update and test TileJSON model (developmentseed#363)

CHANGES.md

@@ -1,5 +1,11 @@
 # Release Notes
 
+## Next
+
+### titiler.core
+
+- Update the TileJSON model for better validation and to match with the specification (center is optional) (https://github.com/developmentseed/titiler/pull/363)
+
 ## 0.3.6 (2021-08-23)
 
 ### titiler.core

src/titiler/core/tests/test_models.py

@@ -0,0 +1,26 @@
+"""test titiler.models."""
+
+import pytest
+from pydantic import ValidationError
+
+from titiler.core.models.mapbox import TileJSON
+
+
+def test_tilejson_model():
+    """Make sure TileJSON model validates input and return default."""
+    tj = TileJSON(tiles=["https://something.xyz/{x}/{y}/{z}"])
+    assert tj.center == (0.0, 0.0, 0)
+    assert tj.bounds == [-180, -90, 180, 90]
+    assert tj.minzoom == 0
+    assert tj.maxzoom == 30
+    assert tj.scheme == "xyz"
+
+    tj = TileJSON(
+        tiles=["https://something.xyz/{x}/{y}/{z}"], center=(10, 10, 4), scheme="tms"
+    )
+    assert tj.center == (10.0, 10.0, 4)
+    assert tj.bounds == [-180, -90, 180, 90]
+    assert tj.scheme == "tms"
+
+    with pytest.raises(ValidationError):
+        TileJSON(tiles=["https://something.xyz/{x}/{y}/{z}"], scheme="abc")

src/titiler/core/titiler/core/factory.py

@@ -431,12 +431,8 @@ def tilejson(
 
             with rasterio.Env(**self.gdal_config):
                 with self.reader(src_path, tms=tms, **self.reader_options) as src_dst:
-                    center = list(src_dst.center)
-                    if minzoom:
-                        center[-1] = minzoom
                     tjson = {
                         "bounds": src_dst.bounds,
-                        "center": tuple(center),
                         "minzoom": minzoom if minzoom is not None else src_dst.minzoom,
                         "maxzoom": maxzoom if maxzoom is not None else src_dst.maxzoom,
                         "name": urlparse(src_path).path.lstrip("/") or "cogeotif",

src/titiler/core/titiler/core/models/mapbox.py

@@ -1,8 +1,16 @@
 """Common response models."""
 
+from enum import Enum
 from typing import List, Optional, Tuple
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, root_validator
+
+
+class SchemeEnum(str, Enum):
+    """TileJSON scheme choice."""
+
+    xyz = "xyz"
+    tms = "tms"
 
 
 class TileJSON(BaseModel):
@@ -20,11 +28,28 @@ class TileJSON(BaseModel):
     attribution: Optional[str]
     template: Optional[str]
     legend: Optional[str]
-    scheme: str = "xyz"
+    scheme: SchemeEnum = SchemeEnum.xyz
     tiles: List[str]
     grids: Optional[List[str]]
     data: Optional[List[str]]
     minzoom: int = Field(0, ge=0, le=30)
     maxzoom: int = Field(30, ge=0, le=30)
     bounds: List[float] = [-180, -90, 180, 90]
-    center: Tuple[float, float, int]
+    center: Optional[Tuple[float, float, int]]
+
+    @root_validator
+    def compute_center(cls, values):
+        """Compute center if it does not exist."""
+        bounds = values["bounds"]
+        if not values.get("center"):
+            values["center"] = (
+                (bounds[0] + bounds[2]) / 2,
+                (bounds[1] + bounds[3]) / 2,
+                values["minzoom"],
+            )
+        return values
+
+    class Config:
+        """TileJSON model configuration."""
+
+        use_enum_values = True

src/titiler/mosaic/titiler/mosaic/factory.py

@@ -323,7 +323,7 @@ def tilejson(
 
             with self.reader(src_path, **self.backend_options) as src_dst:
                 center = list(src_dst.center)
-                if minzoom:
+                if minzoom is not None:
                     center[-1] = minzoom
                 return {
                     "bounds": src_dst.bounds,