implement command line status call in Python

nominatim/result_formatter/base.py

@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Helper classes and function for writing result formatting modules.
+"""
+from typing import Type, TypeVar, Dict, Mapping, List, Callable, Generic, Any
+from collections import defaultdict
+
+T = TypeVar('T') # pylint: disable=invalid-name
+FormatFunc = Callable[[T], str]
+
+class ResultFormatter(Generic[T]):
+    """ This class dispatches format calls to the appropriate formatting
+        function previously defined with the `format_func` decorator.
+    """
+
+    def __init__(self, funcs: Mapping[str, FormatFunc[T]]) -> None:
+        self.functions = funcs
+
+
+    def list_formats(self) -> List[str]:
+        """ Return a list of formats supported by this formatter.
+        """
+        return list(self.functions.keys())
+
+
+    def format(self, result: T, fmt: str) -> str:
+        """ Convert the given result into a string using the given format.
+
+            The format is expected to be in the list returned by
+            `list_formats()`.
+        """
+        return self.functions[fmt](result)
+
+
+class FormatDispatcher:
+    """ A factory class for result formatters.
+    """
+
+    def __init__(self) -> None:
+        self.format_functions: Dict[Type[Any], Dict[str, FormatFunc[Any]]] = defaultdict(dict)
+
+
+    def format_func(self, result_class: Type[T],
+                    fmt: str) -> Callable[[FormatFunc[T]], FormatFunc[T]]:
+        """ Decorator for a function that formats a given type of result into the
+            selected format.
+        """
+        def decorator(func: FormatFunc[T]) -> FormatFunc[T]:
+            self.format_functions[result_class][fmt] = func
+            return func
+
+        return decorator
+
+
+    def __call__(self, result_class: Type[T]) -> ResultFormatter[T]:
+        """ Create an instance of a format class for the given result type.
+        """
+        return ResultFormatter(self.format_functions[result_class])

nominatim/result_formatter/v1.py

@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Output formatters for API version v1.
+"""
+from typing import Dict, Any
+from collections import OrderedDict
+import json
+
+from nominatim.result_formatter.base import FormatDispatcher
+from nominatim.apicmd.status import StatusResult
+
+create = FormatDispatcher()
+
+@create.format_func(StatusResult, 'text')
+def _format_status_text(result: StatusResult) -> str:
+    return result.message
+
+
+@create.format_func(StatusResult, 'json')
+def _format_status_json(result: StatusResult) -> str:
+    # XXX write a simple JSON serializer
+    out: Dict[str, Any] = OrderedDict()
+    out['status'] = result.status
+    out['message'] = result.message
+    if result.data_updated is not None:
+        out['data_updated'] = result.data_updated
+    out['software_version'] = result.software_version
+    if result.database_version is not None:
+        out['database_version'] = result.database_version
+
+    return json.dumps(out)