Submitted 18 hours ago by ReedReads@lemmy.zip to selfhosted@lemmy.world
https://lemmy.zip/pictrs/image/48374d66-082b-4e8f-b36f-58f76e8aa5cc.webp
Links are almost always base64 encoded now and the online url decoders always produce garbage. I was wondering if there is a project out there that would allow me to self-host this type of tool?
I’d probably network this container through gluetun because, yanno, privacy.
There is no such thing as a base64 encoded url. Part of an url might hold base64 encoded data, but never the url itself.
These online tools aren’t working because you’re using them wrong.
There's base64 -d on the command line.
base64 -d
Right but the / in the url trips it up and I’d like to just copy/paste the full url and have it spit out the proper, decoded link.
The / character isn’t a part of the base64 encoding. In fact, only one part of the URL looks like base64. No plain base64 tool (whether via CLI, self-hosted, or otherwise) will be able to decode an entire URL like that. You’ll first need to parse the URL to isolate the base64 part. This is literally solved with a single line of bash:
echo "https://link.sfchronicle.com/external/41488169.38548/aHR0cHM6Ly93d3cuaG90ZG9nYmlsbHMuY29tL2hhbWJ1cmdlci1tb2xkcy9idXJnZXItZG9nLW1vbGQ_c2lkPTY4MTNkMTljYzM0ZWJjZTE4NDA1ZGVjYSZzcz1QJnN0X3JpZD1udWxsJnV0bV9zb3VyY2U9bmV3c2xldHRlciZ1dG1fbWVkaXVtPWVtYWlsJnV0bV90ZXJtPWJyaWVmaW5nJnV0bV9jYW1wYWlnbj1zZmNfYml0ZWN1cmlvdXM/6813d19cc34ebce18405decaB7ef84e41" | cut -d/ -f6 | base64 -d
Well, the URL is a bit weird.
echo "aHR0cHM6Ly93d3cuaG90ZG9nYmlsbHMuY29tL2hhbWJ1cmdlci1tb2xkcy9idXJnZXItZG9nLW1vbGRzCg" | base64 -d
gives me your string. But there are a few characters off at the end. And then there are 176 characters left. I suppose the underscore is some delimiter. The rest is:
echo "c2lkPTY4MTNkMTljYzM0ZWJjZTE4NDA1ZGVjYSZzcz1QJnN0X3JpZD1udWxsJnV0bV9zb3VyY2U9bmV3c2xldHRlciZ1dG1fbWVkaXVtPWVtYWlsJnV0bV90ZXJtPWJyaWVmaW5nJnV0bV9jYW1wYWlnbj1zZmNfYml0ZWN1cmlvdXM" | base64 -d
"sid=6813d19cc34ebce18405deca&ss=P&st_rid=null&utm_source=newsletter&utm_medium=email&utm_term=briefing&utm_campaign=sfc_bitecurious"
Just put it in quotes?
This is the internet, maybe build it yourself instead of demanding others do the work for you?
You could also just as easily only paste in the encoded part and put it back into the link yourself.
That url isn’t base64 encoded. You can tell by the fact that it’s still a URL……
…that one little detail everyone missed
It’s 3 lines of code in basically every programming language, no need for selfhosting, just open the terminal?
Got an example in BASH?
echo “base64 text” | base64 --decode
Cyberchef!
Cyberchef does this and so so much more github.com/gchq/CyberChef
IT-Tools is kind of fun: a web page full of common tools, converters, references, cheat sheets, etc.
This is amazing, thank you!
Don’t include the non-encoded part of the data or it will corrupt the decryption. The decoder can’t tell the difference between data that’s not encoded and data that is encoded since it’s all text.
There’s something else going on there besides base64 encoding of the URL – possibly they have some binary tracking data or other crap that only makes sense to the creator of the link.
It’s not hard to write a small Python script that gets what you want out of a URL like that though. Here’s one that works with your sample link:
#!/usr/bin/env python3 import base64 import binascii import itertools import string import sys input_url = sys.argv[1] parts = input_url.split("/") for chunk in itertools.accumulate(reversed(parts), lambda b,a: "/".join([a,b])): try: text = base64.b64decode(chunk).decode("ascii", errors="ignore") clean = "".join(itertools.takewhile(lambda x: x in string.printable, text)) print(clean) except binascii.Error: continue
Save that to a file like decode.py and then you can you run it on the command line like python3 ./decode.py ‘YOUR-LINK-HERE’
e.g.
$ python3 ./decode.py 'https://link.sfchronicle.com/external/41488169.38548/aHR0cHM6Ly93d3cuaG90ZG9nYmlsbHMuY29tL2hhbWJ1cmdlci1tb2xkcy9idXJnZXItZG9nLW1vbGQ_c2lkPTY4MTNkMTljYzM0ZWJjZTE4NDA1ZGVjYSZzcz1QJnN0X3JpZD1udWxsJnV0bV9zb3VyY2U9bmV3c2xldHRlciZ1dG1fbWVkaXVtPWVtYWlsJnV0bV90ZXJtPWJyaWVmaW5nJnV0bV9jYW1wYWlnbj1zZmNfYml0ZWN1cmlvdXM/6813d19cc34ebce18405decaB7ef84e41' https://www.hotdogbills.com/hamburger-molds/burger-dog-mold
This script works by spitting the URL at ‘/’ characters and then recombining the parts (right-to-left) and checking if that chunk of text can be base64 decoded successfully. If it does, it then takes any printable ASCII characters at the start of the string and outputs it (to clean up the garbage characters at the end). If there’s more than one possible valid interpretation as base64 it will print them all as it finds them.
Wow, this is really helpful. Thank you!!
I have nothing to add except the appreciation for everyone who helped and amazement at the vastly differing ways people produced working results.
I wrote this little webapp thing some time ago. It’s not exactly what you asked for but is a good example.
All it does is base64 encode a link and adds the server url in front of it. When someone visits that link it will redirect them to the destination. The intent is to bypass simple link tracking / blocking in discord and other platforms.
There are also checks for known bad domains and an attempt to remove known tracking query parameters.
Use a bash command line:
CorentinTh/it-tools does that and a lot more
https://addons.mozilla.org/en-US/firefox/addon/redirect-bypasser-webextension/ in desktop Firefox seems to work for your link. For mobile there might be apps that you share the link to and they dissect it, but a very quick search didn't turn up anything.
Finadil@lemmy.world 1 hour ago
I mean… It’s decoding into garbage because you’re feeding it more than just the base64 section. I suppose if you’re already running nginx or something you could easily make a page that uses javascript to break the link down (possibly using /, ?, = as separators) and decode sections that look like base64. If you make it javascript and client side there’s not really any privacy concerns.