Resolve a Download URL via CKAN package_search — resolve_via_ckan

Fallback for resolve_via_ckan() when the dataset slug has changed. Derives the CKAN portal base URL from the provenance's package_show endpoint, runs a package_search query (from resource$search_query, or derived from the name-match pattern), and returns the URL of the first matching resource, preferring CSV format when specified.

Usage

resolve_via_ckan_search(provenance)

Arguments

provenance: A provenance list as returned by load_provenance(). Uses resource$search_query, resource$name_match_pattern, resource$format, and dataset$ckan_api_endpoint.

Value

The matched resource URL as a character string, or NULL if no query or base URL can be derived, the request fails, or nothing matches.

Examples

# Missing fields return NULL rather than erroring:
resolve_via_ckan_search(list())
#> NULL
# \donttest{
prov <- list(
  dataset  = list(ckan_api_endpoint = paste0(
    "https://data.ontario.ca/api/3/action/package_show",
    "?id=ontario-public-library-statistics")),
  resource = list(name_match_pattern = "2014",
                  search_query = "public library statistics")
)
resolve_via_ckan_search(prov)
#> [1] "https://files.ontario.ca/ontario_public_library_statistics_2014_open_data_csv_february_17_2016.csv"
# }