pySim-shell: JSONpath support for updating files/records

Change-Id: Iad09b3d878b8b58ad34cb549c80f8a6eb3149faa

pySim/jsonpath.py

@@ -0,0 +1,48 @@
+# coding=utf-8
+import json
+import pprint
+import jsonpath_ng
+
+"""JSONpath utility functions as needed within pysim.
+
+As pySim-sell has the ability to represent SIM files as JSON strings,
+adding JSONpath allows us to conveniently modify individual sub-fields
+of a file or record in its JSON representation.
+"""
+
+# (C) 2021 by Harald Welte <laforge@osmocom.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+def js_path_find(js_dict, js_path):
+    """Find/Match a JSON path within a given JSON-serializable dict.
+    Args:
+        js_dict : JSON-serializable dict to operate on
+        js_path : JSONpath string
+    Returns: Result of the JSONpath expression
+    """
+    jsonpath_expr = jsonpath_ng.parse(js_path)
+    return jsonpath_expr.find(js_dict)
+
+def js_path_modify(js_dict, js_path, new_val):
+    """Find/Match a JSON path within a given JSON-serializable dict.
+    Args:
+        js_dict : JSON-serializable dict to operate on
+        js_path : JSONpath string
+        new_val : New value for field in js_dict at js_path
+    """
+    jsonpath_expr = jsonpath_ng.parse(js_path)
+    jsonpath_expr.find(js_dict)
+    jsonpath_expr.update(js_dict, new_val)
+