Nested Serializers with django-rest-framework - django

Question

I'm trying to generate a nested Json output using django-rest-framework.
But can't find the correct way to go...
Can someone please drive me to correct direction?
Thanks a lot!
--
Here are my models:
class Pacmr(models.Model):
package = models.ForeignKey(Package)
architecture = models.ForeignKey(Architecture)
component = models.ForeignKey(Component)
mirror = models.ForeignKey(Mirror)
release = models.ForeignKey(Release)
version = DebVersionField()
Package, Architecture, Component, Mirror, Release are all equivalent to:
class Package(models.Model):
name = models.CharField(max_length=50)
comment = models.CharField(max_length=200)
An example of the Pacmr table content:
SELECT id, package_id, architecture_id, component_id, mirror_id, release_id, version from pacmr_pacmr where package_id = 20671;
id | package_id | architecture_id | component_id | mirror_id | release_id | version
--------+------------+-----------------+--------------+-----------+------------+--------------
965201 | 20671 | 236 | 146 | 73 | 111 | 3.0-2.1b-1
965200 | 20671 | 236 | 146 | 73 | 109 | 3.0-2.1b-2.1
965199 | 20671 | 236 | 146 | 73 | 113 | 3.0-2.1a-5
691277 | 20671 | 236 | 146 | 73 | 105 | 3.0-2.1b-3
691276 | 20671 | 236 | 146 | 73 | 107 | 3.0-2.1b-3
691275 | 20671 | 236 | 146 | 73 | 104 | 3.0-2.1b-3
691274 | 20671 | 236 | 146 | 75 | 113 | 3.0-2.1a-5
691273 | 20671 | 236 | 146 | 72 | 111 | 3.0-2.1b-1
691272 | 20671 | 236 | 146 | 72 | 110 | 3.0-2.1b-1
691271 | 20671 | 236 | 146 | 72 | 109 | 3.0-2.1b-2.1
691270 | 20671 | 236 | 146 | 72 | 108 | 3.0-2.1b-2.1
691269 | 20671 | 236 | 146 | 72 | 113 | 3.0-2.1a-5
691268 | 20671 | 236 | 146 | 72 | 115 | 3.0-2.1a-5
691267 | 20671 | 236 | 146 | 72 | 107 | 3.0-2.1b-3
691266 | 20671 | 236 | 146 | 72 | 106 | 3.0-2.1b-3
691265 | 20671 | 236 | 146 | 72 | 104 | 3.0-2.1b-3
691264 | 20671 | 236 | 146 | 72 | 103 | 3.0-2.1b-3
691263 | 20671 | 236 | 144 | 71 | 97 | 3.0-2.1b-2.1
691262 | 20671 | 236 | 144 | 71 | 67 | 3.0-2.1b-3
691261 | 20671 | 236 | 144 | 71 | 114 | 3.0-2.1b-3
691260 | 20671 | 236 | 144 | 71 | 68 | 3.0-2.1b-3
691259 | 20671 | 236 | 144 | 71 | 101 | 3.0-2.1b-3
691258 | 20671 | 236 | 144 | 71 | 100 | 3.0-2.1b-3
691257 | 20671 | 236 | 144 | 70 | 97 | 3.0-2.1b-2.1
691256 | 20671 | 236 | 144 | 70 | 98 | 3.0-2.1b-2.1
691255 | 20671 | 236 | 144 | 70 | 67 | 3.0-2.1b-3
691254 | 20671 | 236 | 144 | 70 | 99 | 3.0-2.1b-3
691253 | 20671 | 236 | 144 | 70 | 68 | 3.0-2.1b-3
691252 | 20671 | 236 | 144 | 70 | 96 | 3.0-2.1b-3
With joins it look like this:
SELECT pacmr_pacmr.id as id, pacmr_package.name as package, pacmr_architecture.name as architecture, pacmr_component.name as component, pacmr_mirror.name as mirror, pacmr_release.name as release, version from pacmr_pacmr, pacmr_package, pacmr_architecture, pacmr_component, pacmr_mirror, pacmr_release where package_id=pacmr_package.id and architecture_id=pacmr_architecture.id and component_id=pacmr_component.id and mirror_id=pacmr_mirror.id and release_id=pacmr_release.id and package_id = 20671;
id | package | architecture | component | mirror | release | version
--------+---------+--------------+-----------+-------------------+-----------------+--------------
965201 | jvim | source | main | debian | etch | 3.0-2.1b-1
965200 | jvim | source | main | debian | lenny | 3.0-2.1b-2.1
965199 | jvim | source | main | debian | sarge | 3.0-2.1a-5
691277 | jvim | source | main | debian | sid | 3.0-2.1b-3
691276 | jvim | source | main | debian | squeeze | 3.0-2.1b-3
691275 | jvim | source | main | debian | wheezy | 3.0-2.1b-3
691274 | jvim | source | main | debian-amd64 | sarge | 3.0-2.1a-5
691273 | jvim | source | main | debian-production | etch | 3.0-2.1b-1
691272 | jvim | source | main | debian-production | etch-testing | 3.0-2.1b-1
691271 | jvim | source | main | debian-production | lenny | 3.0-2.1b-2.1
691270 | jvim | source | main | debian-production | lenny-testing | 3.0-2.1b-2.1
691269 | jvim | source | main | debian-production | sarge | 3.0-2.1a-5
691268 | jvim | source | main | debian-production | sarge-testing | 3.0-2.1a-5
691267 | jvim | source | main | debian-production | squeeze | 3.0-2.1b-3
691266 | jvim | source | main | debian-production | squeeze-testing | 3.0-2.1b-3
691265 | jvim | source | main | debian-production | wheezy | 3.0-2.1b-3
691264 | jvim | source | main | debian-production | wheezy-testing | 3.0-2.1b-3
691263 | jvim | source | universe | ubuntu | hardy | 3.0-2.1b-2.1
691262 | jvim | source | universe | ubuntu | lucid | 3.0-2.1b-3
691261 | jvim | source | universe | ubuntu | oneiric | 3.0-2.1b-3
691260 | jvim | source | universe | ubuntu | precise | 3.0-2.1b-3
691259 | jvim | source | universe | ubuntu | quantal | 3.0-2.1b-3
691258 | jvim | source | universe | ubuntu | raring | 3.0-2.1b-3
691257 | jvim | source | universe | ubuntu-production | hardy | 3.0-2.1b-2.1
691256 | jvim | source | universe | ubuntu-production | hardy-testing | 3.0-2.1b-2.1
691255 | jvim | source | universe | ubuntu-production | lucid | 3.0-2.1b-3
691254 | jvim | source | universe | ubuntu-production | lucid-testing | 3.0-2.1b-3
691253 | jvim | source | universe | ubuntu-production | precise | 3.0-2.1b-3
691252 | jvim | source | universe | ubuntu-production | precise-testing | 3.0-2.1b-3
(29 rows)
Here an example of what I would like to have with django-rest-framework (hand written):
{
"package_id": 20671,
"package": "jvim",
"mirrors": [
{
"name": "debian",
"components": [
{
"name": "main",
"releases": [
{
"name": "etch",
"version": "3.0-2.1b-1"
},
{
"name": "lenny",
"version": "3.0-2.1b-2.1"
},
{
"name": "sarge",
"version": "3.0-2.1a-5"
},
{
"name": "sid",
"version": "3.0-2.1b-3"
},
{
"name": "squeeze",
"version": "3.0-2.1b-3"
},
{
"name": "wheezy",
"version": "3.0-2.1b-3"
}
]
}
]
},
{
"name": "debian-amd64",
"components": [
{
"name": "main",
"releases": [
{
"name": "sarge",
"version": "3.0-2.1a-5"
}
]
}
]
},
{
"name": "debian-production",
"components": [
{
"name": "main",
"releases": [
{
"name": "etch",
"version": "3.0-2.1a-5"
},
{
"name": "etch-testing",
"version": "3.0-2.1a-5"
},
{
"name": "lenny",
"version": "3.0-2.1a-5"
},
{
"name": "lenny-testing",
"version": "3.0-2.1a-5"
},
{
"name": "sarge",
"version": "3.0-2.1a-5"
},
{
"name": "sarge-testing",
"version": "3.0-2.1a-5"
},
{
"name": "squeeze",
"version": "3.0-2.1a-5"
},
{
"name": "squeeze-testing",
"version": "3.0-2.1a-5"
},
{
"name": "wheezy",
"version": "3.0-2.1a-5"
},
{
"name": "wheezy-testing",
"version": "3.0-2.1a-5"
}
]
}
]
},
{
"name": "ubuntu",
"components": [
{
"name": "universe",
"releases": [
{
"name": "hardy",
"version": "3.0-2.1b-2.1"
},
{
"name": "lucid",
"version": "3.0-2.1b-3"
},
{
"name": "oneiric",
"version": "3.0-2.1b-3"
},
{
"name": "precise",
"version": "3.0-2.1b-3"
},
{
"name": "quantal",
"version": "3.0-2.1b-3"
},
{
"name": "raring",
"version": "3.0-2.1b-3"
}
]
}
]
},
{
"name": "ubuntu-production",
"components": [
{
"name": "universe",
"releases": [
{
"name": "hardy",
"version": "3.0-2.1b-2.1"
},
{
"name": "hardy-testing",
"version": "3.0-2.1b-2.1"
},
{
"name": "lucid",
"version": "3.0-2.1b-3"
},
{
"name": "lucid-testing",
"version": "3.0-2.1b-3"
},
{
"name": "precise",
"version": "3.0-2.1b-3"
},
{
"name": "precise-testing",
"version": "3.0-2.1b-3"
}
]
}
]
}
]
}

Answer 1

Answer myself...
Found a solution based on Django REST framework: non-model serializer
Maybe a better solution could be implemented?
class Pmcra(object):
package = None
package_id = None
def __init__(self, package, *args, **kw):
self.package = package
pass
def do_work(self):
my_dict = {}
if self.package:
pacmrs = Pacmr.objects.filter(package__name=self.package)
mirrors = pacmrs.all().distinct('mirror')
mirrors_array = []
for mirror in mirrors:
self.package_id = mirror.package.id
components = mirrors.filter(mirror=mirror.mirror).distinct('component')
components_array = []
for component in components:
releases = components.filter(component=component.component).distinct('release')
releases_array = []
for release in releases:
releases_array.append( {'name': release.release.__str__(), 'version': release.version.__str__() })
components_array.append( {'name': component.component.__str__(), 'releases': releases_array} )
mirrors_array.append( {'name': mirror.mirror.__str__(), 'components': components_array} )
return { 'package': self.package, 'package_id': self.package_id, 'mirrors': mirrors_array }
class MyView(APIView):
def get(self, request, *args, **kw):
# Process any get params that you may need
# If you don't need to process get params,
# you can skip this part
get_arg1 = request.GET.get('pkg', None)
# Any URL parameters get passed in **kw
myClass = Pmcra(get_arg1, *args, **kw)
result = myClass.do_work()
response = Response(result, status=status.HTTP_200_OK)
return response