Simplify utilities and core write logic

Author: jonhadfield

README.md

@@ -5,6 +5,7 @@ python-hosts
 
 This is a python library for managing a hosts file.
 It enables you to add and remove entries, or import them from a file or URL.
+Utility functions have been streamlined for easier maintenance.
 It remains compatible with Python 2.7 as well as modern Python 3 releases.
 
 Documentation

python_hosts/hosts.py

@@ -196,50 +196,38 @@ def write(self, path=None, mode='w'):
         :param path: override the write path
         :return: Dictionary containing counts
         """
-        written_count = 0
-        comments_written = 0
-        blanks_written = 0
-        ipv4_entries_written = 0
-        ipv6_entries_written = 0
-        if path:
-            output_file_path = path
-        else:
-            output_file_path = self.path
+
+        counters = {
+            'total_written': 0,
+            'comments_written': 0,
+            'blanks_written': 0,
+            'ipv4_entries_written': 0,
+            'ipv6_entries_written': 0,
+        }
+        output_file_path = path if path else self.path
         try:
             with open(output_file_path, mode) as hosts_file:
-                for written_count, line in enumerate(self.entries):
-                    if line.entry_type == 'comment':
-                        hosts_file.write(line.comment + "\n")
-                        comments_written += 1
-                    if line.entry_type == 'blank':
+                for entry in self.entries:
+                    if entry.entry_type == 'comment':
+                        hosts_file.write(entry.comment + "\n")
+                        counters['comments_written'] += 1
+                    elif entry.entry_type == 'blank':
                         hosts_file.write("\n")
-                        blanks_written += 1
-                    if line.entry_type == 'ipv4':
-                        hosts_file.write(
-                            "{0}\t{1}{2}\n".format(
-                                line.address,
-                                ' '.join(line.names),
-                                " # " + line.comment if line.comment else ""
-                            )
-                        )
-                        ipv4_entries_written += 1
-                    if line.entry_type == 'ipv6':
+                        counters['blanks_written'] += 1
+                    else:
                         hosts_file.write(
                             "{0}\t{1}{2}\n".format(
-                                line.address,
-                                ' '.join(line.names),
-                                " # " + line.comment if line.comment else ""
+                                entry.address,
+                                ' '.join(entry.names),
+                                " # " + entry.comment if entry.comment else "",
                             )
                         )
-                        ipv6_entries_written += 1
+                        key = 'ipv6_entries_written' if entry.entry_type == 'ipv6' else 'ipv4_entries_written'
+                        counters[key] += 1
+                    counters['total_written'] += 1
         except Exception:
             raise UnableToWriteHosts()
-        return {'total_written': written_count + 1,
-                'comments_written': comments_written,
-                'blanks_written': blanks_written,
-                'ipv4_entries_written': ipv4_entries_written,
-                'ipv6_entries_written': ipv6_entries_written}
-
+        return counters
     @staticmethod
     def get_hosts_by_url(url=None):
         """
@@ -264,8 +252,10 @@ def exists(self, address=None, names=None, comment=None):
             if self.find_all_matching(address=address, name=name, comment=comment):
                 return True
 
-        return any(entry.entry_type == 'comment' and entry.comment == comment
-                   for entry in self.entries)
+        if comment:
+            return any(entry.entry_type == 'comment' and entry.comment == comment
+                       for entry in self.entries)
+        return False
 
     def remove_all_matching(self, address=None, name=None, comment=None):
         """

python_hosts/utils.py

@@ -9,55 +9,34 @@
 
 
 def is_ipv4(entry):
-    """
-    Check if the string provided is a valid ipv4 address
-    :param entry: A string representation of an IP address
-    :return: True if valid, False if invalid
-    """
+    """Return ``True`` if ``entry`` is a valid IPv4 address."""
     try:
-        if socket.inet_aton(entry):
-            return True
+        socket.inet_aton(entry)
     except socket.error:
         return False
+    return True
 
 
 def is_ipv6(entry):
-    """
-    Check if the string provided is a valid ipv6 address
-    :param entry: A string representation of an IP address
-    :return: True if valid, False if invalid
-    """
+    """Return ``True`` if ``entry`` is a valid IPv6 address."""
     try:
-        if socket.inet_pton(socket.AF_INET6, entry):
-            return True
+        socket.inet_pton(socket.AF_INET6, entry)
     except socket.error:
         return False
+    return True
 
 
 def valid_hostnames(hostname_list):
-    """
-    Check if the supplied list of strings are valid hostnames
-    :param hostname_list: A list of strings
-    :return: True if the strings are valid hostnames, False if not
-    """
-    for entry in hostname_list:
-        if len(entry) > 255:
-            return False
-        allowed = re.compile(r'(?!-)[A-Z\d-]{1,63}(?<!-)$', re.IGNORECASE)
-        if not all(allowed.match(x) for x in entry.split(".")):
-            return False
-    return True
+    """Return ``True`` if all items in ``hostname_list`` are valid hostnames."""
+    allowed = re.compile(r'(?!-)[A-Z\d-]{1,63}(?<!-)$', re.IGNORECASE)
+    return all(len(entry) <= 255 and
+               all(allowed.match(x) for x in entry.split('.'))
+               for entry in hostname_list)
 
 
 def is_readable(path=None):
-    """
-    Test if the supplied filesystem path can be read
-    :param path: A filesystem path
-    :return: True if the path is a file that can be read. Otherwise, False
-    """
-    if os.path.isfile(path) and os.access(path, os.R_OK):
-        return True
-    return False
+    """Return ``True`` if ``path`` exists and is readable."""
+    return os.path.isfile(path) and os.access(path, os.R_OK)
 
 
 def dedupe_list(seq):