R/ahrf.R

In ajdamico/lodown: locally download and prepare publicly-available microdata

get_catalog_ahrf <-
  function( data_name = "ahrf" , output_dir , ... ){

    lines_with_links <- grep( "(.*)\\.zip" , readLines( "https://data.hrsa.gov/data/download" , warn = FALSE ) , value = TRUE , ignore.case = TRUE )

	lines_with_links <- unlist( strsplit( lines_with_links , '\\<a' ) )
	
    lines_with_links <- grep( "AHRF" , lines_with_links , value = TRUE )

    partial_url <- gsub( '(.*)href=\"(.+?)\"(.*)' , '\\2' , lines_with_links )
	
	full_url <- ifelse( grepl( "^https" , partial_url ) , partial_url , paste0( "https://data.hrsa.gov" , partial_url ) )

	full_url <- full_url[ !grepl( "_SAS" , full_url ) & grepl( "zip" , full_url , ignore.case = TRUE ) ]
	
	full_url <- gsub( "//DataDownload" , "/DataDownload" , full_url )
	
    this_catalog <-
      data.frame(
          directory = ifelse( grepl( "_SN_" , full_url ) , "state" , "county" ) ,
          tech_doc = grepl( "_tech" , full_url , ignore.case = TRUE ) ,
          year = gsub( "(.*)([0-9][0-9][0-9][0-9])-([0-9][0-9][0-9][0-9])(.*)" , "\\2" , full_url )
      )

    this_catalog$full_url = as.character( full_url )

	this_catalog$output_filename <- paste0( output_dir , "/" , this_catalog$directory , "/" , gsub( "\\.zip" , ".rds" , basename( this_catalog$full_url ) , ignore.case = TRUE ) )
	
    unique( this_catalog[ !this_catalog[ , "tech_doc" ] , ] )
  }


lodown_ahrf <-
	function( data_name = "ahrf" , catalog , ... ){

		on.exit( print( catalog ) )

		tf <- tempfile()


		for ( i in seq_len( nrow( catalog ) ) ){

			# download the file
			cachaca( catalog[ i , "full_url" ] , tf , mode = 'wb' , filesize_fun = 'unzip_verify' )


			# extract the contents of the zipped file
			# into the current year-specific directory
			# and (at the same time) create an object called
			# `unzipped_files` that contains the paths on
			# your local computer to each of the unzipped files
			unzipped_files <- unzip_warn_fail( tf , exdir = np_dirname( catalog[ i , 'output_filename' ] ) )

			sas_path <- grep( "\\.sas$" , unzipped_files , value = TRUE )

			dat_path <- grep( "\\.asc$" , unzipped_files , value = TRUE )

			x <- read_SAScii( dat_path , sas_path , na_values = "." )

			# convert all column names to lowercase
			names( x ) <- tolower( names( x ) )

			saveRDS( x , file = catalog[ i , 'output_filename' ] , compress = FALSE )

			# add the number of records to the catalog
			catalog[ i , 'case_count' ] <- nrow( x )

			# delete the temporary files
			file.remove( tf )

			cat( paste0( data_name , " catalog entry " , i , " of " , nrow( catalog ) , " stored at '" , catalog[ i , 'output_filename' ] , "'\r\n\n" ) )

		}

		on.exit()
		
		catalog

	}