2 files changed, 200 insertions, 0 deletions
diff --git a/modules/statusbot/.gitignore b/modules/statusbot/.gitignore
new file mode 100644
index 0000000..cc941e3
--- /dev/null
+++ b/modules/statusbot/.gitignore
@@ -0,0 +1,3 @@
+matrix.json
+accounts.json
+faillog.txt
diff --git a/modules/statusbot/statusbot.js b/modules/statusbot/statusbot.js
new file mode 100644
index 0000000..0fd9ce5
--- /dev/null
+++ b/modules/statusbot/statusbot.js
@@ -0,0 +1,197 @@
+// Format of the required matrix.json file:
+// {
+//   "user_id": "@statusbot:tomsmeding.com",
+//   "password": "PASSWORD OF THE USER",
+//   "room_id": "!ROOMID:tomsmeding.com"
+// }
+
+// Furthermore, accounts.json is required in the standard format ([[user, pass]])
+
+// API:
+// POST /statusbot
+// { "sender": "who are you", "text": "content of the status message" }
+
+// State in this file: the above matrix.json plus:
+// {
+//   config: the above matrix.json,
+//   home_server: "tomsmeding.com",  // nominal server in the user id
+//   matrix_server: "matrix.tomsmeding.com",  // actual matrix server address, without port
+//   access_token: "some access token",
+//   req_counter: 1  // counter for transaction requests to the matrix server
+// }
+
+// Saves persist state under key "access_tokens":
+// {
+//   "@statusbot:tomsmeding.com|!ROOMID:tomsmeding.com": ["access token", req_counter: int]
+// }
+
+const cmn = require("../$common.js");
+const fs = require("fs");
+const https = require("https");
+const URL = require("url");
+const bodyParser = require("body-parser");
+
+let moddir = null;
+
+const persist = require("node-persist").create({
+  dir: cmn.persistdir + "/statusbot",
+  continuous: false,
+  interval: false
+});
+persist.initSync();
+
+let persistTokens = persist.getItemSync("access_tokens");
+if (!persistTokens) {
+  persistTokens = {};
+  persist.setItemSync("access_tokens", persistTokens);
+}
+
+// cb: (status: int, body: string) => ()
+function fetch(method, headers, hostname, path, data, cb) {
+  const req = https.request({method, headers, hostname, path}, res => {
+    let body = "";
+    res.on("data", data => { body += data; });
+    res.on("end", () => cb(res.statusCode, body));
+  });
+  req.on("error", () => cb(null, null))
+  req.write(data);
+  req.end();
+}
+
+// cb: (state) => ()
+function augmentConfig(config, cb) {
+  const m = config.user_id.match(/^@[^:]+:(.*)$/);
+  if (!m) {
+    throw new Error("statusbot: Cannot parse matrix ID (must be in @user:domain format)");
+  }
+  const home_server = m[1];
+
+  const pkey = `${config.user_id}|${config.room_id}`
+  let access_token = undefined;
+  let req_counter = undefined;
+  if (pkey in persistTokens) {
+    [access_token, req_counter] = persistTokens[pkey];
+  }
+
+  fetch("GET", {}, home_server, "/.well-known/matrix/server", "", (status, body) => {
+    if (status != 200) {
+      throw new Error(`statusbot: Failed getting https://${home_server}/.well-known/matrix/server`);
+    }
+    const mserver = JSON.parse(body)["m.server"];
+    const m = mserver.match(/^([^:]*)(:443)?$/);
+    if (!m) {
+      throw new Error(`statusbot: Matrix server port not 443 (sorry): <${mserver}>`);
+    }
+    const matrix_server = m[1];
+    cb({config, home_server, matrix_server, access_token, req_counter});
+  });
+}
+
+function updatePersist(state) {
+  persistTokens[`${state.config.user_id}|${state.config.room_id}`] = [state.access_token, state.req_counter];
+  persist.setItemSync("access_tokens", persistTokens);
+}
+
+// Sets access token in state.
+// cb: (success: bool, body: string) => ()
+function matrixLogin(state, cb) {
+  const data = JSON.stringify({
+    type: "m.login.password",
+    identifier: {type: "m.id.user", user: state.config.user_id},
+    password: state.config.password,
+  });
+  fetch("POST", {}, state.matrix_server, "/_matrix/client/v3/login", data, (status, body) => {
+    if (status != 200) { cb(false, body); return; }
+    try {
+      const response = JSON.parse(body);
+      state.access_token = response.access_token;
+      state.req_counter = 1;
+      updatePersist(state);
+      cb(true, body);
+    } catch (e) {
+      cb(false, body);
+    }
+  });
+}
+
+// cb: (status: int, body: string) => ()
+// Status 401: access token invalid
+// Status 200: success
+// Anything else: ? (see body?)
+function matrixSendMsg(state, text, cb) {
+  if (state.access_token == undefined) { cb(401); return; }
+
+  const headers = {Authorization: `Bearer ${state.access_token}`};
+  const url = `/_matrix/client/v3/rooms/${state.config.room_id}/send/m.room.message/${state.req_counter}`;
+  state.req_counter++;
+  updatePersist(state);  // req_counter changed
+
+  const data = JSON.stringify({
+    msgtype: "m.text",
+    body: text,
+  });
+
+  fetch("PUT", headers, state.matrix_server, url, data, (status, body) => {
+    cb(status, body);
+  });
+}
+
+// cb: () => ()
+function logFailure(message, cb) {
+  fs.appendFile(moddir + "/faillog.txt", `[${new Date().toISOString()}] ${message}\n`, err => {
+    if (err) console.error(err);
+    cb();
+  });
+}
+
+// Tries to send a message, trying login if the access token is invalid.
+// cb: (success: bool) => ()
+function matrixSendMsgLogin(state, text, cb) {
+  matrixSendMsg(state, text, (status, body) => {
+    switch (status) {
+      case 200:
+        cb(true);
+        break;
+
+      case 401:
+        matrixLogin(state, (success, body) => {
+          if (!success) {
+            logFailure(`Failed to log in: ${body}`, () => cb(false));
+            return;
+          }
+
+          matrixSendMsg(state, text, (status, body) => {
+            switch (status) {
+              case 200: cb(true); return;
+              case 401: logFailure(`401 even after login: ${body}`, () => cb(false)); break;
+              default: logFailure(`Failed to send message: ${body}`, () => cb(false)); break;
+            }
+          });
+        });
+        break;
+
+      default:
+        logFailure(`Failed to send message: ${body}`, () => cb(false));
+        break;
+    }
+  })
+}
+
+module.exports = function(app, io, _moddir) {
+  moddir = _moddir;
+
+  const config = require("./matrix.json");
+  const accounts = require("./accounts.json");
+
+  augmentConfig(config, state => {
+    app.post("/statusbot", bodyParser.json(), cmn.authgen(accounts), (req, res) => {
+      if (typeof req.body.sender != "string" || typeof req.body.text != "string") {
+        return res.sendStatus(400);
+      }
+      matrixSendMsgLogin(state, `[${req.body.sender}] ${req.body.text}`, success => {
+        if (success) res.sendStatus(200);
+        else res.sendStatus(503);  // service unavailable
+      });
+    });
+  });
+};