process error with formatting

pywps/app/exceptions.py

@@ -7,42 +7,57 @@
 Process exceptions raised intentionally in processes to provide information for users.
 """
 
+import re
+
+DEFAULT_ALLOWED_CHARS = ".:!?=,;-_/"
+
+import logging
+
+LOGGER = logging.getLogger('PYWPS')
+
+
+def format_message(text, min_length=3, max_length=300, allowed_chars=None):
+    allowed_chars = allowed_chars or DEFAULT_ALLOWED_CHARS
+    special = re.escape(allowed_chars)
+    pattern = rf'[\w{special}]+'
+    msg = ' '.join(re.findall(pattern, text))
+    msg.strip()
+    if len(msg) >= min_length:
+        msg = msg[:max_length]
+    else:
+        msg = ''
+    return msg
+
 
 class ProcessError(Exception):
     """:class:`pywps.app.exceptions.ProcessError` is an :class:`Exception`
     you can intentionally raise in a process
     to provide a user-friendly error message.
-    The error message gets validated (3<= message length <=144) and only
+    The error message gets formatted (3<= message length <=300) and only
     alpha numeric characters and a few special characters are allowed.
-    The special characters are: `.`, `:`, `!`, `?`, `=`, `,`, `-`.
     """
-    min_msg_length = 3
-    max_msg_length = 144
-    allowed_chars = ['.', ':', '!', '?', '=', ',', '-']
     default_msg = 'Sorry, process failed. Please check server error log.'
 
-    def __init__(self, msg=None):
+    def __init__(self, msg=None, min_length=3, max_length=300, allowed_chars=None):
         self.msg = msg
+        self.min_length = min_length
+        self.max_length = max_length
+        self.allowed_chars = allowed_chars or DEFAULT_ALLOWED_CHARS
 
     def __str__(self):
         return self.message
 
-    def _validate_message(self):
-        valid = False
-        if self.msg and self.min_msg_length <= len(self.msg) <= self.max_msg_length:
-            # remove spaces
-            test_str = self.msg.replace(' ', '')
-            # remove allowed non alpha-numeric chars
-            for char in self.allowed_chars:
-                test_str = test_str.replace(char, '')
-            # only alpha numeric string accepted
-            valid = test_str.isalnum()
-        return valid
-
     @property
     def message(self):
-        if self._validate_message():
-            new_msg = "{}".format(self.msg)
-        else:
-            new_msg = self.default_msg
-        return new_msg
+        try:
+            msg = format_message(
+                self.msg,
+                min_length=self.min_length,
+                max_length=self.max_length,
+                allowed_chars=self.allowed_chars)
+        except Exception as e:
+            LOGGER.warning(f"process error formatting failed: {e}")
+            msg = None
+        if not msg:
+            msg = self.default_msg
+        return msg

tests/test_app_exceptions.py

@@ -0,0 +1,35 @@
+##################################################################
+# Copyright 2018 Open Source Geospatial Foundation and others    #
+# licensed under MIT, Please consult LICENSE.txt for details     #
+##################################################################
+
+import unittest
+from pywps.app.exceptions import format_message, ProcessError, DEFAULT_ALLOWED_CHARS
+
+
+class AppExceptionsTest(unittest.TestCase):
+
+    def setUp(self):
+        pass
+
+    def test_format_message(self):
+        assert format_message('no data available') == 'no data available'
+        assert format_message(' no data available! ') == 'no data available!'
+        assert format_message('no') == ''
+        assert format_message('no data available', max_length=7) == 'no data'
+        assert format_message('no &data% available') == 'no data available'
+        assert format_message(DEFAULT_ALLOWED_CHARS) == DEFAULT_ALLOWED_CHARS
+
+    def test_process_error(self):
+        assert ProcessError(' no &data available!').message == 'no data available!'
+        assert ProcessError('no', min_length=2).message == 'no'
+        assert ProcessError('0 data available', max_length=6).message == '0 data'
+        assert ProcessError('no data? not available!', allowed_chars='?').message == 'no data? not available'
+        assert ProcessError('').message == 'Sorry, process failed. Please check server error log.'
+        assert ProcessError(1234).message == 'Sorry, process failed. Please check server error log.'
+        try:
+            raise ProcessError('no data!!')
+        except ProcessError as e:
+            assert f"{e}" == 'no data!!'
+        else:
+            assert False