Proposal: Refactor render to create InertiaResponse class (#61)

* Refactor to class based views

* Refactor to class based views

* cleanup

* move to a mixin for better flexibility

* PR review feedback

README.md

@@ -95,6 +95,22 @@ def index(request):
   }
 ```
 
+If you need more control, you can also directly return the InertiaResponse class. It has the same arguments as the render method and subclasses HttpResponse to accept of all its arguments as well.
+
+```python
+from inertia import InertiaResponse
+from .models import Event
+
+def index(request):
+  return InertiaResponse(
+    request,
+    'Event/Index',
+    props={
+      'events': Event.objects.all()
+    }
+  )
+```
+
 ### Shared Data
 
 If you have data that you want to be provided as a prop to every component (a common use-case is information about the authenticated user) you can use the `share` method. A common place to put this would be in some custom middleware.

inertia/__init__.py

@@ -1,3 +1,3 @@
-from .http import inertia, render, location
+from .http import inertia, render, location, InertiaResponse
 from .utils import lazy, optional, defer, merge
 from .share import share

inertia/helpers.py

@@ -0,0 +1,14 @@
+def deep_transform_callables(prop):
+  if not isinstance(prop, dict):
+    return prop() if callable(prop) else prop
+
+  for key in list(prop.keys()):
+    prop[key] = deep_transform_callables(prop[key])
+
+  return prop
+
+def validate_type(value, name, expected_type):
+  if not isinstance(value, expected_type):
+    raise TypeError(f"Expected {expected_type.__name__} for {name}, got {type(value).__name__}")
+
+  return value

inertia/http.py

@@ -1,133 +1,191 @@
 from http import HTTPStatus
-from django.http import HttpResponse, JsonResponse
-from django.shortcuts import render as base_render
+from django.template.loader import render_to_string
+from django.http import HttpResponse
 from .settings import settings
 from json import dumps as json_encode
 from functools import wraps
 import requests
 from .prop_classes import IgnoreOnFirstLoadProp, DeferredProp, MergeableProp
+from .helpers import deep_transform_callables, validate_type
 
 INERTIA_REQUEST_ENCRYPT_HISTORY = "_inertia_encrypt_history"
 INERTIA_SESSION_CLEAR_HISTORY = "_inertia_clear_history"
 
-def render(request, component, props={}, template_data={}):
-  def is_a_partial_render():
-    return 'X-Inertia-Partial-Data' in request.headers and request.headers.get('X-Inertia-Partial-Component', '') == component
+INERTIA_TEMPLATE = 'inertia.html'
+INERTIA_SSR_TEMPLATE = 'inertia_ssr.html'
 
-  def partial_keys():
-    return request.headers.get('X-Inertia-Partial-Data', '').split(',')
+class InertiaRequest:
+  def __init__(self, request):
+    self.request = request
+
+  def __getattr__(self, name):
+    return getattr(self.request, name)
+
+  @property
+  def headers(self):
+    return self.request.headers
+
+  @property
+  def inertia(self):
+    return self.request.inertia.all() if hasattr(self.request, 'inertia') else {}
+
+  def is_a_partial_render(self, component):
+    return 'X-Inertia-Partial-Data' in self.headers and self.headers.get('X-Inertia-Partial-Component', '') == component
 
-  def deep_transform_callables(prop):
-    if not isinstance(prop, dict):
-      return prop() if callable(prop) else prop
-
-    for key in list(prop.keys()):
-      prop[key] = deep_transform_callables(prop[key])
+  def partial_keys(self):
+    return self.headers.get('X-Inertia-Partial-Data', '').split(',')
+
+  def reset_keys(self):
+    return self.headers.get('X-Inertia-Reset', '').split(',')
+
+  def is_inertia(self):
+    return 'X-Inertia' in self.headers
+
+  def should_encrypt_history(self):
+    return validate_type(
+      getattr(self.request, INERTIA_REQUEST_ENCRYPT_HISTORY, settings.INERTIA_ENCRYPT_HISTORY),
+      expected_type=bool,
+      name="encrypt_history"
+    )
+
+class BaseInertiaResponseMixin:
+  def page_data(self):
+    clear_history = validate_type(
+      self.request.session.pop(INERTIA_SESSION_CLEAR_HISTORY, False),
+      expected_type=bool,
+      name="clear_history"
+    )
+
+    _page = {
+      'component': self.component,
+      'props': self.build_props(),
+      'url': self.request.get_full_path(),
+      'version': settings.INERTIA_VERSION,
+      'encryptHistory': self.request.should_encrypt_history(),
+      'clearHistory': clear_history,
+    }
 
-    return prop
+    _deferred_props = self.build_deferred_props()
+    if _deferred_props:
+      _page['deferredProps'] = _deferred_props
+
+    _merge_props = self.build_merge_props()
+    if _merge_props:
+      _page['mergeProps'] = _merge_props
+
+    return _page
 
-  def build_props():
+  def build_props(self):
     _props = {
-      **(request.inertia.all() if hasattr(request, 'inertia') else {}),
-      **props,
+      **(self.request.inertia),
+      **self.props,
     }
 
     for key in list(_props.keys()):
-      if is_a_partial_render():
-        if key not in partial_keys():
+      if self.request.is_a_partial_render(self.component):
+        if key not in self.request.partial_keys():
           del _props[key]
       else:
         if isinstance(_props[key], IgnoreOnFirstLoadProp):
           del _props[key]
 
     return deep_transform_callables(_props)
 
-  def build_deferred_props():
-    if is_a_partial_render():
+  def build_deferred_props(self):
+    if self.request.is_a_partial_render(self.component):
       return None
 
     _deferred_props = {}
-    for key, prop in props.items():
+    for key, prop in self.props.items():
       if isinstance(prop, DeferredProp):
         _deferred_props.setdefault(prop.group, []).append(key)
 
     return _deferred_props
-
-  def build_merge_props():
-    reset_keys = request.headers.get('X-Inertia-Reset', '').split(',')
 
+  def build_merge_props(self):
     return [
       key 
-      for key, prop in props.items()
+      for key, prop in self.props.items()
       if (
         isinstance(prop, MergeableProp)
         and prop.should_merge()
-        and key not in reset_keys
+        and key not in self.request.reset_keys()
       )
     ]
-
-  def render_ssr():
-    data = json_encode(page_data(), cls=settings.INERTIA_JSON_ENCODER)
-    response = requests.post(
-      f"{settings.INERTIA_SSR_URL}/render",
-      data=data,
-      headers={"Content-Type": "application/json"},
+
+  def build_first_load(self, data):
+    context, template = self.build_first_load_context_and_template(data)
+
+    return render_to_string(
+      template,
+      {
+        'inertia_layout': settings.INERTIA_LAYOUT,
+        **context,
+      },
+      self.request,
+      using=None,
     )
-    response.raise_for_status()
-    return base_render(request, 'inertia_ssr.html', {
-     'inertia_layout': settings.INERTIA_LAYOUT,
-      **response.json()
-    })
 
-  def page_data():
-    encrypt_history = getattr(request, INERTIA_REQUEST_ENCRYPT_HISTORY, settings.INERTIA_ENCRYPT_HISTORY)
-    if not isinstance(encrypt_history, bool):
-      raise TypeError(f"Expected boolean for encrypt_history, got {type(encrypt_history).__name__}")
+
+  def build_first_load_context_and_template(self, data):
+    if settings.INERTIA_SSR_ENABLED:
+      try: 
+        response = requests.post(
+          f"{settings.INERTIA_SSR_URL}/render",
+          data=data,
+          headers={"Content-Type": "application/json"},
+        )
+        response.raise_for_status()
+        return {
+          **response.json(),
+          **self.template_data,
+        }, INERTIA_SSR_TEMPLATE
+      except Exception:
+        pass
+
+    return {
+      'page': data,
+      **(self.template_data),
+    }, INERTIA_TEMPLATE
 
-    clear_history = request.session.pop(INERTIA_SESSION_CLEAR_HISTORY, False)
-    if not isinstance(clear_history, bool):
-      raise TypeError(f"Expected boolean for clear_history, got {type(clear_history).__name__}")
 
-    _page = {
-      'component': component,
-      'props': build_props(),
-      'url': request.build_absolute_uri(),
-      'version': settings.INERTIA_VERSION,
-      'encryptHistory': encrypt_history,
-      'clearHistory': clear_history,
-    }
+class InertiaResponse(BaseInertiaResponseMixin, HttpResponse):
+  json_encoder = settings.INERTIA_JSON_ENCODER
 
-    _deferred_props = build_deferred_props()
-    if _deferred_props:
-      _page['deferredProps'] = _deferred_props
-
-    _merge_props = build_merge_props()
-    if _merge_props:
-      _page['mergeProps'] = _merge_props
-
-    return _page
+  def __init__(self, request, component, props=None, template_data=None, headers=None, *args, **kwargs):
+    self.request = InertiaRequest(request)
+    self.component = component
+    self.props = props or {}
+    self.template_data = template_data or {}
+    _headers = headers or {}
+
+    data = json_encode(self.page_data(), cls=self.json_encoder)
 
-  if 'X-Inertia' in request.headers:
-    return JsonResponse(
-      data=page_data(),
-      headers={
+    if self.request.is_inertia():
+      _headers = {
+        **_headers,
         'Vary': 'X-Inertia',
         'X-Inertia': 'true',
-      },
-      encoder=settings.INERTIA_JSON_ENCODER,
+        'Content-Type': 'application/json',
+      }
+      content = data
+    else:    
+      content = self.build_first_load(data)
+
+    super().__init__(
+      content=content,
+      headers=_headers,
+      *args,
+      **kwargs,
     )
 
-  if settings.INERTIA_SSR_ENABLED:
-    try:
-      return render_ssr()
-    except Exception:
-      pass
-
-  return base_render(request, 'inertia.html', {
-    'inertia_layout': settings.INERTIA_LAYOUT,
-    'page': json_encode(page_data(), cls=settings.INERTIA_JSON_ENCODER),
-    **template_data,
-  })
+def render(request, component, props=None, template_data=None):
+  return InertiaResponse(
+    request,
+    component,
+    props or {},
+    template_data or {}
+  )
 
 def location(location):
     return HttpResponse('', status=HTTPStatus.CONFLICT, headers={

inertia/test.py

@@ -1,31 +1,48 @@
 from django.test import TestCase, Client
 from unittest.mock import patch
-from django.http.response import JsonResponse
+from django.template.loader import render_to_string as base_render_to_string
 from inertia.settings import settings
 from json import dumps, loads
 from django.utils.html import escape
-from django.shortcuts import render
+
+class ClientWithLastResponse:
+  def __init__(self, client):
+    self.client = client
+    self.last_response = None
+
+  def get(self, *args, **kwargs):
+    self.last_response = self.client.get(*args, **kwargs)
+    return self.last_response
+
+  def __getattr__(self, name):
+    return getattr(self.client, name)
 
 class BaseInertiaTestCase:
   def setUp(self):
-    self.inertia = Client(HTTP_X_INERTIA=True)
+    self.inertia = ClientWithLastResponse(Client(HTTP_X_INERTIA=True))
+    self.client = ClientWithLastResponse(Client())
+
+  def last_response(self):
+    return self.inertia.last_response or self.client.last_response
 
   def assertJSONResponse(self, response, json_obj):
-    self.assertIsInstance(response, JsonResponse)
+    self.assertEqual(response.headers['Content-Type'], 'application/json')
     self.assertEqual(response.json(), json_obj)
 
 class InertiaTestCase(BaseInertiaTestCase, TestCase):
   def setUp(self):
     super().setUp()
 
-    self.mock_inertia = patch('inertia.http.base_render', wraps=render)
+    self.mock_inertia = patch('inertia.http.render_to_string', wraps=base_render_to_string)
     self.mock_render = self.mock_inertia.start()
 
   def tearDown(self):
     self.mock_inertia.stop()
 
   def page(self):
-    return loads(self.mock_render.call_args.args[2]['page'])
+    page_data = self.mock_render.call_args[0][1]['page'] if self.mock_render.call_args else self.last_response().content
+
+    return loads(page_data)
 
   def props(self):
     return self.page()['props']
@@ -37,8 +54,7 @@ def deferred_props(self):
     return self.page()['deferredProps']
 
   def template_data(self):
-    context = self.mock_render.call_args.args[2]
-
+    context = self.mock_render.call_args[0][1]
     return {key: context[key] for key in context if key not in ['page', 'inertia_layout']}
 
   def component(self):
@@ -63,7 +79,7 @@ def inertia_page(url, component='TestComponent', props={}, template_data={}, def
   _page = {
     'component': component,
     'props': props,
-    'url': f'http://testserver/{url}/',
+    'url': f'/{url}/',
     'version': settings.INERTIA_VERSION,
     'encryptHistory': False,
     'clearHistory': False,