download_data

library(amadeus)

Motivation

The download_data function was developed to improve researchers’ access to publicly available environmental data. Although the data are already available online, using a web browser to manually download hundreds or thousands of data files is slow, arduous, and not efficiently repeatable. Additionally, as users may not be familiar with creating download recipes in Bash (Unix shell), download_data allows researchers to download data directly with R, a common coding language in the field of environmental health research. Finally, function-izing data downloads is useful for repeated code or automated analysis pipelines.

download_data is acccesses and downloads environmental datasets, collections, and variables from a variety of sources. This wrapper function calls source-specific data download functions, each utilizing a unique combination of input parameters, host URL, naming convention, and data formats.

Source-specific download functions and data sources
	Download Function	Data Source
14	download_gridmet	Climatology Lab GridMet
13	download_terraclimate	Climatology Lab TerraClimate
5	download_koppen_geiger	Köppen-Geiger Climate Classification (Beck et al., 2018)
8	download_nlcd	MRLC Consortium National Land Cover Database (NLCD)
3	download_geos_data	NASA Goddard Earth Observing System Composition Forecasting (GEOS-CF)
12	download_modis	NASA Moderate Resolution Imaging Spectroradiometer (MODIS)
6	download_merra2	NASA Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2)
10	download_sedac_groads	NASA SEDAC Global Roads Open Access Data Set
11	download_sedac_population	NASA SEDAC UN WPP-Adjusted Population Density
9	download_hms	NOAA Hazard Mapping System Fire and Smoke Product
7	download_narr	NOAA NCEP North American Regional Reanalysis (NARR)
15	download_osm	OpenGeoHub Foundation OpenLandMap
16	download_prism	Parameter Elevation Regression on Independent Slopes Model (PRISM)
1	download_aqs	US EPA Air Data Pre-Generated Data Files
2	download_ecoregion	US EPA Ecoregions
17	download_nei	US EPA National Emissions Inventory (NEI)
18	download_tri	US EPA Toxic Release Inventory (TRI) Program
4	download_gmted	USGS Global Multi-resolution Terrain Elevation Data (GMTED2010)
19	download_huc	USGS National Hydrography Dataset (NHD)

It is important to note that download_data calls a source-specific function based on the dataset_name parameter. Using the source-specific function directly will return the same data if the parameters are the same, but the error messages produced by each differ slightly.

Parameters

User-defined parameters differ based on the data source. Required parameters for each source can be checked with names(formals()).

names(formals(download_hms))
#> [1] "data_format"       "date"              "directory_to_save"
#> [4] "acknowledgement"   "download"          "remove_command"   
#> [7] "unzip"             "remove_zip"        "hash"
names(formals(download_narr))
#> [1] "variables"         "year"              "directory_to_save"
#> [4] "acknowledgement"   "download"          "remove_command"   
#> [7] "hash"

The two functions have different required parameters because download_hms uses a daily temporal resolution while download_narr uses yearly, but they share some common, standard parameters.

Standard parameters

Four parameters are included in all of the data download functions.

Parameter	Type	Description
directory_to_save	Character	There must be a directory to save downloaded data. Default = ‘./input/DATASET_NAME/’.
acknowledgement	Logical	User must acknowledge that downloading geospatial data can be very lage and may use lots of machine storage and memory.
download	Logical	Run or skip the data download. Utilized primarily for unit tests (see Unit Tests).
remove_command	Logical	Remove or retain the text file containing the generated download commands. Utilized primarily for unit tests (see Unit Tests and 4. Initiate “…commands.txt”).

Additionally, the dataset_name parameter must be specified when using download_data, but is assumed when using a source-specific download function.

Function Structure

Although each source-specific download function is unique, they all follow the same general structure. The following chunks of code have been adopted from download_hms to demonstrate the functions’ structure.

1. Clean Parameters

2. Generate Download URLs

3. Generate download file names

4. Initiate “…commands.txt”

5. Concatenate download commands

6. Finalize “…commands.txt”

7. Run commands in “…commands.txt”

8. Zip files (if applicable)

1. Clean parameters

Cleaning the user-defined parameters is highly dependent on the parameters themselves and the desired URL to be created. A common parameter cleaning step is creating a date-time sequence based on a given temporal range and required format, in this case YYYYMMDD.

# user defined parameters
dates <- c("2023-12-28", "2024-01-02")

date_sequence <- seq(
  as.Date(dates[1], format = "%Y-%m-%d"),
  as.Date(dates[2], format = "%Y-%m-%d"),
  "day"
)
date_sequence <- gsub("-", "", as.character(date_sequence))
date_sequence
#> [1] "20231228" "20231229" "20231230" "20231231" "20240101" "20240102"

2. Generate download URLs

The URL base and pattern are identified by manually inspecting the download link on the source-specific web page. download_hms utilizes the year, month, date, and data format to generate the download url.

# user defined parameters
data_format <- "Shapefile"
suffix <- ".zip"

urls <- NULL
for (d in seq_along(date_sequence)) {
  year <- substr(date_sequence[d], 1, 4)
  month <- substr(date_sequence[d], 5, 6)
  base <- "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/"
  url <- paste0(
    base,
    data_format,
    "/",
    year,
    "/",
    month,
    "/hms_smoke",
    date_sequence[d],
    suffix
  )
  urls <- c(urls, url)
}
urls
#> [1] "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/Shapefile/2023/12/hms_smoke20231228.zip"
#> [2] "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/Shapefile/2023/12/hms_smoke20231229.zip"
#> [3] "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/Shapefile/2023/12/hms_smoke20231230.zip"
#> [4] "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/Shapefile/2023/12/hms_smoke20231231.zip"
#> [5] "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/Shapefile/2024/01/hms_smoke20240101.zip"
#> [6] "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/Shapefile/2024/01/hms_smoke20240102.zip"

A download URL is created for each date in date_sequence based on the fixed pattern.

3. Generate download file names

The generation of download file names also follows a fixed pattern, typically a combination of the user-defined download directory, dataset name, spatiotemporal characteristic, data type, and, if applicable, specific variable name. Unlike the download URLs, the download file names can be defined in any way by the writer of the function, but using the previously defined characteristics is useful for identification.

# user defined parameters
directory_to_download <- "./data/"

download_file_names <- NULL
for (d in seq_along(date_sequence)) {
  download_file_name <- paste0(
    directory_to_download,
    "hms_smoke_",
    data_format,
    "_",
    date_sequence[d],
    suffix
  )
  download_file_names <- c(download_file_names, download_file_name)
}
download_file_names
#> [1] "./data/hms_smoke_Shapefile_20231228.zip"
#> [2] "./data/hms_smoke_Shapefile_20231229.zip"
#> [3] "./data/hms_smoke_Shapefile_20231230.zip"
#> [4] "./data/hms_smoke_Shapefile_20231231.zip"
#> [5] "./data/hms_smoke_Shapefile_20240101.zip"
#> [6] "./data/hms_smoke_Shapefile_20240102.zip"

A download URL is created for each date in date_sequence based on the fixed pattern.

4. Initiate “…commands.txt”

An important aspect of the data download function is its sink...cat...sink structure. Rather than using the utils::download.file function, a text file is created to store all of the download commands generated from the URLs and file names.

This structure is utilized for several reasons:

Consistent structure for all the source-specific download functions.
The download.file function cannot accept vectors of URLs and destination files for downloading. An additional for loop to download data will increase function complexity and may reduce performance.
Writing commands in Bash (Unix shell) script allows for specific arguments and flags.
Storing the download URLs without immediately running the download allows for unit testing and URL checking (more on this in Unit Tests).

The text file containing the download commands is named based on the dataset, temporal range, and data transfer method.

commands_txt <- paste0(
  directory_to_download,
  "hms_smoke_",
  head(date_sequence, n = 1),
  "_",
  tail(date_sequence, n = 1),
  "_curl_commands.txt"
)

Create and sink the text file.

sink(commands_txt)

5. Concatenate download commands

The Linux-based download commands are written according to the data transfer method, download URL, download file name, and additional arguments. Which additional arguments are included, and their order, depend on the data transfer method and URL type.

For more information on curl and wget, the two data transfer methods utilized by the data download functions, see curl.1 the man page and GNU Wget 1.21.1-dirty Manual (latest version as of January 8, 2024).

The cat() function will store each of the download commands written in the for loop to the previously sunk commands text file (commands_txt).

for (d in seq_along(date_sequence)) {
  download_comamnd <- paste0(
    "curl -s -o ",
    download_file_names[d],
    " --url ",
    urls[d],
    "\n"
  )
  cat(download_comamnd)
}

6. Finalize “…commands.txt”

After the download commands have been concatenated to the commands text file, a second sink command is run to finalize the file and stop the appending of R output.

sink()

7. Run commands in “…commands.txt”

A “system command” must be created to run all of the download commands stored in the commands text file. In bash script, . indicates to run all of the commands within a given script. In this case, we will run all of the commands within the commands text file.

system_command <- paste0(
  ". ",
  commands_txt,
  "\n"
)
system_command
#> [1] ". ./data/hms_smoke_20231228_20240102_curl_commands.txt\n"

Running the system_command deploys an “auxiliary” function, download_run, a function created to reduce repeated code across the source-specific download functions. The function takes two parameters, system_command, which indicates the command to be run, and download, a user-defined logical parameter.

download_run <- function(
    download = FALSE,
    system_command = NULL) {
  if (download == TRUE) {
    cat(paste0("Downloading requested files...\n"))
    system(command = system_command)
    cat(paste0("Requested files have been downloaded.\n"))
  } else {
    cat(paste0("Skipping data download.\n"))
    return(NULL)
  }
}

The data download is initiated by running download_run with the system command identified and download = TRUE.

download_run(
  download = TRUE,
  system_command = system_command
)

Checking the download directory shows that all of the requested files have been downloaded.

list.files(path = directory_to_download)

#> [1] "hms_smoke_Shapefile_20231228.zip" "hms_smoke_Shapefile_20231229.zip"
#> [3] "hms_smoke_Shapefile_20231230.zip" "hms_smoke_Shapefile_20231231.zip"
#> [5] "hms_smoke_Shapefile_20240101.zip" "hms_smoke_Shapefile_20240102.zip"

8. Zip files (if applicable)

All of the source-specific data download functions follow this general pattern, but those functions which download zip files require additional steps to inflate and remove the downloaded zip files, if desired. Each of these two steps are run by helper functions, and they are run by the user-defined unzip and remove_zip parameters in download_data.

download_unzip inflates zip files if unzip = TRUE, and skips inflation if unzip = FALSE.

download_unzip <-
  function(file_name,
           directory_to_unzip,
           unzip = TRUE) {
    if (!unzip) {
      cat(paste0("Downloaded files will not be unzipped.\n"))
      return(NULL)
    }
    cat(paste0("Unzipping files...\n"))
    unzip(file_name,
      exdir = directory_to_unzip
    )
    cat(paste0(
      "Files unzipped and saved in ",
      directory_to_unzip,
      ".\n"
    ))
  }

download_remove_zips removes the downloaded zip files if remove = TRUE, and skips removal if remove = FALSE.

download_remove_zips <-
  function(remove = FALSE,
           download_name) {
    if (remove) {
      cat(paste0("Removing download files...\n"))
      file.remove(download_name)
      cat(paste0("Download files removed.\n"))
    }
  }

For this demonstration we will unzip (inflate) the downloaded zip files but we will not delete them.

for (f in seq_along(download_file_names)) {
  download_unzip(
    file_name = download_file_names[f],
    directory_to_unzip = directory_to_download,
    unzip = TRUE
  )
}
download_remove_zips(
  download_name = download_file_names,
  remove = FALSE
)

#> Unzipping files...
#> Files unzipped and saved in ./data/.
#> Unzipping files...
#> Files unzipped and saved in ./data/.
#> Unzipping files...
#> Files unzipped and saved in ./data/.
#> Unzipping files...
#> Files unzipped and saved in ./data/.
#> Unzipping files...
#> Files unzipped and saved in ./data/.
#> Unzipping files...
#> Files unzipped and saved in ./data/.

Listing the files again shows that the contents of the zip files have been inflated and the zip files have been retained.

list.files(path = directory_to_download)

#>  [1] "hms_smoke_Shapefile_20231228.zip" "hms_smoke_Shapefile_20231229.zip"
#>  [3] "hms_smoke_Shapefile_20231230.zip" "hms_smoke_Shapefile_20231231.zip"
#>  [5] "hms_smoke_Shapefile_20240101.zip" "hms_smoke_Shapefile_20240102.zip"
#>  [7] "hms_smoke20231228.dbf"            "hms_smoke20231228.prj"           
#>  [9] "hms_smoke20231228.shp"            "hms_smoke20231228.shx"           
#> [11] "hms_smoke20231229.dbf"            "hms_smoke20231229.prj"           
#> [13] "hms_smoke20231229.shp"            "hms_smoke20231229.shx"           
#> [15] "hms_smoke20231230.dbf"            "hms_smoke20231230.prj"           
#> [17] "hms_smoke20231230.shp"            "hms_smoke20231230.shx"           
#> [19] "hms_smoke20231231.dbf"            "hms_smoke20231231.prj"           
#> [21] "hms_smoke20231231.shp"            "hms_smoke20231231.shx"           
#> [23] "hms_smoke20240101.dbf"            "hms_smoke20240101.prj"           
#> [25] "hms_smoke20240101.shp"            "hms_smoke20240101.shx"           
#> [27] "hms_smoke20240102.dbf"            "hms_smoke20240102.prj"           
#> [29] "hms_smoke20240102.shp"            "hms_smoke20240102.shx"

The download function was structured successfully.

Unit Tests

The previous outline successfully cleaned parameters, generated URLs, and downloaded data, but how can we be sure that it will continue to work with different temporal ranges and data types? To this end, unit tests have been implemented to ensure that each data download function runs properly and that URLs produced by 2. Generate download URLs are valid and accessible. Like the download functions, the unit tests rely on “helper” functions to reduce repeated code across the tests.

Helper functions

read_commands imports the commands text file and converts the data frame to a vector.

read_commands <- function(
    commands_path = commands_path) {
  commands <- utils::read.csv(commands_path, header = FALSE)
  commands <- commands[seq_len(nrow(commands)), ]
  return(commands)
}

extract_urls extracts each download URL from the vector of commands. The position of the URL within the download command is determined in 5. Concatenate download commands.

# function to extract URLs from vector
extract_urls <- function(
    commands = commands,
    position = NULL) {
  if (is.null(position)) {
    cat(paste0("URL position in command is not defined.\n"))
    return(NULL)
  }
  url_list <- NULL
  for (c in seq_along(commands)) {
    url <- stringr::str_split_i(commands[c], " ", position)
    url_list <- c(url_list, url)
  }
  return(url_list)
}

check_url_status is the most important of the download test “helper” functions. This function utilizes httr::HEAD and httr::GET to check the HTTP response status of a given URL. The desired HTTP response status is 200, which means the URL is valid and accessible. check_url_status returns a logical value to indicate whether the URL returns HTTP status 200 (TRUE) or not (FALSE). For more information on HTTP status’, see HTTP response status codes.

check_url_status <- function(
    url,
    method = "HEAD") {
  http_status_ok <- 200
  if (method == "HEAD") {
    hd <- httr::HEAD(url)
  } else if (method == "GET") {
    hd <- httr::GET(url)
  }
  status <- hd$status_code
  return(status == http_status_ok)
}

check_urls applies check_url_status to a random sample of URLs extracted by extract_urls. The sample size will vary based on the dataset and spatio-temporal parameters being tested. The function returns a logical vector containing the output from check_url_status.

check_urls <- function(
    urls = urls,
    size = NULL,
    method = "HEAD") {
  if (is.null(size)) {
    cat(paste0("URL sample size is not defined.\n"))
    return(NULL)
  }
  if (length(urls) < size) {
    size <- length(urls)
  }
  url_sample <- sample(urls, size, replace = FALSE)
  url_status <- sapply(url_sample,
    check_url_status,
    method = method
  )
  return(url_status)
}

testthat

To demonstrate a test in action, test the URLs generated by download_data for the NOAA HMS Smoke dataset.

For more information see testthat.

library(testthat)
testthat::test_that(
  "Valid dates return HTTP response status = 200.",
  {
    # parameters
    test_start <- "2023-12-28"
    test_end <- "2024-01-02"
    test_directory <- "./data/"
    # download
    download_data(
      dataset_name = "hms",
      date = c(test_start, test_end),
      data_format = "Shapefile",
      directory_to_save = test_directory,
      acknowledgement = TRUE,
      download = FALSE,
      remove_command = FALSE,
      unzip = FALSE,
      remove_zip = FALSE
    )
    commands_path <- paste0(
      test_directory,
      "hms_smoke_",
      gsub("-", "", test_start),
      "_",
      gsub("-", "", test_end),
      "_curl_commands.txt"
    )
    # helpers
    commands <- read_commands(commands_path = commands_path)
    urls <- extract_urls(commands = commands, position = 6)
    url_status <- check_urls(urls = urls, size = 6, method = "HEAD")
    # test for true
    expect_true(all(url_status))
  }
)

#> Test passed 🎊

Although the testthat::test_that(...) chunk contains 32 lines of code, the unit test is performed by expect_true(all(url_status)). In words, this line is expecting (expect_true) that all (all) of the sampled URLs return HTTP response status 200 (url_status). Since this expectation was met, the test passed!

For an alternate example, we can use a start and end date that are known to not have data. As the URLs associated with these dates do not exist, we expect the function will fail. This test utilizes expect_error() because the download_data wrapper function returns an error message if the underlying source-specific download function returns an error.

testthat::test_that(
  "Invalid dates cause function to fail.",
  {
    # parameters
    test_start <- "1800-01-01"
    test_end <- "1800-01-02"
    test_directory <- "../inst/extdata/"
    # test for error
    testthat::expect_error(
      download_data(
        dataset_name = "hms",
        date = c(test_start, test_end),
        data_format = "Shapefile",
        directory_to_download = test_directory,
        directory_to_save = test_directory,
        acknowledgement = TRUE,
        download = FALSE,
        remove_command = FALSE,
        unzip = FALSE,
        remove_zip = FALSE
      )
    )
  }
)
#> Test passed 🎊

This test utilizes testthat::expect_error because the download_data wrapper function returns an error message if the underlying source-specific download function returns an error. If we directly used the download_hms function, we would expect and receive an error.

testthat::test_that(
  "Invalid dates cause function to fail.",
  {
    # parameters
    test_start <- "1800-01-01"
    test_end <- "1800-01-02"
    test_directory <- "../inst/extdata/"
    # test for error
    testthat::expect_error(
      download_hms(
        date = c(test_start, test_end),
        data_format = "Shapefile",
        directory_to_download = test_directory,
        directory_to_save = test_directory,
        acknowledgement = TRUE,
        download = FALSE,
        remove_command = FALSE,
        unzip = FALSE,
        remove_zip = FALSE
      )
    )
  }
)
#> Test passed 🌈

As expected, the test passes because the NOAA HMS Smoke dataset does not contain data for January 1-2, 1800.

These unit tests are just two of many implemented on download_data and the accompanying source-specific download functions, but they demonstrate how unit testing helps build stable code.

Download Example

With the function structure outlined and the unit tests in place, we can now perform a data download. To begin, check the parameters required by the source-specific data download function.

names(formals(download_hms))
#> [1] "data_format"       "date"              "directory_to_save"
#> [4] "acknowledgement"   "download"          "remove_command"   
#> [7] "unzip"             "remove_zip"        "hash"

Define the parameters.

dates <- c("2023-12-28", "2024-01-02")
data_format <- "Shapefile"
data_directory <- "./download_example/"
acknowledgement <- TRUE
download <- TRUE # run data download
remove_command <- TRUE # delete "...commands.txt" file
unzip <- TRUE # inflate (unzip) downloaded zip files
remove_zip <- FALSE # retain downloaded zip files

Download the data.

download_data(
  dataset_name = "hms",
  date = dates,
  directory_to_save = data_directory,
  acknowledgement = acknowledgement,
  download = download,
  remove_command = remove_command,
  unzip = unzip,
  remove_zip = remove_zip
)

#> Downloading requested files...
#> Requested files have been downloaded.
#> Unzipping files...
#> Files unzipped and saved in ./download_example/.
#> Unzipping files...
#> Files unzipped and saved in ./download_example/.
#> Unzipping files...
#> Files unzipped and saved in ./download_example/.
#> Unzipping files...
#> Files unzipped and saved in ./download_example/.
#> Unzipping files...
#> Files unzipped and saved in ./download_example/.
#> Unzipping files...
#> Files unzipped and saved in ./download_example/.

Checking the directory shows that all of our desired data has been downloaded and inflated, and the original zip files have been retained.

list.files(data_directory)

#>  [1] "hms_smoke_Shapefile_20231228.zip" "hms_smoke_Shapefile_20231229.zip"
#>  [3] "hms_smoke_Shapefile_20231230.zip" "hms_smoke_Shapefile_20231231.zip"
#>  [5] "hms_smoke_Shapefile_20240101.zip" "hms_smoke_Shapefile_20240102.zip"
#>  [7] "hms_smoke20231228.dbf"            "hms_smoke20231228.prj"           
#>  [9] "hms_smoke20231228.shp"            "hms_smoke20231228.shx"           
#> [11] "hms_smoke20231229.dbf"            "hms_smoke20231229.prj"           
#> [13] "hms_smoke20231229.shp"            "hms_smoke20231229.shx"           
#> [15] "hms_smoke20231230.dbf"            "hms_smoke20231230.prj"           
#> [17] "hms_smoke20231230.shp"            "hms_smoke20231230.shx"           
#> [19] "hms_smoke20231231.dbf"            "hms_smoke20231231.prj"           
#> [21] "hms_smoke20231231.shp"            "hms_smoke20231231.shx"           
#> [23] "hms_smoke20240101.dbf"            "hms_smoke20240101.prj"           
#> [25] "hms_smoke20240101.shp"            "hms_smoke20240101.shx"           
#> [27] "hms_smoke20240102.dbf"            "hms_smoke20240102.prj"           
#> [29] "hms_smoke20240102.shp"            "hms_smoke20240102.shx"

`download_hms` function code

The following is the entire R code used to create download_hms.

download_hms
#> function (data_format = "Shapefile", date = c("2018-01-01", "2018-01-01"), 
#>     directory_to_save = NULL, acknowledgement = FALSE, download = FALSE, 
#>     remove_command = FALSE, unzip = TRUE, remove_zip = FALSE, 
#>     hash = FALSE) 
#> {
#>     download_permit(acknowledgement = acknowledgement)
#>     check_for_null_parameters(mget(ls()))
#>     if (length(date) == 1) 
#>         date <- c(date, date)
#>     stopifnot(length(date) == 2)
#>     date <- date[order(as.Date(date))]
#>     directory_original <- download_sanitize_path(directory_to_save)
#>     directories <- download_setup_dir(directory_original, zip = TRUE)
#>     directory_to_download <- directories[1]
#>     directory_to_save <- directories[2]
#>     if (unzip == FALSE && remove_zip == TRUE) {
#>         stop(paste0("Arguments unzip = FALSE and remove_zip = TRUE are not ", 
#>             "acceptable together. Please change one.\n"))
#>     }
#>     date_sequence <- generate_date_sequence(date[1], date[2], 
#>         sub_hyphen = TRUE)
#>     base <- "https://satepsanone.nesdis.noaa.gov/pub/FIRE/web/HMS/Smoke_Polygons/"
#>     commands_txt <- paste0(directory_original, "hms_smoke_", 
#>         utils::head(date_sequence, n = 1), "_", utils::tail(date_sequence, 
#>             n = 1), "_curl_commands.txt")
#>     download_sink(commands_txt)
#>     download_names <- NULL
#>     for (f in seq_along(date_sequence)) {
#>         year <- substr(date_sequence[f], 1, 4)
#>         month <- substr(date_sequence[f], 5, 6)
#>         if (tolower(data_format) == "shapefile") {
#>             data_format <- "Shapefile"
#>             suffix <- ".zip"
#>             directory_to_cat <- directory_to_download
#>         }
#>         else if (tolower(data_format) == "kml") {
#>             data_format <- "KML"
#>             suffix <- ".kml"
#>             directory_to_cat <- directory_to_save
#>         }
#>         url <- paste0(base, data_format, "/", year, "/", month, 
#>             "/hms_smoke", date_sequence[f], suffix)
#>         if (f == 1) {
#>             if (!(check_url_status(url))) {
#>                 sink()
#>                 file.remove(commands_txt)
#>                 stop(paste0("Invalid date returns HTTP code 404. ", 
#>                   "Check `date` parameter.\n"))
#>             }
#>         }
#>         destfile <- paste0(directory_to_cat, "hms_smoke_", data_format, 
#>             "_", date_sequence[f], suffix)
#>         download_names <- c(download_names, destfile)
#>         command <- paste0("curl -s -o ", destfile, " --url ", 
#>             url, "\n")
#>         if (check_destfile(destfile)) {
#>             cat(command)
#>         }
#>     }
#>     sink()
#>     download_run(download = download, commands_txt = commands_txt, 
#>         remove = remove_command)
#>     if (data_format == "KML") {
#>         unlink(directory_to_download, recursive = TRUE)
#>         message(paste0("KML files cannot be unzipped.\n"))
#>         return(TRUE)
#>     }
#>     for (d in seq_along(download_names)) {
#>         download_unzip(file_name = download_names[d], directory_to_unzip = directory_to_save, 
#>             unzip = unzip)
#>     }
#>     download_remove_zips(remove = remove_zip, download_name = download_names)
#>     return(download_hash(hash, directory_to_save))
#> }
#> <bytecode: 0x55a63a98c400>
#> <environment: namespace:amadeus>

download_data

Mitchell Manware

2024-07-09

Motivation

download_data

Parameters

Standard parameters

Function Structure

1. Clean parameters

2. Generate download URLs

3. Generate download file names

4. Initiate “…commands.txt”

5. Concatenate download commands

6. Finalize “…commands.txt”

7. Run commands in “…commands.txt”

8. Zip files (if applicable)

Unit Tests

Helper functions

testthat

Download Example

`download_hms` function code

download_data

Mitchell Manware

2024-07-09

Motivation

download_data

Parameters

Standard parameters

Function Structure

1. Clean parameters

2. Generate download URLs

3. Generate download file names

4. Initiate “…commands.txt”

5. Concatenate download commands

6. Finalize “…commands.txt”

7. Run commands in “…commands.txt”

8. Zip files (if applicable)

Unit Tests

Helper functions

testthat

Download Example

download_hms function code

`download_hms` function code