add media codecs evasion strategy module

pyppeteer_stealth/media_codecs.py

@@ -0,0 +1,78 @@
+from pyppeteer.page import Page
+
+
+async def media_codecs(page: Page) -> None:
+    await page.evaluateOnNewDocument(
+        """
+    () => {
+  try {
+    /**
+     * Input might look funky, we need to normalize it so e.g. whitespace isn't an issue for our spoofing.
+     *
+     * @example
+     * video/webm; codecs="vp8, vorbis"
+     * video/mp4; codecs="avc1.42E01E"
+     * audio/x-m4a;
+     * audio/ogg; codecs="vorbis"
+     * @param {String} arg
+     */
+    const parseInput = arg => {
+      const [mime, codecStr] = arg.trim().split(';')
+      let codecs = []
+      if (codecStr && codecStr.includes('codecs="')) {
+        codecs = codecStr
+          .trim()
+          .replace(`codecs="`, '')
+          .replace(`"`, '')
+          .trim()
+          .split(',')
+          .filter(x => !!x)
+          .map(x => x.trim())
+      }
+      return { mime, codecStr, codecs }
+    }
+
+    /* global HTMLMediaElement */
+    const canPlayType = {
+      // Make toString() native
+      get(target, key) {
+        // Mitigate Chromium bug (#130)
+        if (typeof target[key] === 'function') {
+          return target[key].bind(target)
+        }
+        return Reflect.get(target, key)
+      },
+      // Intercept certain requests
+      apply: function(target, ctx, args) {
+        if (!args || !args.length) {
+          return target.apply(ctx, args)
+        }
+        const { mime, codecs } = parseInput(args[0])
+        // This specific mp4 codec is missing in Chromium
+        if (mime === 'video/mp4') {
+          if (codecs.includes('avc1.42E01E')) {
+            return 'probably'
+          }
+        }
+        // This mimetype is only supported if no codecs are specified
+        if (mime === 'audio/x-m4a' && !codecs.length) {
+          return 'maybe'
+        }
+
+        // This mimetype is only supported if no codecs are specified
+        if (mime === 'audio/aac' && !codecs.length) {
+          return 'probably'
+        }
+        // Everything else as usual
+        return target.apply(ctx, args)
+      }
+    }
+    HTMLMediaElement.prototype.canPlayType = new Proxy(
+      HTMLMediaElement.prototype.canPlayType,
+      canPlayType
+    )
+  } catch (err) {}
+}
+"""
+    )
+