Manifest options lookups and payload-field extraction shared by every
provider that reads a code, names, attributes, and external codes out of
a manifest and a staged payload the way GeoGenius.Providers.GeoJSON and
GeoGenius.Providers.CSV both do.
A provider resolves its own format-specific option keys ("code_property"
vs "code_column", and so on -- see the table in GeoGenius.Provider's
moduledoc) and passes the resolved field name or field list in here; this
module never reads the vocabulary a specific format calls its own.
Summary
Functions
Resolves the three keys every area needs -- its code field, area type, and authority -- into one map rather than three positional strings.
Takes the manifest-selected attribute fields out of payload, keyed by
option_key ("attribute_properties" for GeoJSON, "attribute_columns"
for CSV).
Resolves the authority key from options["authority"], falling back to the
manifest's own authority when the option is absent.
Builds external codes for one payload from a manifest-configured list of
%{"type" => code_type, field_key => payload_field} entries.
Builds the official and alias names for one payload.
Fetches key out of options, returning an error naming the key rather than raising.
Functions
@spec area_keys(GeoGenius.Manifest.t(), map(), String.t()) :: {:ok, %{ code_field: String.t(), area_type_key: String.t(), authority_key: String.t() }} | {:error, String.t()}
Resolves the three keys every area needs -- its code field, area type, and authority -- into one map rather than three positional strings.
code_option_key is the format-specific option key naming the code field
("code_property" for GeoJSON, "code_column" for CSV); "area_type" is
the same key for every provider. Returning a map rather than a
{code_field, area_type_key, authority_key} tuple means a caller cannot
transpose area_type_key and authority_key by getting their position
wrong -- both are plain strings, so a transposition here would type-check
and silently mis-file every area in the catalog.
Takes the manifest-selected attribute fields out of payload, keyed by
option_key ("attribute_properties" for GeoJSON, "attribute_columns"
for CSV).
Defaults to [] when option_key is absent from options -- an explicit,
provider-agreed default rather than "every other field", which would
silently widen a catalog's attributes the moment a source added a column
nobody asked to carry forward.
@spec authority_key(GeoGenius.Manifest.t(), map()) :: {:ok, String.t()} | {:error, String.t()}
Resolves the authority key from options["authority"], falling back to the
manifest's own authority when the option is absent.
The fallback needs the manifest to name exactly one authority. A manifest
declaring several is describing areas keyed under more than one, which one
option key cannot express, so it must say which under "authority" rather
than have the first entry chosen for it -- a silent choice would file every
area of the release under whichever authority happened to be listed first.
@spec codes(map(), map(), String.t(), String.t()) :: [ GeoGenius.Provider.Area.Code.t() ]
Builds external codes for one payload from a manifest-configured list of
%{"type" => code_type, field_key => payload_field} entries.
option_key names the manifest option carrying that list
("code_properties" for GeoJSON, "code_columns" for CSV); field_key
names the key each entry uses for the payload field
("property" for GeoJSON, "column" for CSV). Defaults to []. A row
whose named payload field is blank produces no code for that entry, rather
than a %Code{} with an empty code_value.
@spec names(map(), String.t(), [String.t()]) :: [GeoGenius.Provider.Area.Name.t()]
Builds the official and alias names for one payload.
name_field names the payload key holding the official name; alias_fields
names the payload keys holding alias names. Both are already resolved by
the caller from its own format-specific option keys and defaults.
Fetches key out of options, returning an error naming the key rather than raising.