Fix fenrir realm verifying message by matthewsong18 · Pull Request #3115 · dteviot/WebToEpub

matthewsong18 · 2026-11-04T02:07:33Z

To get the actual chapters instead of a “verifying access” message, I studied how Fenrir Realm loads its content. I guessed they had switched to API requests and that was indeed how they were retrieving the chapter contents.
Getting the API response wasn't enough though because the chapter content was encrypted. I used AI to figure out how the site decrypts the content and implemented that in the parser.
I noticed in the responses with the encrypted chapters that they mentioned a "fragments-v1" and learned that there's supposedly a "fragments-v2" incoming. What that means is that there's going to be another way to decrypt the chapters. But randomly testing novels on the site show that they're all using v1. I only implemented v1, but I split chapter retrieval and decryption into smaller, abstracted functions so the affected parts can be updated easily in the future.
To make Turnstile challenges easier to resolve, I added custom handling that links to the chapter page when authorization is required. It brings you to the chapter, where you can complete the Turnstile, instead of bringing you to the API request.

dteviot · 2026-11-04T06:51:23Z

@matthewsong18 Thank you very much for this, but we can't accept it as it stands.
Having an extension decrypt encrypted content violates Google's terms of service for an extension.
Please see https://github.com/dteviot/WebToEpub/wiki/FAQ#request-to-decryptdescramble-text-for-sites-eg-chrysanthemumgarden-dragontea-ink for how WebToEpub works around this rule.

Site errors because rate is too fast at 3000ms

Remove the extra delay between read-token authorization and chapter retrieval.

Volumes were messing up chapter order

- Based on NoveliParser using chrome extension API - Chrome documentation is transitioning to browser.* namespace, but minimum required version is 148. Our manifest lists 120, so I left it as chrome.

- Based on Wuxiaworld parser using an observer - Typically narrows tab blocking from 3 seconds to 2 seconds

matthewsong18 · 2026-11-05T03:35:44Z

@dteviot Since we're not allowed to decrypt ourselves, I took inspiration from NoveliParser and used the chrome.tabs API (which is being migrated to browser.* as mentioned in the docs but requires minimum Chrome 148) to open the chapters inside of a new tab, wait for the site itself to decrypt the chapter, then read the rendered html.

The main trade-off is a massively longer download time. This is because the throttle only controls the delay between chapter tabs. But on each tab, we can't control the requests Fenrir Realm makes while loading the site. This caused their rate limit to trigger until I raised the minimum throttle to 10 seconds. On top of this, each tab takes around 2 seconds to grab the chapter contents (improved from 3 seconds by using an observer). Each chapter takes around 12 seconds to download.

Downloads now take roughly 3 times as long, but the parser works without performing decryption itself.

dteviot · 2026-11-05T06:38:02Z

+        const { json: data } = await HttpClient.fetchJson(apiUrl);
+        const chapterListIsInvalid = !Array.isArray(data);
+        if (chapterListIsInvalid) {
+            throw new Error("Fenrir Realm returned an invalid chapter list.");


Text that is shown to a user should go in https://github.com/dteviot/WebToEpub/blob/ExperimentalTabMode/plugin/_locales/en/messages.json, so it can be translated. (At least in theory.)

I'll try to use those i18n messages from now on.

dteviot · 2026-11-05T06:38:25Z

+        const identifiersAreInvalid = !hasNumericId || !hasSlug;
+        if (identifiersAreInvalid) {
+            throw new Error(
+                "Fenrir Realm returned invalid chapter identifiers.",


dteviot · 2026-11-05T06:38:40Z

+        const seriesCannotBeIdentified = !isSeriesPath || !hasSeriesSlug;
+        if (seriesCannotBeIdentified) {
+            throw new Error(
+                `Cannot identify the Fenrir Realm series from ${url.href}`,


dteviot · 2026-11-05T06:38:48Z

+
+            if (tabMissing) {
+                throw new Error(
+                    "The reading tab opened by WebToEpub was closed. Please do not close " +


dteviot · 2026-11-05T06:39:06Z

+
+    promptForChapterRetry(url) {
+        const message = new Error(
+            "Fenrir Realm has not displayed the chapter. Open the chapter URL, " +


dteviot · 2026-11-05T06:39:25Z

+                return true;
+            }
+            const accessIsBeingVerified =
+                reader.textContent.includes("Verifying access");


dteviot · 2026-11-05T07:00:12Z

@matthewsong18
My complements on your ingenuity.
Unfortunately, I believe this is still in violation of Google's ToCs. The fact that we're letting the Browser do the decrypting rather than WebToEpub really doesn't make a difference. Ultimately, we're still packaging the unprotected content.
FYI. the relevant ToC is number 5 on this list. https://developer.chrome.com/docs/webstore/program-policies/malicious-and-prohibited.

Feel free to correct me if you think I'm wrong.

dteviot · 2026-11-05T07:12:57Z

@matthewsong18
Going to suggest, you could add this to the "experimental" folder under "parsers". Then it's available for private builds. It just doesn't get included in the versions we submit to Google or Firefox stores.

dteviot · 2026-11-05T07:29:36Z

@matthewsong18
On second thoughts, let's push our luck

matthewsong18 marked this pull request as draft November 4, 2026 17:25

matthewsong18 added 7 commits November 4, 2026 21:08

fix: increase rate-limit to 4000ms

6e99b48

Site errors because rate is too fast at 3000ms

fix: retrieve Fenrir Realm chapters through the reader API

7784d9c

fix: open Fenrir chapter pages for authorization challenges

9b093f8

fix: fetch Fenrir chapters immediately after authorization

f98d1a5

Remove the extra delay between read-token authorization and chapter retrieval.

refactor: abstract away Fenrir chapter retrieval and decryption

3803c3d

refactor: rename and add comments to explain decisions

015ceeb

fix: preserve volume order for Fenrir Realm chapters

fa6ce42

Volumes were messing up chapter order

matthewsong18 force-pushed the fix-fenrir-realm-verifying-message branch from 2ff05e9 to 1183ec5 Compare November 5, 2026 02:08

fix(fenrir): fetch rendered chapters with cross-browser tab support

8a38d60

- Based on NoveliParser using chrome extension API - Chrome documentation is transitioning to browser.* namespace, but minimum required version is 148. Our manifest lists 120, so I left it as chrome.

matthewsong18 force-pushed the fix-fenrir-realm-verifying-message branch from 1183ec5 to 8a38d60 Compare November 5, 2026 03:19

fix(fenrir): use observer to watch tab load chapter

171031e

- Based on Wuxiaworld parser using an observer - Typically narrows tab blocking from 3 seconds to 2 seconds

matthewsong18 marked this pull request as ready for review November 5, 2026 03:35

fix(fenrir): add detection for rare turnstile dialog display

d9b4390

dteviot reviewed Nov 5, 2026

View reviewed changes

dteviot merged commit 4d03d3c into dteviot:ExperimentalTabMode Nov 5, 2026
1 check passed

matthewsong18 deleted the fix-fenrir-realm-verifying-message branch November 5, 2026 13:46

github-actions Bot mentioned this pull request Nov 9, 2026

https://fenrirealm.com broken again #3133

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Fix fenrir realm verifying message - #3115

Fix fenrir realm verifying message#3115
dteviot merged 10 commits into
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