Add timezone grid caching to CLI (#17) (#21)

* add cli caching, will read from timezone.json or --grid argument

* update output in test_executable_without_args

* update find_sun to use cached timezone_grid.json

* Bump minor version number

---------

Co-authored-by: Galen Reich <[email protected]>

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "ShadowFinder"
-version = "0.4.0"
+version = "0.5.0"
 description = "Find possible locations of shadows."
 authors = ["Bellingcat"]
 license = "MIT License"

src/shadowfinder/cli.py

@@ -41,6 +41,7 @@ def find(
         date: str,
         time: str,
         time_format: str = "utc",
+        grid: str = "timezone_grid.json",
     ) -> None:
         """
         Find the shadow length of an object given its height and the date and time.
@@ -59,14 +60,15 @@ def find(
         shadow_finder = ShadowFinder(
             object_height, shadow_length, date_time, time_format
         )
-        shadow_finder.quick_find()
+        shadow_finder.quick_find(grid)
 
     @staticmethod
     def find_sun(
         sun_altitude_angle: float,
         date: str,
         time: str,
         time_format: str = "utc",
+        grid: str = "timezene_grid.json",
     ) -> None:
         """
         Locate a shadow based on the solar altitude angle and the date and time.
@@ -86,4 +88,17 @@ def find_sun(
             time_format=time_format,
             sun_altitude_angle=sun_altitude_angle,
         )
-        shadow_finder.quick_find()
+        shadow_finder.quick_find(grid)
+
+    @staticmethod
+    def generate_timezone_grid(
+        grid: str = "timezone_grid.json",
+    ) -> None:
+        """
+        Generate a timezone grid file.
+        :param grid: File path to save the timezone grid.
+        """
+
+        shadow_finder = ShadowFinder()
+        shadow_finder.generate_timezone_grid()
+        shadow_finder.save_timezone_grid(grid)

src/shadowfinder/shadowfinder.py

@@ -93,8 +93,13 @@ def set_details(
             # Lengths and angle are None and we use the same values as before
             pass
 
-    def quick_find(self):
-        self.generate_timezone_grid()
+    def quick_find(self, timezone_grid="timezone_grid.json"):
+        # try to load timezone grid from file, generate if not found
+        try:
+            self.load_timezone_grid(timezone_grid)
+        except FileNotFoundError:
+            self.generate_timezone_grid()
+
         self.find_shadows()
         fig = self.plot_shadows()
 

tests/test_executable.py

@@ -24,6 +24,9 @@ def test_executable_without_args():
 
      find_sun
        Locate a shadow based on the solar altitude angle and the date and time.
+
+     generate_timezone_grid
+       Generate a timezone grid file.
 """
 
     # WHEN