feat(backend): refactor/cleaned/ infer get_serializer

* Cleaned all init files
* Infer the serializer from the model instead of having it in the models
* Updated the doc accordingly
* Fixed typos

Fixes #93
Fixes #85

backend/backend_app/admin.py

@@ -2,20 +2,12 @@ from django.contrib import admin
 
 from reversion_compare.admin import CompareVersionAdmin
 from backend_app.config.models import get_models
-from backend_app.checks import check_classic_models, check_versionned_models
 
 # We need to register testing models, otherwise we won't be able to test properly,
 # Since no migrations would privide those models.
 # So don't put requires_testing=True
-VERSIONED_MODELS = get_models(versionned=True)  # , requires_testing=False)
-CLASSIC_MODELS = get_models(versionned=False)  # , requires_testing=False)
-
-#######
-# Perform some dynamic checks
-#######
-
-check_classic_models(CLASSIC_MODELS)
-check_versionned_models(VERSIONED_MODELS)
+VERSIONED_MODELS = get_models(versioned=True)  # , requires_testing=False)
+CLASSIC_MODELS = get_models(versioned=False)  # , requires_testing=False)
 
 #######
 # Register the models

backend/backend_app/checks.py

-def check_classic_models(classic_models):
-    """
-    Check that all "classic" models don't have a `get_serializer` method:
-    they don't need it.
-    See doc for more information:
-    http://localhost:5000/#/Application/Backend/models_serializers_viewsets
-    """
-    for Model in classic_models:
-        try:
-            # Check that it doesn't have the get_serializer method
-            Model.get_serializer()
-            raise Exception(
-                "A 'CLASSIC MODEL' SHOULDN'T have the "
-                "get_serializer method, {}".format(Model)
-            )
-        except AttributeError:
-            pass
+from collections import Counter
 
 
-def check_versionned_models(versionned_models):
+def check_viewsets(viewsets):
     """
-    Check that all "versionned" models have a `get_serializer` method.
-    See doc for more information:
+    Check that if 2 serializers are registered for the same model. Then that model
+    has a get_serializer method to point to the serializer to use to deserialize it.
+    There should be only one of serializer being used per model. Otherwise extra
+    configuration is required.
+
     http://localhost:5000/#/Application/Backend/models_serializers_viewsets
     """
-    for Model in versionned_models:
+    # Prevent cyclic imports
+    from backend_app.models.abstract.versionedEssentialModule import (
+        VersionedEssentialModule,
+    )
+
+    serializers = list()
+    models = []
+    for viewset in viewsets:
+        serializer = viewset().get_serializer_class()
+        model = serializer.Meta.model
+
+        if issubclass(model, VersionedEssentialModule):
+            if serializer not in serializers:
+                serializers.append(serializer)
+                models.append(model)
+
+    models = dict(Counter(models))
+    for model, n in models.items():
+        if n > 1:
+            try:
+                # Check that the model has a get_serializer method
+                model.get_serializer()
 
-        # Check that it has a get_serializer method
-        if Model.get_serializer().Meta.model != Model:
-            raise Exception("Get_serializer configuration incorrect in", str(Model))
+            except AttributeError:
+                raise Exception(
+                    "The model {} has multiple serializers pointing to it. "
+                    "In such case, you must define the get_serializer method inside the model. "
+                    "Have a look at the documentation.".format(model)
+                )

backend/backend_app/config/models.py

@@ -10,7 +10,7 @@ from .utils import load_viewsets_config
 
 
 def get_models(
-    versionned: Optional[bool] = None,
+    versioned: Optional[bool] = None,
     requires_testing: Union[None, bool, "smart"] = None,
 ) -> List[object]:
     """
@@ -51,10 +51,10 @@ def get_models(
             continue
 
         Model = Viewset.serializer_class.Meta.model
-        if versionned is not None:
-            if versionned and not issubclass(Model, VersionedEssentialModule):
+        if versioned is not None:
+            if versioned and not issubclass(Model, VersionedEssentialModule):
                 continue
-            if not versionned and issubclass(Model, VersionedEssentialModule):
+            if not versioned and issubclass(Model, VersionedEssentialModule):
                 continue
 
         out.append(Model)

backend/backend_app/load_data/__init__.py

-# We firest need to define ASSETS_PATH to prevent cyclic imports
-from os import path
-
-ASSETS_PATH = path.join(path.realpath(__file__), "../assets/")  # noqa: E402
-
-from .load_all import load_all  # noqa: E402
-
-__all__ = ["load_all", "ASSETS_PATH"]

backend/backend_app/load_data/load_all.py

 import reversion
 
-from .loading_scripts import (
-    LoadAdminUser,
-    LoadCountries,
-    LoadCurrencies,
-    LoadGroups,
-    LoadTags,
-    LoadUniversities,
-    LoadUniversityEx,
-)
+from backend_app.load_data.loading_scripts.loadAdminUser import LoadAdminUser
+from backend_app.load_data.loading_scripts.loadCountries import LoadCountries
+from backend_app.load_data.loading_scripts.loadCurrencies import LoadCurrencies
+from backend_app.load_data.loading_scripts.loadGroups import LoadGroups
+from backend_app.load_data.loading_scripts.loadTags import LoadTags
+from backend_app.load_data.loading_scripts.loadUniversities import LoadUniversities
+from backend_app.load_data.loading_scripts.loadUniversityEx import LoadUniversityEx
 
 
 def load_all():
-    """Function to load all the initial data in the app
+    """
+    Function to load all the initial data in the app
     """
 
     with reversion.create_revision():

backend/backend_app/load_data/loading_scripts/__init__.py

-from .loadGroups import LoadGroups
-from .loadAdminUser import LoadAdminUser
-from .loadCountries import LoadCountries
-from .loadUniversities import LoadUniversities
-from .loadTags import LoadTags
-from .loadCurrencies import LoadCurrencies
-from .loadUniversityEx import LoadUniversityEx
-
-
-__all__ = [
-    "LoadGroups",
-    "LoadAdminUser",
-    "LoadCountries",
-    "LoadUniversities",
-    "LoadTags",
-    "LoadCurrencies",
-    "LoadUniversityEx",
-]

backend/backend_app/load_data/loading_scripts/loadCountries.py

 from os.path import abspath, join
 
 import pandas as pd
-from backend_app.load_data import ASSETS_PATH
+from backend_app.load_data.shared import ASSETS_PATH
 from backend_app.models.country import Country
 from base_app.models import User
 

backend/backend_app/load_data/loading_scripts/loadCurrencies.py

@@ -2,7 +2,7 @@ import csv
 from decimal import Decimal
 from os.path import abspath, join
 
-from backend_app.load_data import ASSETS_PATH
+from backend_app.load_data.shared import ASSETS_PATH
 from backend_app.models.currency import Currency
 from base_app.models import User
 

backend/backend_app/load_data/loading_scripts/loadUniversities.py

 from os.path import abspath, join
 
 import pandas as pd
-from backend_app.load_data import ASSETS_PATH
+from backend_app.load_data.shared import ASSETS_PATH
 from backend_app.models.campus import Campus
 from backend_app.models.city import City
 from backend_app.models.country import Country

backend/backend_app/load_data/shared.py

+from os import path
+
+ASSETS_PATH = path.join(path.realpath(__file__), "../assets/")  # noqa: E402

backend/backend_app/models/__init__.py

-SEMESTER_OPTIONS = (("a", "autumn"), ("p", "spring"))
-
-__all__ = ["SEMESTER_OPTIONS"]

backend/backend_app/models/abstract/module.py

@@ -6,8 +6,8 @@ from backend_app.models.abstract.versionedEssentialModule import (
     VersionedEssentialModuleSerializer,
     VersionedEssentialModuleViewSet,
 )
-from backend_app.validators.tag import validate_content_against_config
-from backend_app.validators.tag.tags_config import USEFULL_LINKS_CONFIG
+from backend_app.validators.tags import validate_content_against_config
+from backend_app.validators.tags_config.useful_links import USEFULL_LINKS_CONFIG
 
 IMPORTANCE_LEVEL = (("-", "normal"), ("+", "important"), ("++", "IMPORTANT"))
 
@@ -19,7 +19,7 @@ class Module(VersionedEssentialModule):
 
     Those field will be inherited.
 
-    All Basic modules are also "versionned" modules
+    All Basic modules are also "versioned" modules
     """
 
     title = models.CharField(default="", blank=True, max_length=150)

backend/backend_app/models/abstract/taggedItem.py

@@ -3,7 +3,7 @@ from django.db import models
 from backend_app.fields import JSONField
 from backend_app.models.abstract.module import Module, ModuleSerializer, ModuleViewSet
 from backend_app.models.tag import Tag
-from backend_app.validators.tag import tagged_item_validation
+from backend_app.validators.tags import tagged_item_validation
 
 
 class TaggedItem(Module):

backend/backend_app/models/abstract/versionedEssentialModule.py

@@ -13,21 +13,12 @@ from reversion.models import Version
 
 class VersionedEssentialModule(EssentialModule):
     """
-    Custom EssentialModule that will be versionned in the app
+    Custom EssentialModule that will be versioned in the app
     """
 
     # We store the current number of versions for better performance
     nb_versions = models.PositiveIntegerField(default=0)
 
-    @classmethod
-    def get_serializer(cls):
-        """
-            This function is required for handling
-            versioning easily.
-            You have to put the correct value in each subclass
-        """
-        raise Exception("Get_serializer must be redefined in subclass")
-
     def delete(self, using=None, keep_parents=False):
         """
         Override the default delete behavior to make sure
@@ -44,7 +35,7 @@ class VersionedEssentialModule(EssentialModule):
 
 class VersionedEssentialModuleSerializer(EssentialModuleSerializer):
     """
-    Serializer for versionned models
+    Serializer for versioned models
     """
 
     # Add a nb_versions field
@@ -64,7 +55,7 @@ class VersionedEssentialModuleSerializer(EssentialModuleSerializer):
 
 class VersionedEssentialModuleViewSet(EssentialModuleViewSet):
     """
-    Viewset for the versionned models
+    Viewset for the versioned models
     """
 
     serializer_class = VersionedEssentialModuleSerializer

backend/backend_app/models/campus.py

@@ -32,10 +32,6 @@ class Campus(Module):
     def location(self):
         return {"lat": self.lat, "lon": self.lon}
 
-    @classmethod
-    def get_serializer(cls):
-        return CampusSerializer
-
     class Meta:
         unique_together = ("is_main_campus", "university")
 

backend/backend_app/models/campusTaggedItem.py

@@ -13,10 +13,6 @@ class CampusTaggedItem(TaggedItem):
         Campus, on_delete=models.PROTECT, related_name="campus_tagged_items"
     )
 
-    @classmethod
-    def get_serializer(cls):
-        return CampusTaggedItemSerializer
-
     class Meta:
         unique_together = ("campus", "tag", "importance_level")
 

backend/backend_app/models/cityTaggedItem.py

@@ -13,10 +13,6 @@ class CityTaggedItem(TaggedItem):
         City, on_delete=models.PROTECT, related_name="city_tagged_items"
     )
 
-    @classmethod
-    def get_serializer(cls):
-        return CityTaggedItemSerializer
-
     class Meta:
         unique_together = ("city", "tag", "importance_level")
 

backend/backend_app/models/countryDri.py

@@ -7,10 +7,6 @@ class CountryDri(Module):
 
     countries = models.ManyToManyField(Country, related_name="country_dri")
 
-    @classmethod
-    def get_serializer(cls):
-        return CountryDriSerializer
-
 
 class CountryDriSerializer(ModuleSerializer):
     class Meta:

backend/backend_app/models/countryScholarship.py

@@ -11,10 +11,6 @@ class CountryScholarship(Scholarship):
 
     countries = models.ManyToManyField(Country, related_name="country_scholarships")
 
-    @classmethod
-    def get_serializer(cls):
-        return CountryScholarshipSerializer
-
 
 class CountryScholarshipSerializer(ScholarshipSerializer):
     class Meta:

backend/backend_app/models/countryTaggedItem.py

@@ -13,10 +13,6 @@ class CountryTaggedItem(TaggedItem):
         Country, on_delete=models.PROTECT, related_name="country_tagged_items"
     )
 
-    @classmethod
-    def get_serializer(cls):
-        return CountryTaggedItemSerializer
-
     class Meta:
         unique_together = ("country", "tag", "importance_level")
 

backend/backend_app/models/for_testing/versioning.py

@@ -17,10 +17,6 @@ class ForTestingVersioning(VersionedEssentialModule):
 
     bbb = models.CharField(max_length=100)
 
-    @classmethod
-    def get_serializer(cls):
-        return ForTestingVersioningSerializer
-
 
 class ForTestingVersioningSerializer(VersionedEssentialModuleSerializer):
     """

backend/backend_app/models/offer.py

@@ -6,7 +6,7 @@ from backend_app.models.abstract.base import (
     BaseModelSerializer,
     BaseModelViewSet,
 )
-from backend_app.models import SEMESTER_OPTIONS
+from backend_app.models.shared import SEMESTER_OPTIONS
 
 
 class Offer(BaseModel):

backend/backend_app/models/previousDeparture.py

@@ -8,7 +8,7 @@ from backend_app.models.abstract.essentialModule import (
     EssentialModuleSerializer,
     EssentialModuleViewSet,
 )
-from backend_app.models import SEMESTER_OPTIONS
+from backend_app.models.shared import SEMESTER_OPTIONS
 
 
 class PreviousDeparture(EssentialModule):

backend/backend_app/models/shared.py

+# This file is not a model. It is file to hold shared things across models.
+
+SEMESTER_OPTIONS = (("a", "autumn"), ("p", "spring"))

backend/backend_app/models/university.py

@@ -6,7 +6,7 @@ from backend_app.models.abstract.essentialModule import (
 )
 from django.core.exceptions import ValidationError
 from rest_framework.validators import ValidationError as RFValidationError
-from backend_app.validators.tag.url import validate_extension
+from backend_app.validators.tags import validate_extension
 from django.conf import settings
 
 

backend/backend_app/models/universityDri.py

@@ -7,10 +7,6 @@ class UniversityDri(Module):
 
     universities = models.ManyToManyField(University, related_name="university_dri")
 
-    @classmethod
-    def get_serializer(cls):
-        return UniversityDriSerializer
-
 
 class UniversityDriSerializer(ModuleSerializer):
     class Meta:

backend/backend_app/models/universityInfo.py

@@ -25,10 +25,6 @@ class UniversityInfo(Module):
 
     costs_currency = models.ForeignKey(Currency, on_delete=models.PROTECT, null=True)
 
-    @classmethod
-    def get_serializer(cls):
-        return UniversityInfoSerializer
-
 
 class UniversityInfoSerializer(ModuleSerializer):
     class Meta:

backend/backend_app/models/universityScholarship.py

@@ -13,10 +13,6 @@ class UniversityScholarship(Scholarship):
         University, related_name="university_scholarships"
     )
 
-    @classmethod
-    def get_serializer(cls):
-        return UniversityScholarshipSerializer
-
 
 class UniversityScholarshipSerializer(ScholarshipSerializer):
     class Meta:

backend/backend_app/models/universitySemestersDates.py

@@ -25,10 +25,6 @@ class UniversitySemestersDates(Module):
     autumn_begin = models.DateField(null=True, blank=True)
     autumn_end = models.DateField(null=True, blank=True)
 
-    @classmethod
-    def get_serializer(cls):
-        return UniversitySemestersDatesSerializer
-
 
 class UniversitySemestersDatesSerializer(ModuleSerializer):
     def validate(self, attrs):

backend/backend_app/models/universityTaggedItem.py

@@ -13,10 +13,6 @@ class UniversityTaggedItem(TaggedItem):
         University, on_delete=models.PROTECT, related_name="university_tagged_items"
     )
 
-    @classmethod
-    def get_serializer(cls):
-        return UniversityTaggedItemSerializer
-
     class Meta:
         unique_together = ("university", "tag", "importance_level")
 

backend/backend_app/models/version.py

@@ -14,6 +14,39 @@ class VersionSerializer(BaseModelSerializer):
 
     data = serializers.SerializerMethodField()
 
+    serializers_mapping = None
+
+    @classmethod
+    def get_serializers_mapping(cls) -> dict:
+        """
+        Function that returns a mapping from model name to the serializer
+        class that should be used to return the versioned data.
+        """
+        if cls.serializers_mapping is None:
+            # Prevent cyclic imports
+            from backend_app.config.viewsets import get_viewsets_info
+
+            # A little bit of optimization to easily find the serializer class associated with a model
+            cls.serializers_mapping = dict()
+            viewsets = map(
+                lambda v: v.Viewset,
+                get_viewsets_info(requires_testing="smart", is_api_view=False),
+            )
+
+            for viewset in viewsets:
+                serializer = viewset().get_serializer_class()
+                model = serializer.Meta.model
+                cls.serializers_mapping[model.__name__] = serializer
+
+            # Override if models has a get_serializer method
+            for viewset in viewsets:
+                model = viewset().get_serializer_class().Meta.model
+                try:
+                    cls.serializers_mapping[model.__name__] = model.get_serializer()
+                except AttributeError:
+                    pass
+        return cls.serializers_mapping
+
     def get_data(self, obj):
         """
         Serilizer for the data field
@@ -26,7 +59,8 @@ class VersionSerializer(BaseModelSerializer):
                 djangoSerializers.deserialize(obj.format, data, ignorenonexistent=True)
             )[0]
             # Version is valid,
-            obj_serializer = tmp.object.get_serializer()
+            print(self.get_serializers_mapping())
+            obj_serializer = self.get_serializers_mapping()[type(tmp.object).__name__]
             new_context = dict(self.context)
             new_context["view"].action = "list"
             return obj_serializer(tmp.object, context=new_context).data

backend/backend_app/signals/squash_revisions.py

@@ -4,7 +4,7 @@ from reversion.models import Version
 
 def squash_revision_by_user(sender, obj, **kwargs):
     """
-    It should also work with moderation as obj will be a versionned object
+    It should also work with moderation as obj will be a versioned object
     """
     versions = (
         Version.objects.get_for_object(obj)

backend/backend_app/tests/test_loading_data.py

 from django.test import TestCase
-from backend_app.load_data import load_all
+from backend_app.load_data.load_all import load_all
 
 
 class ModerationTestCase(TestCase):

backend/backend_app/tests/test_validation_url.py

@@ -2,7 +2,7 @@ from django.test import TestCase
 import pytest
 from rest_framework.validators import ValidationError as RFValidationError
 from django.core.validators import ValidationError as DJValidationError
-from backend_app.validators.tag.url import validate_extension, validate_url
+from backend_app.validators.tags import validate_extension, validate_url
 
 
 class ValidationUrlTestCase(TestCase):

backend/backend_app/tests/test_versionning.py

@@ -4,6 +4,7 @@ from django.conf import settings
 from reversion.models import Version
 from backend_app.signals.squash_revisions import new_revision_saved
 from django.test import override_settings
+from django.contrib.contenttypes.models import ContentType
 
 
 class VersioningTestCase(WithUserTestCase):
@@ -69,3 +70,7 @@ class VersioningTestCase(WithUserTestCase):
         self.assertEqual(len(versions), 2)
         self.assertEqual(len(versions), instance.nb_versions)
         self.assertTrue(self.signal_was_called)
+
+        # Final test: we query the version viewset itself
+        ct = ContentType.objects.get_for_model(instance).id
+        self.authenticated_client.get("/api/versions/{}/{}/".format(ct, instance.pk))

backend/backend_app/urls.py

 from django.conf.urls import include, url
 
 from backend_app.config.viewsets import get_viewsets_info
+from backend_app.checks import check_viewsets
 from rest_framework import routers
 from rest_framework.documentation import include_docs_urls
 
 STANDARD_VIEWSETS = get_viewsets_info(requires_testing="smart", is_api_view=False)
 API_VIEW_VIEWSETS = get_viewsets_info(requires_testing="smart", is_api_view=True)
 
+check_viewsets(map(lambda v: v.Viewset, STANDARD_VIEWSETS))
 
 #######
 # Building the API routing

backend/backend_app/validators/tag/__init__.py

-from .url import validate_url
-from .text import validate_text
-from .tagged_item_validation import (
-    validate_content_against_config,
-    tagged_item_validation,
-)
-
-__all__ = [
-    "validate_url",
-    "validate_text",
-    "validate_content_against_config",
-    "tagged_item_validation",
-]

backend/backend_app/validators/tag/checks.py

-from rest_framework.validators import ValidationError
-
-
-def missing_field(field):
-    return ValidationError("{} : this field is required".format(field))
-
-
-def check_required(config, content):
-    for field in config:
-        if config[field]["required"]:
-            try:
-                val = content[field]
-                if type(val) is str:
-                    if len(val) == 0:
-                        raise missing_field(field)
-                if val is None:
-                    raise missing_field(field)
-            except KeyError:
-                raise missing_field(field)

backend/backend_app/validators/tag/tags_config/__init__.py

-from .photos import PHOTOS_TAG_CONFIG
-from .useful_links import USEFULL_LINKS_CONFIG
-
-__all__ = ["PHOTOS_TAG_CONFIG", "USEFULL_LINKS_CONFIG"]

backend/backend_app/validators/tag/text.py

-from rest_framework.validators import ValidationError
-
-
-def validate_text(config, string):
-    string = str(string)  # might cause error with number ?
-    try:
-        validators = config["validators"]
-        for validator in validators:
-            validator_content = validators[validator]
-            if validator == "max_length":
-                if len(string) > validator_content:
-                    raise ValidationError("Your text is too long !")
-            else:
-                raise Exception("Dev, you have implement something here...")
-
-    except KeyError:
-        pass