fix a single file in a repo

fix-file-in-repo.R

library("gh")
library("base64enc")

# get a file from a repository
get_repo_file <- function(org = "carpentries", lesson = "sandpaper-docs", file = "CONTRIBUTING.md", ...) {
  gh("GET /repos/{org}/{lesson}/contents/{file}", 
    .params = list(
      org = org,
      lesson = lesson,
      file = file
    ),
    ...
  )
}

# create a branch or force-update it if it exists
create_branch <- function(org = "carpentries", lesson = "sandpaper-docs", branch = "core/updates", ...) {
  # https://docs.github.com/en/rest/commits/commits?apiVersion=2022-11-28
  HEAD <- gh("GET /repos/{org}/{lesson}/commits", 
    .params = list(
      org = org,
      lesson = lesson
    ),
    per_page = 1, page = 1, ...)
  tryCatch({
    # https://docs.github.com/en/rest/git/refs?apiVersion=2022-11-28#get-a-reference
    ref <- gh("GET /repos/{org}/{lesson}/git/refs/heads/{branch}",
    .params = list(
      org = org,
      lesson = lesson,
      branch = branch
    ))
    if (ref$object$sha == HEAD[[1]]$sha) {
      message("branch exists and is up to date")
      return(TRUE)
    }
    # https://docs.github.com/en/rest/git/refs?apiVersion=2022-11-28#update-a-reference
    message("updating branch")
    gh("PATCH /repos/{org}/{lesson}/git/refs/heads/{branch}",
      .params = list(
        org = org,
        lesson = lesson,
        branch = branch
      ),
      sha = HEAD[[1]]$sha,
      force = TRUE
    )
  },
  http_error_404 = function(e) {
    # https://docs.github.com/en/rest/git/refs?apiVersion=2022-11-28#create-a-reference
    message("creating branch")
    gh("POST /repos/{org}/{lesson}/git/refs",
      .params = list(
        org = org,
        lesson = lesson
      ),
      ref = paste0("refs/heads/", branch),
      sha = HEAD[[1]]$sha
    )
  })
}

# base 64 to text
to_text <- function(b64) {
  rawToChar(base64enc::base64decode(b64))
}

# text to base 64
to_b64 <- function(txt) {
  base64enc::base64encode(charToRaw(txt))
}

# update the contents of a file in a branch and create a pull request
update_repo_file <- function(contents = NULL, message = "updating CONTRIBUTING", org = "carpentries", lesson = "sandpaper-docs", file = "CONTRIBUTING.md", branch = "core/updates", body = "An update to the slack URL", ...) {
  if (is.null(contents)) {
    return(NULL)
  }
  # note: this is not working because I do not know how to calculate the sha for the modified content
  gh("PUT /repos/{owner}/{repo}/contents/{path}", 
    .params = list(
      owner = org,
      repo = lesson,
      path = file
    ),
    branch = branch,
    message = message,
    content = contents$content,
    sha = contents$sha,
    ...
  )
  gh("POST /repos/{owner}/{repo}/pulls", 
    .params = list(
      owner = org,
      repo = lesson
    ),
    title = message,
    head = paste0(org, ":", branch),
    base = "main",
    body = body,
    ...
  )
}

if (FALSE) {
# manually run this to test
ctb <- get_repo_file("zkamvar", "r-ecology-lesson", "CONTRIBUTING.Rmd")
create_branch("zkamvar", "r-ecology-lesson")
ctb$content <- ctb$content |>
  to_text() |>
  stringr::str_replace_all("swc-slack-invite.herokuapp.com", "slack-invite.carpentries.org") |>
  to_b64()
# this part still does not work
update_repo_file(ctb, "update slack invite", "zkamvar", "r-ecology-lesson", "CONTRIBUTING.Rmd")
}