feat(list-cmd-flow): check if server support some command

src/app/@dataflow/rclone/index.ts

@@ -4,3 +4,4 @@ export * from './core-stats-flow';
 export * from './list-remotes-flow';
 export * from './operations-list-flow';
 export * from './connection-flow';
+export * from './list-cmd-flow';

src/app/@dataflow/rclone/list-cmd-flow.ts

@@ -0,0 +1,39 @@
+import { PostFlow } from './post-flow';
+import { IRcloneServer } from '../extra';
+import { AjaxFlowInteralNode, CombErr } from '../core';
+import { Observable } from 'rxjs';
+import { map, distinctUntilChanged } from 'rxjs/operators';
+
+export interface IRcloneCmd {
+	Path: string;
+	Title: string;
+	AuthRequired: boolean;
+	Help: string;
+}
+
+export interface ListCmdFlowOutNode {
+	commands: IRcloneCmd[];
+}
+
+export abstract class ListCmdFlow extends PostFlow<IRcloneServer, ListCmdFlowOutNode> {
+	// public prerequest$: Observable<CombErr<IRcloneServer>>;
+	protected cmd = 'rc/list';
+	protected params = {};
+	protected cacheSupport = false;
+	protected reconstructAjaxResult(x: AjaxFlowInteralNode): CombErr<ListCmdFlowOutNode> {
+		if (x[1].length !== 0) return [{}, x[1]] as any;
+		const rsp = x[0].ajaxRsp.response;
+		return [{ commands: rsp['commands'] }, []];
+	}
+	public verify(cmd: string): Observable<CombErr<IRcloneServer>> {
+		return this.getSupersetOutput().pipe(
+			map((sup) => {
+				if (sup[1].length !== 0) return [{}, sup[1]] as any;
+				if (-1 === sup[0].commands.findIndex((x) => x.Path == cmd))
+					return [{}, [new Error(`not support command: ${cmd}`)]];
+				else return [{ url: sup[0].url, password: sup[0].password, user: sup[0].user }, []];
+			}),
+			distinctUntilChanged((x, y) => JSON.stringify(x) === JSON.stringify(y))
+		);
+	}
+}