g1t/services/repos/src/refs.rs
| 1 | //! Listing a repository's branches. |
| 2 | //! |
| 3 | //! The Artifacts binding reads commits, trees and blobs but does not list |
| 4 | //! refs, so this asks the way a git client does: the ref advertisement of |
| 5 | //! the smart HTTP protocol. |
| 6 | |
| 7 | use g1t_contracts::repos::{Branch, GitAccess}; |
| 8 | use worker::{Error, Fetch, Headers, Method, Request, RequestInit, Result}; |
| 9 | |
| 10 | use crate::land::read_pkt_lines; |
| 11 | |
| 12 | const HEADS: &str = "refs/heads/"; |
| 13 | |
| 14 | /// The branches in a ref advertisement, in the order advertised. |
| 15 | fn parse_advertisement(bytes: &[u8]) -> Vec<Branch> { |
| 16 | let (lines, _) = read_pkt_lines(bytes); |
| 17 | lines |
| 18 | .into_iter() |
| 19 | .filter_map(|line| { |
| 20 | // `<hash> <ref>`, and on the first ref a NUL then capabilities. |
| 21 | let line = line.split(|byte| *byte == 0).next()?; |
| 22 | let line = std::str::from_utf8(line).ok()?.trim_end(); |
| 23 | let (hash, name) = line.split_once(' ')?; |
| 24 | Some(Branch { |
| 25 | name: name.strip_prefix(HEADS)?.to_owned(), |
| 26 | hash: hash.to_owned(), |
| 27 | }) |
| 28 | }) |
| 29 | .collect() |
| 30 | } |
| 31 | |
| 32 | pub async fn branches(access: &GitAccess) -> Result<Vec<Branch>> { |
| 33 | let headers = Headers::new(); |
| 34 | headers.set("authorization", &format!("Bearer {}", access.token))?; |
| 35 | let mut init = RequestInit::new(); |
| 36 | init.with_method(Method::Get).with_headers(headers); |
| 37 | let request = Request::new_with_init( |
| 38 | &format!("{}/info/refs?service=git-upload-pack", access.remote), |
| 39 | &init, |
| 40 | )?; |
| 41 | let mut response = Fetch::Request(request).send().await?; |
| 42 | let bytes = response.bytes().await?; |
| 43 | if response.status_code() != 200 { |
| 44 | return Err(Error::RustError(format!( |
| 45 | "listing refs returned {}", |
| 46 | response.status_code() |
| 47 | ))); |
| 48 | } |
| 49 | Ok(parse_advertisement(&bytes)) |
| 50 | } |
| 51 | |
| 52 | #[cfg(test)] |
| 53 | mod tests { |
| 54 | use super::parse_advertisement; |
| 55 | |
| 56 | fn pkt(payload: &str) -> Vec<u8> { |
| 57 | format!("{:04x}{payload}", payload.len() + 4).into_bytes() |
| 58 | } |
| 59 | |
| 60 | #[test] |
| 61 | fn branches_are_read_from_an_advertisement() { |
| 62 | let main = "c71546fcd893ef8b0f57388b65e620d759705dda"; |
| 63 | let shout = "4807077b296e6edbf410d55e72749d3e1170c291"; |
| 64 | let advertisement = [ |
| 65 | pkt("# service=git-upload-pack\n"), |
| 66 | b"0000".to_vec(), |
| 67 | pkt(&format!( |
| 68 | "{main} HEAD\0side-band-64k symref=HEAD:refs/heads/main\n" |
| 69 | )), |
| 70 | pkt(&format!("{main} refs/heads/main\n")), |
| 71 | pkt(&format!("{shout} refs/heads/shout\n")), |
| 72 | pkt(&format!("{shout} refs/tags/v1.0.0\n")), |
| 73 | b"0000".to_vec(), |
| 74 | ] |
| 75 | .concat(); |
| 76 | let branches = parse_advertisement(&advertisement); |
| 77 | let names: Vec<&str> = branches.iter().map(|branch| branch.name.as_str()).collect(); |
| 78 | assert_eq!(names, ["main", "shout"]); |
| 79 | assert_eq!(branches[1].hash, shout); |
| 80 | } |
| 81 | |
| 82 | #[test] |
| 83 | fn an_empty_repository_has_no_branches() { |
| 84 | let advertisement = [pkt("# service=git-upload-pack\n"), b"00000000".to_vec()].concat(); |
| 85 | assert!(parse_advertisement(&advertisement).is_empty()); |
| 86 | } |
| 87 | } |