add basic query function for chronontology

DESCRIPTION

@@ -16,7 +16,8 @@ Description: This package provides convenience functions that are helpful
 License: GPL (>= 3)
 Depends: 
     R (>= 3.3),
-    jsonlite
+    jsonlite,
+    crul
 Suggests: 
     covr,
     dplyr,
@@ -27,5 +28,5 @@ Config/testthat/edition: 3
 Encoding: UTF-8
 LazyData: true
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.1
 VignetteBuilder: knitr

NAMESPACE

@@ -6,6 +6,7 @@ export(duplicate_by)
 export(from_chronontology)
 export(group_periods)
 export(make_chrongler_conc)
+export(query_chronontology)
 export(ungroup_periods)
 importFrom(jsonlite,fromJSON)
 importFrom(utils,read.csv)

R/query_chronontology.R

@@ -0,0 +1,35 @@
+#' Basic Query for iDAI.chronontology
+#'
+#'
+#'
+#' @param value (chr) The value you want to search for in all chronontology-periods.
+#'
+#' @return A list of results as handed out by iDAI.chronontology.
+#'
+#' @export
+#'
+#' @examples
+#' roman_periods <- query_chronontology(value = "roman")
+#' names <- unlist(lapply(roman_periods, function(x) x$resource$names$en))
+query_chronontology <- function(value = "roman") {
+  stopifnot(is.character(value))
+
+  url <- "https://chronontology.dainst.org"
+  headers <- list(`Content-Type` = "application/json",
+                  Accept = "application/json")
+  ChronClient <- crul::HttpClient$new(url = url, headers = headers)
+
+  response <- ChronClient$get(path = paste0('data/period/?q=', value, '&size=1'))
+  response <- response$parse("UTF-8")
+  list <- jsonlite::fromJSON(response, FALSE)
+
+  if (list$total > length(list$results)) {
+    response <- ChronClient$get(path = paste0('data/', type, '/?q=', value, '&size=', list$total))
+    response <- response$parse("UTF-8")
+    list <- jsonlite::fromJSON(response, FALSE)
+  }
+
+  result <- list$results
+
+  return(result)
+}

README.md

@@ -5,9 +5,11 @@
 <!-- badges: end -->
 
 # chrongler wrangles categorical chronological data
+
 This package provides convenience functions that are helpful for working with archaeological or historical data, where chronological information is stored as a 'period' (categorical values that may indicate chronology in one way or another). The functions are purely for formatting and 'wrangling' such data, and do not contain any means of analysis or further processing. 
 
 # Installation
+
 chrongler is not on CRAN. You can install the current version from GitHub using: 
 ``` r
 remotes::install_github("lsteinmann/chrongler", build_vignettes = TRUE)
@@ -23,6 +25,7 @@ Using chrongler (and a concordance of periods and their grouping and absolute da
 * download the data for one period from [iDAI.chronontology](https://chronontology.dainst.org/) (`from_chronontology()`, it's a bit of a work in progress...)
 
 The inaccurately named "example_workflow"-vignette explains the functions and especially setting up the concordance in detail, see:
+
 ``` r
 browseVignettes("chrongler")
 ```