Daniel Lange's blog (Entries tagged as automate)

Get Youtube Channel ID from username

nospam@example.com (Daniel Lange) — Wed, 01 Jun 2022 16:45:00 +0000

Youtube has a really nice RSS feature that is extremely well hidden.

If you postfix a Channel ID to

https://www.youtube.com/feeds/videos.xml?channel_id=<id goes here>

you get a really nice Atom 1.0 (~RSS) feed for your feedreader.

Unfortunately the Channel ID is hard to find while you are navigating Youtube with usernames in the URL.

E.g. https://www.youtube.com/c/TED is TED's channel, full of interesting and worth-to-watch content (and some assorted horse toppings, of course).

But you have to read a lot of ugly HTML / JSON in that page to find and combine

https://www.youtube.com/feeds/videos.xml?channel_id=UCAuUUnT6oDeKwE6v1NGQxug

which is the related RSS feed.

Jeff Keeling wrote a simple Youtube RSS Extractor that does well if you have a ../playlist?... or a .../channel/... URL but it will (currently) fail on user name channels or Youtube landing pages.

So how do we get the Channel ID for a Youtube user we are interested to follow?

Youtube has a great API but that is gated by API keys even for the most simple calls (that came only with v3 of the API but the previous version is depreciated since 2015)¹:

dl@laptop:~$ curl 'https://www.googleapis.com/youtube/v3/channels?part=contentDetails&forUsername=DebConfVideos'
{
"error": {
"code": 403,
"message": "The request is missing a valid API key.",
"errors": [
{
"message": "The request is missing a valid API key.",
"domain": "global",
"reason": "forbidden"
}
],
"status": "PERMISSION_DENIED"
}
}

Luckily we can throw the same (example) user name DebConfVideos at curl and grep:

dl@laptop:~$ curl -s "https://www.youtube.com/c/DebConfVideos/videos" | grep -Po '"channelId":".+?"'
"channelId":"UC7SbfAPZf8SMvAxp8t51qtQ"

So https://www.youtube.com/feeds/videos.xml?channel_id=UC7SbfAPZf8SMvAxp8t51qtQ is the RSS feed for DebConfVideos.

We can use individual Youtube video URLs as well. With the hack above, it'll work to find us the Chanel ID from a Youtube video URL:

Now, some user pages may have multiple valid RSS feeds because they contain multiple channels.

Remember the TED page from above? Well run:

dl@laptop:~$ curl -s "https://www.youtube.com/c/TED" | grep -Po '"channelId":".+?"' | cut -d \" -f 4 | while read -r YTID ; do echo -n "Youtube-ID: $YTID " ; curl -s "https://www.youtube.com/feeds/videos.xml?channel_id=$YTID" | grep -m 1 -P -o "(?<=<title>).+(?=</title>)" ; done

This will iterate through the Channel IDs found and show you the titles. That way you can assess which one you want to add to your feedreader.

You probably want the last Channel ID listed above, the non-selective "TED" one. And that's the one from the example above.

Update

02.06.2022: smpl wrote in and has the much better solution for the most frequent use cases:

You can also use get a feed directly with a username:
https://www.youtube.com/feeds/videos.xml?user=<username>

The one I use most is the one for playlists (if creators remember to
use them).

https://www.youtube.com/feeds/videos.xml?playlist_id=<playlist id>

For the common case you don't even need the channel ID that way. But it is also conveniently given in a <yt:channelId> tag (or the topmost <id> tag) within the Atom XML document.

Thanks, smpl!

Actually it is even more complicated as some channels, like our DebConfVideos example, will only get you an incomplete result, cf. this StackOverflow entry. I.e. the forUsername iterator may not even work and the "best practice" seems to be mucking around with the search call. ↩

Frustrating spammers

nospam@example.com (Daniel Lange) — Fri, 16 Nov 2018 08:00:00 +0000

Sometimes tiny things make my day at 9am already.

That spammer got frustrated because none of his bots would get comments pasted to my blog:

Greetings to Cambodia.

BTW: Mikrotik RouterOS 6.41, CVE-2018-7445. RCE unpatched for 9+ months.

Cygwin automatic updates

nospam@example.com (Daniel Lange) — Wed, 17 Feb 2016 12:37:00 +0000

Cygwin is a fantastic product for people that need to use Microsoft Windows and require some compatibility to Linux (or BSD or UNIX in general).

Unfortunately it is not trivial to keep it updated (and thus safe) as the update process requires downloading the latest installer and then clicking through the package list again and again on every update.
No apt-get update, no emerge --update @world, no dnf update.

But ... the people at Red Hat (who now own Cygwin) are not mean, they are just not good at documenting things ...

Be sure to have wget installed via cygwin, you'll need it to fetch the installer automatically.
Then drop the following batch file as cyg_update.bat into C:\cygwin64 (or where you have installed cygwin¹):

@echo off
cd /d C:\cygwin64
del /Q cygwinSetup-x86_64.exe
bin\wget.exe --progress=dot -S -N http://cygwin.com/setup-x86_64.exe
move /y setup-x86_64.exe cygwinSetup-x86_64.exe
REM S-1-1-0 is the SID for "Everyone"
icacls cygwinSetup-x86_64.exe /grant *S-1-1-0:RX
cygwinSetup-x86_64.exe --no-desktop --no-shortcuts --no-startmenu --quiet-mode

Once you start the batch (e.g. by double-clicking from Windows Explorer) it will download the latest installer from Cygwin.com and perform a silent update. You need to approve the Windows installer warning as you do with every manual install / update as well. So it's not a no-click update but a one-or-two-clicks update.
Still much better than the click fest without the batch file.

Update

01.06.2017: I've changed icacls cygwinSetup-x86_64.exe /grant Everyone:RX to icacls cygwinSetup-x86_64.exe /grant *S-1-1-0:RX which is the SID and not language dependent. 'cause otherwise German Windows would like to see "Jeder" and French "Tous publics", Chinese "任何人", etc. Looking them up on Microsoft's terminology search is quite nice but not really scalable.

If you have installed the 32bit version and/or used a different install path, adjust line 2 of the batch file accordingly. Did I need to say that? Hm, well, I did ... have a cookie. ↩