redcap_file_download_oneshot function

Download a file from a REDCap project record

This function uses REDCap's API to download a file.

redcap_file_download_oneshot(
  file_name = NULL,
  directory = NULL,
  overwrite = FALSE,
  redcap_uri,
  token,
  record,
  field,
  event = "",
  repeat_instance = NULL,
  verbose = TRUE,
  config_options = NULL,
  handle_httr = NULL
)

Arguments

• file_name: The name of the file where the downloaded file is saved. If empty the original name of the file will be used and saved in the default directory. Optional.
• directory: The directory where the file is saved. By default current directory. Optional
• overwrite: Boolean value indicating if existing files should be overwritten. Optional
• redcap_uri: The uri/url of the REDCap server typically formatted as "https://server.org/apps/redcap/api/". Required.
• token: The user-specific string that serves as the password for a project. Required.
• record: The record ID where the file is to be imported. Required
• field: The name of the field where the file is saved in REDCap. Required
• event: The name of the event where the file is saved in REDCap. Optional
• repeat_instance: (only for projects with repeating instruments/events) The repeat instance number of the repeating event (if longitudinal) or the repeating instrument (if classic or longitudinal). Default value is '1'. Optional
• verbose: A boolean value indicating if messages should be printed to the R console during the operation. Optional.
• config_options: A list of options passed to httr::POST(). See details at httr::httr_options(). Optional.
• handle_httr: The value passed to the handle parameter of httr::POST(). This is useful for only unconventional authentication approaches. It should be NULL for most institutions. Optional.

Returns

Currently, a list is returned with the following elements,

• success: A boolean value indicating if the operation was apparently successful.

• status_code: The http status code

  of the operation.

• outcome_message: A human readable string indicating the operation's outcome.

• records_affected_count: The number of records inserted or updated.

• affected_ids: The subject IDs of the inserted or updated records.

• elapsed_seconds: The duration of the function.

• raw_text: If an operation is NOT successful, the text returned by REDCap. If an operation is successful, the raw_text is returned as an empty string to save RAM.

• file_name: The name of the file persisted to disk. This is useful if the name stored in REDCap is used (which is the default).

Details

For files in a repeating instrument, don't specify repeating_instrument. The server only needs field (name) and repeating_instance.

The function redcap_download_file_oneshot() is soft-deprecated as of REDCapR 1.2.0. Please rename to redcap_file_download_oneshot().

Examples

## Not run:

uri     <- "https://redcap-dev-2.ouhsc.edu/redcap/api/"
token   <- "F9CBFFF78C3D78F641BAE9623F6B7E6A" # simple-write
record  <- 1
field   <- "mugshot"
# event <- "" # only for longitudinal projects

result_1 <- REDCapR::redcap_file_download_oneshot(
  record        = record,
  field         = field,
  redcap_uri    = uri,
  token         = token
)
base::unlink("mugshot-1.jpg")

(full_name <- base::tempfile(pattern="mugshot", fileext = ".jpg"))
result_2   <- REDCapR::redcap_file_download_oneshot(
  file_name     = full_name,
  record        = record,
  field         = field,
  redcap_uri    = uri,
  token         = token
)
base::unlink(full_name)

(relative_name <- "ssss.jpg")
result_3 <- REDCapR::redcap_file_download_oneshot(
  file_name    = relative_name,
  record       = record,
  field        = field,
  redcap_uri   = uri,
  token        = token
)
base::unlink(relative_name)
## End(Not run)

References

The official documentation can be found on the 'API Help Page' and 'API Examples' pages on the REDCap wiki (i.e., https://community.projectredcap.org/articles/456/api-documentation.html and https://community.projectredcap.org/articles/462/api-examples.html). If you do not have an account for the wiki, please ask your campus REDCap administrator to send you the static material.

Author(s)

Will Beasley, John J. Aponte