telegram-decoder

Telegram decoder plugin used by the IPED project to parse the serialized objects (blobs) stored in the database of Telegram for Android.

The parsing code is the org.telegram.tgnet package copied from the official client DrKLO/Telegram, compiled against minimal stubs of the Android/app classes it depends on.

Modules and licenses:

• telegram-decoder-api: interfaces used by IPED — Apache v2
• telegram-decoder-impl: upstream tgnet code, stubs and DecoderTelegram — GNU GPL v3

Build

Requires JDK 11+ and Maven:

mvn clean install

Branches

• main: released code (upstream tgnet + local customizations).
• DrKLO/Telegram: pristine copy of upstream tgnet. Never edit it by hand.
• update_1.0.x: branch where DrKLO/Telegram is merged into main.

Local customizations

Changes made to upstream files in org/telegram/tgnet (check them after each merge):

• ConnectionsManager.java removed; TextUtils.java added.
• TLParseException.java: UI debug notification in doThrowOrLog commented out (parse errors still throw when exception is true; DecoderTelegram relies on it to reject blobs it cannot fully decode).
• TLRPC.java: PotatoChat support (TL_user_potato and message constructors 0x41df7460, 0x8c75c832); TranslateController usage removed.
• tl/TL_stars.java: PaidReactionPrivacy.getDialogId() returns 0.
• tl/TL_stories.java: StoryPrivacyBottomSheet usage removed.

Prefer adding a stub over editing an upstream file: each edit is a future merge conflict.

Upgrade

1. Clone or update the upstream project in a separate folder:

cd ..
git clone https://github.com/DrKLO/Telegram.git   # or: cd Telegram && git pull origin master
cd Telegram
grep -E 'APP_VERSION_(NAME|CODE)' gradle.properties  # version for the commit message
git log -1 --format=%h                               # commit for the commit message

2. Copy the upstream files into the DrKLO/Telegram branch:

cd ../telegram-decoder
git checkout DrKLO/Telegram
git pull origin DrKLO/Telegram

rm -rf telegram-decoder-impl/src/main/java/org/telegram/tgnet/*
cp -r ../Telegram/TMessagesProj/src/main/java/org/telegram/tgnet/* telegram-decoder-impl/src/main/java/org/telegram/tgnet/

git add -A
git commit -m "update to x.x.x (xxxx) DrKLO/Telegram@xxxxxxx"
git push origin DrKLO/Telegram

3. Merge it into a new branch and set the version 1.0.xx-SNAPSHOT in the three pom.xml:

git checkout main
git pull origin main
git checkout -b update_1.0.xx
git merge DrKLO/Telegram

4. Resolve the conflicts, keeping the upstream code and re-applying the local customizations listed above. Before committing:

   • delete merge leftovers (*.orig, *_BACKUP_*, *_BASE_*, *_LOCAL_*, *_REMOTE_*): they break the build;
   • run mvn clean compile. For each new class referenced by upstream code (cannot find symbol), add a stub with the same package and signature under telegram-decoder-impl/src/main/java, keeping upstream values for flags/helpers used while parsing.

5. Test with IPED, commit, push and open a pull request to main.