curl: handle – R documentation

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handle

Create and configure a curl handle

Description

Handles are the work horses of libcurl. A handle is used to configure a request with custom options, headers and payload. Once the handle has been set up, it can be passed to any of the download functions such as curl ,curl_download or curl_fetch_memory. The handle will maintain state in between requests, including keep-alive connections, cookies and settings.

Usage

new_handle(...)

handle_setopt(handle, ..., .list = list())

handle_setheaders(handle, ..., .list = list())

handle_getheaders(handle)

handle_getcustom(handle)

handle_setform(handle, ..., .list = list())

handle_reset(handle)

handle_data(handle)

Arguments

`...`	named options / headers to be set in the handle. To send a file, see `form_file`. To list all allowed options, see `curl_options`
`handle`	Handle to modify
`.list`	A named list of options. This is useful if you've created a list of options elsewhere, avoiding the use of `do.call()`.

Details

Use new_handle() to create a new clean curl handle that can be configured with custom options and headers. Note that handle_setopt appends or overrides options in the handle, whereas handle_setheaders replaces the entire set of headers with the new ones. The handle_reset function resets only options/headers/forms in the handle. It does not affect active connections, cookies or response data from previous requests. The safest way to perform multiple independent requests is by using a separate handle for each request. There is very little performance overhead in creating handles.

Value

A handle object (external pointer to the underlying curl handle). All functions modify the handle in place but also return the handle so you can create a pipeline of operations.

Examples

h <- new_handle()
handle_setopt(h, customrequest = "PUT")
handle_setform(h, a = "1", b = "2")
r <- curl_fetch_memory("http://httpbin.org/put", h)
cat(rawToChar(r$content))

# Or use the list form
h <- new_handle()
handle_setopt(h, .list = list(customrequest = "PUT"))
handle_setform(h, .list = list(a = "1", b = "2"))
r <- curl_fetch_memory("http://httpbin.org/put", h)
cat(rawToChar(r$content))

curl

A Modern and Flexible Web Client for R

v4.3.1

MIT + file LICENSE

Authors

Jeroen Ooms [aut, cre] (<https://orcid.org/0000-0002-4035-0289>), Hadley Wickham [ctb], RStudio [cph]

Initial release