commands: add a Path argument type

This is just an alias for str, and in this patch is used mostly to give an
appropriate type in help strings. More to come.

Fixes #2198

mitmproxy/addons/core.py

@@ -221,7 +221,7 @@ class Core:
         return ["gzip", "deflate", "br"]
 
     @command.command("options.load")
-    def options_load(self, path: str) -> None:
+    def options_load(self, path: command.Path) -> None:
         """
             Load options from a file.
         """
@@ -233,7 +233,7 @@ class Core:
             ) from e
 
     @command.command("options.save")
-    def options_save(self, path: str) -> None:
+    def options_save(self, path: command.Path) -> None:
         """
             Save options to a file.
         """

mitmproxy/addons/cut.py

@@ -96,7 +96,7 @@ class Cut:
         return ret
 
     @command.command("cut.save")
-    def save(self, cuts: command.Cuts, path: str) -> None:
+    def save(self, cuts: command.Cuts, path: command.Path) -> None:
         """
             Save cuts to file. If there are multiple rows or columns, the format
             is UTF-8 encoded CSV. If there is exactly one row and one column,
@@ -107,7 +107,7 @@ class Cut:
         append = False
         if path.startswith("+"):
             append = True
-            path = path[1:]
+            path = command.Path(path[1:])
         if len(cuts) == 1 and len(cuts[0]) == 1:
             with open(path, "ab" if append else "wb") as fp:
                 if fp.tell() > 0:

mitmproxy/addons/export.py

@@ -49,7 +49,7 @@ class Export():
         return list(sorted(formats.keys()))
 
     @command.command("export.file")
-    def file(self, fmt: str, f: flow.Flow, path: str) -> None:
+    def file(self, fmt: str, f: flow.Flow, path: command.Path) -> None:
         """
             Export a flow to path.
         """

mitmproxy/addons/save.py

@@ -1,6 +1,7 @@
 import os.path
 import typing
 
+from mitmproxy import command
 from mitmproxy import exceptions
 from mitmproxy import flowfilter
 from mitmproxy import io
@@ -48,7 +49,8 @@ class Save:
             if ctx.options.save_stream_file:
                 self.start_stream_to_path(ctx.options.save_stream_file, self.filt)
 
-    def save(self, flows: typing.Sequence[flow.Flow], path: str) -> None:
+    @command.command("save.file")
+    def save(self, flows: typing.Sequence[flow.Flow], path: command.Path) -> None:
         """
             Save flows to a file. If the path starts with a +, flows are
             appended to the file, otherwise it is over-written.
@@ -63,9 +65,6 @@ class Save:
         f.close()
         ctx.log.alert("Saved %s flows." % len(flows))
 
-    def load(self, l):
-        l.add_command("save.file", self.save)
-
     def tcp_start(self, flow):
         if self.stream:
             self.active_flows.add(flow)

mitmproxy/addons/view.py

@@ -351,13 +351,13 @@ class View(collections.Sequence):
         ctx.master.addons.trigger("update", updated)
 
     @command.command("view.load")
-    def load_file(self, path: str) -> None:
+    def load_file(self, path: command.Path) -> None:
         """
             Load flows into the view, without processing them with addons.
         """
-        path = os.path.expanduser(path)
+        spath = os.path.expanduser(path)
         try:
-            with open(path, "rb") as f:
+            with open(spath, "rb") as f:
                 for i in io.FlowReader(f).stream():
                     # Do this to get a new ID, so we can load the same file N times and
                     # get new flows each time. It would be more efficient to just have a

mitmproxy/command.py

@@ -37,6 +37,9 @@ class Choice(str):
     options_command = ""
 
 
+Path = typing.NewType("Path", str)
+
+
 def typename(t: type, ret: bool) -> str:
     """
         Translates a type to an explanatory string. If ret is True, we're
@@ -44,8 +47,6 @@ def typename(t: type, ret: bool) -> str:
     """
     if hasattr(t, "options_command"):
         return "choice"
-    elif issubclass(t, (str, int, bool)):
-        return t.__name__
     elif t == typing.Sequence[flow.Flow]:
         return "[flow]" if ret else "flowspec"
     elif t == typing.Sequence[str]:
@@ -54,6 +55,10 @@ def typename(t: type, ret: bool) -> str:
         return "[cuts]" if ret else "cutspec"
     elif t == flow.Flow:
         return "flow"
+    elif t == Path:
+        return "path"
+    elif issubclass(t, (str, int, bool)):
+        return t.__name__
     else:  # pragma: no cover
         raise NotImplementedError(t)
 
@@ -186,7 +191,9 @@ def parsearg(manager: CommandManager, spec: str, argtype: type) -> typing.Any:
                 "Invalid choice: see %s for options" % cmd
             )
         return spec
-    if issubclass(argtype, str):
+    if argtype == Path:
+        return spec
+    elif issubclass(argtype, str):
         return spec
     elif argtype == bool:
         if spec == "true":

mitmproxy/tools/console/consoleaddons.py

@@ -414,14 +414,14 @@ class ConsoleAddon:
         self._grideditor().cmd_delete()
 
     @command.command("console.grideditor.readfile")
-    def grideditor_readfile(self, path: str) -> None:
+    def grideditor_readfile(self, path: command.Path) -> None:
         """
             Read a file into the currrent cell.
         """
         self._grideditor().cmd_read_file(path)
 
     @command.command("console.grideditor.readfile_escaped")
-    def grideditor_readfile_escaped(self, path: str) -> None:
+    def grideditor_readfile_escaped(self, path: command.Path) -> None:
         """
             Read a file containing a Python-style escaped stringinto the
             currrent cell.

test/mitmproxy/test_command.py

@@ -35,6 +35,9 @@ class TAddon:
     def choose(self, arg: TChoice) -> typing.Sequence[str]:  # type: ignore
         return ["one", "two", "three"]
 
+    def path(self, arg: command.Path) -> None:
+        pass
+
 
 class TestCommand:
     def test_varargs(self):
@@ -97,6 +100,7 @@ def test_typename():
     assert command.typename(typing.Sequence[str], False) == "[str]"
 
     assert command.typename(TChoice, False) == "choice"
+    assert command.typename(command.Path, False) == "path"
 
 
 class DummyConsole:
@@ -156,6 +160,10 @@ def test_parsearg():
                 tctx.master.commands, "invalid", TChoice,
             )
 
+        assert command.parsearg(
+            tctx.master.commands, "foo", command.Path
+        ) == "foo"
+
 
 class TDec:
     @command.command("cmd1")