vnext: `releases` middleware

* Help android app to find upgrade path

1 files changed, 43 insertions, 0 deletions

diff --git a/vnext/server/middleware/android.js b/vnext/server/middleware/android.js
new file mode 100644
index 00000000..ae5f8fe8
--- /dev/null
+++ b/vnext/server/middleware/android.js
@@ -0,0 +1,43 @@
+import debug from 'debug'
+var log = debug('android')
+
+import * as legacy_data from './legacy.json'
+
+const releases_url = 'https://api.github.com/repos/Juick/Juick-Android/releases'
+
+/**
+ * Return android releases
+ * @type {import('express').RequestParamHandler}
+ */
+const releases = async (req, res) => {
+    let agent = req.headers['user-agent'] || 'unknown'
+    let android_version = parse_agent_android_sdk_version(agent)
+    log(`releases request from ${android_version || agent}`)
+    if (android_version > 0) {
+        if (is_legacy_android(android_version)) {
+            log('responding with legacy stub')
+            return res.json([legacy_data])
+        } else {
+            log('redirecting to Github')
+            return res.redirect(releases_url)
+        }
+    }
+    return res.json([])
+}
+
+const parse_agent_android_sdk_version = (agent = '') => {
+    let version = agent.split(' ', 3)
+    let is_android_app = version.length == 3 && version[2].startsWith('Android')
+    if (is_android_app) {
+        let android_version = version[2].split('/')
+        let is_valid_version = android_version.length == 2
+        return is_valid_version ? +(android_version[1]) : NaN
+    }
+    return NaN
+}
+
+const is_legacy_android = (version) => {
+    return version < 24
+}
+
+export default releases