[OMCSessionZMQ] escape strings to be used via OMC (#369)

* [OMCSessionZMQ] add method to escape strings

* [test_OMCPath] add test_OMCPath_write_file

test escape of double quotes and backslash in OMCPath.write_text() / .read_text()

---------

Co-authored-by: Adeel Asghar <adeel.asghar@liu.se>

Author: syntron

OMPython/ModelicaSystem.py

@@ -2054,7 +2054,7 @@ def prepare(self) -> int:
 
                 pk_value = pc_structure[idx_structure]
                 if isinstance(pk_value, str):
-                    pk_value_str = pk_value.replace('"', '\\"')
+                    pk_value_str = self.session().escape_str(pk_value)
                     expression = f"setParameterValue({self._model_name}, {pk_structure}, \"{pk_value_str}\")"
                 elif isinstance(pk_value, bool):
                     pk_value_bool_str = "true" if pk_value else "false"

OMPython/OMCSession.py

@@ -336,7 +336,7 @@ def write_text(self, data: str, encoding=None, errors=None, newline=None):
         if not isinstance(data, str):
             raise TypeError(f"data must be str, not {data.__class__.__name__}")
 
-        data_omc = data.replace('"', '\\"')
+        data_omc = self._session.escape_str(data)
         self._session.sendExpression(f'writeFile("{self.as_posix()}", "{data_omc}", false);')
 
         return len(data)
@@ -576,6 +576,13 @@ def __del__(self):
 
         self.omc_zmq = None
 
+    @staticmethod
+    def escape_str(value: str) -> str:
+        """
+        Escape a string such that it can be used as string within OMC expressions, i.e. escape all double quotes.
+        """
+        return value.replace("\\", "\\\\").replace('"', '\\"')
+
     def omcpath(self, *path) -> OMCPath:
         """
         Create an OMCPath object based on the given path segments and the current OMC session.

tests/test_OMCPath.py

@@ -76,3 +76,17 @@ def _run_OMCPath_checks(om: OMPython.OMCSessionZMQ):
     assert p3.parent.is_dir()
     p3.unlink()
     assert p3.is_file() is False
+
+
+def test_OMCPath_write_file(tmpdir):
+    om = OMPython.OMCSessionZMQ()
+
+    data = "abc # \\t # \" # \\n # xyz"
+
+    p1 = om.omcpath_tempdir()
+    p2 = p1 / 'test.txt'
+    p2.write_text(data=data)
+
+    assert data == p2.read_text()
+
+    del om