rs_request: AppEEARS data request and download

Description

Stage a data request, and optionally download the data to disk. Alternatively you can only stage requests, logging the request URLs to submit download queries later on using rs_transfer.

Usage

rs_request(
  request,
  user,
  transfer = TRUE,
  path = tempdir(),
  time_out = 3600,
  job_name,
  verbose = TRUE
)
rs_request_batch(
  request_list,
  workers = 2,
  user,
  path = tempdir(),
  time_out = 7200,
  total_timeout = length(request_list) * time_out/workers,
  verbose = TRUE
)

Value

the path of the downloaded (requested file) or the an R6 object with download/transfer information

Arguments

request: nested list with query parameters following the layout as specified on the AppEEARS APIs page
user: user (email address or ID) provided by the AppEEARS data service, used to retrieve the token set by rs_set_key
transfer: logical, download data TRUE or FALSE (default = TRUE)
path: path were to store the downloaded data
time_out: individual time out for each request
job_name: optional name to use as an RStudio job and as output variable name. It has to be a syntactically valid name.
verbose: show feedback on processing
request_list: a list of requests that will be processed in parallel.
workers: maximum number of simultaneous request that will be submitted to the service. Most services are limited to ~20 concurrent requests (default = 2).
total_timeout: overall timeout limit for all the requests in seconds. (note that the overall timeout on a session is 48h)

Author

Koen Hufkens

Examples

Run this code


if (FALSE) {
# specify a task/request as a
# data frame
df <- data.frame(
 task = "grand canyon",
 subtask = c("test1", "test2"),
 latitude = c(36.206228, 36.206228),
 longitude = c(-112.127134, -112.127134),
 start = c("2018-01-01","2018-01-01"),
 end = c("2018-01-15","2018-01-15"),
 product = c("MOD11A2.061","MCD12Q2.006"),
 layer = c("LST_Day_1km","Dormancy")
)

# build a proper JSON query
task <- rs_build_task(df = df)

# request the task to be executed
rs_request(
 request = task,
 user = "earth_data_user",
 transfer = TRUE,
 path = "~/some_path",
 verbose = TRUE
)
}