser_context['kwargs']['your_param']
You have two common ways to do that in case your URL looks like that:
https://domain/method/?a=x&b=y
Version 1:
If a specific key is mandatory you can use:
key_a = request.GET['a']
This will return a value of a if the key exists and an exception if not.
Version 2:
If your keys are optional:
request.GET.get('a')
You can try that without any argument and this will not crash.
So you can wrap it with try: except: and return HttpResponseBadRequest() in example.
This is a simple way to make your code less complex, without using special exceptions handling.
I would like to share a tip that may save you some time.
If you plan to use something like this in your urls.py file:
url(r'^(?P<username>\w+)/$', views.profile_page,),
Which basically means www.example.com/<username>. Be sure to place it at the end of your URL entries, because otherwise, it is prone to cause conflicts with the URL entries that follow below, i.e. accessing one of them will give you the nice error: User matching query does not exist.
I've just experienced it myself; hope it helps!
These queries are currently done in two ways. If you want to access the query parameters (GET) you can query the following:
http://myserver:port/resource/?status=1
request.query_params.get('status', None) => 1
If you want to access the parameters passed by POST, you need to access this way:
request.data.get('role', None)
Accessing the dictionary (QueryDict) with 'get()', you can set a default value. In the cases above, if 'status' or 'role' are not informed, the values are None.
If you don't know the name of params and want to work with them all, you can use request.GET.keys() or dict(request.GET) functions
This is not exactly what you asked for, but this snippet is helpful for managing query_strings in templates.
If you only have access to the view object, then you can get the parameters defined in the URL path this way:
view.kwargs.get('url_param')
If you only have access to the request object, use the following:
request.resolver_match.kwargs.get('url_param')
Tested on Django 3.
views.py
from rest_framework.response import Response
def update_product(request, pk):
return Response({"pk":pk})
pk means primary_key.
urls.py
from products.views import update_product
from django.urls import path
urlpatterns = [
...,
path('update/products/<int:pk>', update_product)
]
You might as well check request.META dictionary to access many useful things like
PATH_INFO, QUERY_STRING
# for example
request.META['QUERY_STRING']
# or to avoid any exceptions provide a fallback
request.META.get('QUERY_STRING', False)
you said that it returns empty query dict
I think you need to tune your url to accept required or optional args or kwargs
Django got you all the power you need with regrex like:
url(r'^project_config/(?P<product>\w+)/$', views.foo),
more about this at django-optional-url-parameters
This is another alternate solution that can be implemented:
In the URL configuration:
urlpatterns = [path('runreport/<str:queryparams>', views.get)]
In the views:
list2 = queryparams.split("&")
url parameters may be captured by request.query_params
It seems more recommended to use request.query_params. For example,
When a URL is like domain/search/?q=haha, you would use request.query_params.get('q', None)
https://www.django-rest-framework.org/api-guide/requests/
"request.query_params is a more correctly named synonym for request.GET.
For clarity inside your code, we recommend using request.query_params instead of the Django's standard request.GET. Doing so will help keep your codebase more correct and obvious - any HTTP method type may include query parameters, not just GET requests."
My query is quite simple, I have a model Vendor in my Django REST app. What I want is to use a get response with a few ID and get back all the respective models with these ID. The GET url pattern could be something like this: r'^api/vendors?id=1,2,3'.
What I'm thinking of right now is to use ListAPIView, and in the list method filter my queryset with all the id in the url. But I'm not sure exactly how to achieve this (filtering queryset with a list of id, I'm very new to both Python and Django), so if anyone can provide any advice on this it would be greatly appreciated.
(Unfortunately I do not know django REST, so here is a pure django solution)
Using the ListAPIView you can access the URL (or GET) params and modify the queryset.
class MyVendorView(ListAPIView):
# attributes
def get_queryset(self):
id_string = self.request.GET.get('id')
if id_string is not None:
ids = [int(id) for id in id_string.split(',')]
return Vendor.objects.filter(id__in=ids)
else:
return Vendor.objects.all()
# other methods
please note that I'm ingoring any attributes or other attributes needed
What's happening here then?
Overriding get_queryset will control what results we get from hitting the view
self.request.GET.get('id') Will extract the value of the id query parameter from the url like so localhost:8000/api/vendors?id=1,2,3 the result will be a string "1,2,3".
filter(id__in=ids) lets you say select stuff that has an value in this list of ids
I have a base template for when a user is logged in, and on that base template, I need to add user specific options in a drop down menu. This drop down menu with options must be constant across all handlers, i.e., any time the base template is invoked (extended) with a child template.
Other than performing the necessary DB query, assigning the query results to a variable, and passing that variable to every handler (there are many), how can I consolidate this into one query and one variable, which gets passed directly to the base template? I am using jinja2 templates as well.
I would hate to do something so cumbersome in exchange for something far more simple and maintainable.
Any ideas? Thanks.
EDIT
So I still haven't found anything that's exactly what I'm looking for; however, I decided to at least make some headway in the interim. So, I made a custom decorator that takes a view's returned dict() and appends the appropriate data to it. For example:
def get_base_data(func):
def wrapper(request):
d = func(request)
user_id = request.user.id # used in query
contact_group_data = ContactGroups.query.filter(...criteria...).all()
d['contact_group_data'] = contact_group_data
return d
return wrapper
Now, I can at least decorate each method very concisely and simply by putting:
#view_config(...)
#get_base_data
def my_handler(request):
pass # rest of code...
This is one of most inobvious things in Pyramid and took a while to find for me, too.
You can modify the global template context in BeforeRender event.
http://docs.pylonsproject.org/projects/pyramid/en/latest/narr/hooks.html#using-the-before-render-event
Alternatively, you could use class based views, inherit all your views from one base view class which has get_base_data(), then the class instance is passed to the template context to all your views and then you could extract the data with {{ view.get_base_data }}.
http://ruslanspivak.com/2012/03/02/class-based-views-in-pyramid/
I vouch for the latter approach as it is more beautiful, predictable and easier to maintain engineering wise.
I would like to be able to submit a form in an HTML source (string). In other words I need at least the ability to generate POST parameters from a string containing HTML source of the form. This is needed in unit tests for a Django project. I would like a solution that possibly;
Uses only standard Python library and Django.
Allows parameter generation from a specific form if there is more than one form present.
Allows me to change the values before submission.
A solution that returns a (Django) form instance from a given form class is best. Because it would allow me to use validation. Ideally it would consume the source (which is a string), a form class, and optionally a form name and return the instance as it was before rendering.
NOTE: I am aware this is not an easy task, and probably the gains would hardly justify the effort needed. But I am just curious about how this can be done, in a practical and reliable way. If possible.
You should re-read the documentation about Django's testing framework, specifically the part about testing views (and forms) with the test client.
The test client acts as a simple web browser, and lets you make GET and POST requests to your Django views. You can read the response HTML or get the same Context object the template received. Your Context object should contain the actual forms.Form instance you're looking for.
As an example, if your view at the URL /form/ passes the context {'myform': forms.Form()} to the template, you could get to it this way:
from django.test.client import Client
c = Client()
# request the web page:
response = c.get('/form/')
# get the Form object:
form = response.context['myform']
form_data = form.cleaned_data
my_form_data = {} # put your filled-out data in here...
form_data.update(my_form_data)
# submit the form back to the web page:
new_form = forms.Form(form_data)
if new_form.is_valid():
c.post('/form/', new_form.cleaned_data)
Hopefully that accomplishes what you want, without having to mess with parsing HTML.
Edit: After I re-read the Django docs about Forms, it turns out that forms are immutable. That's okay, though, just create a new Form instance and submit that; I've changed my code example to match this.
Since the Django test framework does this, I'm not sure what you're asking.
Do you want to test a Django app that has a form?
In which case, you need to do an initial GET
followed by the resulting POST
Do you want to write (and test) a Django app that submits a form to another site?
Here's how we test Django apps with forms.
class Test_HTML_Change_User( django.test.TestCase ):
fixtures = [ 'auth.json', 'someApp.json' ]
def test_chg_user_1( self ):
self.client.login( username='this', password='this' )
response= self.client.get( "/support/html/user/2/change/" )
self.assertEquals( 200, response.status_code )
self.assertTemplateUsed( response, "someApp/user.html")
def test_chg_user( self ):
self.client.login( username='this', password='this' )
# The truly fussy would redo the test_chg_user_1 test here
response= self.client.post(
"/support/html/user/2/change/",
{'web_services': 'P',
'username':'olduser',
'first_name':'asdf',
'last_name':'asdf',
'email':'asdf#asdf.com',
'password1':'passw0rd',
'password2':'passw0rd',} )
self.assertRedirects(response, "/support/html/user/2/" )
response= self.client.get( "/support/html/user/2/" )
self.assertContains( response, "<h2>Users: Details for", status_code=200 )
self.assertContains( response, "olduser" )
self.assertTemplateUsed( response, "someApp/user_detail.html")
Note - we don't parse the HTML in detail. If it has the right template and has the right response string, it has to be right.
It is simple... and hard at the same time.
Disclaimer: I don't know much about Python and nothing at all about Django... So I give general, language agnostic advices...
If one of the above advices doesn't work for you, you might want to do it manually:
Load the page with an HTML parser, list the forms.
If the method attribute is POST (case insensitive), get the action attribute to get the URL of the request (can be relative).
In the form, get all input and select tags. The name (or id if no name) attributes are the keys of the request parameters. The value attributes (empty if absent) are the corresponding values.
For select, the value is the one of the selected option or the displayed text is no value attribute.
These names and values must be URL encoded in GET requests, but not in POST ones.
HTH.
Check out mechanize or it's wrapper twill. I think it's ClientForm module will work for you.