Add node.js-based adblock server, part of #410.

resources/desktop/com.github.rssguard.appdata.xml

@@ -30,7 +30,7 @@
   <url type="donation">https://martinrotter.github.io/donate/</url>
   <content_rating type="oars-1.1" />
   <releases>
-    <release version="3.9.0" date="2021-04-28"/>
+    <release version="3.9.0" date="2021-05-03"/>
   </releases>
   <content_rating type="oars-1.0">
     <content_attribute id="violence-cartoon">none</content_attribute>

resources/scripts/adblock/adblock-server.js

@@ -0,0 +1,93 @@
+// Simple local HTTP server providing ad-blocking
+// functionality via https://github.com/cliqz-oss/adblocker
+//
+// How to install:
+//     npm i -g @cliqz/adblocker
+//     npm i -g concat-stream
+//     npm i -g psl
+//     npm i -g node-fetch
+//
+// How to run:
+//     NODE_PATH="C:\Users\<user>\AppData\Roaming\npm\node_modules" node ./adblock-server.js
+//
+// How to use:
+//     curl -i -X POST --data '{"url": "http://gompoozu.net", "url_type": "main_frame"}' 'http://localhost:48484'
+
+const fs = require('fs');
+const psl = require('psl');
+const adblock = require('@cliqz/adblocker')
+const http = require('http');
+const concat = require('concat-stream');
+const constants = require('node:http2');
+const fetch = require("node-fetch");
+
+let engine;
+
+adblock.FiltersEngine.fromLists(fetch, [
+  'https://easylist.to/easylist/easylist.txt',
+  'https://raw.githubusercontent.com/tomasko126/easylistczechandslovak/master/filters.txt',
+]).then(function (res) { engine = res; });
+
+const hostname = '127.0.0.1';
+const port = 48484;
+
+const server = http.createServer((req, res) => {
+  try {
+    const chunks = [];
+    req.on('data', chunk => chunks.push(chunk));
+    req.on('end', () => {
+      try {
+        const jsonData = Buffer.concat(chunks);
+        const jsonStruct = JSON.parse(jsonData.toString());
+
+        const askUrl = jsonStruct['url'];
+        const askCosmetic = jsonStruct['cosmetic'];
+        const askUrlType = jsonStruct['url_type'];
+        const fullUrl = new URL(askUrl);
+
+        resultJson = {};
+
+        const adblockMatch = engine.match(adblock.Request.fromRawDetails({
+          type: askUrlType,
+          url: askUrl,
+        }));
+
+        resultJson["filter"] = adblockMatch;
+        console.log(`adblocker: Filter is:\n${JSON.stringify(adblockMatch)}.`)
+
+        if (askCosmetic) {
+          const adblockCosmetic = engine.getCosmeticsFilters({
+            url: askUrl,
+            hostname: fullUrl.hostname,
+            domain: psl.parse(fullUrl.hostname).domain
+          });
+
+          resultJson["cosmetic"] = adblockCosmetic;
+          console.log(`adblocker: Cosmetic is:\n${JSON.stringify(adblockCosmetic)}.`)
+        }
+        
+        res.statusCode = 200;
+        res.setHeader('Content-Type', 'application/json');
+        res.end(JSON.stringify(resultJson));
+      }
+      catch (inner_error) {
+        console.error(`adblocker: ${inner_error}.`);
+
+        res.statusCode = 500;
+        res.setHeader('Content-Type', 'text/plain');
+        res.end(String(inner_error));
+      }
+    })
+  }
+  catch (error) {
+    console.error(`adblocker: ${inner_error}.`);
+
+    res.statusCode = 500;
+    res.setHeader('Content-Type', 'text/plain');
+    res.end(String(error));
+  }
+});
+
+server.listen(port, hostname, () => {
+  console.log(`adblocker: Server started at local port ${port}.`);
+});