1 files changed, 137 insertions, 0 deletions
diff --git a/packages/megalodon/src/detector.ts b/packages/megalodon/src/detector.ts
new file mode 100644
index 0000000000..31f34d72f7
--- /dev/null
+++ b/packages/megalodon/src/detector.ts
@@ -0,0 +1,137 @@
+import axios, { AxiosRequestConfig } from 'axios'
+import proxyAgent, { ProxyConfig } from './proxy_config'
+import { NodeinfoError } from './megalodon'
+
+const NODEINFO_10 = 'http://nodeinfo.diaspora.software/ns/schema/1.0'
+const NODEINFO_20 = 'http://nodeinfo.diaspora.software/ns/schema/2.0'
+const NODEINFO_21 = 'http://nodeinfo.diaspora.software/ns/schema/2.1'
+
+type Links = {
+  links: Array<Link>
+}
+
+type Link = {
+  href: string
+  rel: string
+}
+
+type Nodeinfo10 = {
+  software: Software
+  metadata: Metadata
+}
+
+type Nodeinfo20 = {
+  software: Software
+  metadata: Metadata
+}
+
+type Nodeinfo21 = {
+  software: Software
+  metadata: Metadata
+}
+
+type Software = {
+  name: string
+}
+
+type Metadata = {
+  upstream?: {
+    name: string
+  }
+}
+
+/**
+ * Detect SNS type.
+ * Now support Mastodon, Pleroma and Pixelfed. Throws an error when no known platform can be detected.
+ *
+ * @param url Base URL of SNS.
+ * @param proxyConfig Proxy setting, or set false if don't use proxy.
+ * @return SNS name.
+ */
+export const detector = async (
+  url: string,
+  proxyConfig: ProxyConfig | false = false
+): Promise<'mastodon' | 'pleroma' | 'misskey' | 'friendica'> => {
+  let options: AxiosRequestConfig = {
+    timeout: 20000
+  }
+  if (proxyConfig) {
+    options = Object.assign(options, {
+      httpsAgent: proxyAgent(proxyConfig)
+    })
+  }
+
+  const res = await axios.get<Links>(url + '/.well-known/nodeinfo', options)
+  const link = res.data.links.find(l => l.rel === NODEINFO_20 || l.rel === NODEINFO_21)
+  if (!link) throw new NodeinfoError('Could not find nodeinfo')
+  switch (link.rel) {
+    case NODEINFO_10: {
+      const res = await axios.get<Nodeinfo10>(link.href, options)
+      switch (res.data.software.name) {
+        case 'pleroma':
+          return 'pleroma'
+        case 'akkoma':
+          return 'pleroma'
+        case 'mastodon':
+          return 'mastodon'
+        case "wildebeest":
+          return "mastodon"
+        case 'misskey':
+          return 'misskey'
+        case 'friendica':
+          return 'friendica'
+        default:
+          if (res.data.metadata.upstream?.name && res.data.metadata.upstream.name === 'mastodon') {
+            return 'mastodon'
+          }
+          throw new NodeinfoError('Unknown SNS')
+      }
+    }
+    case NODEINFO_20: {
+      const res = await axios.get<Nodeinfo20>(link.href, options)
+      switch (res.data.software.name) {
+        case 'pleroma':
+          return 'pleroma'
+        case 'akkoma':
+          return 'pleroma'
+        case 'mastodon':
+          return 'mastodon'
+        case "wildebeest":
+          return "mastodon"
+        case 'misskey':
+          return 'misskey'
+        case 'friendica':
+          return 'friendica'
+        default:
+          if (res.data.metadata.upstream?.name && res.data.metadata.upstream.name === 'mastodon') {
+            return 'mastodon'
+          }
+          throw new NodeinfoError('Unknown SNS')
+      }
+    }
+    case NODEINFO_21: {
+      const res = await axios.get<Nodeinfo21>(link.href, options)
+      switch (res.data.software.name) {
+        case 'pleroma':
+          return 'pleroma'
+        case 'akkoma':
+          return 'pleroma'
+        case 'mastodon':
+          return 'mastodon'
+        case "wildebeest":
+          return "mastodon"
+        case 'misskey':
+          return 'misskey'
+        case 'friendica':
+          return 'friendica'
+        default:
+          if (res.data.metadata.upstream?.name && res.data.metadata.upstream.name === 'mastodon') {
+            return 'mastodon'
+          }
+          throw new NodeinfoError('Unknown SNS')
+      }
+    }
+    default:
+      throw new NodeinfoError('Could not find nodeinfo')
+  }
+}