✨ Add first version of data_package()

Create a data-package.json based on csv files without additional metadata.

DESCRIPTION

@@ -46,6 +46,7 @@ Imports:
     yaml
 Suggests:
     ggplot2,
+    jsonlite,
     knitr,
     microbenchmark,
     rmarkdown,
@@ -60,6 +61,7 @@ Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.2
 Collate:
     'clean_data_path.R'
+    'data_package.R'
     'datahash.R'
     'display_metadata.R'
     'git2rdata_package.R'

NAMESPACE

@@ -51,6 +51,7 @@ S3method(write_vc,character)
 S3method(write_vc,default)
 S3method(write_vc,git_repository)
 export(commit)
+export(data_package)
 export(display_metadata)
 export(is_git2rdata)
 export(is_git2rmeta)

R/data_package.R

@@ -0,0 +1,87 @@
+#' Create a Data Package for a directory of CSV files
+#'
+#' @description
+#' Create a `datapackage.json` file for a directory of CSV files.
+#' The function will look for all `.csv` files in the directory and its
+#' subdirectories.
+#' It will then create a `datapackage.json` file with the metadata of each CSV
+#' file.
+#'
+#' @param path the directory in which to create the `datapackage.json` file.
+#' @family storage
+#' @export
+#' @importFrom assertthat assert_that is.string noNA
+data_package <- function(path = ".") {
+  assert_that(
+    is.string(path), noNA(path), requireNamespace("jsonlite", quietly = TRUE)
+  )
+  stopifnot("`path` is not a directory" = file_test("-d", path))
+
+  data_files <- list.files(path, pattern = ".csv$", recursive = TRUE)
+  relevant <- vapply(
+    data_files, FUN = is_git2rdata, FUN.VALUE = logical(1), root = path
+  )
+  stopifnot(
+    "no non-optimized git2rdata objects found at `path`" = any(relevant)
+  )
+  data_files <- data_files[relevant]
+
+  list(
+    resources = vapply(
+        data_files, path = path, FUN = data_resource,
+        FUN.VALUE = vector(mode = "list", length = 1)
+      ) |>
+        unname()
+  ) |>
+    jsonlite::toJSON(pretty = TRUE, auto_unbox = TRUE) |>
+    writeLines(file.path(path, "datapackage.json"))
+  return(file.path(path, "datapackage.json"))
+}
+
+#' @importFrom assertthat assert_that is.string noNA
+#' @importFrom yaml read_yaml
+data_resource <- function(file, path = ".") {
+  assert_that(
+    is.string(file), is.string(path), noNA(file), noNA(path)
+  )
+  stopifnot("`path` is not a directory" = file_test("-d", path))
+
+  clean_data_path(root = path, file = file)[2] |>
+    read_yaml() -> metadata
+  list(
+    name = file, path = file, "encoding" = "utf-8",
+    format = "csv", media_type = "text/csv",
+    hash = paste0("sha1:", metadata[["..generic"]][["data_hash"]]),
+    schema = list(
+      fields = vapply(
+        names(metadata)[-1], metadata = metadata, FUN = field_schema,
+        FUN.VALUE = vector(mode = "list", length = 1)
+      ) |>
+        unname(),
+      missingValues = list(
+        c(value = metadata[["..generic"]][["NA string"]], label = "missing")
+      )
+    )
+  ) |>
+    list()
+}
+
+field_schema <- function(x, metadata) {
+  list(switch(
+    metadata[[x]]$class,
+    "character" = list(name = x, type = "string"),
+    "Date" = list(name = x, type = "date"),
+    "logical" = list(
+      name = x, type = "boolean", trueValues = c("TRUE", "true"),
+      falseValues = c("FALSE", "false")
+    ),
+    "factor" = list(
+      name = x, type = "string", categories = metadata[[x]][["labels"]],
+      categoriesOrdered = metadata[[x]][["ordered"]]
+    ),
+    "integer" = list(name = x, type = "integer"),
+    "numeric" = list(name = x, type = "number"),
+    "POSIXct" = list(name = x, type = "datetime"),
+    stop("field_schema() can't handle ", metadata[[x]]$class)
+  ))
+}