Merge pull request #70 from lsst/tickets/DM-41267

DM-41267: Allow header text files to be in JSON format

python/astro_metadata_translator/file_helpers.py

@@ -127,8 +127,8 @@ def read_basic_metadata_from_file(
     Parameters
     ----------
     file : `str`
-        Name of file to read. Can be FITS or YAML. YAML must be a simple
-        top-level dict.
+        Name of file to read. Can be FITS, YAML or JSON. YAML or JSON must be
+        a simple top-level dict.
     hdrnum : `int`
         Header number to read. Only relevant for FITS. If greater than 1
         it will be merged with the primary header. If a negative number is
@@ -149,7 +149,7 @@ def read_basic_metadata_from_file(
         The header as a dict. Can be `None` if there was a problem reading
         the file.
     """
-    if file.endswith(".yaml"):
+    if file.endswith(".yaml") or file.endswith(".json"):
         try:
             md = read_test_file(
                 file,

python/astro_metadata_translator/headers.py

@@ -351,7 +351,7 @@ def _find_from_resource(
         Name of resource read. `None` if no corrections found.
     """
     if package is not None and resource_root is not None:
-        resource_path = resources.files(package).joinpath(resource_root, target_file)  # type: ignore
+        resource_path = resources.files(package).joinpath(resource_root, target_file)
         if resource_path.is_file():
             resource_uri = f"resource://{package}/{posixpath.join(resource_root, target_file)}"
             log.debug("Applying header corrections from package resource %s", resource_uri)

python/astro_metadata_translator/tests.py

@@ -13,6 +13,7 @@
 
 __all__ = ("read_test_file", "MetadataAssertHelper")
 
+import json
 import os
 import pickle
 import warnings
@@ -83,7 +84,13 @@ def read_test_file(filename: str, dir: str | None = None) -> MutableMapping[str,
     if dir is not None and not os.path.isabs(filename):
         filename = os.path.join(dir, filename)
     with open(filename) as fd:
-        header = yaml.load(fd, Loader=Loader)
+        if filename.endswith(".yaml"):
+            header = yaml.load(fd, Loader=Loader)
+        elif filename.endswith(".json"):
+            header = json.load(fd)
+        else:
+            raise RuntimeError(f"Unrecognized file format: {filename}")
+
     # Cannot directly check for Mapping because PropertyList is not one
     if not hasattr(header, "items"):
         raise ValueError(f"Contents of YAML file {filename} are not a mapping, they are {type(header)}")