library(httr)
library(digest)
library(base64enc)

hex_to_raw <- function(hex_string) {
  result <- raw(0)
  
  if (nchar(hex_string) > 0) {
    as.raw(
      strtoi(
        substring(
          hex_string, 
          seq(1, nchar(hex_string), by=2), 
          seq(2, nchar(hex_string), by=2)
        ), 
        16L
      )
    ) -> result
  }
  
  result
}

base32_encode <- function(raw_data) {

  alphabet <- c(LETTERS[1:26], as.character(0:5))
  
  bits <- as.integer(rawToBits(raw_data))
  
  n_bits <- length(bits)
  padding_needed <- (8 - (n_bits %% 40) %% 8) %% 8
  bits <- c(bits, rep(0, padding_needed))
  n_bits <- length(bits)
  
  result <- character(n_bits %/% 5)
  for (i in seq(1, n_bits, by=5)) {
    if (i+4 <= n_bits) {
      value <- sum(bits[i:(i+4)] * 2^(4:0))
      result[i %/% 5 + 1] <- alphabet[value + 1]
    }
  }
  
  if (padding_needed > 0) {
    padding_chars <- padding_needed %/% 8 * 8
    result <- c(result[1:(length(result) - padding_chars / 5)], rep("=", padding_chars / 5))
  }
  
  paste(result, collapse="")
}

process_url <- function(url) {
  response <- httr::GET(url)
  content <- httr::content(response, "raw")
  
  hash <- digest(content, algo="sha1", serialize=FALSE, raw=TRUE)
  hash_hex <- paste(sprintf("%02x", as.integer(hash)), collapse="")
  raw_bytes <- hex_to_raw(hash_hex)

  base32_encode(raw_bytes)
}

(process_url("https://reporter.nih.gov/services/Projects/ProjectInfo?projectId=8008517"))
## [1] "XCQMKFZVSWQ01EGKMMAPGG0QM0NED1DK"