feat(channels): add Discord channel (Exa search + public Invite API) (#230)

Zero-config channel (tier=0). Uses Discord Invite API to read public
server info (no auth), and Exa via mcporter for content search.
Tested: discord.gg/python returns 419K members, description, channel.
104 tests passing.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

agent_reach/channels/__init__.py

@@ -24,6 +24,7 @@ from .xiaoyuzhou import XiaoyuzhouChannel
 from .v2ex import V2EXChannel
 from .xueqiu import XueqiuChannel
 from .toutiao import ToutiaoChannel
+from .discord import DiscordChannel
 
 
 ALL_CHANNELS: List[Channel] = [
@@ -41,6 +42,7 @@ ALL_CHANNELS: List[Channel] = [
     V2EXChannel(),
     XueqiuChannel(),
     ToutiaoChannel(),
+    DiscordChannel(),
     RSSChannel(),
     ExaSearchChannel(),
     WebChannel(),

agent_reach/channels/discord.py

@@ -0,0 +1,97 @@
+# -*- coding: utf-8 -*-
+"""Discord channel — search via Exa, read public server info via Invite API."""
+
+import json
+import shutil
+import subprocess
+import urllib.request
+from typing import Tuple
+
+from .base import Channel
+
+_UA = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36"
+_INVITE_API = "https://discord.com/api/v10/invites/{code}?with_counts=true"
+
+
+def _exa_available() -> bool:
+    mcporter = shutil.which("mcporter")
+    if not mcporter:
+        return False
+    try:
+        r = subprocess.run(
+            [mcporter, "config", "list"],
+            capture_output=True, text=True, timeout=5
+        )
+        return "exa" in r.stdout.lower()
+    except Exception:
+        return False
+
+
+def _get_invite_code(url: str) -> str:
+    """Extract invite code from discord.gg/xxx or discord.com/invite/xxx URLs."""
+    url = url.rstrip("/")
+    for prefix in ("discord.gg/", "discord.com/invite/"):
+        if prefix in url:
+            return url.split(prefix)[-1].split("/")[0].split("?")[0]
+    return ""
+
+
+class DiscordChannel(Channel):
+    name = "discord"
+    description = "Discord 服务器信息与内容搜索"
+    backends = ["Exa via mcporter (搜索)", "Discord Invite API (服务器信息)"]
+    tier = 0
+
+    def can_handle(self, url: str) -> bool:
+        return "discord.gg" in url or "discord.com" in url
+
+    def check(self, config=None) -> Tuple[str, str]:
+        if _exa_available():
+            return "ok", "Discord 可用：Exa 搜索内容，Invite API 读取公开服务器信息"
+        return "warn", (
+            "Discord Invite API 可用（无需配置），但搜索功能需要 mcporter + Exa MCP。"
+            "运行 `agent-reach install --env=auto` 安装 Exa。"
+        )
+
+    def read(self, url: str) -> str:
+        """读取 Discord 服务器公开信息（Invite API）或通过 Jina 读取页面。"""
+        code = _get_invite_code(url)
+        if code:
+            api_url = _INVITE_API.format(code=code)
+            req = urllib.request.Request(api_url, headers={"User-Agent": _UA})
+            with urllib.request.urlopen(req, timeout=10) as resp:
+                data = json.loads(resp.read().decode("utf-8"))
+            guild = data.get("guild", {})
+            channel = data.get("channel", {})
+            members = data.get("approximate_member_count", "未知")
+            online = data.get("approximate_presence_count", "未知")
+            return (
+                f"# {guild.get('name', '未知服务器')}\n\n"
+                f"**描述**: {guild.get('description') or '无'}\n"
+                f"**成员**: {members:,} 人（在线 {online:,}）\n"
+                f"**频道**: #{channel.get('name', '未知')}\n"
+                f"**邀请链接**: {url}\n"
+            )
+        # Fallback: Jina Reader
+        if not url.startswith(("http://", "https://")):
+            url = "https://" + url
+        jina_url = f"https://r.jina.ai/{url}"
+        req = urllib.request.Request(
+            jina_url, headers={"User-Agent": _UA, "Accept": "text/plain"}
+        )
+        with urllib.request.urlopen(req, timeout=15) as resp:
+            return resp.read().decode("utf-8")
+
+    def search(self, query: str, limit: int = 5) -> str:
+        """通过 Exa 搜索 Discord 内容（服务器、帖子、讨论）。"""
+        mcporter = shutil.which("mcporter")
+        if not mcporter:
+            return "搜索需要 mcporter，请运行 `npm install -g mcporter` 安装。"
+        cmd = (
+            f"mcporter call 'exa.web_search_exa("
+            f"query: \"{query} site:discord.com OR site:discord.gg\", "
+            f"numResults: {limit}, "
+            f"includeDomains: [\"discord.com\", \"discord.gg\"])'"
+        )
+        r = subprocess.run(cmd, shell=True, capture_output=True, text=True, timeout=30)
+        return r.stdout or r.stderr

tests/test_discord_channel.py

@@ -0,0 +1,87 @@
+# -*- coding: utf-8 -*-
+"""Tests for DiscordChannel."""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from agent_reach.channels.discord import DiscordChannel, _get_invite_code
+
+
+@pytest.fixture
+def ch():
+    return DiscordChannel()
+
+
+class TestDiscordChannelAttributes:
+    def test_name(self, ch):
+        assert ch.name == "discord"
+
+    def test_tier(self, ch):
+        assert ch.tier == 0
+
+    def test_backends(self, ch):
+        assert ch.backends
+
+
+class TestDiscordCanHandle:
+    def test_discord_gg(self, ch):
+        assert ch.can_handle("https://discord.gg/python")
+
+    def test_discord_com(self, ch):
+        assert ch.can_handle("https://discord.com/invite/rust")
+
+    def test_discord_channel_url(self, ch):
+        assert ch.can_handle("https://discord.com/channels/123/456")
+
+    def test_rejects_other(self, ch):
+        assert not ch.can_handle("https://www.slack.com")
+
+
+class TestGetInviteCode:
+    def test_discord_gg(self):
+        assert _get_invite_code("https://discord.gg/python") == "python"
+
+    def test_discord_com_invite(self):
+        assert _get_invite_code("https://discord.com/invite/rust-lang") == "rust-lang"
+
+    def test_trailing_slash(self):
+        assert _get_invite_code("https://discord.gg/python/") == "python"
+
+    def test_no_invite_code(self):
+        assert _get_invite_code("https://discord.com/channels/123/456") == ""
+
+
+class TestDiscordCheck:
+    def test_check_ok_with_exa(self, ch):
+        with patch("agent_reach.channels.discord._exa_available", return_value=True):
+            status, msg = ch.check()
+        assert status == "ok"
+        assert "Exa" in msg
+
+    def test_check_warn_without_exa(self, ch):
+        with patch("agent_reach.channels.discord._exa_available", return_value=False):
+            status, msg = ch.check()
+        assert status == "warn"
+        assert "Invite API" in msg
+
+
+class TestDiscordRead:
+    def test_read_invite_url(self, ch):
+        mock_data = {
+            "guild": {"name": "Python", "description": "The Python community"},
+            "channel": {"name": "general"},
+            "approximate_member_count": 400000,
+            "approximate_presence_count": 30000,
+        }
+        mock_resp = MagicMock()
+        mock_resp.__enter__ = lambda s: s
+        mock_resp.__exit__ = MagicMock(return_value=False)
+        mock_resp.read.return_value = __import__("json").dumps(mock_data).encode()
+
+        with patch("urllib.request.urlopen", return_value=mock_resp):
+            result = ch.read("https://discord.gg/python")
+
+        assert "Python" in result
+        assert "400,000" in result
+        assert "general" in result