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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/req-perform-stream.R
\name{req_perform_stream}
\alias{req_perform_stream}
\title{Perform a request and handle data as it streams back}
\usage{
req_perform_stream(
req,
callback,
timeout_sec = Inf,
buffer_kb = 64,
round = c("byte", "line")
)
}
\arguments{
\item{req}{A httr2 \link{request} object.}
\item{callback}{A single argument callback function. It will be called
repeatedly with a raw vector whenever there is at least \code{buffer_kb}
worth of data to process. It must return \code{TRUE} to continue streaming.}
\item{timeout_sec}{Number of seconds to process stream for.}
\item{buffer_kb}{Buffer size, in kilobytes.}
\item{round}{How should the raw vector sent to \code{callback} be rounded?
Choose \code{"byte"}, \code{"line"}, or supply your own function that takes a
raw vector of \code{bytes} and returns the locations of possible cut points
(or \code{integer()} if there are none).}
}
\value{
An HTTP \link{response}. The body will be empty if the request was
successful (since the \code{callback} function will have handled it). The body
will contain the HTTP response body if the request was unsuccessful.
}
\description{
\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}}
Please use \code{\link[=req_perform_connection]{req_perform_connection()}} instead.
After preparing a request, call \code{req_perform_stream()} to perform the request
and handle the result with a streaming callback. This is useful for
streaming HTTP APIs where potentially the stream never ends.
The \code{callback} will only be called if the result is successful. If you need
to stream an error response, you can use \code{\link[=req_error]{req_error()}} to suppress error
handling so that the body is streamed to you.
}
\examples{
# PREVIOSULY
show_bytes <- function(x) {
cat("Got ", length(x), " bytes\n", sep = "")
TRUE
}
resp <- request(example_url()) |>
req_url_path("/stream-bytes/100000") |>
req_perform_stream(show_bytes, buffer_kb = 32)
# NOW
resp <- request(example_url()) |>
req_url_path("/stream-bytes/100000") |>
req_perform_connection()
while (!resp_stream_is_complete(resp)) {
x <- resp_stream_raw(resp, kb = 32)
cat("Got ", length(x), " bytes\n", sep = "")
}
close(resp)
}
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