allow pre-generated (human-offline-created) codes

Just make up a code like NUMBER-STUFF, and add --code= to the
send-text/send-file command. Also don't use tab-completion on the
codewords part of the receiving side, unless you stuck to the even/odd
PGP wordlist. (tab still works for the channel-id).

src/wormhole/blocking/transcribe.py

@@ -1,5 +1,5 @@
 from __future__ import print_function
-import sys, time, requests, json, textwrap
+import sys, time, re, requests, json, textwrap
 from binascii import hexlify, unhexlify
 from spake2 import SPAKE2_A, SPAKE2_B
 from nacl.secret import SecretBox
@@ -214,14 +214,22 @@ class Initiator(Common):
         self.key = None
         self.verifier = None
 
-    def get_code(self, code_length=2):
-        self.channel_id = self._allocate() # allocate channel
-        self.code = codes.make_code(self.channel_id, code_length)
+    def set_code(self, code): # used for human-made pre-generated codes
+        mo = re.search(r'^(\d+)-', code)
+        if not mo:
+            raise ValueError("code (%s) must start with NN-" % code)
+        self.channel_id = int(mo.group(1))
+        self.code = code
         self.sp = SPAKE2_A(self.code.encode("ascii"),
                            idA=self.appid+":Initiator",
                            idB=self.appid+":Receiver")
         self._post_pake()
-        return self.code
+
+    def get_code(self, code_length=2):
+        channel_id = self._allocate() # allocate channel
+        code = codes.make_code(channel_id, code_length)
+        self.set_code(code)
+        return code
 
     def _wait_for_key(self):
         if not self.key:

src/wormhole/scripts/cmd_send_file.py

@@ -16,7 +16,11 @@ def send_file(args):
     transit_sender = TransitSender(args.transit_helper)
 
     i = Initiator(APPID, args.relay_url)
-    code = i.get_code(args.code_length)
+    if args.code:
+        i.set_code(args.code)
+        code = args.code
+    else:
+        code = i.get_code(args.code_length)
     print("On the other computer, please run: wormhole receive-file")
     print("Wormhole code is '%s'" % code)
     print()

src/wormhole/scripts/cmd_send_text.py

@@ -10,7 +10,11 @@ def send_text(args):
     from ..blocking.transcribe import Initiator, WrongPasswordError
 
     i = Initiator(APPID, args.relay_url)
-    code = i.get_code(args.code_length)
+    if args.code:
+        i.set_code(args.code)
+        code = args.code
+    else:
+        code = i.get_code(args.code_length)
     print("On the other computer, please run: wormhole receive-text")
     print("Wormhole code is: %s" % code)
     print("")

src/wormhole/scripts/runner.py

@@ -56,6 +56,7 @@ sp_restart.set_defaults(func=cmd_server.restart_server)
 # CLI: send-text
 p = subparsers.add_parser("send-text", description="Send a text mesasge",
                           usage="wormhole send-text TEXT")
+p.add_argument("--code", metavar="CODE", help="human-generated code phrase")
 p.add_argument("text", metavar="TEXT", help="the message to send (a string)")
 p.set_defaults(func=cmd_send_text.send_text)
 
@@ -72,6 +73,7 @@ p.set_defaults(func=cmd_receive_text.receive_text)
 # CLI: send-file
 p = subparsers.add_parser("send-file", description="Send a file",
                           usage="wormhole send-file FILENAME")
+p.add_argument("--code", metavar="CODE", help="human-generated code phrase")
 p.add_argument("filename", metavar="FILENAME", help="The file to be sent")
 p.set_defaults(func=cmd_send_file.send_file)