Only pin a data frame to Connect if it has changed

pin_unique

library(pins)

board <- board_rsconnect()

# Start with a reference pin
ref_pin <- mtcars
pin_write(board, ref_pin, description = "A pin that might change.")

# Make a changed data frame
mtcars2 <- mtcars %>% dplyr::mutate(cyl = cyl*2)

# Parameters for `pin_unique`
# board = a rsconnect board object defined by board_rsconnect()
# pin_name = the name of the pinned object on Connect
# new_pin = a data frame to be pinned as a new, changed version of the pin
# n_prune = optional number to pass to pin_versions_prune 


pin_unique <- function(board, pin_name, new_pin, n_prune=NA, ...){
  # read most recent pin
  reference <- pins::pin_read(board, {{pin_name}})
  
  # Use `diffdf` to determine if pin is unique
  diff <- diffdf::diffdf(reference, new_pin, suppress_warnings = TRUE)
  
  if(diffdf_has_issues(diff)){
    pins::pin_write(board = board, x = new_pin, name = pin_name, ...)
    
    message(paste(
      "Pin has changed. Wrote updated pin to", pin_name)
      )
    
    if(is.numeric(n_prune)){
      pins::pin_versions_prune(board = board, name = pin_name, n = n_prune)
      num_versions <- nrow(pins::pin_versions(board = board, name = pin_name))
      message(paste("There are ", num_versions, "pinned versions of", pin_name))
    }
  }else{
    message("No changes detected from previously-pinned version. Did not pin or prune anything.")
  }
}

# Test it out
board %>% 
  pin_unique("katie.masiello/ref_pin", mtcars2, 6, description = "A pin that changed from the last version.")


# Also see pin comparison function at https://gist.github.com/kmasiello/0b2ca8bb89bcf0692a074da5d9557236