1 files changed, 100 insertions, 0 deletions
diff --git a/netlib/utils.py b/netlib/utils.py
index 86e33f33..39354605 100644
--- a/netlib/utils.py
+++ b/netlib/utils.py
@@ -1,5 +1,10 @@
 from __future__ import (absolute_import, print_function, division)
 import os.path
+import cgi
+import urllib
+import urlparse
+import string
+
 
 def isascii(s):
     try:
@@ -131,6 +136,81 @@ class Data(object):
         return fullpath
 
 
+
+
+def is_valid_port(port):
+    if not 0 <= port <= 65535:
+        return False
+    return True
+
+
+def is_valid_host(host):
+    try:
+        host.decode("idna")
+    except ValueError:
+        return False
+    if "\0" in host:
+        return None
+    return True
+
+
+def parse_url(url):
+    """
+        Returns a (scheme, host, port, path) tuple, or None on error.
+
+        Checks that:
+            port is an integer 0-65535
+            host is a valid IDNA-encoded hostname with no null-bytes
+            path is valid ASCII
+    """
+    try:
+        scheme, netloc, path, params, query, fragment = urlparse.urlparse(url)
+    except ValueError:
+        return None
+    if not scheme:
+        return None
+    if '@' in netloc:
+        # FIXME: Consider what to do with the discarded credentials here Most
+        # probably we should extend the signature to return these as a separate
+        # value.
+        _, netloc = string.rsplit(netloc, '@', maxsplit=1)
+    if ':' in netloc:
+        host, port = string.rsplit(netloc, ':', maxsplit=1)
+        try:
+            port = int(port)
+        except ValueError:
+            return None
+    else:
+        host = netloc
+        if scheme == "https":
+            port = 443
+        else:
+            port = 80
+    path = urlparse.urlunparse(('', '', path, params, query, fragment))
+    if not path.startswith("/"):
+        path = "/" + path
+    if not is_valid_host(host):
+        return None
+    if not isascii(path):
+        return None
+    if not is_valid_port(port):
+        return None
+    return scheme, host, port, path
+
+
+def get_header_tokens(headers, key):
+    """
+        Retrieve all tokens for a header key. A number of different headers
+        follow a pattern where each header line can containe comma-separated
+        tokens, and headers can be set multiple times.
+    """
+    toks = []
+    for i in headers[key]:
+        for j in i.split(","):
+            toks.append(j.strip())
+    return toks
+
+
 def hostport(scheme, host, port):
     """
         Returns the host component, with a port specifcation if needed.
@@ -139,3 +219,23 @@ def hostport(scheme, host, port):
         return host
     else:
         return "%s:%s" % (host, port)
+
+def unparse_url(scheme, host, port, path=""):
+    """
+        Returns a URL string, constructed from the specified compnents.
+    """
+    return "%s://%s%s" % (scheme, hostport(scheme, host, port), path)
+
+
+def urlencode(s):
+    """
+        Takes a list of (key, value) tuples and returns a urlencoded string.
+    """
+    s = [tuple(i) for i in s]
+    return urllib.urlencode(s, False)
+
+def urldecode(s):
+    """
+        Takes a urlencoded string and returns a list of (key, value) tuples.
+    """
+    return cgi.parse_qsl(s, keep_blank_values=True)