Writes a manifest to a JSON file, so the record of a run (its metadata,
cross-checks and environment) can be kept next to the outputs, shared,
and read back by any JSON reader. By default the file is pretty-printed
for people; canonical = TRUE writes the byte-stable form that
mnfdgst() hashes. The package's own JSON codec
(tojs()) is used; jsonlite
is not needed.
Arguments
- man
A manifest as returned by
mkmnf()and built up withrecrd().- path
Character scalar, the destination file path.
- canon
Logical scalar, default
FALSE.TRUEwrites the canonical form instead of the pretty-printed one: one line, keys sorted, which is whatmnfdgst()hashes. Use it when the file itself has to be byte-stable rather than read by a person.
Details
Numbers are written with 17 significant digits, so every double reads
back exactly; NA and NULL are written as null, and
length-one vectors as scalars. When the manifest's meta$synthetic
is TRUE, or the session is flagged synthetic (see
mkmnf()), meta$synthetic = true is
written whatever the
list says, so a file written from generated data always says so. An
existing file at path is overwritten; the folder must exist.
Errors when path is not a single non-empty string, and (from base
R) when the file cannot be opened for writing.
Examples
man <- mkmnf(list(project = "demo"), env = FALSE)
man <- recrd(man, "rowcount", obs = 20, expd = 20)
#> rowcount observed = 20.0000 expected = 20.0000 [INFO]
path <- wrmnfjs(man, tempfile(fileext = ".json"))
file.exists(path)
#> [1] TRUE
# Round-trips back through the package's own codec.
back <- fromjs(path, simplifyVector = FALSE)
# "PASS" ("INFO" after synthetic data, see mkmnf())
back$results$rowcount$status
#> [1] "INFO"
# the canonical form: one line whose SHA-256 is the manifest digest
cpath <- wrmnfjs(man, tempfile(fileext = ".json"), canon = TRUE)
identical(readLines(cpath), as.character(mnfcanon(man)))
#> [1] TRUE
# the path must be one string
try(wrmnfjs(man, c("a.json", "b.json")))
#> Error : wrmnfjs: `path` must be a single non-empty string