map settings api endpoint (fixes #201)

src/c3nav/mapdata/api/map.py

@@ -1,6 +1,7 @@
 import json
 from typing import Annotated, Union
 
+from celery import chain
 from django.core.serializers.json import DjangoJSONEncoder
 from django.db.models import Prefetch
 from django.shortcuts import redirect
@@ -16,6 +17,7 @@ from c3nav.api.exceptions import API404, APIPermissionDenied, APIRequestValidati
 from c3nav.api.schema import BaseSchema
 from c3nav.api.utils import NonEmptyStr
 from c3nav.mapdata.api.base import api_etag, api_stats, can_access_geometry
+from c3nav.mapdata.grid import grid
 from c3nav.mapdata.models import Source, Theme, Area, Space
 from c3nav.mapdata.models.geometry.space import ObstacleGroup, Obstacle
 from c3nav.mapdata.models.locations import DynamicLocation, LocationRedirect, Position, LocationGroup
@@ -26,7 +28,7 @@ from c3nav.mapdata.schemas.models import (AnyPositionStatusSchema, FullListableL
                                           LocationDisplay, ProjectionPipelineSchema, ProjectionSchema,
                                           SlimListableLocationSchema, SlimLocationSchema, all_location_definitions,
                                           listable_location_definitions, LegendSchema, LegendItemSchema)
-from c3nav.mapdata.schemas.responses import LocationGeometry, WithBoundsSchema
+from c3nav.mapdata.schemas.responses import LocationGeometry, WithBoundsSchema, MapSettingsSchema
 from c3nav.mapdata.utils.locations import (get_location_by_id_for_request, get_location_by_slug_for_request,
                                            searchable_locations_for_request, visible_locations_for_request)
 from c3nav.mapdata.utils.user import can_access_editor
@@ -34,6 +36,25 @@ from c3nav.mapdata.utils.user import can_access_editor
 map_api_router = APIRouter(tags=["map"])
 
 
+@map_api_router.get('/settings/', summary="get map settings",
+                    description="get useful/required settings for displaying the map",
+                    response={200: MapSettingsSchema, **auth_responses})
+@api_etag(permissions=False)
+def map_settings(request):
+    initial_bounds = settings.INITIAL_BOUNDS
+    if not initial_bounds:
+        initial_bounds = tuple(chain(*Source.max_bounds()))
+    else:
+        initial_bounds = (tuple(settings.INITIAL_BOUNDS)[:2], tuple(settings.INITIAL_BOUNDS)[2:])
+
+    return MapSettingsSchema(
+        initial_bounds=initial_bounds,
+        initial_level=settings.INITIAL_LEVEL or None,
+        grid=grid.serialize().model_dump() if grid else None,
+        tile_server=settings.TILE_CACHE_SERVER,
+    )
+
+
 @map_api_router.get('/bounds/', summary="get boundaries",
                     description="get maximum boundaries of everything on the map",
                     response={200: WithBoundsSchema, **auth_responses})

src/c3nav/mapdata/grid.py

@@ -1,9 +1,11 @@
 import bisect
 import string
 from abc import ABC, abstractmethod
-from typing import Optional
+from dataclasses import dataclass, field
+from typing import Optional, ClassVar, Sequence
 
 from django.conf import settings
+from ninja import Schema
 
 
 class AbstractGrid(ABC):
@@ -18,6 +20,13 @@ class AbstractGrid(ABC):
         pass
 
 
+class GridSchema(Schema):
+    rows: Sequence[float]
+    cols: Sequence[float]
+    invert_x: bool
+    invert_y: bool
+
+
 class Grid(AbstractGrid):
     enabled = True
 
@@ -41,6 +50,14 @@ class Grid(AbstractGrid):
         else:
             raise ValueError('column coordinates are not ordered')
 
+    def serialize(self) -> GridSchema:
+        return GridSchema(
+            rows=self.rows,
+            cols=self.cols,
+            invert_x=self.invert_y,
+            invert_y=self.invert_y,
+        )
+
     def get_square_for_point(self, x, y):
         x = bisect.bisect(self.cols, x)
         if x <= 0 or x >= len(self.cols):

src/c3nav/mapdata/schemas/responses.py

@@ -1,12 +1,36 @@
-from typing import Annotated, Union
+from typing import Annotated, Union, Optional
 
 from pydantic import Field as APIField
 from pydantic import PositiveInt
 
 from c3nav.api.schema import BaseSchema, GeometrySchema
+from c3nav.mapdata.grid import GridSchema
 from c3nav.mapdata.schemas.model_base import AnyLocationID, BoundsSchema
 
 
+class MapSettingsSchema(BaseSchema):
+    """
+    various c3nav instance settings
+    """
+    initial_bounds: Optional[BoundsSchema] = APIField(
+        title="initial boundaries",
+        description="(left, bottom) to (top, right)",
+    )
+    initial_level: Optional[PositiveInt] = APIField(
+        title="initial level id",
+        description="the level id that is intially shown when opening the map",
+    )
+
+    grid: Optional[GridSchema] = APIField(
+        title="grid config",
+        description="grid configuration, if available",
+    )
+    tile_server: Optional[str] = APIField(
+        title="tile server base URL",
+        description="tile server base URL to use, if configured",
+    )
+
+
 class WithBoundsSchema(BaseSchema):
     """
     Describing a bounding box

src/c3nav/site/views.py

@@ -217,12 +217,7 @@ def map_index(request, mode=None, slug=None, slug2=None, details=None, options=N
     }
 
     if grid.enabled:
-        ctx['grid'] = json.dumps({
-            'rows': grid.rows,
-            'cols': grid.cols,
-            'invert_x': grid.invert_x,
-            'invert_y': grid.invert_y,
-        }, separators=(',', ':'), cls=DjangoJSONEncoder)
+        ctx['grid'] = json.dumps(grid.serialize().model_dump(), separators=(',', ':'), cls=DjangoJSONEncoder)
 
     csrf.get_token(request)