Suggestion: add remote connection for unzip()

[ArtemSokolov]

In R, it is generally possible to read remote files directly. For example,

rmt1 <- file.path("https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5674813",
                  "bin/13024_2017_219_MOESM2_ESM.tsv")
read.delim( rmt1 )
#     Gene    Module
#  1 RPH3A turquoise
#  2  PLEC turquoise
#  3  DLG4 turquoise
#  4 SEPT5 turquoise
#  5 PLCB1 turquoise
#  6 ACTN2 turquoise
# ...

However, unzipping a remote file always requires that the file is first downloaded:

rmt2 <- file.path("https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5674813",
                  "bin/13024_2017_219_MOESM5_ESM.zip")
download.file( rmt2, "local.zip" )
zip::unzip( "local.zip", "Data 1.tsv" )

I think it could help with workflow streamlining, if it was possible to extract files directly, through a remote connection (similar to how read.delim() works):

zip::unzip( rmt2, "Data 1.tsv" )
# Error in zip::unzip(rmt2, "Data 1.tsv") :
#   zip error: `Cannot open zip file `https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5674813/bin/13024_2017_219_MOESM5_ESM.zip` for reading` in file `zip.c:238`
# In addition: Warning message:
# In normalizePath(zipfile) :
#   path[1]="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5674813/bin/13024_2017_219_MOESM5_ESM.zip": No such file or directory

[gaborcsardi]

This is not (easily) possible, because R core does not let us use the R connection API in packages.

[ArtemSokolov]

Thanks for a quick response @gaborcsardi! I'm not extremely familiar with the zip format, but perhaps readBin() could be used for the task?

[gaborcsardi]

I understand that this would make sense from an API stand point, but the implementation cannot be streaming, anyway, I believe, because unzip needs random access to parts of the file.