Add basic Python plugins support

examples/plugins/example

@@ -1,11 +0,0 @@
-#!/bin/sh
-
-user="$1"  # User nickname.
-admin="$2"  # If one is an admin.
-
-if [ "$admin" != 'true' ]; then
-    printf "%s\n" "$user: you are not an admin"
-else
-    printf "%s\n" "$user: you are an admin"
-fi
-

examples/plugins/example.py

@@ -0,0 +1,12 @@
+# -*- python -*-
+
+class Plugin:
+    def command(self, command, body, nick, from_id, is_admin):
+        if command != "example":
+            return {"handled": False}
+
+        if is_admin:
+            reply = "%s: you are an admin" % nick
+        else:
+            reply = "%s: you are not an admin" % nick
+        return {"handled": True, "reply": reply}

examples/plugins/shell_cmds.py

@@ -0,0 +1,62 @@
+# -*- python -*-
+import asyncio
+import os
+import re
+
+class Plugin:
+    _trim_regexp = re.compile("(`|\\$|\\.\\.)")
+    _quote_regexp = re.compile("(\"|')")
+
+    @classmethod
+    def _trim(cls, s):
+        result = cls._trim_regexp.sub("", s)
+        result = cls._quote_regexp.sub("“", result).strip()
+        return result
+
+    # letter(ASCII or cyrillic), number, underscore only.
+    _cmd_validator_regexp = re.compile("^(\\w|\\p{Cyrillic})*$")
+
+    @asyncio.coroutine
+    def _exec_cmd(self, cmd, body, nick, dir_path, is_admin):
+        is_admin = "true" if is_admin else "false"
+        path = os.path.join(dir_path, self._trim(cmd))
+
+        if not self._cmd_validator_regexp.match(cmd) or \
+           not os.access(path, os.F_OK | os.X_OK) or not os.path.isfile(path):
+            return {"handled": False}
+
+        if not os.access(path, os.R_OK):
+            return {"handled": True,
+                    "error": "\"%s\" is not readable" % path}
+
+        cmd = [path, self._trim(nick), is_admin, self._trim(body)]
+        try:
+            pipe = asyncio.subprocess.PIPE
+            proc = yield from asyncio.create_subprocess_exec(*cmd,
+                                                             stdout=pipe,
+                                                             stderr=pipe)
+            cmd_reply, cmd_error = yield from proc.communicate()
+        except OSError as e:
+            return {"handled": True,
+                    "error": "Execute: %s" % str(e)}
+
+        result = {}
+        if cmd_error and len(cmd_error.strip()) > 0:
+            result["error"] = "Process: %s" % cmd_error.strip()
+        if cmd_reply and len(cmd_reply.strip()) > 0:
+            result["reply"] = cmd_reply.decode().strip()
+        if result:
+            result["handled"] = True
+        return result
+
+    @asyncio.coroutine
+    def command(self, command, body, nick, from_id, is_admin):
+        result = yield from self._exec_cmd(command, body, nick,
+                                           "plugins", is_admin)
+        return result
+
+    @asyncio.coroutine
+    def question(self, body, nick, from_id, is_admin):
+        result = yield from self._exec_cmd("answer", body, nick,
+                                           "chat", is_admin)
+        return result