Work With Filesystem Object Extended Attributes

Filesystem path target extended attributes store extra, customizable, small bits of info. For example, author name, file character encoding, short comments, security status, etc. Methods are provided to list, extract and work with these attributes.

Examples

# Create a temp file for the example
tf <- tempfile(fileext = ".csv")
write.csv(mtcars, tf)

# has attributes? (shld be FALSE)
has_xattrs(tf)
#> [1] FALSE
get_xattr(tf, "is.rud.setting")
#> character(0)

# set an attribute
set_xattr(tf, "is.rud.setting.a", "first attribut")
get_xattr(tf, "is.rud.setting.a")
#> [1] "first attribut"
get_xattr_size(tf, "is.rud.setting.a")
#> [1] 14

# shld be TRUE
has_xattrs(tf)
#> [1] TRUE

set_xattr(tf, "is.rud.setting.b", "second attribute")
get_xattr(tf, "is.rud.setting.b")
#> [1] "second attribute"
get_xattr_size(tf, "is.rud.setting.b")
#> [1] 16

# overwrite an attribute
set_xattr(tf, "is.rud.setting.a", "first attribute")
get_xattr(tf, "is.rud.setting.a")
#> [1] "first attribute"
get_xattr_size(tf, "is.rud.setting.a")
#> [1] 15

# see all the attributes
list_xattrs(tf)
#> [1] "is.rud.setting.a" "is.rud.setting.b"

# data frame vs individual functions
get_xattr_df(tf)
#> # A tibble: 2 x 3
#>   name              size contents  
#>   <chr>            <dbl> <list>    
#> 1 is.rud.setting.a    15 <raw [15]>
#> 2 is.rud.setting.b    16 <raw [16]>

# remove attribute
rm_xattr(tf, "is.rud.setting")
get_xattr(tf, "is.rud.setting")
#> character(0)

# cleanup
unlink(tf)