Develop Reference

Handle missing key from dict

I have this script which I use to pull in some data from an API call.
# list of each api url to use
link =[]
#for every device id , create a new url link into the link list
for i in deviceIDList:
link.append('https://website/v2/accounts/accountid/devices/'+i)
#create a list with all the different requests
deviceReq = []
for i in link:
deviceReq.append(requests.get(i, headers=headers).json())
# write to a txt file
with open('masterSheet.txt', 'x') as f:
for i in deviceReq:
devices =[i['data']]
for x in devices:
models = [x['provision']]
for data in models:
sheet=(data['endpoint_model']+" ",x['name'])
f.write(str(sheet)+"\n")
Some devices do not have the provision key.
Here is some sample data looks like from a device that is different.
Let's say I want to grab the device_type key value instead if provision key is non-existent.
"data": {
"sip": {
"username": "xxxxxxxxxxxxxxxx",
"password": "xxxxxxxxxxxxxxxx",
"expire_seconds": xxxxxxxxxxxxxxxx,
"invite_format": "xxxxxxxxxxxxxxxx",
"method": "xxxxxxxxxxxxxxxx",
"route": "xxxxxxxxxxxxxxxx"
},
"device_type": "msteams",
"enabled": xxxxxxxxxxxxxxxx,
"suppress_unregister_notifications": xxxxxxxxxxxxxxxx,
"owner_id": "xxxxxxxxxxxxxxxx",
"name": "xxxxxxxxxxxxxxxx",
}
How do I cater for missing keys?

You can use .get(key, defualt_value) to get the value from a dict, or if one is not present it will use the default like this:
provision = x.get('provision', None)
if provision is None:
provision = x.get('device_type')
models = [provision]
or if you prefer you can do the same on one line and without the extra if or assignment (though some people might find it more difficult to read and understand.
models = [x.get('provision', x.get('device_type'))]

How can I make checking the value for the parameter?

I want to write a program that will save information from the API, in the form of a JSON file. The API has the 'exchangeId' parameter. When I save information from the API, I want to save only those files in which the 'exchangeId' will be different and his value will be more then one. How can I make it? Please, give me hand.
My Code:
exchangeIds = {102,311,200,302,521,433,482,406,42,400}
for pair in json_data["marketPairs"]:
if (id := pair.get("exchangeId")):
if id in exchangeIds:
json_data["marketPairs"].append(pair)
exchangeIds.remove(id)
pairs.append({
"exchange_name": pair["exchangeName"],
"market_url": pair["marketUrl"],
"price": pair["price"],
"last_update" : pair["lastUpdated"],
"exchange_id": pair["exchangeId"]
})
out_object["name_of_coin"] = json_data["name"]
out_object["marketPairs"] = pairs
out_object["pairs"] = json_data["numMarketPairs"]
name = json_data["name"]
Example of ExchangeIds output, that I don't need:
{200} #with the one id in `ExchangeId`
Example of JSON output:
{
"name_of_coin": "Pax Dollar",
"marketPairs": [
{
"exchange_name": "Bitrue",
"market_url": "https://www.bitrue.com/trade/usdp_usdt",
"price": 1.0000617355334473,
"last_update": "2021-12-24T16:39:09.000Z",
"exchange_id": 433
},
{
"exchange_name": "Hotbit",
"market_url": "https://www.hotbit.io/exchange?symbol=USDP_USDT",
"price": 0.964348817699553,
"last_update": "2021-12-24T16:39:08.000Z",
"exchange_id": 400
}
],
"pairs": 22
} #this one of exapmle that I need, because there are two id

How to access ForeignKey data without making extra queries in Wagtail(django)

I have the following two classes in my app.models and i'm using the wagtail APIs to get the data as json
class AuthorMeta(Page):
author=models.OneToOneField(User)
city = models.ForeignKey('Cities', related_name='related_author')
class Cities(Page):
name = models.CharField(max_length=30)
So, when I try /api/v1/pages/?type=dashboard.AuthorMeta&fields=title,city, it returns the following data:
{
"meta": {
"total_count": 1
},
"pages": [
{
"id": 11,
"meta": {
"type": "dashboard.AuthorMeta",
"detail_url": "http://localhost:8000/api/v1/pages/11/"
},
"title": "Suneet Choudhary",
"city": {
"id": 10,
"meta": {
"type": "dashboard.Cities",
"detail_url": "http://localhost:8000/api/v1/pages/10/"
}
}
}
]
}
In the city field, it returns the id and meta of the city. How can I get the name of the city in the response here, without making an extra query? :/
I couldn't find any solution in the Documentation. Am I missing something?

Use Django model property to return through the ForeignKey:
class AuthorMeta(Page):
author=models.OneToOneField(User)
city = models.ForeignKey('Cities', related_name='related_author')
city_name = property(get_city_name)
def get_city_name(self):
return self.city.name
Check Term Property to better understand the concept

In case you have the foreign key in a Streamfield, e.g. a PageChooserBlock, you can customize the api response by overwriting the get_api_representation of a block, as described in the example as provided here:
class CustomPageChooserBlock(blocks.PageChooserBlock):
""" Customize the api response. """
def get_api_representation(self, value, context=None):
""" Return the url path instead of the id. """
return value.url_path

need to list all friends with facebook.py

i use facebook.py from:
https://github.com/pythonforfacebook/facebook-sdk
my problem is:
I don't know to use the next-url from graph.get_object("me/friends")
graph = facebook.GraphAPI(access_token)
friends = graph.get_object("me/friends")

If you type in /me/friends into the Graph API Explorer, you'll see that it returns a JSON file, which is just a combination of dictionaries and lists inside one another.
For example, the output could be:
{
"data": [
{
"name": "Foo",
"id": "1"
},
{
"name": "Bar",
"id": "1"
}
],
"paging": {
"next": "some_link"
}
}
This JSON file is already converted to a Python dictionary/list. In the outer dictionary, the key data maps to a list of dictionaries, which contain information about your friends.
So to print your friends list:
graph = facebook.GraphAPI(access_token)
friends = graph.get_object("me/friends")
for friend in friends['data']:
print "{0} has id {1}".format(friend['name'].encode('utf-8'), friend['id'])
The .encode('utf-8') is to properly print out special characters.

The above answer is mislead, as Facebook has shut down graph users from getting lists of friends UNLESS THE FRIENDS HAVE ALSO INSTALLED THE APP.
See:
graph = facebook.GraphAPI( token )
friends = graph.get_object("me/friends")
if friends['data']:
for friend in friends['data']:
print ("{0} has id {1}".format(friend['name'].encode('utf-8'), friend['id']))
else:
print('NO FRIENDS LIST')

Google App Engine Model Parents

I am somewhat new to the google app engine models system(and all database models for that matter), and I am trying to figure out how make a model have a collection of model instances as one of the properties. Some how I feel that there has to be a better way to model the data I have.
So here is the example. I'm writing a journal webapp. I want to allow users to have multible journals as defined by the model Journals
#Represents a collection of journals
class Journals(db.Model):
user = db.UserProperty()
journals = db.ListProperty(int) #there has to be a better way of keeping track of journals then by a list of their id
In the property journals I keep a list of the id's of the Journal model(shown below).
class Journal(db.Model):
user = db.UserProperty()
name = db.StringProperty()
date_created = db.DateTimeProperty(auto_now_add=True)
last_modified = db.DateTimeProperty(auto_now=True)
journal_item = db.ListProperty(int)
In the Journal model I store a list of id's of JournalItem instances as a list of id's
class JournalItem(db.Model):
user = db.UserProperty()
name = db.StringProperty()
date_created = db.DateTimeProperty(auto_now_add=True)
last_modified = db.DateTimeProperty(auto_now=True)
content = db.StringProperty(multiline=True)
So I guess the question really is how should I model data with this structure(I omitted some properties to simplify it)(shown in json).
"Journals": {
"Journal": {
"user": "GAE user object",
"name": "journal 1",
"JournalItems": {
"JournalItem": {
"name": "entry 1",
"content": "some example content"
},
"JournalItem": {
"name": "entry 2",
"content": "some example content"
},
"JournalItem": {
"name": "entry n",
"content": "some example content"
}
}
}
"Journal": {
"user": "GAE user object",
"name": "journal 2",
"JournalItems": {
"JournalItem": {
"name": "entry 1",
"content": "some example content"
},
"JournalItem": {
"name": "entry 2",
"content": "some example content"
},
"JournalItem": {
"name": "entry n",
"content": "some example content"
}
}
}
}
I hope that wasn't to long-winded to be annoying. Any help on the matter would be greatly appreciated.

That's pretty much the way to do it, except I would use a ListProperty(db.Key) instead of int. Then you can do db.get(userjournals.journals) to get all the user's journals once you have the Journals instance belonging to that user (note that to avoid confusion, you should probably call that something like UserJournals).
Remember that GAE is a non-relational datastore, and sometimes you have to think a bit differently from how you would using SQL.

You can follow this guide which describes in an elegant fashion how you can model your entities relationships on Google Appengine.
The reversed approach you can take is to create a reference for example of a Journal in the JournalItem entity and assign a collection_name to it.
class JournalItem:
Journal = db.ReferencePoperty(Journal, collection_name='journal_items')
name = db....
content = db...
The you will be able to iterate through the JournalItems of the Journal in this fashion:
for item in journal.journal_items
logging.info(item.content)