# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1411403336 -7200
# Node ID aa8c34d84ad2fc58eab8b2fbf2d9fa0c971a87be
# Parent  dddb17c1aa28dc25df93e3dc945f7d730c333f77
Convert to a more regular structure for calendar details.
Added MIME part production for handler results.

diff -r dddb17c1aa28 -r aa8c34d84ad2 imip_agent.py
--- a/imip_agent.py	Mon Sep 22 18:26:59 2014 +0200
+++ b/imip_agent.py	Mon Sep 22 18:28:56 2014 +0200
@@ -1,7 +1,9 @@
 #!/usr/bin/env python
 
 from email import message_from_file
-from vCalendar import parse, iterwrite
+from email.mime.text import MIMEText
+from smtplib import SMTP
+from vCalendar import parse, iterwrite, ParseError, SECTION_TYPES
 import imip_store
 import sys
 
@@ -35,7 +37,21 @@
     "text/x-vcalendar", "application/ics",  # other possibilities
     ]
 
+# Sending of outgoing messages.
+
+def sendmail(sender, recipients, data):
+    smtp = SMTP("localhost")
+    smtp.sendmail(sender, recipients, data)
+    smtp.quit()
+
+# Processing of incoming messages.
+
 def process(f, args):
+
+    "Process content from the stream 'f' accompanied by the given 'args'."
+
+    recipient = args[0]
+
     msg = message_from_file(f)
     print >>open("/tmp/imip.txt", "a"), "----"
     print >>open("/tmp/imip.txt", "a"), args
@@ -49,25 +65,23 @@
         if part.get_content_type() in itip_content_types and \
             part.get_param("method"):
 
-            handle_itip_part(part)
+            handle_itip_part(part, recipient)
 
 def get_itip_elements(elements):
     d = {}
     for name, attr, value in elements:
-        if isinstance(value, list):
-            d[name] = attr, get_itip_elements(value)
+        if not d.has_key(name):
+            d[name] = []
+        if name in SECTION_TYPES:
+            d[name].append((attr, get_itip_elements(value)))
         else:
-            if not d.has_key(name):
-                d[name] = []
             d[name].append((attr, value))
     return d
 
 def get_attr_value(d, name, single=True):
     if d.has_key(name):
         values = d[name]
-        if isinstance(values, tuple):
-            return values
-        elif single and len(values) == 1:
+        if single and len(values) == 1:
             return values[0]
         else:
             return values
@@ -77,36 +91,51 @@
 def get_value(d, name, single=True):
     if d.has_key(name):
         values = d[name]
-        if isinstance(values, tuple):
-            return values[1]
-        elif single and len(values) == 1:
+        if single and len(values) == 1:
             return values[0][1]
         else:
             return map(lambda x: x[1], values)
     else:
         return None
 
-def handle_itip_part(part):
+def handle_itip_part(part, recipient):
     method = part.get_param("method")
 
+    # Decode the data and parse it.
+
     f = StringIO(part.get_payload(decode=True))
-    doctype, attrs, elements = parse(f, encoding=part.get_content_charset())
+
+    try:
+        doctype, attrs, elements = parse(f, encoding=part.get_content_charset())
+    except (ParseError, ValueError):
+        sys.exit(EX_DATAERR)
+
+    # Only handle calendar information.
 
     if doctype == "VCALENDAR":
         itip = get_itip_elements(elements)
 
+        # Require consistency between declared and employed methods.
+
         if get_value(itip, "METHOD") == method:
 
+            # Look for different kinds of sections.
+
             for name, cls in handlers:
-                details = get_value(itip, name)
+                for details in get_value(itip, name, False) or []:
+
+                    # Dispatch to a handler and obtain any response.
 
-                if details:
-                    print >>open("/tmp/imip.txt", "a"), details
                     handler = cls(details)
-                    print >>open("/tmp/imip.txt", "a"), "Handling", method, "with", handler, "->", methods[method](handler)
-                    methods[method](handler)()
+                    part = methods[method](handler)()
+
+                    if part:
+                        print >>open("/tmp/imip.txt", "a"), part.as_string()
 
 class Handler:
+
+    "General handler support."
+
     def __init__(self, details):
         self.details = details
         self.uid = get_value(details, "UID")
@@ -180,9 +209,9 @@
 
         # Get the details for the attendee.
 
-        out = open("/tmp/imip.txt", "a")
+        out = StringIO()
         try:
-            w = iterwrite(out)
+            w = iterwrite(out, encoding="utf-8")
 
             calendar = []
             cwrite = calendar.append
@@ -207,6 +236,8 @@
 
             w.write("VCALENDAR", {}, calendar)
 
+            return MIMEText(out.getvalue(), "calendar", "utf-8")
+
         finally:
             out.close()