From 07686f3de751aa38d386f818303b99ef536224f9 Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 17:52:13 -0800
Subject: [PATCH 1/8] make self.channel internal

---
 src/wormhole/blocking/transcribe.py | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index 4386c59..965738f 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -156,6 +156,7 @@ class Wormhole:
         side = hexlify(os.urandom(5)).decode("ascii")
         self._channel_manager = ChannelManager(relay_url, appid, side,
                                                self.handle_welcome)
+        self._channel = None
         self.code = None
         self.key = None
         self.verifier = None
@@ -212,8 +213,8 @@ class Wormhole:
             raise ValueError("code (%s) must start with NN-" % code)
         self.code = code
         channelid = int(mo.group(1))
-        self.channel = self._channel_manager.connect(channelid)
-        monitor.add(self.channel)
+        self._channel = self._channel_manager.connect(channelid)
+        monitor.add(self._channel)
 
     def _start(self):
         # allocate the rest now too, so it can be serialized
@@ -244,14 +245,14 @@ class Wormhole:
 
     def _get_key(self):
         if not self.key:
-            self.channel.send(u"pake", self.msg1)
-            pake_msg = self.channel.get(u"pake")
+            self._channel.send(u"pake", self.msg1)
+            pake_msg = self._channel.get(u"pake")
             self.key = self.sp.finish(pake_msg)
             self.verifier = self.derive_key(u"wormhole:verifier")
 
     def get_verifier(self):
         if self.code is None: raise UsageError
-        if self.channel is None: raise UsageError
+        if self._channel is None: raise UsageError
         self._get_key()
         return self.verifier
 
@@ -261,7 +262,7 @@ class Wormhole:
         if not isinstance(phase, type(u"")): raise TypeError(type(phase))
         if phase in self._sent_data: raise UsageError # only call this once
         if self.code is None: raise UsageError
-        if self.channel is None: raise UsageError
+        if self._channel is None: raise UsageError
         # Without predefined roles, we can't derive predictably unique keys
         # for each side, so we use the same key for both. We use random
         # nonces to keep the messages distinct, and the Channel automatically
@@ -270,17 +271,17 @@ class Wormhole:
         self._get_key()
         data_key = self.derive_key(u"wormhole:phase:%s" % phase)
         outbound_encrypted = self._encrypt_data(data_key, outbound_data)
-        self.channel.send(phase, outbound_encrypted)
+        self._channel.send(phase, outbound_encrypted)
 
     def get_data(self, phase=u"data"):
         if not isinstance(phase, type(u"")): raise TypeError(type(phase))
         if phase in self._got_data: raise UsageError # only call this once
         if self.code is None: raise UsageError
-        if self.channel is None: raise UsageError
+        if self._channel is None: raise UsageError
         self._got_data.add(phase)
         self._get_key()
         data_key = self.derive_key(u"wormhole:phase:%s" % phase)
-        inbound_encrypted = self.channel.get(phase)
+        inbound_encrypted = self._channel.get(phase)
         try:
             inbound_data = self._decrypt_data(data_key, inbound_encrypted)
             return inbound_data
@@ -288,5 +289,5 @@ class Wormhole:
             raise WrongPasswordError
 
     def close(self):
-        monitor.close(self.channel)
-        self.channel.deallocate()
+        monitor.close(self._channel)
+        self._channel.deallocate()

From fa3be3523deedeef02f98c8084fcd0e188947ebd Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 17:56:08 -0800
Subject: [PATCH 2/8] pass timeouts down

---
 src/wormhole/blocking/transcribe.py | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index 965738f..94de91b 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -30,7 +30,8 @@ def to_bytes(u):
 # all JSON responses include a "welcome:{..}" key
 
 class Channel:
-    def __init__(self, relay_url, appid, channelid, side, handle_welcome):
+    def __init__(self, relay_url, appid, channelid, side, handle_welcome,
+                 wait, timeout):
         self._relay_url = relay_url
         self._appid = appid
         self._channelid = channelid
@@ -39,8 +40,8 @@ class Channel:
         self._messages = set() # (phase,body) , body is bytes
         self._sent_messages = set() # (phase,body)
         self._started = time.time()
-        self._wait = 0.5*SECOND
-        self._timeout = 3*MINUTE
+        self._wait = wait
+        self._timeout = timeout
 
     def _add_inbound_messages(self, messages):
         for msg in messages:
@@ -114,11 +115,14 @@ class Channel:
         # ignore POST failure, don't call r.raise_for_status()
 
 class ChannelManager:
-    def __init__(self, relay_url, appid, side, handle_welcome):
+    def __init__(self, relay_url, appid, side, handle_welcome,
+                 wait=0.5*SECOND, timeout=3*MINUTE):
         self._relay_url = relay_url
         self._appid = appid
         self._side = side
         self._handle_welcome = handle_welcome
+        self._wait = wait
+        self._timeout = timeout
 
     def list_channels(self):
         queryargs = urlencode([("appid", self._appid)])
@@ -140,22 +144,25 @@ class ChannelManager:
 
     def connect(self, channelid):
         return Channel(self._relay_url, self._appid, channelid, self._side,
-                       self._handle_welcome)
+                       self._handle_welcome, self._wait, self._timeout)
 
 class Wormhole:
     motd_displayed = False
     version_warning_displayed = False
 
-    def __init__(self, appid, relay_url):
+    def __init__(self, appid, relay_url, wait=0.5*SECOND, timeout=3*MINUTE):
         if not isinstance(appid, type(u"")): raise TypeError(type(appid))
         if not isinstance(relay_url, type(u"")):
             raise TypeError(type(relay_url))
         if not relay_url.endswith(u"/"): raise UsageError
         self._appid = appid
         self._relay_url = relay_url
+        self._wait = wait
+        self._timeout = timeout
         side = hexlify(os.urandom(5)).decode("ascii")
         self._channel_manager = ChannelManager(relay_url, appid, side,
-                                               self.handle_welcome)
+                                               self.handle_welcome,
+                                               self._wait, self._timeout)
         self._channel = None
         self.code = None
         self.key = None

From 6de677c1dff09fed03913c60c8fd9cd4caee040e Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 18:00:06 -0800
Subject: [PATCH 3/8] use timeouts for allocate and list_channels too

---
 src/wormhole/blocking/transcribe.py | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index 94de91b..52ebc49 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -67,7 +67,8 @@ class Channel:
                    "phase": phase,
                    "body": hexlify(msg).decode("ascii")}
         data = json.dumps(payload).encode("utf-8")
-        r = requests.post(self._relay_url+"add", data=data)
+        r = requests.post(self._relay_url+"add", data=data,
+                          timeout=self._timeout)
         r.raise_for_status()
         resp = r.json()
         self._add_inbound_messages(resp["messages"])
@@ -111,8 +112,13 @@ class Channel:
                            "channelid": self._channelid,
                            "side": self._side,
                            "mood": mood}).encode("utf-8")
-        requests.post(self._relay_url+"deallocate", data=data)
-        # ignore POST failure, don't call r.raise_for_status()
+        try:
+            # ignore POST failure, don't call r.raise_for_status(), set a
+            # short timeout and ignore failures
+            requests.post(self._relay_url+"deallocate", data=data,
+                          timeout=5)
+        except requests.exceptions.Timeout:
+            pass
 
 class ChannelManager:
     def __init__(self, relay_url, appid, side, handle_welcome,
@@ -126,7 +132,8 @@ class ChannelManager:
 
     def list_channels(self):
         queryargs = urlencode([("appid", self._appid)])
-        r = requests.get(self._relay_url+"list?%s" % queryargs)
+        r = requests.get(self._relay_url+"list?%s" % queryargs,
+                         timeout=self._timeout)
         r.raise_for_status()
         channelids = r.json()["channelids"]
         return channelids
@@ -134,7 +141,8 @@ class ChannelManager:
     def allocate(self):
         data = json.dumps({"appid": self._appid,
                            "side": self._side}).encode("utf-8")
-        r = requests.post(self._relay_url+"allocate", data=data)
+        r = requests.post(self._relay_url+"allocate", data=data,
+                          timeout=self._timeout)
         r.raise_for_status()
         data = r.json()
         if "welcome" in data:

From cb5ad8ced12b36ed4711e1f995558c34d707b8e4 Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 18:01:22 -0800
Subject: [PATCH 4/8] Use exception for Timeout, not return value

---
 src/wormhole/blocking/transcribe.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index 52ebc49..f028ad7 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -86,7 +86,7 @@ class Channel:
         while body is None:
             remaining = self._started + self._timeout - time.time()
             if remaining < 0:
-                return Timeout
+                raise Timeout
             queryargs = urlencode([("appid", self._appid),
                                    ("channelid", self._channelid)])
             f = EventSourceFollower(self._relay_url+"get?%s" % queryargs,

From 3daef13ac0ede2c82eb7b4bc17d81f9576ec6380 Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 18:10:18 -0800
Subject: [PATCH 5/8] indent commands: no functional changes

---
 src/wormhole/scripts/cmd_receive.py | 149 ++++++++++++++--------------
 src/wormhole/scripts/cmd_send.py    | 119 +++++++++++-----------
 2 files changed, 135 insertions(+), 133 deletions(-)

diff --git a/src/wormhole/scripts/cmd_receive.py b/src/wormhole/scripts/cmd_receive.py
index d369b09..cfc98ad 100644
--- a/src/wormhole/scripts/cmd_receive.py
+++ b/src/wormhole/scripts/cmd_receive.py
@@ -12,85 +12,86 @@ def receive(args):
     from .progress import start_progress, update_progress, finish_progress
     assert isinstance(args.relay_url, type(u""))
 
-    w = Wormhole(APPID, args.relay_url)
-    if args.zeromode:
-        assert not args.code
-        args.code = u"0-"
-    code = args.code
-    if not code:
-        code = w.input_code("Enter receive wormhole code: ", args.code_length)
-    w.set_code(code)
+    if True:
+        w = Wormhole(APPID, args.relay_url)
+        if args.zeromode:
+            assert not args.code
+            args.code = u"0-"
+        code = args.code
+        if not code:
+            code = w.input_code("Enter receive wormhole code: ", args.code_length)
+        w.set_code(code)
 
-    if args.verify:
-        verifier = binascii.hexlify(w.get_verifier()).decode("ascii")
-        print("Verifier %s." % verifier)
+        if args.verify:
+            verifier = binascii.hexlify(w.get_verifier()).decode("ascii")
+            print("Verifier %s." % verifier)
 
-    try:
-        them_bytes = w.get_data()
-    except WrongPasswordError as e:
-        print("ERROR: " + e.explain(), file=sys.stderr)
-        w.close()
-        return 1
-    them_d = json.loads(them_bytes.decode("utf-8"))
-    if "error" in them_d:
-        print("ERROR: " + them_d["error"], file=sys.stderr)
-        w.close()
-        return 1
+        try:
+            them_bytes = w.get_data()
+        except WrongPasswordError as e:
+            print("ERROR: " + e.explain(), file=sys.stderr)
+            w.close()
+            return 1
+        them_d = json.loads(them_bytes.decode("utf-8"))
+        if "error" in them_d:
+            print("ERROR: " + them_d["error"], file=sys.stderr)
+            w.close()
+            return 1
 
-    if "message" in them_d:
-        # we're receiving a text message
-        print(them_d["message"])
-        data = json.dumps({"message_ack": "ok"}).encode("utf-8")
+        if "message" in them_d:
+            # we're receiving a text message
+            print(them_d["message"])
+            data = json.dumps({"message_ack": "ok"}).encode("utf-8")
+            w.send_data(data)
+            w.close()
+            return 0
+
+        if not "file" in them_d:
+            print("I don't know what they're offering\n")
+            print(them_d)
+            w.close()
+            return 1
+
+        if "error" in them_d:
+            print("ERROR: " + data["error"], file=sys.stderr)
+            w.close()
+            return 1
+
+        file_data = them_d["file"]
+        # the basename() is intended to protect us against
+        # "~/.ssh/authorized_keys" and other attacks
+        filename = os.path.basename(file_data["filename"]) # unicode
+        filesize = file_data["filesize"]
+
+        # get confirmation from the user before writing to the local directory
+        if os.path.exists(filename):
+            print("Error: refusing to overwrite existing file %s" % (filename,))
+            data = json.dumps({"error": "file already exists"}).encode("utf-8")
+            w.send_data(data)
+            w.close()
+            return 1
+
+        print("Receiving file (%d bytes) into: %s" % (filesize, filename))
+        while True and not args.accept_file:
+            ok = six.moves.input("ok? (y/n): ")
+            if ok.lower().startswith("y"):
+                break
+            print("transfer rejected", file=sys.stderr)
+            data = json.dumps({"error": "transfer rejected"}).encode("utf-8")
+            w.send_data(data)
+            w.close()
+            return 1
+
+        transit_receiver = TransitReceiver(args.transit_helper)
+        data = json.dumps({
+            "file_ack": "ok",
+            "transit": {
+                "direct_connection_hints": transit_receiver.get_direct_hints(),
+                "relay_connection_hints": transit_receiver.get_relay_hints(),
+                },
+            }).encode("utf-8")
         w.send_data(data)
         w.close()
-        return 0
-
-    if not "file" in them_d:
-        print("I don't know what they're offering\n")
-        print(them_d)
-        w.close()
-        return 1
-
-    if "error" in them_d:
-        print("ERROR: " + data["error"], file=sys.stderr)
-        w.close()
-        return 1
-
-    file_data = them_d["file"]
-    # the basename() is intended to protect us against
-    # "~/.ssh/authorized_keys" and other attacks
-    filename = os.path.basename(file_data["filename"]) # unicode
-    filesize = file_data["filesize"]
-
-    # get confirmation from the user before writing to the local directory
-    if os.path.exists(filename):
-        print("Error: refusing to overwrite existing file %s" % (filename,))
-        data = json.dumps({"error": "file already exists"}).encode("utf-8")
-        w.send_data(data)
-        w.close()
-        return 1
-
-    print("Receiving file (%d bytes) into: %s" % (filesize, filename))
-    while True and not args.accept_file:
-        ok = six.moves.input("ok? (y/n): ")
-        if ok.lower().startswith("y"):
-            break
-        print("transfer rejected", file=sys.stderr)
-        data = json.dumps({"error": "transfer rejected"}).encode("utf-8")
-        w.send_data(data)
-        w.close()
-        return 1
-
-    transit_receiver = TransitReceiver(args.transit_helper)
-    data = json.dumps({
-        "file_ack": "ok",
-        "transit": {
-            "direct_connection_hints": transit_receiver.get_direct_hints(),
-            "relay_connection_hints": transit_receiver.get_relay_hints(),
-            },
-        }).encode("utf-8")
-    w.send_data(data)
-    w.close()
 
     # now receive the rest of the owl
     tdata = them_d["transit"]
diff --git a/src/wormhole/scripts/cmd_send.py b/src/wormhole/scripts/cmd_send.py
index 6f10c0f..cb3d2f4 100644
--- a/src/wormhole/scripts/cmd_send.py
+++ b/src/wormhole/scripts/cmd_send.py
@@ -46,70 +46,71 @@ def send(args):
                 },
             }
 
-    w = Wormhole(APPID, args.relay_url)
-    if args.zeromode:
-        assert not args.code
-        args.code = u"0-"
-    if args.code:
-        w.set_code(args.code)
-        code = args.code
-    else:
-        code = w.get_code(args.code_length)
-    other_cmd = "wormhole receive"
-    if args.verify:
-        other_cmd = "wormhole --verify receive"
-    if args.zeromode:
-        other_cmd += " -0"
-    print("On the other computer, please run: %s" % other_cmd)
-    if not args.zeromode:
-        print("Wormhole code is: %s" % code)
-    print("")
+    if True:
+        w = Wormhole(APPID, args.relay_url)
+        if args.zeromode:
+            assert not args.code
+            args.code = u"0-"
+        if args.code:
+            w.set_code(args.code)
+            code = args.code
+        else:
+            code = w.get_code(args.code_length)
+        other_cmd = "wormhole receive"
+        if args.verify:
+            other_cmd = "wormhole --verify receive"
+        if args.zeromode:
+            other_cmd += " -0"
+        print("On the other computer, please run: %s" % other_cmd)
+        if not args.zeromode:
+            print("Wormhole code is: %s" % code)
+        print("")
 
-    if args.verify:
-        verifier = binascii.hexlify(w.get_verifier()).decode("ascii")
-        while True:
-            ok = six.moves.input("Verifier %s. ok? (yes/no): " % verifier)
-            if ok.lower() == "yes":
-                break
-            if ok.lower() == "no":
-                print("verification rejected, abandoning transfer",
-                      file=sys.stderr)
-                reject_data = json.dumps({"error": "verification rejected",
-                                          }).encode("utf-8")
-                w.send_data(reject_data)
-                w.close()
-                return 1
+        if args.verify:
+            verifier = binascii.hexlify(w.get_verifier()).decode("ascii")
+            while True:
+                ok = six.moves.input("Verifier %s. ok? (yes/no): " % verifier)
+                if ok.lower() == "yes":
+                    break
+                if ok.lower() == "no":
+                    print("verification rejected, abandoning transfer",
+                          file=sys.stderr)
+                    reject_data = json.dumps({"error": "verification rejected",
+                                              }).encode("utf-8")
+                    w.send_data(reject_data)
+                    w.close()
+                    return 1
 
-    my_phase1_bytes = json.dumps(phase1).encode("utf-8")
-    w.send_data(my_phase1_bytes)
-    try:
-        them_phase1_bytes = w.get_data()
-    except WrongPasswordError as e:
-        print("ERROR: " + e.explain(), file=sys.stderr)
-        w.close()
-        return 1
-    them_phase1 = json.loads(them_phase1_bytes.decode("utf-8"))
-
-    if sending_message:
-        if them_phase1["message_ack"] == "ok":
-            print("text message sent")
+        my_phase1_bytes = json.dumps(phase1).encode("utf-8")
+        w.send_data(my_phase1_bytes)
+        try:
+            them_phase1_bytes = w.get_data()
+        except WrongPasswordError as e:
+            print("ERROR: " + e.explain(), file=sys.stderr)
             w.close()
-            return 0
-        print("error sending text: %r" % (them_phase1,))
-        w.close()
-        return 1
+            return 1
+        them_phase1 = json.loads(them_phase1_bytes.decode("utf-8"))
 
-    if "error" in them_phase1:
-        print("remote error: %s" % them_phase1["error"])
-        print("transfer abandoned")
+        if sending_message:
+            if them_phase1["message_ack"] == "ok":
+                print("text message sent")
+                w.close()
+                return 0
+            print("error sending text: %r" % (them_phase1,))
+            w.close()
+            return 1
+
+        if "error" in them_phase1:
+            print("remote error: %s" % them_phase1["error"])
+            print("transfer abandoned")
+            w.close()
+            return 1
+        if them_phase1.get("file_ack") != "ok":
+            print("ambiguous response from remote: %s" % (them_phase1,))
+            print("transfer abandoned")
+            w.close()
+            return 1
         w.close()
-        return 1
-    if them_phase1.get("file_ack") != "ok":
-        print("ambiguous response from remote: %s" % (them_phase1,))
-        print("transfer abandoned")
-        w.close()
-        return 1
-    w.close()
 
     tdata = them_phase1["transit"]
     transit_key = w.derive_key(APPID+"/transit-key")

From 0748647049c8c9c7f4463c5b2b338b600e7d8b5d Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 18:17:52 -0800
Subject: [PATCH 6/8] allow multiple close() calls, throw error when using a
 closed Wormhole

---
 src/wormhole/blocking/transcribe.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index f028ad7..927869c 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -106,7 +106,7 @@ class Channel:
                 time.sleep(self._wait)
         return body
 
-    def deallocate(self, mood=u"unknown"):
+    def deallocate(self, mood=None):
         # only try once, no retries
         data = json.dumps({"appid": self._appid,
                            "channelid": self._channelid,
@@ -177,6 +177,7 @@ class Wormhole:
         self.verifier = None
         self._sent_data = set() # phases
         self._got_data = set()
+        self._closed = False
 
     def handle_welcome(self, welcome):
         if ("motd" in welcome and
@@ -266,6 +267,7 @@ class Wormhole:
             self.verifier = self.derive_key(u"wormhole:verifier")
 
     def get_verifier(self):
+        if self._closed: raise UsageError
         if self.code is None: raise UsageError
         if self._channel is None: raise UsageError
         self._get_key()
@@ -275,6 +277,7 @@ class Wormhole:
         if not isinstance(outbound_data, type(b"")):
             raise TypeError(type(outbound_data))
         if not isinstance(phase, type(u"")): raise TypeError(type(phase))
+        if self._closed: raise UsageError
         if phase in self._sent_data: raise UsageError # only call this once
         if self.code is None: raise UsageError
         if self._channel is None: raise UsageError
@@ -291,6 +294,7 @@ class Wormhole:
     def get_data(self, phase=u"data"):
         if not isinstance(phase, type(u"")): raise TypeError(type(phase))
         if phase in self._got_data: raise UsageError # only call this once
+        if self._closed: raise UsageError
         if self.code is None: raise UsageError
         if self._channel is None: raise UsageError
         self._got_data.add(phase)
@@ -303,6 +307,9 @@ class Wormhole:
         except CryptoError:
             raise WrongPasswordError
 
-    def close(self):
-        monitor.close(self._channel)
-        self._channel.deallocate()
+    def close(self, mood=None):
+        self._closed = True
+        if self._channel:
+            c, self._channel = self._channel, None
+            monitor.close(c)
+            c.deallocate(mood)

From a881d6055f1da43ff21d6440ffd37f36c81ec21b Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 21:54:45 -0800
Subject: [PATCH 7/8] auto-close Channel (with a "mood") upon server or crypto
 error

---
 src/wormhole/blocking/transcribe.py | 32 ++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index 927869c..8b9004f 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -117,7 +117,8 @@ class Channel:
             # short timeout and ignore failures
             requests.post(self._relay_url+"deallocate", data=data,
                           timeout=5)
-        except requests.exceptions.Timeout:
+        except (requests.exceptions.ConnectionError,
+                requests.exceptions.Timeout):
             pass
 
 class ChannelManager:
@@ -154,6 +155,29 @@ class ChannelManager:
         return Channel(self._relay_url, self._appid, channelid, self._side,
                        self._handle_welcome, self._wait, self._timeout)
 
+def close_on_error(f): # method decorator
+    # Clients report certain errors as "moods", so the server can make a
+    # rough count failed connections (due to mismatched passwords, attacks,
+    # or timeouts). We don't report precondition failures, as those are the
+    # responsibility/fault of the local application code. We count
+    # non-precondition errors in case they represent server-side problems.
+    def _f(self, *args, **kwargs):
+        try:
+            return f(self, *args, **kwargs)
+        except Timeout:
+            self.close(u"lonely")
+            raise
+        except WrongPasswordError:
+            self.close(u"scared")
+            raise
+        except (TypeError, UsageError):
+            # preconditions don't warrant _close_with_error()
+            raise
+        except:
+            self.close(u"other-error")
+            raise
+    return _f
+
 class Wormhole:
     motd_displayed = False
     version_warning_displayed = False
@@ -238,6 +262,7 @@ class Wormhole:
                                    idSymmetric=to_bytes(self._appid))
         self.msg1 = self.sp.start()
 
+    @close_on_error
     def derive_key(self, purpose, length=SecretBox.KEY_SIZE):
         if not isinstance(purpose, type(u"")): raise TypeError(type(purpose))
         return HKDF(self.key, length, CTXinfo=to_bytes(purpose))
@@ -266,6 +291,7 @@ class Wormhole:
             self.key = self.sp.finish(pake_msg)
             self.verifier = self.derive_key(u"wormhole:verifier")
 
+    @close_on_error
     def get_verifier(self):
         if self._closed: raise UsageError
         if self.code is None: raise UsageError
@@ -273,6 +299,7 @@ class Wormhole:
         self._get_key()
         return self.verifier
 
+    @close_on_error
     def send_data(self, outbound_data, phase=u"data"):
         if not isinstance(outbound_data, type(b"")):
             raise TypeError(type(outbound_data))
@@ -291,6 +318,7 @@ class Wormhole:
         outbound_encrypted = self._encrypt_data(data_key, outbound_data)
         self._channel.send(phase, outbound_encrypted)
 
+    @close_on_error
     def get_data(self, phase=u"data"):
         if not isinstance(phase, type(u"")): raise TypeError(type(phase))
         if phase in self._got_data: raise UsageError # only call this once
@@ -308,6 +336,8 @@ class Wormhole:
             raise WrongPasswordError
 
     def close(self, mood=None):
+        if not isinstance(mood, (type(None), type(u""))):
+            raise TypeError(type(mood))
         self._closed = True
         if self._channel:
             c, self._channel = self._channel, None

From 80beb206315d489dd336492d9eaa75cf23aa304c Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Wed, 11 Nov 2015 21:59:16 -0800
Subject: [PATCH 8/8] make blocking.Wormhole into a context manager

---
 docs/api.md                         | 29 ++++++++++++++++-------------
 src/wormhole/blocking/transcribe.py |  6 ++++++
 src/wormhole/scripts/cmd_receive.py | 11 +----------
 src/wormhole/scripts/cmd_send.py    | 10 +---------
 4 files changed, 24 insertions(+), 32 deletions(-)

diff --git a/docs/api.md b/docs/api.md
index e443c41..2166d6c 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -56,6 +56,11 @@ suffer longer invitation codes as a result. To encourage `close()`, the
 library will log an error if a Wormhole object is destroyed before being
 closed.
 
+To make it easier to call `close()`, the blocking Wormhole objects can be
+used as a context manager. Just put your code in the body of a `with
+Wormhole(ARGS) as w:` statement, and `close()` will automatically be called
+when the block exits (either successfully or due to an exception).
+
 ## Examples
 
 The synchronous+blocking flow looks like this:
@@ -64,13 +69,12 @@ The synchronous+blocking flow looks like this:
 from wormhole.blocking.transcribe import Wormhole
 from wormhole.public_relay import RENDEZVOUS_RELAY
 mydata = b"initiator's data"
-i = Wormhole(u"appid", RENDEZVOUS_RELAY)
-code = i.get_code()
-print("Invitation Code: %s" % code)
-i.send_data(mydata)
-theirdata = i.get_data()
-i.close()
-print("Their data: %s" % theirdata.decode("ascii"))
+with Wormhole(u"appid", RENDEZVOUS_RELAY) as i:
+    code = i.get_code()
+    print("Invitation Code: %s" % code)
+    i.send_data(mydata)
+    theirdata = i.get_data()
+    print("Their data: %s" % theirdata.decode("ascii"))
 ```
 
 ```python
@@ -79,12 +83,11 @@ from wormhole.blocking.transcribe import Wormhole
 from wormhole.public_relay import RENDEZVOUS_RELAY
 mydata = b"receiver's data"
 code = sys.argv[1]
-r = Wormhole(u"appid", RENDEZVOUS_RELAY)
-r.set_code(code)
-r.send_data(mydata)
-theirdata = r.get_data()
-r.close()
-print("Their data: %s" % theirdata.decode("ascii"))
+with Wormhole(u"appid", RENDEZVOUS_RELAY) as r:
+    r.set_code(code)
+    r.send_data(mydata)
+    theirdata = r.get_data()
+    print("Their data: %s" % theirdata.decode("ascii"))
 ```
 
 ## Twisted
diff --git a/src/wormhole/blocking/transcribe.py b/src/wormhole/blocking/transcribe.py
index 8b9004f..c2d3407 100644
--- a/src/wormhole/blocking/transcribe.py
+++ b/src/wormhole/blocking/transcribe.py
@@ -203,6 +203,12 @@ class Wormhole:
         self._got_data = set()
         self._closed = False
 
+    def __enter__(self):
+        return self
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.close()
+        return False
+
     def handle_welcome(self, welcome):
         if ("motd" in welcome and
             not self.motd_displayed):
diff --git a/src/wormhole/scripts/cmd_receive.py b/src/wormhole/scripts/cmd_receive.py
index cfc98ad..2936638 100644
--- a/src/wormhole/scripts/cmd_receive.py
+++ b/src/wormhole/scripts/cmd_receive.py
@@ -12,8 +12,7 @@ def receive(args):
     from .progress import start_progress, update_progress, finish_progress
     assert isinstance(args.relay_url, type(u""))
 
-    if True:
-        w = Wormhole(APPID, args.relay_url)
+    with Wormhole(APPID, args.relay_url) as w:
         if args.zeromode:
             assert not args.code
             args.code = u"0-"
@@ -30,12 +29,10 @@ def receive(args):
             them_bytes = w.get_data()
         except WrongPasswordError as e:
             print("ERROR: " + e.explain(), file=sys.stderr)
-            w.close()
             return 1
         them_d = json.loads(them_bytes.decode("utf-8"))
         if "error" in them_d:
             print("ERROR: " + them_d["error"], file=sys.stderr)
-            w.close()
             return 1
 
         if "message" in them_d:
@@ -43,18 +40,15 @@ def receive(args):
             print(them_d["message"])
             data = json.dumps({"message_ack": "ok"}).encode("utf-8")
             w.send_data(data)
-            w.close()
             return 0
 
         if not "file" in them_d:
             print("I don't know what they're offering\n")
             print(them_d)
-            w.close()
             return 1
 
         if "error" in them_d:
             print("ERROR: " + data["error"], file=sys.stderr)
-            w.close()
             return 1
 
         file_data = them_d["file"]
@@ -68,7 +62,6 @@ def receive(args):
             print("Error: refusing to overwrite existing file %s" % (filename,))
             data = json.dumps({"error": "file already exists"}).encode("utf-8")
             w.send_data(data)
-            w.close()
             return 1
 
         print("Receiving file (%d bytes) into: %s" % (filesize, filename))
@@ -79,7 +72,6 @@ def receive(args):
             print("transfer rejected", file=sys.stderr)
             data = json.dumps({"error": "transfer rejected"}).encode("utf-8")
             w.send_data(data)
-            w.close()
             return 1
 
         transit_receiver = TransitReceiver(args.transit_helper)
@@ -91,7 +83,6 @@ def receive(args):
                 },
             }).encode("utf-8")
         w.send_data(data)
-        w.close()
 
     # now receive the rest of the owl
     tdata = them_d["transit"]
diff --git a/src/wormhole/scripts/cmd_send.py b/src/wormhole/scripts/cmd_send.py
index cb3d2f4..9daf6cb 100644
--- a/src/wormhole/scripts/cmd_send.py
+++ b/src/wormhole/scripts/cmd_send.py
@@ -46,8 +46,7 @@ def send(args):
                 },
             }
 
-    if True:
-        w = Wormhole(APPID, args.relay_url)
+    with Wormhole(APPID, args.relay_url) as w:
         if args.zeromode:
             assert not args.code
             args.code = u"0-"
@@ -78,7 +77,6 @@ def send(args):
                     reject_data = json.dumps({"error": "verification rejected",
                                               }).encode("utf-8")
                     w.send_data(reject_data)
-                    w.close()
                     return 1
 
         my_phase1_bytes = json.dumps(phase1).encode("utf-8")
@@ -87,30 +85,24 @@ def send(args):
             them_phase1_bytes = w.get_data()
         except WrongPasswordError as e:
             print("ERROR: " + e.explain(), file=sys.stderr)
-            w.close()
             return 1
         them_phase1 = json.loads(them_phase1_bytes.decode("utf-8"))
 
         if sending_message:
             if them_phase1["message_ack"] == "ok":
                 print("text message sent")
-                w.close()
                 return 0
             print("error sending text: %r" % (them_phase1,))
-            w.close()
             return 1
 
         if "error" in them_phase1:
             print("remote error: %s" % them_phase1["error"])
             print("transfer abandoned")
-            w.close()
             return 1
         if them_phase1.get("file_ack") != "ok":
             print("ambiguous response from remote: %s" % (them_phase1,))
             print("transfer abandoned")
-            w.close()
             return 1
-        w.close()
 
     tdata = them_phase1["transit"]
     transit_key = w.derive_key(APPID+"/transit-key")