I was watching the new Boston Django tutorials. I know they are older, but he explains them well. I’m having trouble with one thing though.
He made a url
url[r’(?P<album_id)[0-9]+]
I know in Django 2.0 it’s a better way to do this. That’s not the question
His view looks like
def details(request,alblum_id):
return HttpResponse("<h2>The detail for the album ID:" + str(album_id) + "</h2>")
My question is how does Django know to get the id of the object from album_id if he never declared it. He just typed in a random variable?
is the "_id" part important for Django ? and that's how it knows the get the id of the database reference?
I understand i need to look at the view, I'm just confused on how Django knows to actually get the ID of the database reference. in the view it looks exactly like what i typed above. he just passed album_id beside request inside the parameters. I am still confused on how Django knows that "album_id" means go find the id of the database object. is that built in ?
link : [https://www.youtube.com/watch?v=mWofrhTwGWQ&list=PL6gx4Cwl9DGBlmzzFcLgDhKTTfNLfX1IK&index=12][1]
The view that is specified on the URL line takes the id most likely as a parameter then use that to look up in the database.
Essentially you need to look at the view to understand what he is doing.
Related
I am working on some Django/Python code.
Basically, the backend of my code gets sent a dict of parameters named 'p'. These values all come off Django models.
When I tried to override them as such:
p['age']=25
I got a 'model error'. Yet, if I write:
p.age=25
it works fine.
My suspicion is that, internally, choice #1 tries to set a new value to an instance of a class created by Django that objects to being overridden, but internally Python3 simply replaces the Django instance with a "new" attribute of the same name ('age'), without regard for the prior origin, type, or class of what Django created.
All of this is in a RESTful framework, and actually in test code. So even if I am right I don't believe it changes anything for me in reality.
But can anyone explain why one type of assignment to an existing dict works, and the other fails?
p is a class, not a dict. Django built it that way.
But, as such, one approach (p.age) lets you change an attribute of the object in the class.
My django app uses update_or_create() to update a bunch of records. In some cases, updates are really few within a ton of records, and it would be nice to know what got updated within those records. Is it possible to know what got updated (i.e fields whose values got changed)? If not, does any one has ideas of workarounds to achieve that?
This will be invoked from the shell, so ideally it would be nice to be prompted for confirmation just before a value is being changed within update_or_create(), but if not that, knowing what got changed will also help.
Update (more context): Thought I'd give more context here. The data in this Django app gets updated through various means (through users coming on the web site, through the admin page, through scripts (run from the shell) that populate data from a csv etc.). The above question is important mostly for the shell scripts that update data from csvs, hence a solution at the database/trigger/signal level may not be helpful here (I guess).
This is what I ended up doing:
for row in reader:
school_obj0, created = Org.objects.get_or_create(school_id = row[0])
if (school_obj0.name != row[1]):
print (school_obj0.name, '==>', row[1])
confirmation = input('proceed? [y/n]: ')
if (confirmation == 'y'):
school_obj1, created = Org.objects.update_or_create(
school_id = row[0], defaults={"name": row[1],})
Happy to know about improvements to this approach (please see the update in the question with more context)
This will be invoked from the shell, so ideally it would be nice to be
prompted for confirmation just before a value is being changed
Unfortunately, databases don't work like that. It's the responsibility of applications to provide this functionality. And django isn't an application. You can however use django to write an application that provides this functionality.
As for finding out whether an object was updated or created, that's what the return value gives you. A tuple where the second value is a flag for update or create
How do I make the buying process very simple without registration:
What I need is here?
catalog/controller/checkout
catalog/language/english/checkout
catalog/model/checkout
catalog/view/theme/default/template/checkout
Or somewhere else?
I have simplified the registration form:
http://i62.tinypic.com/veufqp.jpg
A problem with catalog\model\account\customer.php
http://i59.tinypic.com/11ujfq0.jpg
I understand what went wrong, the model does not receive the necessary variables.
But how to drown out the missing variables?
The right to request in the model or you can somehow do it in the controller?
Location data model takes ?:
- POST
- date
- session
I'm helping develop a new API for an existing database.
I'm using Python 2.7.3, Django 1.5 and the django-rest-framework 2.2.4 with PostgreSQL 9.1
I need/want good documentation for the API, but I'm shorthanded and I hate writing/maintaining documentation (one of my many flaws).
I need to allow consumers of the API to add new "POS" (points of sale) locations. In the Postgres database, there is a foreign key from pos to pos_location_type. So, here is a simplified table structure.
pos_location_type(
id serial,
description text not null
);
pos(
id serial,
pos_name text not null,
pos_location_type_id int not null references pos_location_type(id)
);
So, to allow them to POST a new pos, they will need to give me a "pos_name" an a valid pos_location_type. So, I've been reading about this stuff all weekend. Lots of debates out there.
How is my API consumers going to know what a pos_location_type is? Or what value to pass here?
It seems like I need to tell them where to get a valid list of pos_locations. Something like:
GET /pos_location/
As a quick note, examples of pos_location_type descriptions might be: ('school', 'park', 'office').
I really like the "Browseability" of of the Django REST Framework, but, it doesn't seem to address this type of thing, and I actually had a very nice chat on IRC with Tom Christie earlier today, and he didn't really have an answer on what to do here (or maybe I never made my question clear).
I've looked at Swagger, and that's a very cool/interesting project, but take a look at their "pet" resource on their demo here. Notice it is pretty similar to what I need to do. To add a new pet, you need to pass a category, which they define as class Category(id: long, name: string). How is the consumer suppose to know what to pass here? What's a valid id? or name?
In Django rest framework, I can define/override what is returned in the OPTION call. I guess I could come up with my own little "system" here and return some information like:
pos-location-url: '/pos_location/'
in the generic form, it would be: {resource}-url: '/path/to/resource_list'
and that would sort of work for the documentation side, but I'm not sure if that's really a nice solution programmatically. What if I change the resources location. That would mean that my consumers would need to programmatically make and OPTIONS call for the resource to figure out all of the relations. Maybe not a bad thing, but feels like a little weird.
So, how do people handle this kind of thing?
Final notes: I get the fact that I don't really want a "leaking" abstaction here and have my database peaking thru the API layer, but the fact remains that there is a foreign_key constraint on this existing database and any insert that doesn't have a valid pos_location_type_id is raising an error.
Also, I'm not trying to open up the URI vs. ID debate. Whether the user has to use the pos_location_type_id int value or a URI doesn't matter for this discussion. In either case, they have no idea what to send me.
I've worked with this kind of stuff in the past. I think there is two ways of approaching this problem, the first you already said it, allow an endpoint for users of the API to know what is the id-like value of the pos_location_type. Many API's do this because a person developing from your API is gonna have to read your documentation and will know where to get the pos_location_type values from. End-users should not worry about this, because they will have an interface showing probably a dropdown list of text values.
On the other hand, the way I've also worked this, not very RESTful-like. Let's suppose you have a location in New York, and the POST could be something like:
POST /pos/new_york/
You can handle /pos/(location_name)/ by normalizing the text, then just search on the database for the value or some similarity, if place does not exist then you just create a new one. That in case users can add new places, if not, then the user would have to know what fixed places exist, which again is the first situation we are in.
that way you can avoid pos_location_type in the request data, you could programatically map it to a valid ID.
I was about ready to start giving a jqgrid in a django app greater functionality (pagination, searching, etc). In order to do this it looks as though jqgrid sends its parameters in the GET to the server. I plan to write an urlpattern to pull out the necessary stuff (page number, records per page, search term, etc) so I can pass it along to my view to return the correct rows to the grid. Has anyone out there already created this urlpattern I am in search of?
Thanks much.
The answer to this was simpler than I realized. As stated in Chapter 7 of the djangobook in the section titled "Query string parameters" one can simply do something as follows, where "someParam" is the parameter in the query string you want to retrieve. However, Django is designed to be clean in that address bar at the top of the page so you should only use this option if you must.
The query string might look something like this.
http://somedomainname.com/?someString=1
The view might look like this.
def someView(request):
if 'someParam' in request.GET and request.GET['someParam']:
someParam = request.GET['someParam']
Hopefully this is of some help to someone else down the road.