--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wikked/fs.py	Mon Dec 10 22:40:52 2012 -0800
@@ -0,0 +1,83 @@
+import os
+import os.path
+import re
+import string
+
+
+class PageNotFoundError(Exception):
+    """ An error raised when no physical file
+       is found for a given URL.
+    """
+    pass
+
+
+class FileSystem(object):
+    """ A class responsible for mapping page URLs to
+        file-system paths, and for scanning the file-system
+        to list existing pages.
+    """
+    def __init__(self, root):
+        self.root = root
+        self.excluded = []
+
+    def getPageNames(self, subdir=None):
+        basepath = self.root
+        if subdir is not None:
+            basepath = self.getPhysicalNamespacePath(subdir)
+
+        for dirpath, dirnames, filenames in os.walk(basepath):
+            dirnames[:] = [d for d in dirnames if os.path.join(dirpath, d) not in self.excluded]
+            for filename in filenames:
+                path = os.path.join(dirpath, filename)
+                path_split = os.path.splitext(os.path.relpath(path, self.root))
+                if path_split[1] != '':
+                    yield path_split[0]
+
+    def getPage(self, url):
+        path = self.getPhysicalPagePath(url)
+        with open(path, 'r') as f:
+            content = f.read()
+        name = os.path.basename(path)
+        name_split = os.path.splitext(name)
+        return {
+                'url': url,
+                'path': path,
+                'name': name_split[0],
+                'ext': name_split[1],
+                'content': content
+                }
+
+    def getPhysicalNamespacePath(self, url):
+        return self._getPhysicalPath(url, False)
+
+    def getPhysicalPagePath(self, url):
+        return self._getPhysicalPath(url, True)
+
+    def _getPhysicalPath(self, url, is_file):
+        if string.find(url, '..') >= 0:
+            raise ValueError("Page URLs can't contain '..': " + url)
+
+        # For each "part" in the given URL, find the first
+        # file-system entry that would get slugified to an
+        # equal string.
+        current = self.root
+        parts = url.lower().split('/')
+        for i, part in enumerate(parts):
+            names = os.listdir(current)
+            for name in names:
+                name_formatted = re.sub(r'[^A-Za-z0-9_\.\-\(\)]+', '-', name.lower())
+                if is_file and i == len(parts) - 1:
+                    # If we're looking for a file and this is the last part,
+                    # look for something similar but with an extension.
+                    if re.match("%s\.[a-z]+" % re.escape(part), name_formatted):
+                        current = os.path.join(current, name)
+                        break
+                else:
+                    if name_formatted == part:
+                        current = os.path.join(current, name)
+                        break
+            else:
+                # Failed to find a part of the URL.
+                raise PageNotFoundError("No such page: " + url)
+        return current
+