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.
The following functions are implemented:
get_xattr_df
: Retrieve a data frame of xattr names, sizes and (raw) contents for a target pathget_xattr_raw
: Get raw contents of an extended attributeget_xattr
: Get an extended attributeget_xattr_size
: Get size of an extended attributehandle_user_prefix_param
: handle_user_prefix_paramhandle_user_prefix_return
: handle_user_prefix_returnhas_xattrs
: Test if a target path has xattrsis_bplist
: Tests whether a raw vector is really a binary plistlist_xattrs
: List attributesread_bplist
: Convert binary plist to something usable in Rrm_xattr
: Remove an extended attributeset_xattr
: Set or modify an extended attributeinstall.packages("xattrs", repos = "https://cinc.rud.is")
# or
remotes::install_git("https://git.rud.is/hrbrmstr/xattrs.git")
# or
remotes::install_git("https://git.sr.ht/~hrbrmstr/xattrs")
# or
remotes::install_gitlab("hrbrmstr/xattrs")
# or
remotes::install_bitbucket("hrbrmstr/xattrs")
# or
remotes::install_github("hrbrmstr/xattrs")
NOTE: To use the ‘remotes’ install options you will need to have the {remotes} package installed.
library(xattrs)
library(tidyverse) # for printing
# current verison
packageVersion("xattrs")
## [1] '0.1.1'
Extended attributes seem to get stripped when R builds pkgs so until I can figure out an easy way not to do that, just find any file on your system that has an @
next to the permissions string in an ls -l
directory listing.
sample_file <- "~/Downloads/AdvancedTechniquesWithAWSGlueETLJobs.pdf"
list_xattrs(sample_file)
## [1] "com.apple.metadata:kMDItemWhereFroms"
## [2] "com.apple.quarantine"
get_xattr_size(sample_file, "com.apple.metadata:kMDItemWhereFroms")
## 157
Extended attributes can be anything so it makes alot of sense to work with the contents as a raw vector:
get_xattr_raw(sample_file, "com.apple.metadata:kMDItemWhereFroms")
## [1] 62 70 6c 69 73 74 30 30 a2 01 02 5f 10 6b 68 74 74 70 73 3a 2f
## [22] 2f 66 69 6c 65 73 2e 73 6c 61 63 6b 2e 63 6f 6d 2f 66 69 6c 65
## [43] 73 2d 70 72 69 2f 54 33 56 31 5a 44 51 48 4d 2d 46 44 4a 47 59
## [64] 4b 57 4a 33 2f 64 6f 77 6e 6c 6f 61 64 2f 61 64 76 61 6e 63 65
## [85] 64 74 65 63 68 6e 69 71 75 65 73 77 69 74 68 61 77 73 67 6c 75
## [106] 65 65 74 6c 6a 6f 62 73 5f 5f 31 5f 2e 70 64 66 50 08 0b 79 00
## [127] 00 00 00 00 00 01 01 00 00 00 00 00 00 00 03 00 00 00 00 00 00
## [148] 00 00 00 00 00 00 00 00 00 7a
There is a “string” version of the function, but it may return “nothing” if there are embedded NULLs or other breaking characters in the contents:
get_xattr(sample_file, "com.apple.metadata:kMDItemWhereFroms")
## [1] "bplist00\xa2\001\002_\020khttps://files.slack.com/files-pri/T3V1ZDQHM-FDJGYKWJ3/download/advancedtechniqueswithawsglueetljobs__1_.pdfP\b\vy"
You are really better off doing this if you really want a raw string conversion:
readBin(get_xattr_raw(sample_file, "com.apple.metadata:kMDItemWhereFroms"), "character")
## [1] "bplist00\xa2\001\002_\020khttps://files.slack.com/files-pri/T3V1ZDQHM-FDJGYKWJ3/download/advancedtechniqueswithawsglueetljobs__1_.pdfP\b\vy"
More often than not (on macOS) extended attributes are “binary property lists” (or “binary plist” for short). You can test to see if the returned raw vector is likely a binary plist:
is_bplist(get_xattr_raw(sample_file, "com.apple.metadata:kMDItemWhereFroms"))
## [1] TRUE
If it is, you can get the data out of it. For now, this makes a system call to plutil
on macOS and plistutil
on other systems. You’ll be given a hint on how to install plistutil
if it’s not found.
read_bplist(get_xattr_raw(sample_file, "com.apple.metadata:kMDItemWhereFroms"))
## $plist
## $plist$array
## $plist$array$string
## $plist$array$string[[1]]
## [1] "https://files.slack.com/files-pri/T3V1ZDQHM-FDJGYKWJ3/download/advancedtechniqueswithawsglueetljobs__1_.pdf"
##
##
## $plist$array$string
## list()
##
##
## attr(,"version")
## [1] "1.0"
This is R, so you should really consider doing this instead of any of the above #rectanglesrule:
get_xattr_df(sample_file)
## # A tibble: 2 x 3
## name size contents
## <chr> <dbl> <list>
## 1 com.apple.metadata:kMDItemWhereFroms 157 <raw [157]>
## 2 com.apple.quarantine 56 <raw [56]>
you can live dangerously even with data frames, tho:
get_xattr_df(sample_file) %>%
mutate(txt = map_chr(contents, readBin, "character")) # potentially "dangerous"
## # A tibble: 2 x 4
## name size contents txt
## <chr> <dbl> <list> <chr>
## 1 com.apple.metadata… 157 <raw [15… "bplist00\xa2\x01\x02_\x10khtt…
## 2 com.apple.quaranti… 56 <raw [56… 0083;5bc9c8ca;Slack;44698902-A…
We can process a whole directory of files to see what extended attributes various path targets have:
fils <- list.files("~/Downloads", full.names = TRUE)
xdf <- map_df(set_names(fils, fils), get_xattr_df, .id="path")
count(xdf, name, sort=TRUE)
## # A tibble: 11 x 2
## name n
## <chr> <int>
## 1 com.apple.quarantine 55
## 2 com.apple.metadata:kMDItemWhereFroms 46
## 3 com.apple.lastuseddate#PS 13
## 4 com.apple.metadata:_kMDItemUserTags 3
## 5 com.apple.metadata:kMDItemDownloadedDate 2
## 6 com.apple.diskimages.fsck 1
## 7 com.apple.diskimages.recentcksum 1
## 8 com.apple.FinderInfo 1
## 9 com.apple.metadata:com_apple_mail_dateReceived 1
## 10 com.apple.metadata:com_apple_mail_dateSent 1
## 11 com.apple.metadata:com_apple_mail_isRemoteAttachment 1
And we can work with com.apple.metadata:kMDItemWhereFroms
binary plist data in bulk:
filter(xdf, name == "com.apple.metadata:kMDItemWhereFroms") %>%
filter(map_lgl(contents, is_bplist)) %>%
mutate(converted = map(contents, read_bplist)) %>%
select(size, converted) %>%
mutate(converted = map(converted, ~flatten_chr(.x$plist$array$string))) %>%
unnest() %>%
mutate(converted = urltools::domain(converted)) # you don't rly need to see the full URLs for this example
## # A tibble: 44 x 2
## size converted
## <dbl> <chr>
## 1 189 dl.packetstormsecurity.net
## 2 129 files.slack.com
## 3 120 files.slack.com
## 4 117 files.slack.com
## 5 592 irma.nps.gov
## 6 157 files.slack.com
## 7 624 github-production-release-asset-2e65be.s3.amazonaws.com
## 8 197 images.unsplash.com
## 9 197 images.unsplash.com
## 10 185 files.slack.com
## # … with 34 more rows
# 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 < [15]>
## 2 is.rud.setting.b 16 < [16]>
# remove attribute
rm_xattr(tf, "is.rud.setting")
get_xattr(tf, "is.rud.setting")
## character(0)
# cleanup
unlink(tf)