feat: enhance MihomoGeneratorService to support FlClashX compatibility

- Updated generateConfig method to accept an additional parameter for FlClashX detection.
- Modified addProxy method to handle serverDescription for FlClashX compatibility.

Author: kastov

src/modules/subscription-template/generators/mihomo.generator.service.ts

@@ -48,6 +48,7 @@ interface ProxyNode {
     type: string;
     udp: boolean;
     uuid?: string;
+    serverDescription?: string;
 }
 
 @Injectable()
@@ -56,7 +57,11 @@ export class MihomoGeneratorService {
 
     constructor(private readonly subscriptionTemplateService: SubscriptionTemplateService) {}
 
-    async generateConfig(hosts: IFormattedHost[], isStash = false): Promise<string> {
+    async generateConfig(
+        hosts: IFormattedHost[],
+        isStash = false,
+        isFlClashX = false,
+    ): Promise<string> {
         try {
             const data: ClashData = {
                 proxies: [],
@@ -68,7 +73,7 @@ export class MihomoGeneratorService {
                 if (!host) {
                     continue;
                 }
-                this.addProxy(host, data, proxyRemarks);
+                this.addProxy(host, data, proxyRemarks, isFlClashX);
             }
 
             return await this.renderConfig(data, proxyRemarks, isStash);
@@ -181,7 +186,12 @@ export class MihomoGeneratorService {
         }
     }
 
-    private addProxy(host: IFormattedHost, data: ClashData, proxyRemarks: string[]): void {
+    private addProxy(
+        host: IFormattedHost,
+        data: ClashData,
+        proxyRemarks: string[],
+        isFlClashX: boolean,
+    ): void {
         if (host.network === 'xhttp') {
             return;
         }
@@ -241,6 +251,11 @@ export class MihomoGeneratorService {
                 return;
         }
 
+        if (host.serverDescription && isFlClashX) {
+            // supported in FlClashX, custom field
+            node.serverDescription = Buffer.from(host.serverDescription, 'base64').toString();
+        }
+
         data.proxies.push(node);
         proxyRemarks.push(proxyRemark);
     }

src/modules/subscription-template/render-templates.service.ts

@@ -144,7 +144,11 @@ export class RenderTemplatesService {
         switch (clientType) {
             case 'MIHOMO':
                 return {
-                    sub: await this.mihomoGeneratorService.generateConfig(formattedHosts, false),
+                    sub: await this.mihomoGeneratorService.generateConfig(
+                        formattedHosts,
+                        false,
+                        /^FlClashX\//.test(userAgent),
+                    ),
                     contentType: SUBSCRIPTION_CONFIG_TYPES.MIHOMO.CONTENT_TYPE,
                 };