I am trying to output a set of database records in JSON as follows:
def json_dbtable(request, p):
t = MyModel.objects.filter({some query})
s = serializers.get_serializer("json")()
re = s.serialize(t, ensure_ascii=False)
return HttpResponse(re, mimetype="application/json")
However, one of the fields i'm trying to return needs to change if it is null, and to remedy this the model has a definition that is used as a property .e.g:
name = property(_get_useful_name)
So, to get to the crux of the question. How can I include this "name" property in my json serialization as well as the raw field data?
The short answer is no, the long answer, is you could serialize your MyModel instance yourself:
simplejson.dumps([{'pk': m.pk, 'name': m.name} for m in MyModel.objects.filter(...)])
I have written a serialization framework for Python called any2any
which include (de)serializers for Django
and which allows you to do that easily.
It will be way cleaner than the DIY way.
Hope that helps !
Related
I'm trying to create a custom field for validating POSTed JSON in my API using Flask-RESTPlus 0.10.1
Below is the basic setup...
from flask_restplus import fields
import re
EMAIL_REGEX = re.compile(r'\S+#\S+\.\S+')
class Email(fields.String):
__schema_type__ = 'string'
__schema_format__ = 'email'
__schema_example__ = 'email#domain.com'
def validate(self, value):
if not value:
return False if self.required else True
if not EMAIL_REGEX.match(value):
return False
return True
I like the way the above documents in Swagger UI, but I can't seem to figure out how to actually use the validate method on it.
Here's how I'm using the custom field.
Json = api.model('Input JSON', {
'subscribers': fields.List(Email),
[...]
})
#api.expect(Json) // validate is globally set to true
def post(self):
pass
I've had luck using
'subscribers': fields.List(fields.String(pattern='\S+#\S+\.\S+')) instead, but this doesn't give me the control to customize the error message, where'd I'd like it to return that the field is not of the email type.
I've also gone on and added a custom validate_payload function (found within http://aviaryan.in/blog/gsoc/restplus-validation-custom-fields.html) that I call again within my POST method (instead of api.expect). This requires me to duplicate some core functionality and call it every time in addition to api.expect to output the proper Swagger documentation and a little bit of finesse to get it to work within nested fields.
It's my understanding that this should work out of box? Am I wrong? What am I missing here?
I appreciate this is a little old but just had the same issue.
It looks like the "validate" actually sat over a python jsonschema impl, if you're still interested in digging, it's available here
That aside - you can configure restplus API to use a better formatchecker as follows: (I also validate date-time and date)
format_checker = FormatChecker(formats=["date-time", "email", "date"])
api_v1 = Api(
app, version='1.4',
title='[Anon]',
description='[Anon] API for developers',
format_checker=format_checker
)
I have a table that contains values saved as a dictionary.
FIELD_NAME: extra_data
VALUE:
{"code": null, "user_id": "103713616419757182414", "access_token": "ya29.IwBloLKFALsddhsAAADlliOoDeE-PD_--yz1i_BZvujw8ixGPh4zH-teMNgkIA", "expires": 3599}
I need to retrieve the user_id value from the field "extra_data" only not the dictionnary like below.
event_list = Event.objects.filter(season_id=season_id, event_status_id=2).value('extra_data')
If you are storing a dictionary as text in the code you can easily convert it to a python dictionary using eval - although I don't know why you'd want to as it opens you to all sorts of potential malicious code injections.
event_list = eval(Event.objects.filter(season_id=season_id, event_status_id=2).value('extra_data'))
user_id = event_list['user_id']
print user_id
Would give:
"103713616419757182414"
Edit:
On deeper inspection , thats not a Python dictionary, you could import a JSON library to import this, or declare what null is like so:
null = None
event_list = eval(Event.objects.filter(season_id=season_id, event_status_id=2).value('extra_data'))
user_id = event_list['user_id']
Either way, the idea of storing any structured data in a django textfield is fraught with danger that will come back to bite you. The best solution is to rethink your data structures.
This method worked for me. However, this works with a json compliant string
import json
json_obj = json.loads(event_list)
dict1 = dict(json_obj)
print dict1['user_id']
I was wondering what is the correct approach,
Do I create HiddenInput fields in my ModelForm and from the
View I pass in the primaryKey for the models I am about to edit into
the hiddenInput fields and then grab those hiddenInput fields from
the AJAX script to use it like this?
item.load(
"/bookmark/save/" + hidden_input_field_1,
null,
function () {
$("#save-form").submit(bookmark_save);
}
);
Or is there is some more clever way of doing it and I have no idea?
Thanks
It depends upon how you want to implement.
The basic idea is to edit 1. you need to get the existing instance, 2. Save provided information into this object.
For #1 you can do it multiple ways, like passing ID or any other primary key like attribute in url like http://myserver/edit_object/1 , Or pass ID as hidden input then you have to do it through templates.
For #2, I think you would already know this. Do something like
inst = MyModel.objects.get(id=input_id) # input_id taken as per #1
myform = MyForm(request.POST, instance=inst)
if myform.is_valid():
saved_inst = myform.save()
I just asked in the django IRC room and it says:
since js isn't processed by the django template engine, this is not
possible.
Hence the id or the object passed in from django view can't be accessed within AJAX script.
I have a json field in my database which is like
jsonfield = {'username':'chingo','reputation':'5'}
how can i write a query so that i can find if a user name exists. something like
username = 'chingo'
query = User.objects.get(jsonfield['username']=username)
I know the above query is a wrong but I wanted to know if there is a way to access it?
If you are using the django-jsonfield package, then this is simple. Say you have a model like this:
from jsonfield import JSONField
class User(models.Model):
jsonfield = JSONField()
Then to search for records with a specific username, you can just do this:
User.objects.get(jsonfield__contains={'username':username})
Since Django 1.9, you have been able to use PostgreSQL's native JSONField. This makes search JSON very simple. In your example, this query would work:
User.objects.get(jsonfield__username='chingo')
If you have an older version of Django, or you are using the Django JSONField library for compatibility with MySQL or something similar, you can still perform your query.
In the latter situation, jsonfield will be stored as a text field and mapped to a dict when brought into Django. In the database, your data will be stored like this
{"username":"chingo","reputation":"5"}
Therefore, you can simply search the text. Your query in this siutation would be:
User.objects.get(jsonfield__contains='"username":"chingo"')
2019: As #freethebees points out it's now as simple as:
User.objects.get(jsonfield__username='chingo')
But as the doc examples mention you can query deeply, and if the json is an array you can use an integer to index it:
https://docs.djangoproject.com/en/2.2/ref/contrib/postgres/fields/#querying-jsonfield
>>> Dog.objects.create(name='Rufus', data={
... 'breed': 'labrador',
... 'owner': {
... 'name': 'Bob',
... 'other_pets': [{
... 'name': 'Fishy',
... }],
... },
... })
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': None})
>>> Dog.objects.filter(data__breed='collie')
<QuerySet [<Dog: Meg>]>
>>> Dog.objects.filter(data__owner__name='Bob')
<QuerySet [<Dog: Rufus>]>
>>> Dog.objects.filter(data__owner__other_pets__0__name='Fishy')
<QuerySet [<Dog: Rufus>]>
Although this is for postgres, I believe it works the same in other DBs like MySQL
Postgres: https://docs.djangoproject.com/en/2.2/ref/contrib/postgres/fields/#querying-jsonfield
MySQL: https://django-mysql.readthedocs.io/en/latest/model_fields/json_field.html#querying-jsonfield
This usage is somewhat anti-pattern. Also, its implementation is not going to have regular performance, and perhaps is error-prone.
Normally don't use jsonfield when you need to look up through fields. Use the way the RDBMS provides or MongoDB(which internally operates on faster BSON), as Daniel pointed out.
Due to the deterministic of JSON format,
you could achieve it by using contains (regex has issue when dealing w/ multiple '\' and even slower), I don't think it's good to use username in this way, so use name instead:
def make_cond(name, value):
from django.utils import simplejson
cond = simplejson.dumps({name:value})[1:-1] # remove '{' and '}'
return ' ' + cond # avoid '\"'
User.objects.get(jsonfield__contains=make_cond(name, value))
It works as long as
the jsonfield using the same dump utility (the simplejson here)
name and value are not too special (I don't know any egde-case so far, maybe someone could point it out)
your jsonfield data is not corrupt (unlikely though)
Actually I'm working on a editable jsonfield and thinking about whether to support such operations. The negative proof is as said above, it feels like some black-magic, well.
If you use PostgreSQL you can use raw sql to solve problem.
username = 'chingo'
SQL_QUERY = "SELECT true FROM you_table WHERE jsonfield::json->>'username' = '%s'"
User.objects.extra(where=[SQL_EXCLUDE % username]).get()
where you_table is name of table in your database.
Any methods when you work with JSON like with plain text - looking like very bad way.
So, also I think that you need a better schema of database.
Here is the way I have found out that will solve your problem:
search_filter = '"username":{0}'.format(username)
query = User.objects.get(jsonfield__contains=search_filter)
Hope this helps.
You can't do that. Use normal database fields for structured data, not JSON blobs.
If you need to search on JSON data, consider using a noSQL database like MongoDB.
I'd like to have access to one my model field verbose_name.
I can get it by the field indice like this
model._meta._fields()[2].verbose_name
but I need to get it dynamically. Ideally it would be something like this
model._meta._fields()['location_x'].verbose_name
I've looked at a few things but I just can't find it.
For Django < 1.10:
model._meta.get_field_by_name('location_x')[0].verbose_name
model._meta.get_field('location_x').verbose_name
For Django 1.11 and 2.0:
MyModel._meta.get_field('my_field_name').verbose_name
More info in the Django doc
The selected answer gives a proxy object which might look as below.
<django.utils.functional.__proxy__ object at 0x{SomeMemoryLocation}>
If anyone is seeing the same, you can find the string for the verbose name in the title() member function of the proxy object.
model._meta.get_field_by_name(header)[0].verbose_name.title()
A better way to write this would be:
model._meta.get_field(header).verbose_name.title()
where header will be the name of the field you are interested in. i.e., 'location-x' in OPs context.
NOTE: Developers of Django also feel that using get_field is better and thus have depreciated get_field_by_name in Django 1.10. Thus I would suggest using get_field no matter what version of Django you use.
model._meta.get_field_by_name('location_x')[0].verbose_name
You can also use:
Model.location_x.field.verbose_name
Model being the class name. I tested this on my Animal model:
Animal.sale_price.field.verbose_name
Animal.sale_price returns a DeferredAttribute, which has several meta data, like the verbose_name
Note: I'm using Django 3.1.5
If you want to iterate on all the fields you need to get the field:
for f in BotUser._meta.get_fields():
if hasattr(f, 'verbose_name'):
print(f.verbose_name)
# select fields for bulk_update : exclude primary key and relational
fieldsfields_to_update = []
for field_to_update in Model._meta.get_fields():
if not field_to_update.many_to_many and not field_to_update.many_to_one and not field_to_update.one_to_many and not field_to_update.one_to_one and not field_to_update.primary_key and not field_to_update.is_relation :
fields_to_update = fields_to_update + [field_to_update.name]
Model.objects.bulk_update(models_to_update , fields_to_update)