Generate a content uri for a local file

content_id(
  file,
  algos = default_algos(),
  raw = TRUE,
  as.data.frame = length(algos) > 1
)

Arguments

file	path to the file, URL, or a base::file connection
algos	Which algorithms should we compute contentid for? Default "sha256", see details.
raw	Logical, should compressed data be left as compressed binary?
as.data.frame	should the output be coerced into a data.frame? Default is `FALSE` if only one algorithm is computed, otherwise `TRUE`.

Value

a content identifier URI If multiple algorithms are requested, content_id will return a data.frame with one column per algorithm and one row for each input file. Otherwise it will return a character vector with one identifier URI for each input file. See argument as.data.frame above.

Details

See https://github.com/hash-uri/hash-uri for an overview of the content uri format and comparison to similar approaches.

Compressed file streams will have different raw (binary) and uncompressed hashes. Set raw = FALSE to allow base::file connection to uncompress common compression streams before calculating the hash, but this will be slower.

Examples


## local file
path <- system.file("extdata", "vostok.icecore.co2", package = "contentid")
content_id(path)
#> [1] "hash://sha256/9412325831dab22aeebdd674b6eb53ba6b7bdd04bb99a4dbb21ddff646287e37"
# \donttest{

content_id(paste0("https://knb.ecoinformatics.org/knb/d1/mn/v2/object/",
                  "ess-dive-457358fdc81d3a5-20180726T203952542"))
#> [1] "hash://sha256/9412325831dab22aeebdd674b6eb53ba6b7bdd04bb99a4dbb21ddff646287e37"
# }