A list_filter.py

@@ -0,0 +1,114 @@
+#!/usr/bin/python3
+
+import sys
+import os
+import re
+
+sender = "None"
+recipient = "None"
+if (len(sys.argv) > 2):
+    sender = sys.argv[1]
+    recipient = sys.argv[2]
+
+#print(f"Sender: {sender}")
+#print(f"Recipient: {recipient}")
+#f = open("/tmp/filter.txt", "a")
+#f.write(f"Sender: {sender}\n")
+#f.write(f"Recipient: {recipient}\n")
+#f.close()
+
+orig_to = ""
+orig_from = ""
+list_email = ""
+list_name = ""
+list_domain = ""
+
+stdin= []
+for line in sys.stdin:
+    if (list_email == "" and line[0:4] == "To: "):
+        orig_to = line[4:].rstrip()
+        list_email = re.search("\S+@\S+\.\S+", orig_to).group()
+        if (list_email[-1] == ","):
+            list_email = list_email[0:-1]
+        if (list_email[0] == "\"" and list_email[-1] == "\""):
+            list_email = list_email[1:-1]
+        elif (list_email[0] == "<" and list_email[-1] == ">"):
+            list_email = list_email[1:-1]
+        list_name = re.search("^[^@]+", list_email).group()
+        list_domain = re.search("^[^@]+@(.+)$", list_email).group(1)
+    stdin.append(line)
+
+sender_name = ""
+for line in stdin:
+    if (sender_name == "" and line[0:6] == "From: "):
+        orig_from = line[6:].rstrip()
+        if (re.search("^\"[^\"]+\"", orig_from)):
+            sender_name = re.search("^\"([^\"]+)\"", orig_from).group(1)
+        elif (re.search("^[^<]+ <", orig_from)):
+            sender_name = re.search("^([^<]+) <", orig_from).group(1)
+        else:
+            sender_name = re.search("(\S+)@\S+\.\S+", orig_from).group(1)
+            if (sender_name[0] == "\"" or sender_name[0] == "<"):
+                sender_name = sender_name[1:]
+
+for line in stdin:
+    if (re.search("^Auto-Submitted: auto-generated", line, re.IGNORECASE)):
+        exit()
+    if (re.search("^Auto-Submitted: auto-replied", line, re.IGNORECASE)):
+        exit()
+    if (re.search("^\s*$", line)):
+        break
+
+## We add the filter skip header after the from line had been changed
+## and reinjected. This is necessary to get the dkim milter to run
+## for the new "From" header. Otherwise it doesn't run.
+contents = []
+if (re.search(list_email, orig_from)):
+    contents.append(f"List-Skip-Filter: yes\n")
+    for line in stdin:
+        contents.append(line)
+else:
+    contents.append(f"To: {list_email}\n")
+    contents.append(f"From: \"{sender_name} via {list_name}\" <{list_email}>\n")
+    contents.append(f"Reply-To: {list_email}, {sender}\n")
+
+    in_header = 1
+    included = 0
+    for line in stdin:
+        if (in_header == 1):
+            if (re.search("^\s+\S+", line) and included == 1):
+                contents.append(line)
+                continue
+
+            included = 0
+            if (re.search("^Subject: ", line)):
+                contents.append(line)
+                included = 1
+            elif (re.search("^Content-", line)):
+                contents.append(line)
+                included = 1
+            elif (re.search("^\s*$", line)):
+                contents.append(line)
+                in_header = 0
+        else:
+            contents.append(line)
+
+    #found_from = 0
+    #found_to = 0
+    #for line in stdin:
+    #    if (found_from == 0 and line[0:6] == "From: "):
+    #        line = f"From: \"{sender_name} via {list_name}\" <{list_email}>\n"
+    #        contents.append(f"Reply-To: {sender}, {list_email}\n")
+    #        found_from = 1
+    #    elif (found_to == 0 and line[0:4] == "To: "):
+    #        line = f"To: {list_email}\n"
+    #        found_to = 1
+    #    contents.append(line)
+
+#for line in contents:
+#    print(line, end = "")
+
+p = os.popen(f"/usr/sbin/sendmail -G -i {list_email}", "w")
+for line in contents:
+    p.write(line)
+p.close()