deps: localy provided bencode implmentation

[da2ce7]

No description provided.

[codecov]

Codecov Report

Merging #366 (a4ac682) into develop (3a1ac86) will decrease coverage by 1.08%.
Report is 1 commits behind head on develop.
The diff coverage is 80.35%.

@@             Coverage Diff             @@
##           develop     #366      +/-   ##
===========================================
- Coverage    85.02%   83.95%   -1.08%     
===========================================
  Files           89      102      +13     
  Lines         6565     7267     +702     
===========================================
+ Hits          5582     6101     +519     
- Misses         983     1166     +183     

Files Changed	Coverage Δ
src/servers/http/v1/responses/announce.rs	80.23% <ø> (ø)
src/servers/http/v1/responses/scrape.rs	100.00% <ø> (ø)
contrib/bencode/src/error.rs	7.84% <19.04%> (ø)
contrib/bencode/src/access/dict.rs	30.00% <30.00%> (ø)
contrib/bencode/src/access/list.rs	51.42% <51.42%> (ø)
contrib/bencode/src/mutable/bencode_mut.rs	66.66% <66.66%> (ø)
contrib/bencode/src/cow.rs	75.00% <75.00%> (ø)
contrib/bencode/src/reference/bencode_ref.rs	85.10% <85.10%> (ø)
contrib/bencode/src/reference/decode_opt.rs	93.75% <93.75%> (ø)
contrib/bencode/src/reference/decode.rs	96.29% <96.29%> (ø)
... and 4 more

... and 2 files with indirect coverage changes

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[josecelano]

Hi @da2ce7, I want to fix this bug. I need to calculate the infohash from the torrent file. We are using serde_bencode, but it does not work to calculate the infohash because we cannot include the custom fields. I would like to use a different bencoding crate to calculate the infohash:

Something like this:

use bendy::decoding::{Error as BencodeError, FromBencode, Object};
use sha1::{Digest, Sha1};
use std::fs;
use std::path::Path;

fn calculate_infohash<P: AsRef<Path>>(path: P) -> Result<[u8; 20], BencodeError> {
    // Read and decode the torrent file
    let data = fs::read(path)?;
    let torrent = Object::decode(&data)?;

    // Find the "info" dictionary
    let info = torrent
        .lookup("info")
        .ok_or(BencodeError::Unspecified)?
        .to_owned();

    // Encode the "info" dictionary into bytes
    let info_bytes = info.encode()?;

    // Calculate the SHA-1 hash
    let mut hasher = Sha1::new();
    hasher.update(&info_bytes);
    let result = hasher.finalize();

    // Convert the hash to a 20-byte array and return
    Ok(result.into())
}

fn main() {
    let path = "path_to_torrent_file.torrent";
    match calculate_infohash(path) {
        Ok(hash) => {
            println!("Infohash: {:?}", hash);
        }
        Err(e) => {
            eprintln!("Error: {}", e);
        }
    }
}

I need to use a bencoding crate:

• https://crates.io/crates/bip_bencode
• https://crates.io/crates/bendy
• ...

Since we are already using bip_bencode I will probably use it:

use bip_bencode::{Bencode, BencodeRef, BencodeConvert};
use sha1::{Digest, Sha1};
use std::fs;
use std::io::{self, Read};
use std::path::Path;

fn calculate_infohash<P: AsRef<Path>>(path: P) -> io::Result<[u8; 20]> {
    // Read the torrent file
    let mut data = Vec::new();
    let mut file = fs::File::open(path)?;
    file.read_to_end(&mut data)?;

    // Decode the torrent file
    let torrent = BencodeRef::decode(&data).unwrap();

    // Extract the "info" dictionary
    let info = match torrent.dict().unwrap().lookup(b"info") {
        Some(info) => info,
        None => return Err(io::Error::new(io::ErrorKind::Other, "Missing info dictionary")),
    };

    // Re-encode the "info" dictionary into bytes
    let info_bytes = info.encode();

    // Calculate the SHA-1 hash
    let mut hasher = Sha1::new();
    hasher.update(&info_bytes);
    let result = hasher.finalize();

    Ok(result.into())
}

fn main() {
    let path = "path_to_torrent_file.torrent";
    match calculate_infohash(path) {
        Ok(hash) => {
            println!("Infohash: {:?}", hash);
        }
        Err(e) => {
            eprintln!("Error: {}", e);
        }
    }
}

I do not like to parse the torrent bytes twice (with serde_bencode to extract the structs and with bip_encode to extract the info dict and calculate the infohash), but I want to fix the bug asap. After fixing the bug, we can consider using only the bip_encode and construct structs manually instead of using serde_bencode.

[da2ce7]

ACK a4ac682