Basic outline of the command subsystem

- Add a command manager
- Sketch out the type system with a few simple supported types

7 files changed, 160 insertions, 42 deletions

diff --git a/mitmproxy/addonmanager.py b/mitmproxy/addonmanager.py
index 25461338..a9b76f7b 100644
--- a/mitmproxy/addonmanager.py
+++ b/mitmproxy/addonmanager.py
@@ -93,6 +93,9 @@ class Loader:
             choices
         )
 
+    def add_command(self, path: str, func: typing.Callable) -> None:
+        self.master.commands.add_command(path, func)
+
 
 def traverse(chain):
     """
diff --git a/mitmproxy/command.py b/mitmproxy/command.py
new file mode 100644
index 00000000..57ca05ae
--- /dev/null
+++ b/mitmproxy/command.py
@@ -0,0 +1,78 @@
+import inspect
+import typing
+import shlex
+from mitmproxy.utils import typecheck
+
+
+class CommandError(Exception):
+    pass
+
+
+def typename(t: type) -> str:
+    if t in (str, int, bool):
+        return t.__name__
+    else:  # pragma: no cover
+        raise NotImplementedError
+
+
+def parsearg(spec: str, argtype: type) -> typing.Any:
+    """
+        Convert a string to a argument to the appropriate type.
+    """
+    if argtype == str:
+        return spec
+    else:
+        raise CommandError("Unsupported argument type: %s" % argtype)
+
+
+class Command:
+    def __init__(self, manager, path, func) -> None:
+        self.path = path
+        self.manager = manager
+        self.func = func
+        sig = inspect.signature(self.func)
+        self.paramtypes = [v.annotation for v in sig.parameters.values()]
+        self.returntype = sig.return_annotation
+
+    def signature_help(self) -> str:
+        params = " ".join([typename(i) for i in self.paramtypes])
+        ret = " -> " + typename(self.returntype) if self.returntype else ""
+        return "%s %s%s" % (self.path, params, ret)
+
+    def call(self, args: typing.Sequence[str]):
+        """
+            Call the command with a set of arguments. At this point, all argumets are strings.
+        """
+        if len(self.paramtypes) != len(args):
+            raise CommandError("SIGNATURE")
+
+        args = [parsearg(args[i], self.paramtypes[i]) for i in range(len(args))]
+
+        with self.manager.master.handlecontext():
+            ret = self.func(*args)
+
+        if not typecheck.check_command_return_type(ret, self.returntype):
+            raise CommandError("Command returned unexpected data")
+
+        return ret
+
+
+class CommandManager:
+    def __init__(self, master):
+        self.master = master
+        self.commands = {}
+
+    def add(self, path: str, func: typing.Callable):
+        self.commands[path] = Command(self, path, func)
+
+    def call(self, cmdstr: str):
+        """
+            Call a command using a string. May raise CommandError.
+        """
+        parts = shlex.split(cmdstr)
+        if not len(parts) >= 1:
+            raise CommandError("Invalid command: %s" % cmdstr)
+        path = parts[0]
+        if path not in self.commands:
+            raise CommandError("Unknown command: %s" % path)
+        return self.commands[path].call(parts[1:])
diff --git a/mitmproxy/master.py b/mitmproxy/master.py
index 94900915..2a032c4a 100644
--- a/mitmproxy/master.py
+++ b/mitmproxy/master.py
@@ -8,6 +8,7 @@ from mitmproxy import controller
 from mitmproxy import eventsequence
 from mitmproxy import exceptions
 from mitmproxy import connections
+from mitmproxy import command
 from mitmproxy import http
 from mitmproxy import log
 from mitmproxy.proxy.protocol import http_replay
@@ -34,6 +35,7 @@ class Master:
     """
     def __init__(self, opts, server):
         self.options = opts or options.Options()
+        self.commands = command.CommandManager(self)
         self.addons = addonmanager.AddonManager(self)
         self.event_queue = queue.Queue()
         self.should_exit = threading.Event()
diff --git a/mitmproxy/optmanager.py b/mitmproxy/optmanager.py
index 8369a36e..cf6e21b0 100644
--- a/mitmproxy/optmanager.py
+++ b/mitmproxy/optmanager.py
@@ -31,7 +31,7 @@ class _Option:
         help: str,
         choices: typing.Optional[typing.Sequence[str]]
     ) -> None:
-        typecheck.check_type(name, default, typespec)
+        typecheck.check_option_type(name, default, typespec)
         self.name = name
         self.typespec = typespec
         self._default = default
@@ -54,7 +54,7 @@ class _Option:
         return copy.deepcopy(v)
 
     def set(self, value: typing.Any) -> None:
-        typecheck.check_type(self.name, value, self.typespec)
+        typecheck.check_option_type(self.name, value, self.typespec)
         self.value = value
 
     def reset(self) -> None:
diff --git a/mitmproxy/utils/typecheck.py b/mitmproxy/utils/typecheck.py
index 628ea642..7199f2fb 100644
--- a/mitmproxy/utils/typecheck.py
+++ b/mitmproxy/utils/typecheck.py
@@ -1,20 +1,21 @@
 import typing
 
 
-def check_type(name: str, value: typing.Any, typeinfo: typing.Any) -> None:
+def check_command_return_type(value: typing.Any, typeinfo: typing.Any) -> bool:
     """
-    This function checks if the provided value is an instance of typeinfo
-    and raises a TypeError otherwise.
+    Check if the provided value is an instance of typeinfo. Returns True if the
+    types match, False otherwise. This function supports only those types
+    required for command return values.
+    """
+    return True
 
-    The following types from the typing package have specialized support:
 
-    - Union
-    - Tuple
-    - IO
+def check_option_type(name: str, value: typing.Any, typeinfo: typing.Any) -> None:
+    """
+    Check if the provided value is an instance of typeinfo and raises a
+    TypeError otherwise. This function supports only those types required for
+    options.
     """
-    # If we realize that we need to extend this list substantially, it may make sense
-    # to use typeguard for this, but right now it's not worth the hassle for 16 lines of code.
-
     e = TypeError("Expected {} for {}, but got {}.".format(
         typeinfo,
         name,
@@ -32,7 +33,7 @@ def check_type(name: str, value: typing.Any, typeinfo: typing.Any) -> None:
 
         for T in types:
             try:
-                check_type(name, value, T)
+                check_option_type(name, value, T)
             except TypeError:
                 pass
             else:
@@ -50,7 +51,7 @@ def check_type(name: str, value: typing.Any, typeinfo: typing.Any) -> None:
         if len(types) != len(value):
             raise e
         for i, (x, T) in enumerate(zip(value, types)):
-            check_type("{}[{}]".format(name, i), x, T)
+            check_option_type("{}[{}]".format(name, i), x, T)
         return
     elif typename.startswith("typing.Sequence"):
         try:
@@ -58,11 +59,10 @@ def check_type(name: str, value: typing.Any, typeinfo: typing.Any) -> None:
         except AttributeError:
             # Python 3.5.0
             T = typeinfo.__parameters__[0]  # type: ignore
-
         if not isinstance(value, (tuple, list)):
             raise e
         for v in value:
-            check_type(name, v, T)
+            check_option_type(name, v, T)
     elif typename.startswith("typing.IO"):
         if hasattr(value, "read"):
             return
diff --git a/test/mitmproxy/test_command.py b/test/mitmproxy/test_command.py
new file mode 100644
index 00000000..d4da7c32
--- /dev/null
+++ b/test/mitmproxy/test_command.py
@@ -0,0 +1,35 @@
+from mitmproxy import command
+from mitmproxy import master
+from mitmproxy import options
+from mitmproxy import proxy
+import pytest
+
+
+class TAddon:
+    def cmd1(self, foo: str) -> str:
+        return "ret " + foo
+
+
+class TestCommand:
+    def test_call(self):
+        o = options.Options()
+        m = master.Master(o, proxy.DummyServer(o))
+        cm = command.CommandManager(m)
+
+        a = TAddon()
+        c = command.Command(cm, "cmd.path", a.cmd1)
+        assert c.call(["foo"]) == "ret foo"
+        assert c.signature_help() == "cmd.path str -> str"
+
+
+def test_simple():
+    o = options.Options()
+    m = master.Master(o, proxy.DummyServer(o))
+    c = command.CommandManager(m)
+    a = TAddon()
+    c.add("one.two", a.cmd1)
+    assert(c.call("one.two foo") == "ret foo")
+    with pytest.raises(command.CommandError, match="Unknown"):
+        c.call("nonexistent")
+    with pytest.raises(command.CommandError, match="Invalid"):
+        c.call("")
diff --git a/test/mitmproxy/utils/test_typecheck.py b/test/mitmproxy/utils/test_typecheck.py
index fd0c6e0c..388f96ca 100644
--- a/test/mitmproxy/utils/test_typecheck.py
+++ b/test/mitmproxy/utils/test_typecheck.py
@@ -16,72 +16,72 @@ class T(TBase):
         super(T, self).__init__(42)
 
 
-def test_check_type():
-    typecheck.check_type("foo", 42, int)
+def test_check_option_type():
+    typecheck.check_option_type("foo", 42, int)
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", 42, str)
+        typecheck.check_option_type("foo", 42, str)
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", None, str)
+        typecheck.check_option_type("foo", None, str)
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", b"foo", str)
+        typecheck.check_option_type("foo", b"foo", str)
 
 
 def test_check_union():
-    typecheck.check_type("foo", 42, typing.Union[int, str])
-    typecheck.check_type("foo", "42", typing.Union[int, str])
+    typecheck.check_option_type("foo", 42, typing.Union[int, str])
+    typecheck.check_option_type("foo", "42", typing.Union[int, str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", [], typing.Union[int, str])
+        typecheck.check_option_type("foo", [], typing.Union[int, str])
 
     # Python 3.5 only defines __union_params__
     m = mock.Mock()
     m.__str__ = lambda self: "typing.Union"
     m.__union_params__ = (int,)
-    typecheck.check_type("foo", 42, m)
+    typecheck.check_option_type("foo", 42, m)
 
 
 def test_check_tuple():
-    typecheck.check_type("foo", (42, "42"), typing.Tuple[int, str])
+    typecheck.check_option_type("foo", (42, "42"), typing.Tuple[int, str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", None, typing.Tuple[int, str])
+        typecheck.check_option_type("foo", None, typing.Tuple[int, str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", (), typing.Tuple[int, str])
+        typecheck.check_option_type("foo", (), typing.Tuple[int, str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", (42, 42), typing.Tuple[int, str])
+        typecheck.check_option_type("foo", (42, 42), typing.Tuple[int, str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", ("42", 42), typing.Tuple[int, str])
+        typecheck.check_option_type("foo", ("42", 42), typing.Tuple[int, str])
 
     # Python 3.5 only defines __tuple_params__
     m = mock.Mock()
     m.__str__ = lambda self: "typing.Tuple"
     m.__tuple_params__ = (int, str)
-    typecheck.check_type("foo", (42, "42"), m)
+    typecheck.check_option_type("foo", (42, "42"), m)
 
 
 def test_check_sequence():
-    typecheck.check_type("foo", [10], typing.Sequence[int])
+    typecheck.check_option_type("foo", [10], typing.Sequence[int])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", ["foo"], typing.Sequence[int])
+        typecheck.check_option_type("foo", ["foo"], typing.Sequence[int])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", [10, "foo"], typing.Sequence[int])
+        typecheck.check_option_type("foo", [10, "foo"], typing.Sequence[int])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", [b"foo"], typing.Sequence[str])
+        typecheck.check_option_type("foo", [b"foo"], typing.Sequence[str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", "foo", typing.Sequence[str])
+        typecheck.check_option_type("foo", "foo", typing.Sequence[str])
 
     # Python 3.5 only defines __parameters__
     m = mock.Mock()
     m.__str__ = lambda self: "typing.Sequence"
     m.__parameters__ = (int,)
-    typecheck.check_type("foo", [10], m)
+    typecheck.check_option_type("foo", [10], m)
 
 
 def test_check_io():
-    typecheck.check_type("foo", io.StringIO(), typing.IO[str])
+    typecheck.check_option_type("foo", io.StringIO(), typing.IO[str])
     with pytest.raises(TypeError):
-        typecheck.check_type("foo", "foo", typing.IO[str])
+        typecheck.check_option_type("foo", "foo", typing.IO[str])
 
 
 def test_check_any():
-    typecheck.check_type("foo", 42, typing.Any)
-    typecheck.check_type("foo", object(), typing.Any)
-    typecheck.check_type("foo", None, typing.Any)
+    typecheck.check_option_type("foo", 42, typing.Any)
+    typecheck.check_option_type("foo", object(), typing.Any)
+    typecheck.check_option_type("foo", None, typing.Any)