stream_provenance: Streams processed provenance log into writable connection .
In jhpoelen/reston: a biodiversity dataset tracker

Description Usage Arguments Value Examples

View source: R/stream_provenance.R

Streams processed provenance log into writable connection .

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stream_provenance(con, process_func = function(x, version_id,
  line_number_offset) {     x }, version_iter = version_history_iter(),
  n = -1L, line_batch_size = 1)

`con`	the connection (e.g., file) to write into after being processed by process_func
`process_func`	a function that processes provenance lines
`version_iter`	an provenance version iterator @seealso version_history_iter()
`n`	maximum number of (processed) lines to write, -1 means unlimited
`line_batch_size`	number of lines to be processed at once

number of written (processed) lines

 # open an temporary read/write connection
 con <- fifo("", open = "w+b")
 stream_provenance(con, n = 1)
 first_line_first_provenance_log <- readLines(con)
 close(con)

 # open file
 con <- file("somefile.txt", open = "w+b")
 versions_only = function(lines) {
   lines[grepl("hasVersion", lines)]
 }

 # save only provenance lines with "hasVersion" in it
 stream_provenance(con, process_func = versions_only, n = 1)
 first_version_in_provenance_log <- readLines(con)

 close(con)