feat: Add url validation on feed

Author: relekang

src/__tests__/__snapshots__/api.tests.ts.snap

@@ -334,6 +334,35 @@ exports[`
 }
 `;
 
+exports[`
+  feed(url: "not-a-url") { title }
+ 1`] = `
+{
+  "data": {
+    "feed": null,
+  },
+  "errors": [
+    {
+      "extensions": {
+        "code": "invalid-url",
+        "message": "Invalid url",
+        "type": "InvalidUrlError",
+      },
+      "locations": [
+        {
+          "column": 3,
+          "line": 2,
+        },
+      ],
+      "message": "Invalid url",
+      "path": [
+        "feed",
+      ],
+    },
+  ],
+}
+`;
+
 exports[`
   findFeed(url: "https://non--------existing-domain.com") { link }
  1`] = `

src/__tests__/api.tests.ts

@@ -51,6 +51,10 @@ testGraphqlApi`
   feed(url: "https://non--------existing-domain.com") { title }
 `;
 
+testGraphqlApi`
+  feed(url: "not-a-url") { title }
+`;
+
 testGraphqlApi`
   feed(url: "${url}", startTime: "2020-01-01", endTime: "2020-10-31") {
     items { title }

src/handlers/feed.ts

@@ -1,6 +1,8 @@
+import isUrl from "is-url";
 import {
 	BaseError,
 	EmptyParserOutputError,
+	InvalidUrlError,
 	NotAFeedError,
 	ParserError,
 } from "../errors.js";
@@ -53,6 +55,9 @@ export async function parseFromQuery({
 	endTime?: string;
 	startTime?: string;
 }): Promise<ParserResponse> {
+	if (!isUrl(url)) {
+		throw new InvalidUrlError(url);
+	}
 	const response = await request(url);
 
 	const contentType =