Add a simple server playback state object.

We use a loose hash to match incoming requests with recorded flows. At the
moment, this hash is over the host, port, scheme, method, path and content of
the request. Note that headers are not included here - if we do want to include
headers, we would have to do some work to normalize them to remove variations
between user agents, header order, etc. etc.

libmproxy/console.py

@@ -160,7 +160,7 @@ class ConnectionItem(WWrap):
                 self.master.statusbar.message("Can't delete connection mid-intercept.")
             self.master.sync_list_view()
         elif key == "r":
-            r = self.state.replay(self.flow, self.master.masterq)
+            r = self.state.replay_request(self.flow, self.master.masterq)
             if r:
                 self.master.statusbar.message(r)
             self.master.sync_list_view()
@@ -511,7 +511,7 @@ class ConnectionView(WWrap):
         elif key == "p":
             self.master.view_prev_flow(self.flow)
         elif key == "r":
-            r = self.state.replay(self.flow, self.master.masterq)
+            r = self.state.replay_request(self.flow, self.master.masterq)
             if r:
                 self.master.statusbar.message(r)
             self.master.refresh_connection(self.flow)

libmproxy/flow.py

@@ -2,7 +2,7 @@
     This module provides more sophisticated flow tracking. These match requests
     with their responses, and provide filtering and interception facilities.
 """
-import subprocess, base64, sys, json
+import subprocess, base64, sys, json, hashlib
 import proxy, threading, netstring
 import controller
 
@@ -14,7 +14,7 @@ class RunException(Exception):
 
 
 # begin nocover
-class ReplayThread(threading.Thread):
+class RequestReplayThread(threading.Thread):
     def __init__(self, flow, masterq):
         self.flow, self.masterq = flow, masterq
         threading.Thread.__init__(self)
@@ -31,6 +31,49 @@ class ReplayThread(threading.Thread):
 # end nocover
 
 
+class ServerPlaybackState:
+    def __init__(self):
+        self.fmap = {}
+
+    def __len__(self):
+        return sum([len(i) for i in self.fmap.values()])
+    
+    def load(self, flows):
+        """
+            Load a sequence of flows. We assume that the sequence is in
+            chronological order.
+        """
+        for i in flows:
+            h = self._hash(i)
+            l = self.fmap.setdefault(self._hash(i), [])
+            l.append(i)
+
+    def _hash(self, flow):
+        """
+            Calculates a loose hash of the flow request. 
+        """
+        r = flow.request
+        key = [
+            str(r.host),
+            str(r.port),
+            str(r.scheme),
+            str(r.method),
+            str(r.path),
+            str(r.content),
+        ]
+        return hashlib.sha256(repr(key)).digest()
+
+    def next_flow(self, request):
+        """
+            Returns the next flow object, or None if no matching flow was
+            found.
+        """
+        l = self.fmap.get(self._hash(request))
+        if not l:
+            return None
+        return l.pop(0)
+
+
 class Flow:
     def __init__(self, request):
         self.request = request
@@ -262,7 +305,7 @@ class State:
     def revert(self, f):
         f.revert()
 
-    def replay(self, f, masterq):
+    def replay_request(self, f, masterq):
         """
             Returns None if successful, or error message if not.
         """
@@ -276,7 +319,7 @@ class State:
                 f.request.headers["content-length"] = [str(len(f.request.content))]
             f.response = None
             f.error = None
-            rt = ReplayThread(f, masterq)
+            rt = RequestReplayThread(f, masterq)
             rt.start()
         #end nocover
 

test/test_flow.py

@@ -3,6 +3,43 @@ from libmproxy import console, proxy, filt, flow
 import utils
 import libpry
 
+
+class uServerPlaybackState(libpry.AutoTree):
+    def test_hash(self):
+        s = flow.ServerPlaybackState()
+        r = utils.tflow()
+        r2 = utils.tflow()
+
+        assert s._hash(r)
+        assert s._hash(r) == s._hash(r2)
+        r.request.headers["foo"] = ["bar"]
+        assert s._hash(r) == s._hash(r2)
+        r.request.path = "voing"
+        assert s._hash(r) != s._hash(r2)
+
+    def test_load(self):
+        s = flow.ServerPlaybackState()
+        r = utils.tflow()
+        r.request.headers["key"] = ["one"]
+
+        r2 = utils.tflow()
+        r2.request.headers["key"] = ["two"]
+
+        s.load([r, r2])
+        assert len(s) == 2
+        assert len(s.fmap.keys()) == 1
+
+        n = s.next_flow(r)
+        assert n.request.headers["key"] == ["one"]
+        assert len(s) == 1
+
+        n = s.next_flow(r)
+        assert n.request.headers["key"] == ["two"]
+        assert len(s) == 0
+
+        assert not s.next_flow(r)
+
+
 class uFlow(libpry.AutoTree):
     def test_run_script(self):
         f = utils.tflow()
@@ -275,6 +312,7 @@ class uFlowMaster(libpry.AutoTree):
 
 
 tests = [
+    uServerPlaybackState(),
     uFlow(),
     uState(),
     uSerialize(),

test/test_netstring.py

@@ -3,7 +3,6 @@ from cStringIO import StringIO
 import libpry
 
 
-
 class uNetstring(libpry.AutoTree):
     def setUp(self):
         self.test_data = "Netstring module by Will McGugan"