Path to project folder

[mproctor340]

As part of my script I need to download rasters from the net, and use another file which contains functions, so I would like to set the working directory in order to save the rasters to disk and source the functions file.

I've been trying to identify using R the current directory of the script, and the following code spits out:

Find current directory of script and set as working directory

thisFile <- function() {
cmdArgs <- commandArgs(trailingOnly = FALSE)
needle <- "--file="
match <- grep(needle, cmdArgs)
if (length(match) > 0) {
# Rscript
return(normalizePath(sub(needle, "", cmdArgs[match])))
} else {
# 'source'd via R console
return(normalizePath(sys.frames()[[1]]$ofile))
}
}
print(thisFile())

[1] "C:\Users\Matt Proctor\AppData\Local\Temp\processing_0e8b98b4e2154a4a83c579f6d3791d92\aad1a7bbc681497ca28fc19d0e5804e9\processing_script.r"

But the actual script is edited and saved in my project folder in my Documents, so it obviously creates a temp instance of the script to run from.

I would like to know if there is any way of identifying through R?:
a) the current directory of the QGIS project
b) the directory of the R scripts folder pointed to in the Processing options (at least that won't be a temp folder)

[nyalldawson]

Hmm - I think the only way we could do this would be to have some set of tokens which are used to identify a part of the script which contains a (QGIS) expression which needs to be evaluated prior to running the script.

E.g. in QGIS layouts, you can put My label: [% some qgis expression %] and the part between [% %] will be evaluated.

What would you suggest is a safe set of starting/ending characters we could use which wouldn't clash with anything on the R side?