arcgisutils is designed as the backbone of the {arcgis} meta-package.
arcgisutils is a developer oriented package that provides the basic functions to build R packages that work with ArcGIS Location Services. It provides functionality for:
Install arcgisutils from CRAN.
install.packages("arcgisutils", repos = "https://r-arcgis.r-universe.dev")
Or, you can install the development version of arcgisutils r-universe with:
install.packages("arcgisutils", repos = "https://r-arcgis.r-universe.dev")
Authorization tokens are provided through the functions auth_code(), auth_client(), auth_user(), and auth_binding(). Additional token validation functions are provided via refresh_token() and validate_or_refresh_token().
Tokens are managed in a session based cache using set_arc_token() and unset_arc_token(). They are fetched using arc_token(). Here is a minimal example:
library(arcgisutils) #> #> Attaching package: 'arcgisutils' #> The following object is masked from 'package:base': #> #> %||%
tkn <- auth_client() set_arc_token(tkn) arc_token() #> <httr2_token> #> token_type: bearer #> access_token: <REDACTED> #> expires_at: 2024-07-11 09:40:56 #> arcgis_host: https://www.arcgis.com
Alternatively, tokens can be set based on a key-value pair.
set_arc_token("A" = tkn, "B" = tkn)
#> ✔ Named tokens set: `A` and `B`
#> ℹ Access named tokens with `arc_token("name")`
And fetched based on their name via
arc_token("A")
#> <httr2_token>
#> token_type: bearer
#> access_token: <REDACTED>
#> expires_at: 2024-07-11 09:40:56
#> arcgis_host: https://www.arcgis.com
The function arc_base_req() is used to create a standardized httr2 request object. It handles authorization tokens and sets a user agent.
host <- arc_host() # use arcgis.com by default arc_base_req(host) #> <httr2_request> #> GET https://www.arcgis.com #> Body: empty #> Options: #> • useragent: 'arcgisutils v0.3.0'
There are also a number of utility functions for creating and parsing Esri JSON. For example we can create a list that represent an Esri FeatureSet using as_featurset() directly from an sf object. To convert to json, it is recommended to use jsonify::to_json(x, unbox = TRUE).
library(sf) #> Linking to GEOS 3.11.0, GDAL 3.5.3, PROJ 9.1.0; sf_use_s2() is TRUE
nc <- st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)
nc_json <- as_featureset(nc)
str(nc_json, 1)
#> List of 3
#> $ geometryType : chr "esriGeometryPolygon"
#> $ spatialReference:List of 1
#> $ features :List of 100
Alternatively, you can use the set of functions with the _esri_ infix to directly create the json. See the Esri geometry reference page for more on how the conversion functions work.
Additionally, sf’s crs object can be converted to a spatialReference JSON object using validate_crs().
validate_crs(27700) #> $spatialReference #> $spatialReference$wkid #> [1] 27700
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