Add ability to log original and modified M3U content in m3u-prune scr…

…iptlet

src/scriptlets/m3u-prune.js

@@ -35,6 +35,7 @@ import {
  * - `propsToRemove` — optional, string or regular expression
  *   to match the URL line (segment) which will be removed alongside with its tags
  * - `urlToMatch` — optional, string or regular expression for matching the request's URL
+ * - `logContent` — optional, string, if set to 'logContent' will log original and modified M3U content
  *
  * > Usage with no arguments will log response payload and URL to browser console;
  * > it may be useful for debugging but it is not allowed for prod versions of filter lists.
@@ -53,6 +54,12 @@ import {
  *     example.org#%#//scriptlet('m3u-prune', 'example.com/video/', '.m3u8')
  *     ```
  *
+ * 1. Removes a line which contains `example.com/video/`, only if request's URL contains `.m3u8` and log content
+ *
+ *     ```adblock
+ *     example.org#%#//scriptlet('m3u-prune', 'example.com/video/', '.m3u8', 'logContent')
+ *     ```
+ *
  * 1. Call with no arguments will log response payload and URL at the console
  *
  *     ```adblock
@@ -69,7 +76,7 @@ import {
  */
 /* eslint-enable max-len */
 
-export function m3uPrune(source, propsToRemove, urlToMatch = '') {
+export function m3uPrune(source, propsToRemove, urlToMatch = '', logContent) {
     // do nothing if browser does not support fetch or Proxy (e.g. Internet Explorer)
     // https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch
     // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
@@ -83,6 +90,8 @@ export function m3uPrune(source, propsToRemove, urlToMatch = '') {
 
     let shouldPruneResponse = false;
 
+    const shouldLogContent = logContent === 'logContent';
+
     const urlMatchRegexp = toRegExp(urlToMatch);
 
     const SEGMENT_MARKER = '#';
@@ -307,16 +316,23 @@ export function m3uPrune(source, propsToRemove, urlToMatch = '') {
      */
     // TODO: make it compatible with $hls modifier
     const pruneM3U = (text) => {
+        if (shouldLogContent) {
+            logMessage(source, `Original M3U content:\n${text}`);
+        }
+
         let lines = text.split(/\r?\n/);
 
         if (text.includes(COMCAST_AD_MARKER.VMAP_AD_BREAK)) {
             lines = pruneVmapBlock(lines);
-            return lines.filter((l) => !!l).join('\n');
+            lines = lines.filter((l) => !!l).join('\n');
+            if (shouldLogContent) {
+                logMessage(source, `Modified M3U content:\n${lines}`);
+            }
+            return lines;
         }
 
         lines = pruneSegments(lines);
-
-        return lines
+        lines = lines
             .map((line, index, array) => {
                 if (typeof line === 'undefined') {
                     return line;
@@ -329,6 +345,12 @@ export function m3uPrune(source, propsToRemove, urlToMatch = '') {
             })
             .filter((l) => !!l)
             .join('\n');
+
+        if (shouldLogContent) {
+            logMessage(source, `Modified M3U content:\n${lines}`);
+        }
+
+        return lines;
     };
 
     const nativeOpen = window.XMLHttpRequest.prototype.open;

tests/scriptlets/m3u-prune.test.js

@@ -338,6 +338,55 @@ if (!isSupported) {
         done();
     });
 
+    test('fetch match URL - remove ads 1 and log', async (assert) => {
+        assert.expect(8);
+
+        console.log = (...args) => {
+            if (args.length === 1 && args[0].includes('Original M3U content:')) {
+                assert.ok(args[0].includes('tvessaiprod.nbcuni.com/video/'), 'should log original text in console');
+            }
+            if (args.length === 1 && args[0].includes('Modified M3U content:')) {
+                assert.notOk(args[0].includes('tvessaiprod.nbcuni.com/video/'), 'should log modified text in console');
+            }
+            nativeConsole(...args);
+        };
+
+        const M3U8_PATH = M3U8_OBJECTS_PATH_01;
+        const MATCH_DATA = 'tvessaiprod.nbcuni.com/video/';
+        const MATCH_URL = '.m3u8';
+        const LOG_CONTENT = 'logContent';
+        const scriptletArgs = [MATCH_DATA, MATCH_URL, LOG_CONTENT];
+
+        runScriptlet(name, scriptletArgs);
+
+        const done = assert.async();
+
+        const response = await fetch(M3U8_PATH);
+        const responseM3U8 = await response.text();
+        assert.notOk(
+            responseM3U8.includes('tvessaiprod.nbcuni.com/video/'),
+            'check if "tvessaiprod.nbcuni.com/video/" has been removed',
+        );
+        assert.notOk(
+            responseM3U8.includes('#EXT-X-CUE:TYPE="SpliceOut"'),
+            'check if "#EXT-X-CUE:TYPE="SpliceOut"" has been removed',
+        );
+        assert.notOk(
+            responseM3U8.includes('#EXT-X-CUE-IN'),
+            'check if "#EXT-X-CUE-IN" has been removed',
+        );
+        assert.notOk(
+            responseM3U8.includes('#EXT-X-ASSET:CAID'),
+            'check if "#EXT-X-ASSET:CAID" has been removed',
+        );
+        assert.notOk(
+            responseM3U8.includes('#EXT-X-SCTE35:'),
+            'check if "#EXT-X-SCTE35:" has been removed',
+        );
+        assert.strictEqual(window.hit, 'FIRED', 'hit function fired');
+        done();
+    });
+
     test('fetch match URL - remove ads 2', async (assert) => {
         const M3U8_PATH = M3U8_OBJECTS_PATH_02;
         const MATCH_DATA = 'VMAP-AD-BREAK';