Merge pull request #16 from TxtDot/non-html

Redirect in case of non-html content (using exceptions)

src/errors.ts

@@ -0,0 +1,3 @@
+export class EngineParseError extends Error {}
+export class InvalidParameterError extends Error {}
+export class NotHtmlMimetypeError extends Error {}

src/handlers/google.ts

@@ -1,5 +1,6 @@
 import { DOMWindow } from "jsdom";
 import { IHandlerOutput } from "./handler.interface";
+import { EngineParseError } from "../errors";
 
 export default async function google(
   window: DOMWindow
@@ -9,7 +10,9 @@ export default async function google(
   );
 
   if (!googleAnchors) {
-    throw new Error("Failed to find anchors in search result [google]");
+    throw new EngineParseError(
+      "Failed to find anchors in search result [google]"
+    );
   }
   const results = [...googleAnchors];
 

src/handlers/main.ts

@@ -8,6 +8,8 @@ import readability from "./readability";
 import google from "./google";
 import { generateProxyUrl } from "../utils";
 
+import { InvalidParameterError, NotHtmlMimetypeError } from "../errors";
+
 export default async function handlePage(
   url: string,
   requestUrl: URL,
@@ -15,18 +17,24 @@ export default async function handlePage(
 ): Promise<IHandlerOutput> {
 
   if (engine && engineList.indexOf(engine) === -1) {
-    throw new Error("Invalid engine");
+    throw new InvalidParameterError("Invalid engine");
   }
 
   const response = await axios.get(url);
+  const mime: string | undefined = (
+    response.headers["content-type"]?.toString()
+  );
+
+  if (mime && mime.indexOf("text/html") === -1) {
+    throw new NotHtmlMimetypeError();
+  }
+
   const window = new JSDOM(response.data, { url: url }).window;
 
   [...window.document.getElementsByTagName("a")].forEach((link) => {
     link.href = generateProxyUrl(requestUrl, link.href, engine);
   });
 
-  // maybe implement image proxy?
-
   if (engine) {
     return engines[engine](window);
   }

src/handlers/readability.ts

@@ -1,6 +1,7 @@
 import { Readability } from "@mozilla/readability";
 import { IHandlerOutput } from "./handler.interface";
 import { DOMWindow } from "jsdom";
+import { EngineParseError } from "../errors";
 
 export default async function readability(
   window: DOMWindow
@@ -9,7 +10,7 @@ export default async function readability(
   const parsed = reader.parse();
 
   if (!parsed) {
-    throw new Error("Failed to parse [readability]");
+    throw new EngineParseError("Failed to parse [readability]");
   }
 
   return {

src/routes/get.ts

@@ -4,6 +4,8 @@ import { GetSchema, IGetSchema } from "../types/requests";
 import handlePage from "../handlers/main";
 import { generateRequestUrl } from "../utils";
 
+import { NotHtmlMimetypeError } from "../errors";
+
 export default async function getRoute(fastify: FastifyInstance) {
   fastify.get<IGetSchema>(
     "/get",
@@ -12,29 +14,30 @@ export default async function getRoute(fastify: FastifyInstance) {
       const remoteUrl = request.query.url;
       const engine = request.query.engine;
 
-      let format: string;
+      let parsed;
+      try {
+        parsed = await handlePage(
+          remoteUrl,
+          generateRequestUrl(
+            request.protocol,
+            request.hostname,
+            request.originalUrl
+          ),
+          engine
+        );
+      } catch (err) {
+        if (err instanceof NotHtmlMimetypeError) {
+          return reply.redirect(301, remoteUrl);
+        } else {
+          throw err;
+        }
+      }
 
       if (request.query.format === "text") {
         reply.type("text/plain; charset=utf-8");
-        format = "text";
-      } else {
-        reply.type("text/html; charset=utf-8");
-        format = "html";
-      }
-
-      const parsed = await handlePage(
-        remoteUrl,
-        generateRequestUrl(
-          request.protocol,
-          request.hostname,
-          request.originalUrl
-        ),
-        engine
-      );
-
-      if (format === "text") {
         return parsed.textContent;
       } else {
+        reply.type("text/html; charset=utf-8");
         return reply.view("/templates/get.ejs", { parsed: parsed });
       }
     }