add a python module for json handling functions

- currently implements a load and validate function

python/toolbox/json.py

@@ -0,0 +1,43 @@
+import json
+import lzma
+
+from jsonschema import validate
+from jsonschema import exceptions
+
+
+def load_json_file(json_file, uselzma = False):
+    """Load JSON file and return a json object/error msg tuple"""
+    err_msg = None
+    try:
+        if uselzma:
+            input_fp = lzma.open(json_file, 'rt')
+        else:
+            input_fp = open(json_file, 'r')
+        input_json = json.load(input_fp)
+        input_fp.close()
+        return input_json, None
+    except FileNotFoundError as err:
+        err_msg = f"Could not find JSON file { json_file }:{ err }"
+    except IOError as err:
+        err_msg = "Could not open/read JSON file { json_file }:{ err }"
+    except Exception as err:
+        err_msg = f"Unexpected error opening JSON file { json_file }:{ err }"
+    except JSONDecodeError as err:
+        err_msg = f"Decoding JSON file %s has failed: { json_file }:{ err }"
+    except TypeError as err:
+        err_msg = f"JSON object type error: { err }"
+    return None, err_msg
+
+def validate_schema(input_json, schema_file):
+    """Validate json with schema file"""
+    err_msg = None
+
+    try:
+        schema_obj, err_msg = load_json_file(schema_file)
+        if schema_obj is None:
+            return False, err_msg
+        validate(instance = input_json, schema = schema_obj)
+    except Exception as err:
+        err_msg = f"JSON schema validation error: { err }"
+        return False, err_msg
+    return True, err_msg