Backport changes from Cloudproxy (#11)

src/captcha/harvester.ts

@@ -0,0 +1,31 @@
+import got from 'got'
+import { sleep } from '../utils'
+
+/*
+    This method uses the captcha-harvester project:
+        https://github.com/NoahCardoza/CaptchaHarvester
+
+    While the function must take url/sitekey/type args,
+    they aren't used because the harvester server must
+    be preconfigured.
+
+    ENV:
+        HARVESTER_ENDPOINT: This must be the full path
+        to the /token endpoint of the harvester.
+        E.G. "https://127.0.0.1:5000/token"
+*/
+
+export default async function solve(): Promise<string> {
+  const endpoint = process.env.HARVESTER_ENDPOINT
+  if (!endpoint) { throw Error('ENV variable `HARVESTER_ENDPOINT` must be set.') }
+  while (true) {
+    try {
+      return (await got.get(process.env.HARVESTER_ENDPOINT, {
+        https: { rejectUnauthorized: false }
+      })).body
+    } catch (e) {
+      if (e.response.statusCode !== 418) { throw e }
+    }
+    await sleep(3000)
+  }
+}