R/idig_search_records.R

In ridigbio: Interface to the iDigBio Data API

##' Function to query the iDigBio API for specimen records
##'
##' Wraps \code{\link{idig_search}} to provide defaults specific to searching
##' specimen records. Using this function instead of \code{\link{idig_search}}
##' directly is recommened.
##'
##' Queries need to be specified as a nested list structure that will serialize
##' to an iDigBio query object's JSON as expected by the iDigBio API:
##' \url{https://github.com/iDigBio/idigbio-search-api/wiki/Query-Format}
##'
##' As an example, the first sample query looks like this in JSON in the API
##' documentation:
##' \preformatted{
##' {
##'   "scientificname": {
##'     "type": "exists"
##'   },
##'   "family": "asteraceae"
##' }
##' }
##'
##' To rewrite this in R for use as the rq parameter to
##' \code{idig_search_records} or \code{idig_search_media}, it would look like
##' this:
##' \preformatted{
##' rq <- list("scientificname"=list("type"="exists"),
##'            "family"="asteraceae"
##'            )
##' }
##' An example of a more complex JSON query with nested structures:
##' \preformatted{
##' {
##'   "geopoint": {
##'    "type": "geo_bounding_box",
##'    "top_left": {
##'      "lat": 19.23,
##'      "lon": -130
##'     },
##'     "bottom_right": {
##'       "lat": -45.1119,
##'       "lon": 179.99999
##'     }
##'    }
##'  }
##' }
##'
##' To rewrite this in R for use as the rq parameter, use nested calls to the
##' list() function:
##' \preformatted{
##' rq <- list(geopoint=list(
##'                          type="geo_bounding_box",
##'                          top_left=list(lat=19.23, lon=-130),
##'                          bottom_right=list(lat=-45.1119, lon= 179.99999)
##'                         )
##'            )
##' }
##'
##' See the Examples section below for more samples of simpler and more complex
##' queries. Please refer to the API documentation for the full functionality
##' availible in queries.
##'
##' All matching results are returned up to the max_items cap (default 100,000).
##' If more results are wanted, a higher max_items can be passed as an option.
##' This API loads records 5,000 at a time using HTTP so performance with large
##' sets of data is not very good. Expect result sets over 50,000 records to
##' take tens of minutes. You can use the \code{\link{idig_count_records}} or
##' \code{\link{idig_count_media}} functions to find out how many records a
##' query will return; these are fast.
##'
##' The iDigBio API will only return 5,000 records at a time but this function
##' will automatically page through the results and return them all. Limit
##' and offset are availible if manual paging of results is needed though the
##' max_items cap still applies. The item count comes from the results header
##' not the count of actual records in the limit/offset window.
##'
##' Return is a data.frame containing the requested fields (or the default
##' fields). The columns in the data frame are untyped and no factors are pre-
##' built. Attribution and other metadata is attached to the dataframe in the
##' data.frame's attributes. (I.e. \code{attributes(df)})
##' @title Searching of iDigBio records
##' @param rq iDigBio record query in nested list format
##' @param fields vector of fields that will be contained in the data.frame,
##' limited set returned by default, use "all" to get all indexed fields
##' @param max_items maximum number of results allowed to be retrieved (fail
##' -safe)
##' @param limit maximum number of results returned
##' @param offset number of results to skip before returning results
##' @param sort vector of fields to use for sorting, UUID is always appended to
##' make paging safe
##' @param ... additional parameters
##' @return a data frame
##' @author Matthew Collins
##' @examples
##' \dontrun{
##' # Simple example of retriving records in a genus:
##' idig_search_records(rq=list(genus="acer"), limit=10)
##'
##' # This complex query shows that booleans passed to the API are represented
##' # as strings in R, fields used in the query don't have to be returned, and
##' # the syntax for accessing raw data fields:
##' idig_search_records(rq=list("hasImage"="true", genus="acer"),
##'             fields=c("uuid", "data.dwc:verbatimLatitude"), limit=100)
##'
##' # Searching inside a raw data field for a string, note that raw data fields
##' # are searched as full text, indexed fields are search with exact matches:
##'
##' idig_search_records(rq=list("data.dwc:dynamicProperties"="parasite"),
##'             fields=c("uuid", "data.dwc:dynamicProperties"), limit=100)
##'
##' # Retriving a data.frame for use with MaxEnt. Notice geopoint is expanded
##' # to two columns in the data.frame: gepoint.lat and geopoint.lon:
##' df <- idig_search_records(rq=list(genus="acer", geopoint=list(type="exists")),
##'           fields=c("uuid", "geopoint"), limit=10)
##' write.csv(df[c("uuid", "geopoint.lon", "geopoint.lat")],
##'           file="acer_occurrences.csv", row.names=FALSE)
##'
##' }
##' @export
##'

idig_search_records <- function(rq, fields = FALSE, max_items = 100000, limit = 0,
                                offset = 0, sort = FALSE, ...) {
  DEFAULT_FIELDS <- c(
    "uuid",
    "occurrenceid",
    "catalognumber",
    "family",
    "genus",
    "scientificname",
    "country",
    "stateprovince",
    "geopoint",
    "datecollected",
    "collector",
    "recordset"
  )

  # Validate inputs
  if (!(inherits(rq, "list"))) {
    stop("rq is not a list")
  }

  if (!(length(rq) > 0)) {
    stop("rq must not be 0 length")
  }

  if (inherits(fields, "logical") && fields == FALSE) {
    fields <- DEFAULT_FIELDS
  }

  fields_eq_all <- length(fields) == 1 && fields == "all"
  if (!fields_eq_all && !(inherits(fields, "character"))) {
    stop("Invalid value for fields")
  }

  idig_search(
    rq = rq, fields = fields, max_items = max_items, limit = limit,
    offset = offset, sort = sort, ...
  )
}