Download Zip helper

Author

Galen Holt

The issue

When we download files from the internet, we often feed in a url, and it returns a zip, which we then want to unzip to access. There’s a fairly simple way to do that, but we can write a quicky function to do it and clean up the directory afterwards.

The function

we want to give it the dirname for the file(s), the datadir that contains our data, and the URL. Then it checks if it exists, and downloads, unzips, and cleans up.

zip_load <- function(dirname, datadir, sourceurl,  
                      existing_dirs = list.files(datadir)) {
  print(existing_dirs)
  if (!(dirname %in% existing_dirs)) {
    
    zippath <- file.path(datadir, paste0(dirname, '.zip'))
    download.file(sourceurl, destfile = zippath)
    
    unzip(zippath, exdir = file.path(datadir, dirname))
    
    file.remove(zippath)
  }
}

An example

Get the Murray-Darling basin boundary

zip_load('mdb_boundary', 'data', "https://data.gov.au/data/dataset/4ede9aed-5620-47db-a72b-0b3aa0a3ced0/resource/8a6d889d-723b-492d-8c12-b8b0d1ba4b5a/download/sworkingadhocjobsj4430dataoutputsmdb_boundarymdb_boundary.zip")

 [1] "42343_shp"                              
 [2] "ANAE_Rivers_v3_23mar2021"               
 [3] "ANAE_Wetlands_v3_24mar2021"             
 [4] "DATA_362071"                            
 [5] "geofabric"                              
 [6] "MDB_ANAE_Aug2017"                       
 [7] "mdb_boundary"                           
 [8] "negbin_testing"                         
 [9] "pix4dout"                               
[10] "Surface Water Water Resource Plan Areas"

I’ve saved this in functions/ so I have easy access to it everywhere.