Vimm's Downloader

A Bash script to download ROMs from Vimm's Lair with MD5 integrity verification intended for your RomM Library.

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⚠️ Disclaimer ⚠️

This script is intended only to download a game you like directly to your own server, because you do not have a graphical interface.

It is not meant to attack, scrape, automate in bulk, or otherwise hammer Vimm's API.

The current design, because of Vimm's bot protection and my own principles, only works with a valid session on a real browser, passing the bot protection in a legitimate way and getting the provided data.

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Overview

Vimm's Lair serves ROMs through a vault page that points to a dedicated download server URL (dlX.vimm.net). This script automates the whole flow:

1. Asks the user for the download server ID and the download server game ID.
2. Resolves the download URL and reads the file name and size from the HTTP headers.
3. Lets you pick a target platform from your local ROM library.
4. Downloads the file with a progress bar.
5. Streams the ROM files through a pipeline (never writing anything to disk) and verifies each one's MD5 against Vimm's official hash (multi-file ROMs like PSX .bin/.cue are fully supported) and keeps only the compressed file.

⚠️ Some files do not come with HASH for their .bin. Because of this and if someone does not care too much about integrity, a hash mismatch is only reported.

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Use Case

You have a ROM library organized by platform (e.g. /home/user/emu/library/roms/n64). You find the game you want on Vimm's Lair, inspect the download button and get the server and new game IDs:

<form action="//dl3.vimm.net/" method="POST" id="dl-form" onsubmit="return submitDL(this, 'dialog3')">
    <input type="hidden" name="alt" value="0" disabled="">
    <input type="hidden" name="mediaId" value="3329">
    <button type="submit" style="width:100%">Download</button>
</form>

In this case 3 and 3329

Then run:

./vimm-downloader.sh

The script will:

 ╔═══════════════════════════════════╗
 ║          Vimm's Downloader        ║
 ╚═══════════════════════════════════╝

 # Input download server ID: 3
 # Input download server game ID: 30832
 # Does the game have different formats? (y/n): y
 # Input the format number selected (0, 1, 2...): 2
 # Format 2 selected

 # Fetching game information from https://dl3.vimm.net/?alt=2&mediaId=30832...
 # Legend of Zelda, The - The Wind Waker (Europe) (En,Fr,De,Es,It).7z 718MiB

 # These are your current platforms:
     3ds gb gba n64
     nds nes new-nintendo-3ds ngc
     nintendo-dsi ps2 psx switch

 # Select the platform: ngc

 # Downloading Legend of Zelda, The - The Wind Waker (Europe) (En,Fr,De,Es,It).7z...
    718MiB/718MiB [==========================================>] 100% [8.46MiB/s]

 # Calculating hash for Legend of Zelda, The - The Wind Waker (Europe) (En,Fr,De,Es,It).rvz...
 # Calculated hash is 5395ed04c9441e86c2237a64cc41c352
 # Expected hash is empty
 # They don't match!

 # Bye bye!

For Game Cube games the provided hash is for the .iso file so, in this case, they do not match.

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Requirements

The script relies on the following programs being installed and available in PATH, most of them are preinstalled:

Tool	Used for
curl	Fetching pages, headers and downloading.
grep	Extracting headers, hashes and formatting lines.
7z	Reading .7z and .zip files.
numfmt	Formatting file size in human-readable units (MiB).
pv	Progress bar during the download.
md5sum	Computing the MD5 hash of the extracted ROM.
cut	Isolating the MD5 value from md5sum output.
tail	Splitting the HTTP code from the response dump.
sed / xargs	Output formatting.
ls	Listing directories to show available platforms.

Note: grep must support the -P option.

Configuration

Edit the variable at the top of the script to point to your ROM library:

BASE_DIR="/path/to/library/roms"

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Assumptions

The script is tailored to Vimm's Lair as it exists today. It assumes:

Vimm's Lair

• Hash file format is strict: MD5: followed by 32 hex characters on the same line, inside the Vimm's Lair.txt file that ships with the archive. Variations like md5:, MD5 = are not supported as they are not expected.
• No session cookie required: the download server answers without any session cookie.
• Only for .zip and .7z: 7z is used and does not test for other filetypes.
• One MD5 entry per media file: Vimm's Lair.txt lists (sometimes it does, sometimes it doesn't) the MD5 of each file inside the archive.

System & environment

• Designed for a RomM library: the script assumes the RomM server folder structure: BASE_DIR contains one subdirectory per platform (RomM collection) and the names of these platforms contain no spaces.
• BASE_DIR exists and is writable: both it and its platform subdirectories require read/write permissions (of course right?).