Plugin architecture (#4861)

* wip

* Refactor, tasks, processors, routes loading

* Move Slack settings config to plugin

* Fix translations in plugins

* Move Slack auth to plugin

* test

* Move other slack-related files into plugin

* Forgot to save

* refactor

plugins/slack/server/slack.ts

@@ -0,0 +1,60 @@
+import querystring from "querystring";
+import fetch from "fetch-with-proxy";
+import env from "@server/env";
+import { InvalidRequestError } from "@server/errors";
+
+const SLACK_API_URL = "https://slack.com/api";
+
+export async function post(endpoint: string, body: Record<string, any>) {
+  let data;
+  const token = body.token;
+
+  try {
+    const response = await fetch(`${SLACK_API_URL}/${endpoint}`, {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${token}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify(body),
+    });
+    data = await response.json();
+  } catch (err) {
+    throw InvalidRequestError(err.message);
+  }
+
+  if (!data.ok) {
+    throw InvalidRequestError(data.error);
+  }
+  return data;
+}
+
+export async function request(endpoint: string, body: Record<string, any>) {
+  let data;
+
+  try {
+    const response = await fetch(
+      `${SLACK_API_URL}/${endpoint}?${querystring.stringify(body)}`
+    );
+    data = await response.json();
+  } catch (err) {
+    throw InvalidRequestError(err.message);
+  }
+
+  if (!data.ok) {
+    throw InvalidRequestError(data.error);
+  }
+  return data;
+}
+
+export async function oauthAccess(
+  code: string,
+  redirect_uri = `${env.URL}/auth/slack.callback`
+) {
+  return request("oauth.access", {
+    client_id: env.SLACK_CLIENT_ID,
+    client_secret: env.SLACK_CLIENT_SECRET,
+    redirect_uri,
+    code,
+  });
+}