refactor: Download API

Now the download APIs are moved into a new file

backend/src/utils/download.js

@@ -16,12 +16,16 @@ export default async function download(url, ua) {
     });
 
     const result = new Promise((resolve, reject) => {
-        http.get(url).then((resp) => {
-            const body = resp.body;
-            if (body.replace(/\s/g, '').length === 0)
-                reject(new Error('订阅内容为空！'));
-            else resolve(body);
-        });
+        http.get(url)
+            .then((resp) => {
+                const body = resp.body;
+                if (body.replace(/\s/g, '').length === 0)
+                    reject(new Error('订阅内容为空！'));
+                else resolve(body);
+            })
+            .catch(() => {
+                reject(new Error(`无法下载 URL：${url}`));
+            });
     });
 
     cache.set(id, result);

backend/src/utils/flow.js

@@ -0,0 +1,15 @@
+import { HTTP } from '@/vendor/open-api';
+
+export async function getFlowHeaders(url) {
+    const http = HTTP();
+    const { headers } = await http.get({
+        url,
+        headers: {
+            'User-Agent': 'Quantumult%20X/1.0.30 (iPhone14,2; iOS 15.6)',
+        },
+    });
+    const subkey = Object.keys(headers).filter((k) =>
+        /SUBSCRIPTION-USERINFO/i.test(k),
+    )[0];
+    return headers[subkey];
+}

backend/src/utils/platform.js

@@ -0,0 +1,23 @@
+export function getPlatformFromHeaders(headers) {
+    const keys = Object.keys(headers);
+    let UA = '';
+    for (let k of keys) {
+        if (/USER-AGENT/i.test(k)) {
+            UA = headers[k];
+            break;
+        }
+    }
+    if (UA.indexOf('Quantumult%20X') !== -1) {
+        return 'QX';
+    } else if (UA.indexOf('Surge') !== -1) {
+        return 'Surge';
+    } else if (UA.indexOf('Decar') !== -1 || UA.indexOf('Loon') !== -1) {
+        return 'Loon';
+    } else if (UA.indexOf('Shadowrocket') !== -1) {
+        return 'Clash';
+    } else if (UA.indexOf('Stash') !== -1) {
+        return 'Stash';
+    } else {
+        return 'JSON';
+    }
+}