I have the following resource:
class Image(Resource):
def get(self, db_name, col_name, image_id):
col = mongo_client[db_name][col_name]
image = col.find_one({'_id':ObjectId(image_id)})
try:
image['_id'] = str(image['_id'])
except TypeError:
return {'image': 'notFound'}
return {'image':image}
linked to a certain endpoint.
However, image contains certain datetime objects inside. I could wrap this around with `json.dumps(..., default=str), but I see that there is a way of enforcing this on flask-restful. It's just not clear to me what exactly needs to be done.
In particular, I read:
It is possible to configure how the default Flask-RESTful JSON
representation will format JSON by providing a RESTFUL_JSON
attribute on the application configuration.
This setting is a dictionary with keys that
correspond to the keyword arguments of json.dumps().
class MyConfig(object):
RESTFUL_JSON = {'separators': (', ', ': '),
'indent': 2,
'cls': MyCustomEncoder}
But it's not clear to me where exactly this needs to be placed. Tried a few things and it didn't work.
EDIT:
I finally solved with this:
Right after
api = Api(app)
I added:
class CustomEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, datetime.datetime):
#return int(obj.strftime('%s'))
return str(obj)
elif isinstance(obj, datetime.date):
#return int(obj.strftime('%s'))
return str(obj)
return json.JSONEncoder.default(self, obj)
def custom_json_output(data, code, headers=None):
dumped = json.dumps(data, cls=CustomEncoder)
resp = make_response(dumped, code)
resp.headers.extend(headers or {})
return resp
api = Api(app)
api.representations.update({
'application/json': custom_json_output
})
Just cleared this out, you just have to do the following:
app = Flask(__name__)
api = Api(app)
app.config['RESTFUL_JSON'] = {'cls':MyCustomEncoder}
This works both for plain Flask and Flask-RESTful.
NOTES:
1) Apparently the following part of the documentation is not that clear:
It is possible to configure how the default Flask-RESTful JSON
representation will format JSON by providing a RESTFUL_JSON attribute
on the application configuration. This setting is a dictionary with
keys that correspond to the keyword arguments of json.dumps().
class MyConfig(object):
RESTFUL_JSON = {'separators': (', ', ': '),
'indent': 2,
'cls': MyCustomEncoder}
2)Apart from the 'cls' argument you can actually overwrite any keyword argument of the json.dumps function.
Having created a Flask app, e.g. like so:
root_app = Flask(__name__)
place MyConfig in some module e.g. config.py and then configure root_app like:
root_app.config.from_object('config.MyConfig')
Related
Using:
Django 3.x [ Django-Filters 2.2.0, graphene-django 2.8.0, graphql-relay 2.0.1 ]
Vue 2.x [ Vue-Apollo ]
After applying some filters (iContains etc.) on my graphQL search i tried to change or manipulate the connection_args like firstor after. I can fetch a Dictionary on my resolver like {'first': 2, 'name__icontains': 'eagle'} with values i put in the IDE. As you can see (Example 1 /def resolve_all_birds2) i use that already for a logic. But i do not understand where do manipulate the GraphQLArgument states of the before. after first. last function which comes with relay?
Example 1
class ExtendedConnection(Connection):
class Meta:
abstract = True
total_count = Int()
edge_count = Int()
def resolve_total_count(root, info, **kwargs):
return root.length
def resolve_edge_count(root, info, **kwargs):
return len(root.edges)
class Birds2Node(DjangoObjectType):
class Meta:
model = Birds
filter_fields = {
'id': ['exact', 'icontains'],
'name': ['exact', 'icontains', 'istartswith', 'iendswith'],
}
interfaces = (relay.Node, )
connection_class = ExtendedConnection
# --- CUSTOM FIELDS -->
# pkey = _db primary key
pKey = Int()
def resolve_pKey(parent, info):
return parent.pk
# qRank = Item Rank in Edge Array
qRank = Int()
def resolve_qRank(parent, info, **kwargs):
return info.path[2]
class Birds2Query(ObjectType):
birds2 = relay.Node.Field(Birds2Node)
all_birds2 = DjangoFilterConnectionField(Birds2Node)
def resolve_all_birds2(self, info, **kwargs):
if 'name__icontains' in kwargs:
nameIcon = kwargs['name__icontains']
nameIconBool = bool(nameIcon.strip()) # if blanks turns False
if nameIconBool == False: # has blanks
return Birds.objects.filter(name=None)
pass
if 'name__istartswith' in kwargs:
nameIsta = kwargs['name__istartswith']
nameIstaBool = bool(nameIsta.strip()) # if blanks turns False
if nameIstaBool == False: # has blanks
return Birds.objects.filter(name=None)
pass
return
For example, in my IDE i declare allBirds2(first: 2, name_Icontains: "a")... i can fetch these values with my resolver as a Dictionary via **kwargs`` or via args def resolve_all_birds2(self, info, first, name_icontains): so far so good, i can manipulate my ModelQuery and it returned only 2 per Edge.
But Imagine i want to change first: 2 to first: 10 in my BackEnd? Can i update the Dictionary? The Documentation means yes, but it seems strict related to the ObjectTypes (Fields) you resolve.
For Example i tried this...
Example 2
def resolve_all_birds2(self, info, **kwargs):
<...>
return {'first': '20', 'name__icontains': 'd' }
Output IDE: "message": "'dict' object has no attribute 'model'"
Example 3
def resolve_all_birds2(self, info, first, **kwargs):
<...>
return f'20, {first}!'
Output IDE: "message": "name 'first' is not defined",
Question
Unfortunately i found only parameter manipulation on the modelquery in the graphene-python docs.
So my Question is how can i manipulate - in my backend - the Values of the Fields before. after first. last, that relay offers and that are already useable in my IDE. Do i have to declare them extra in my DjangoObjectType or create a custom Node to manipulate and change the values after a user sends a request?
Adding a middleware would probably allow changing the input values after the request is made and before running the query. Graphene has an example at: https://docs.graphene-python.org/en/latest/execution/middleware/
However, it's not clear (to me) from the documentation which of the mentioned parameters would contain the first field you want to manipulate.
The middleware approach does not seem to be highly recommended, though, because this is an undesirable side effect: https://github.com/graphql-python/graphene/issues/1285
I am following the instruction from this page. I am building a slack slash command handling server and I can't rebuild the signature to validate slash request authenticity.
here is the code snippet from my django application (the view uses the django rest-framework APIView):
#property
def x_slack_req_ts(self):
if self.xsrts is not None:
return self.xsrts
self.xsrts = str(self.request.META['HTTP_X_SLACK_REQUEST_TIMESTAMP'])
return self.xsrts
#property
def x_slack_signature(self):
if self.xss is not None:
return self.xss
self.xss = self.request.META['HTTP_X_SLACK_SIGNATURE']
return self.xss
#property
def base_message(self):
if self.bs is not None:
return self.bs
self.bs = ':'.join(["v0", self.x_slack_req_ts, self.raw.decode('utf-8')])
return self.bs
#property
def encoded_secret(self):
return self.app.signing_secret.encode('utf-8')
#property
def signed(self):
if self.non_base is not None:
return self.non_base
hashed = hmac.new(self.encoded_secret, self.base_message.encode('utf-8'), hashlib.sha256)
self.non_base = "v0=" + hashed.hexdigest()
return self.non_base
This is within a class where self.raw = request.body the django request and self.app.signing_secret is a string with the appropriate slack secret string. It doesn't work as the self.non_base yield an innaccurate value.
Now if I open an interactive python repl and do the following:
>>> import hmac
>>> import hashlib
>>> secret = "8f742231b10e8888abcd99yyyzzz85a5"
>>> ts = "1531420618"
>>> msg = "token=xyzz0WbapA4vBCDEFasx0q6G&team_id=T1DC2JH3J&team_domain=testteamnow&channel_id=G8PSS9T3V&channel_name=foobar&user_id=U2CERLKJA&user_name=roadrunner&command=%2Fwebhook-collect&text=&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT1DC2JH3J%2F397700885554%2F96rGlfmibIGlgcZRskXaIFfN&trigger_id=398738663015.47445629121.803a0bc887a14d10d2c447fce8b6703c"
>>> ref_signature = "v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503"
>>> base = ":".join(["v0", ts, msg])
>>> hashed = hmac.new(secret.encode(), base.encode(), hashlib.sha256)
>>> hashed.hexdigest()
>>> 'a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503'
You will recognise the referenced link example. If I use the values from my django app with one of MY examples, it works within the repl but doesn't within the django app.
MY QUESTION: I believe this is caused by the self.raw.decode() encoding not being consistent with the printout I extracted to copy/paste in the repl. Has anyone encountered that issue and what is the fix? I tried a few random things with the urllib.parse library... How can I make sure that the request.body encoding is consistent with the example from flask with get_data() (as suggested by the doc in the link)?
UPDATE: I defined a custom parser:
class SlashParser(BaseParser):
"""
Parser for form data.
"""
media_type = 'application/x-www-form-urlencoded'
def parse(self, stream, media_type=None, parser_context=None):
"""
Parses the incoming bytestream as a URL encoded form,
and returns the resulting QueryDict.
"""
parser_context = parser_context or {}
request = parser_context.get('request')
raw_data = stream.read()
data = QueryDict(raw_data, encoding='utf-8')
setattr(data, 'raw_body', raw_data) # setting a 'body' alike custom attr with raw POST content
return data
To test based on this question and the raw_body in the custom parser generates the exact same hashed signature as the normal "body" but again, copy pasting in the repl to test outside the DRF works. Pretty sure it's an encoding problem but completely at loss...
I found the problem which is very frustrating.
It turns out that the signing secret was stored in too short a str array and were missing trailing characters which obviously, resulted in bad hashing of the message.
I am trying to create a REST API with Neo4j and Django in the backend.
The problem is that even when I have Django models using Neo4Django , I can't use frameworks like Tastypie or Piston that normally serialize models into JSON (or XML).
Sorry if my question is confusing or not clear, I am newbie to webservices.
Thanks for you help
EDIT: So I started with Tastypie and followed the tutorial on this page http://django-tastypie.readthedocs.org/en/latest/tutorial.html. I am looking for displaying the Neo4j JSON response in the browser, but when I try to access to http://127.0.0.1:8000/api/node/?format=json I get this error instead:
{"error_message": "'NoneType' object is not callable", "traceback": "Traceback (most recent call last):\n\n File \"/usr/local/lib/python2.6/dist-packages/tastypie/resources.py\", line 217, in wrapper\n response = callback(request, *args, **kwargs)\n\n File \"/usr/local/lib/python2.6/dist-packages/tastypie/resources.py\", line 459, in dispatch_list\n return self.dispatch('list', request, **kwargs)\n\n File \"/usr/local/lib/python2.6/dist-packages/tastypie/resources.py\", line 491, in dispatch\n response = method(request, **kwargs)\n\n File \"/usr/local/lib/python2.6/dist-packages/tastypie/resources.py\", line 1298, in get_list\n base_bundle = self.build_bundle(request=request)\n\n File \"/usr/local/lib/python2.6/dist-packages/tastypie/resources.py\", line 718, in build_bundle\n obj = self._meta.object_class()\n\nTypeError: 'NoneType' object is not callable\n"}
Here is my code :
api.py file:
class NodeResource (ModelResource): #it doesn't work with Resource neither
class meta:
queryset= Node.objects.all()
resource_name = 'node'
urls.py file:
node_resource= NodeResource()
urlpatterns = patterns('',
url(r'^api/', include(node_resource.urls)),
models.py file :
class Node(models.NodeModel):
p1 = models.StringProperty()
p2 = models.StringProperty()
I would advise steering away from passing Neo4j REST API responses directly through your application. Not only would you not be in control of the structure of these data formats as they evolve and deprecate (which they do) but you would be exposing unnecessary internals of your database layer.
Besides Neo4Django, you have a couple of other options you might want to consider. Neomodel is another model layer designed for Django and intended to act like the built-in ORM; you also have the option of the raw OGM layer provided by py2neo which may help but isn't Django-specific.
It's worth remembering that Django and its plug-ins have been designed around a traditional RDBMS, not a graph database, so none of these solutions will be perfect. Whatever you choose, you're likely to have to carry out a fair amount of transformation work to create your application's API.
Django-Tastypie allows to create REST APIs with NoSQL databases as well as mentioned in http://django-tastypie.readthedocs.org/en/latest/non_orm_data_sources.html.
The principle is to use tastypie.resources.Resource and not tastypie.resources.ModelResource which is SPECIFIC to RDBMS, then main functions must be redefined in order to provide a JSON with the desired parameters.
So I took the example given in the link, modified it and used Neo4j REST Client for Python to get an instance of the db and perform requests, and it worked like a charm.
Thanks for all your responses :)
Thanks to recent contributions, Neo4django now supports Tastypie out of the box! I'd love to know what you think if you try it out.
EDIT:
I've just run through the tastypie tutorial, and posted a gist with the resulting example. I noticed nested resources are a little funny, but otherwise it works great. I'm pretty sure the gents who contributed the patches enabling this support also know how to take care of nested resources- I'll ask them to speak up.
EDIT:
As long as relationships are specified in the ModelResource, they work great. If anyone would like to see examples, let me know.
Well my answer was a bit vague so I'm gonna post how a solved the problem with some code:
Assume that I want to create an airport resource with some attributes. I will structure this in 3 different files (for readability reasons).
First : airport.py
This file will contain all the resource attributes and a constructor too :
from models import *
class Airport(object):
def __init__ (self, iata, icao, name, asciiName, geonamesId, wikipedia, id, latitude, longitude):
self.icao = icao
self.iata = iata
self.name = name
self.geonamesId = geonamesId
self.wikipedia = wikipedia
self.id = id
self.latitude = latitude
self.longitude = longitude
self.asciiName = asciiName
This file will be used in order to create resources.
Then the second file : AirportResource.py:
This file will contain the resource attributes and some basic methods depending on which request we want our resource to handle.
class AirportResource(Resource):
iata = fields.CharField(attribute='iata')
icao = fields.CharField(attribute='icao')
name = fields.CharField(attribute='name')
asciiName = fields.CharField(attribute='asciiName')
latitude = fields.FloatField(attribute='latitude')
longitude = fields.FloatField(attribute='longitude')
wikipedia= fields.CharField(attribute='wikipedia')
geonamesId= fields.IntegerField(attribute='geonamesId')
class Meta:
resource_name = 'airport'
object_class = Airport
allowed_methods=['get', 'put']
collection_name = 'airports'
detail_uri_name = 'id'
def detail_uri_kwargs(self, bundle_or_obj):
kwargs = {}
if isinstance(bundle_or_obj, Bundle):
kwargs['id'] = bundle_or_obj.obj.id
else:
kwargs['id'] = bundle_or_obj.id
return kwargs
As mentioned in the docs, if we want to create an API that handle CREATE, GET, PUT, POST and DELETE requests, we must override/implement the following methods :
def obj_get_list(self, bundle, **kwargs) : to GET a list of objects
def obj_get(self, bundle, **kwargs) : to GET an individual object
def obj_create(self, bundle, **kwargs) to create an object (CREATE method)
def obj_update(self, bundle, **kwargs) to update an object (PUT method)
def obj_delete(self, bundle, **kwargs) to delete an object (DELETE method)
(see http://django-tastypie.readthedocs.org/en/latest/non_orm_data_sources.html)
Normally, in ModelResource all those methods are defined and implemented, so they can be used directly without any difficulty. But in this case, they should be customized according to what we want to do.
Let's see an example of implementing obj_get_list and obj_get :
For obj_get_list:
In ModelResource, the data is FIRSTLY fetched from the database, then it could be FILTERED according to the filter declared in META class ( see http://django-tastypie.readthedocs.org/en/latest/interacting.html). But I didn't wish to implement such behavior (get everything then filter), so I made a query to Neo4j given the query string parameters:
def obj_get_list(self,bundle, **kwargs):
data=[]
params= []
for key in bundle.request.GET.iterkeys():
params.append(key)
if "search" in params :
query= bundle.request.GET['search']
try:
results = manager.searchAirport(query)
data = createAirportResources(results)
except Exception as e:
raise NotFound(e)
else:
raise BadRequest("Non valid URL")
return data
and for obj_get:
def obj_get(self, bundle, **kwargs):
id= kwargs['id']
try :
airportNode = manager.getAirportNode(id)
airport = createAirportResources([airportNode])
return airport[0]
except Exception as e :
raise NotFound(e)
and finally a generic function that takes as parameter a list of nodes and returns a list of Airport objects:
def createAirportResources(nodes):
data= []
for node in nodes:
iata = node.properties['iata']
icao = node.properties['icao']
name = node.properties['name']
asciiName = node.properties['asciiName']
geonamesId = node.properties['geonamesId']
wikipedia = node.properties['wikipedia']
id = node.id
latitude = node.properties['latitude']
longitude = node.properties['longitude']
airport = Airport(iata, icao, name, asciiName, geonamesId, wikipedia, id, latitude, longitude)
data.append(airport)
return data
Now the third manager.py : which is in charge of making queries to the database and returning results :
First of all, I get an instance of the database using neo4j rest client framework :
from neo4jrestclient.client import *
gdb= GraphDatabase("http://localhost:7474/db/data/")
then the function which gets an airport node :
def getAirportNode(id):
if(getNodeType(id) == type):
n= gdb.nodes.get(id)
return n
else:
raise Exception("This airport doesn't exist in the database")
and the one to perform search (I am using a server plugin, see Neo4j docs for more details):
def searchAirport(query):
airports= gdb.extensions.Search.search(query=query.strip(), searchType='airports', max=6)
if len(airports) == 0:
raise Exception('No airports match your query')
else:
return results
Hope this will help :)
Full Disclosure: Cross posted to Tastypie Google Group
I have a situation where I have limited control over what is being sent to my api. Essentially there are two webservices that I need to be able to accept POST data from. Both use plain POST actions with urlencoded data (basic form submission essentially).
Thinking about it in "curl" terms it's like:
curl --data "id=1&foo=2" http://path/to/api
My problem is that I can't update records using POST. So I need to adjust the model resource (I believe) such that if an ID is specified, the POST acts as a PUT instead of a POST.
api.py
class urlencodeSerializer(Serializer):
formats = ['json', 'jsonp', 'xml', 'yaml', 'html', 'plist', 'urlencoded']
content_types = {
'json': 'application/json',
'jsonp': 'text/javascript',
'xml': 'application/xml',
'yaml': 'text/yaml',
'html': 'text/html',
'plist': 'application/x-plist',
'urlencoded': 'application/x-www-form-urlencoded',
}
# cheating
def to_urlencoded(self,content):
pass
# this comes from an old patch on github, it was never implemented
def from_urlencoded(self, data,options=None):
""" handles basic formencoded url posts """
qs = dict((k, v if len(v)>1 else v[0] )
for k, v in urlparse.parse_qs(data).iteritems())
return qs
class FooResource(ModelResource):
class Meta:
queryset = Foo.objects.all() # "id" = models.AutoField(primary_key=True)
resource_name = 'foo'
authorization = Authorization() # only temporary, I know.
serializer = urlencodeSerializer()
urls.py
foo_resource = FooResource
...
url(r'^api/',include(foo_resource.urls)),
)
In #tastypie on Freenode, Ghost[], suggested that I overwrite post_list() by creating a function in the model resource like so, however, I have not been successful in using this as yet.
def post_list(self, request, **kwargs):
if request.POST.get('id'):
return self.put_detail(request,**kwargs)
else:
return super(YourResource, self).post_list(request,**kwargs)
Unfortunately this method isn't working for me. I'm hoping the larger community could provide some guidance or a solution for this problem.
Note: I cannot overwrite the headers that come from the client (as per: http://django-tastypie.readthedocs.org/en/latest/resources.html#using-put-delete-patch-in-unsupported-places)
I had a similar problem on user creation where I wasn't able to check if the record already existed. I ended up creating a custom validation method which validated if the user didn't exist in which case post would work fine. If the user did exist I updated the record from the validation method. The api still returns a 400 response but the record is updated. It feels a bit hacky but...
from tastypie.validation import Validation
class MyValidation(Validation):
def is_valid(self, bundle, request=None):
errors = {}
#if this dict is empty validation passes.
my_foo = foo.objects.filter(id=1)
if not len(my_foo) == 0: #if object exists
foo[0].foo = 'bar' #so existing object updated
errors['status'] = 'object updated' #this will be returned in the api response
return errors
#so errors is empty if object does not exist and validation passes. Otherwise object
#updated and response notifies you of this
class FooResource(ModelResource):
class Meta:
queryset = Foo.objects.all() # "id" = models.AutoField(primary_key=True)
validation = MyValidation()
With Cathal's recommendation I was able to utilize a validation function to update the records I needed. While this does not return a valid code... it works.
from tastypie.validation import Validation
import string # wrapping in int() doesn't work
class Validator(Validation):
def __init__(self,**kwargs):
pass
def is_valid(self,bundle,request=None):
if string.atoi(bundle.data['id']) in Foo.objects.values_list('id',flat=True):
# ... update code here
else:
return {}
Make sure you specify the validation = Validator() in the ModelResource meta.
I'm trying to get a tastypie response to use in another view. I've seen the recipe in the cookbook. Problem is, I'd like to get the list view. In my case, /api/v1/source/. Here's what I've got so far:
sr = SourceResource()
objs = sr.get_object_list(request) # two objects returned
bun = sr.build_bundle(data=objs, request=request)
jsondata = sr.serialize(None, sr.full_dehydrate(bun), 'application/json')
Of course this all falls apart. bun.data doesn't have the required characteristics (a single object). So, has anyone done this successfully? How is it done?
Here's what I've come up with. I don't especially like that both the request and the QueryDict are copied, but I can't think of anything else at the moment, other than copying big portions of the tastypie code.
from copy import copy
from django.views.generic import TemplateView
from incremental.sources.resources import SourceResource
resource = SourceResource()
class AppView(TemplateView):
'Base view for the Source parts of the app'
template_name = 'sources/base.html'
def get_context_data(self, **data):
'get context data'
tmp_r = copy(self.request)
tmp_r.GET = tmp_r.GET.copy()
tmp_r.GET['format'] = 'json'
data.update({
'seed': resource.get_list(tmp_r).content
})
return data
In order to avoid the request copying stuff, you can set json as the default format, for instance in your Resource you can overload the following method:
SourceResource(Resource):
def determine_format(self, request):
return "application/json"