Generate a classed http condition.
This function generate S3 condition objects which are passed to
stop() or warning() to generate classes warnings
and error. These can be used in conjunction with tryCatch()
to respond differently to different type of failure.
http_condition(x, type, task = NULL, call = sys.call(-1))
x |
a response, or numeric http code (or other object with
|
type |
type of condition to generate. Must be one of error, warning or message. |
task |
The text of the message: either |
call |
The call stored in the condition object. |
An S3 object that inherits from (e.g.) condition, type,
http_error, http_400 and http_404.
http://adv-r.had.co.nz/Exceptions-Debugging.html#condition-handling for more details about R's condition handling model
# You can use tryCatch to take different actions based on the type
# of error. Note that tryCatch will call the first handler that
# matches any classes of the condition, not the best matching, so
# always list handlers from most specific to least specific
f <- function(url) {
tryCatch(stop_for_status(GET(url)),
http_404 = function(c) "That url doesn't exist",
http_403 = function(c) "You need to authenticate!",
http_400 = function(c) "You made a mistake!",
http_500 = function(c) "The server screwed up"
)
}
f("http://httpbin.org/status/404")
f("http://httpbin.org/status/403")
f("http://httpbin.org/status/505")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.