ncurl_session: ncurl Session

In nanonext: NNG (Nanomsg Next Gen) Lightweight Messaging Library

ncurl Session

Description

nano cURL - a minimalist http(s) client. A session encapsulates a connection, along with all related parameters, and may be used to return data multiple times by repeatedly calling transact(), which transacts once over the connection.

Usage

ncurl_session(
  url,
  convert = TRUE,
  method = NULL,
  headers = NULL,
  data = NULL,
  response = NULL,
  timeout = NULL,
  tls = NULL
)

transact(session)

Arguments

url	the URL address.
convert	[default TRUE] logical value whether to attempt conversion of the received raw bytes to a character vector. Set to FALSE if downloading non-text data.
method	(optional) the HTTP method as a character string. Defaults to 'GET' if not specified, and could also be 'POST', 'PUT' etc.
headers	(optional) a named character vector specifying the HTTP request headers, for example: c(Authorization = "Bearer APIKEY", "Content-Type" = "text/plain") A non-character or non-named vector will be ignored.
data	(optional) character string request data to be submitted. If a vector, only the first element is taken, and non-character objects are ignored.
response	(optional) a character vector specifying the response headers to return e.g. c("date", "server"). These are case-insensitive and will return NULL if not present. A non-character vector will be ignored.
timeout	(optional) integer value in milliseconds after which the connection and subsequent transact attempts time out.
tls	(optional) applicable to secure HTTPS sites only, a client TLS Configuration object created by tls_config(). If missing or NULL, certificates are not validated.
session	an 'ncurlSession' object.

Value

For ncurl_session: an 'ncurlSession' object if successful, or else an 'errorValue'.

For transact: a named list of 3 elements:

• ⁠$status⁠ - integer HTTP repsonse status code (200 - OK). Use status_code() for a translation of the meaning.

• ⁠$headers⁠ - named list of response headers (if specified in the session), or NULL otherwise. If the status code is within the 300 range, i.e. a redirect, the response header 'Location' is automatically appended to return the redirect address.

• ⁠$data⁠ - the response body as a character string (if convert = TRUE was specified for the session), which may be further parsed as html, json, xml etc. as required, or else a raw byte vector, which may be saved as a file using writeBin().

See Also

ncurl() for synchronous http requests; ncurl_aio() for asynchronous http requests.

Examples

s <- ncurl_session("https://postman-echo.com/get",
                   response = "date",
                   timeout = 2000L)
s
if (is_ncurl_session(s)) transact(s)
if (is_ncurl_session(s)) close(s)

nanonext documentation built on April 4, 2025, 5:18 a.m.