Options to modify download links, e.g. redirect to local mirror.

[mk-pmb]

Role

I'm trying to set up a new modded instance on unreliable network.

Suggestion

I'd like an easy way to redirect download attempts for static files to a local mirror. We should define some categories like 1. modpack's files, 2. mojang files, and then for each category have a text field with replacement rules.

Benefit

I can provide the files on a simple dumb webspace like Python's integrated webserver.

This suggestion is unique

• I have searched the issue tracker and did not find an issue describing my suggestion, especially not one that has been rejected.

You may use the editor below to elaborate further.

My ideas for replacement rules:

• If there is a # anywhere in the line, ignore it an everything behind it.
• Word-split the line, "word" meaning a sequence of non-whitespace characters.
• The 1st word is the pattern. No 1st word = ignore the rule.
• The 2nd word is the replacement text. No 2nd word = empty replacement = remove only.
• If there is a 3rd word, that's a syntax error.
• In a pattern, < denotes the start and > the end of whatever text is currently in the buffer (initially, the original URL). Inspired by RFC 1738, page 3, "delimiters around URLs in free text".
  • <> as the pattern denotes the empty buffer. Someone may want to map that to a fallback URL.
  • > at the start of the pattern with text behind it would never match, so we can use that for future upgrades like using sed if the rules list starts with >>sed<<.

That way it would be easy to remap servers to which my connection is unreliable to a local mirror:

# Example ruleset. Example URLs are picked random from search results.
<http:      :
<https:     :
<://www.mediafire.com/file/                           mediafire/
/file>      # for MediaFire
<://downloads.gtnewhorizons.com/Multi_mc_downloads/   gtnewhorizons/
<://        web/
///         /
//          /
?           __QM__/
=           =/
<           http://mirror.test/

… would transform:

- https://www.mediafire.com/file/buk9khs455r8lkp/Player_API.jar/file
+   http://mirror.test/mediafire/buk9khs455r8lkp/Player_API.jar

- http://downloads.gtnewhorizons.com/Multi_mc_downloads/GT_New_Horizons_2.4.0_Java_17-20.zip
+                      http://mirror.test/gtnewhorizons/GT_New_Horizons_2.4.0_Java_17-20.zip

-                https://example.net/texture.php?player=Steve
+ http://mirror.test/web/example.net/texture.php__QM__/player=/Steve

[phit]

nothing stopping you from doing really edge case stuff like this locally, just hijack dns setup and proxy with self signed certs, multimc will use your OS' cert store

[mk-pmb]

Been there, done that for evil corporate software, but setting up the live on-demand SSL certificate generation and injection is rather cumbersome just to convince a program that is meant to help its users get stuff done.
Would also be a good stopgap for all the chinese users requesting mirror server support.