qwraps2 (version 0.5.2)

file_check: File and Working Directory Check

Description

This check is three-fold: 1) verify the current working directory is as expected, 2) verify the user can access the file, and 3) verify the file contents are as expected (via md5sum).

Usage

file_check(paths, md5sums = NULL, stop = FALSE)

Arguments

paths

a character path to the target file

md5sums

a character string for the expected md5sum of the target file. If NULL then only a file.exists check will be done.

stop

if TRUE then an error is thrown if any of the checks fail. If FALSE (default) a logical is returned.

Value

The function will return a single TRUE/FALSE value with attributes attr(, "checks").

Details

The test for the file access is done to verify the file can be read by the current user.

The return of the function is TRUE if all the files in paths are accessible and all of requested md5sum checks pass. FALSE is any file is not accessible or any md5sum check fails. By default, if the return is TRUE then only TRUE will be printed to the console. If the return is FALSE then the attr(, "checks") is printed by default as well.

Good practice would be to use relative paths, a warning will be given if any of the paths are determined to be absolute paths.

Examples

# NOT RUN {
# create two example files in the working directory:
cat("example file.", file = "QWRAPS2_EXAMPLE_1.txt")
cat("Another example file.", file = "QWRAPS2_EXAMPLE_2.txt")

# Check that you have access to these files:  (Should return TRUE)
test1 <- file_check(c("QWRAPS2_EXAMPLE_1.txt", "QWRAPS2_EXAMPLE_2.txt"))
test1

# By default, when the checks return TRUE the details of the checks are not
# printed.  You can view the details of the checks as follows:
attr(test1, "checks")

# If one or more files is not accessable then return is FALSE and the meta data
# is printed by default.
test2 <- file_check(c("UNLIKELYFILENAME", "QWRAPS2_EXAMPLE_1.txt", "QWRAPS2_EXAMPLE_2.txt"))
test2

# Or have an error thrown:
# }
# NOT RUN {
file_check(c("UNLIKELYFILENAME", "QWRAPS2_EXAMPLE_1.txt", "QWRAPS2_EXAMPLE_2.txt"),
           stop = TRUE)
# }
# NOT RUN {
# Verify the md5sums as well as file access:
file_check("QWRAPS2_EXAMPLE_1.txt", "7a3409e17f9de067740e64448a86e708")

# If you only need to verify a subset of md5sums then use an NA in the md5sums
# argument:
file_check(c("QWRAPS2_EXAMPLE_1.txt", "QWRAPS2_EXAMPLE_2.txt"),
           c("7a3409e17f9de067740e64448a86e708", NA))

# Verify all the md5sums
file_check(c("QWRAPS2_EXAMPLE_1.txt", "QWRAPS2_EXAMPLE_2.txt"),
           c("7a3409e17f9de067740e64448a86e708", "798e52b92e0ae0e60f3f3db1273235d0"))


# clean up working directory
unlink("QWRAPS2_EXAMPLE_1.txt")
unlink("QWRAPS2_EXAMPLE_2.txt")

# }