Attachments

R/attachments.R

@@ -41,6 +41,7 @@
 query_layer_attachments <- function(
     x,
     definition_expression = "1=1",
+    attachments_definition_expression = NULL,
     object_ids = NULL,
     global_ids = NULL,
     attachment_types = NULL,
@@ -50,6 +51,11 @@ query_layer_attachments <- function(
     # Ignored arguments for now:
     # returnMetadata, size,
     ) {
+  check_string(definition_expression, allow_null = TRUE)
+  check_string(attachments_definition_expression, allow_null = TRUE)
+  check_character(global_ids, allow_null = TRUE)
+  # TODO validate that object_ids is a vector
+
   # ensure that attachments are available.
   if (!x[["hasAttachments"]]) {
     cli::cli_abort("{.arg layer} does not support attachments.")
@@ -75,12 +81,21 @@ query_layer_attachments <- function(
 
   req <- httr2::req_body_form(
     b_req,
-    objectIds = object_ids,
-    globalIds = global_ids,
+    # TODO test these why aren't these working?!!
+    objectIds = paste(object_ids, collapse = ","),
+    # TODO create a test for this
+    globalIds = paste(global_ids, collapse = ","),
     attachmentTypes = attachment_types,
+    # TODO document common examples:
+    # filter based on
+    # - date
+    # - common prefix
+    # - numeric value
     definitionExpression = definition_expression,
+    attachmentsDefinitionExpression = attachments_definition_expression,
     keywords = keywords,
     returnUrl = TRUE,
+    returnMetadata = TRUE,
     f = "json"
   )
 
@@ -96,6 +111,11 @@ query_layer_attachments <- function(
 #' @param x the attachmentGroups column from the query results
 #' @noRd
 unnest_attachment_groups <- function(x) {
+  if (is.null(x[["attachmentInfos"]])) {
+    cli::cli_alert_info("No attachments found.")
+    return(NULL)
+  }
+
   n_elem <- vapply(x[["attachmentInfos"]], nrow, integer(1))
   res <- cbind(
     x[rep.int(1:nrow(x), n_elem), c("parentGlobalId", "parentObjectId")],
@@ -128,6 +148,7 @@ download_attachments <- function(
     attachments,
     out_dir,
     ...,
+    overwrite = FALSE,
     .progress = TRUE,
     token = arc_token()) {
   # check that the input is a data frame with the appropriate types
@@ -195,9 +216,32 @@ download_attachments <- function(
 
   # create the output path names
   out_fps <- file.path(out_dir, attachments[["name"]])
+  already_exist <- file.exists(out_fps)
+
+  # required fields
+  urls <- attachments[["url"]]
+  content_types <- attachments[["contentType"]]
+
+  if (!overwrite && any(already_exist)) {
+    # Files with the same name found.
+    cli::cli_inform(
+      c(
+        "Files with the same name found in {.path {out_dir}}",
+        "i" = "Existing files: {.file {out_fps[already_exist]}}",
+        ">" = "set {.arg overwrite = TRUE} to overwrite these files"
+      )
+    )
+    # subset to the files that dont already exist
+    out_fps <- out_fps[!already_exist]
+    urls <- urls[!already_exist]
+    content_types <- content_types[!already_exist]
+  }
+  # TODO check if files exist, if they do provide a message
+  # saying we're skipping downloading.
+  # To download use `overwrite = TRUE`
 
   # create the requests
-  attachment_reqs <- lapply(attachments[["url"]], arc_base_req, token = token)
+  attachment_reqs <- lapply(urls, arc_base_req, token = token)
 
   # perform the requests
   resps <- httr2::req_perform_parallel(
@@ -207,7 +251,7 @@ download_attachments <- function(
   )
 
 
-  Map(.download_attachment, resps, attachments[["contentType"]], out_fps)
+  Map(.download_attachment, resps, content_types, out_fps)
 }
 
 .download_attachment <- function(.resp, .content_type, .fp) {

dev/attachments-demo.R

@@ -0,0 +1,61 @@
+# install the development version
+# install.packages("pak")
+# pak::pak("r-arcgis/arcgislayers")
+
+# for authorizing to your portal
+library(arcgisutils)
+
+# for accessing feature service content
+library(arcgislayers)
+
+# authorize
+set_arc_token(auth_user())
+
+# URL to the Survey123 feature service with attachments
+furl <- "https://services1.arcgis.com/hLJbHVT9ZrDIzK0I/arcgis/rest/services/v8_Wide_Area_Search_Form_Feature_Layer___a2fe9c/FeatureServer/0"
+
+# create a reference to it in R
+layer <- arc_open(furl)
+
+# There are two parts to working with attachments:
+# 1. Finding the attachments associated with a feature service
+# 2. After finding the attachments, we can download them to our machine
+
+# Query the attachments of a layer using query_layer_attachments()
+# By default this returns metadata about every attachment in your
+# feature service
+att <- query_layer_attachments(layer)
+att
+
+# We can limit this by providing a SQL where clause to the
+# definition_expression argument.
+# For example to find all of the attachments that have the
+# followup_status field set to `needs_followup` we can provide the
+# following definition_expression
+query_layer_attachments(
+  layer, "followup_status = 'needs_followup'"
+)
+
+# To find all of the attachments from after a point in time
+query_layer_attachments(
+  layer, "start_time >= '2023-01-01'"
+)
+
+# To find attachments with a name that starts with `image0`
+query_layer_attachments(
+  layer,
+  attachments_definition_expression = "att_name like 'image0%'"
+)
+
+# Find attachments that contain "20221005"
+query_layer_attachments(
+  layer,
+  attachments_definition_expression = "att_name like '%20221005%'"
+)
+
+
+# to download the attachments:
+# res <- download_attachments(
+#   att,
+#   "dev/field_images"
+# )