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fauxpas does http errors!

  • HTTP error classes more in line with Ruby/Python/Etc. (psssttt: that is a good thing)
  • An error class for each HTTP status in case a user wants to be specific to an HTTP status code, and general purpose handlers for any error
  • Work with any of the major R http clients: crul, curl, httr (maybe RCurl later)
  • Provide flexiblity for what to do on an HTTP error, including custom functions and message templates

To see example of fauxpas usage in other packages, check out the code within any of:

There are a lot of functions in this package. Don’t be scared away by that. There are a few major sets of functions that are easy to understand and use:

  • There’s a function http() that is a general purpose function that handles any HTTP status codes. There’s also a set of functions that follow the pattern http*() where * is a HTTP status code (e.g. http201()). You can use the general purpose function http() or the one specific to the status code you are interested in.
  • There’s a lower level R6 class Error that is wrapped by http() that like http() is a general purpose function that handles any HTTP status codes. There’s also a set of R6 classes that follow the pattern HTTP*() where * is a HTTP name (e.g. HTTPGatewayTimeout). You can use the general purpose class Error() or the one specific to the status you are interested in.

fauxpas uses httpcode under the hood - which holds all the info about HTTP status codes.

Install

CRAN version

install.packages("fauxpas")

Dev version

# install.packages("remotes")
remotes::install_github("ropensci/fauxpas")

Find classes for a HTTP status code

When using fauxpas in another package I personally like to use the HTTP* classes.

Since these are named with their HTTP reason (e.g. HTTPGatewayTimeout), it’s not super straightforward to find them with a status code, which is what one always has as a response from a server. A good way to find these is with a new function find_error_class(). Just pass the function a HTTP status code and it will find the matching class.

(x <- find_error_class(418))
#> <HTTPTeaPot> object generator
#>   Inherits from: <Error>
#>   Public:
#>     name: HTTPTeaPot
#>     status_code: 418
#>     mssg: 
#>     do_verbose: function (response, template = self$message_template_verbose) 
#>     clone: function (deep = FALSE) 
#>   Parent env: <environment: 0x55860bfe6e30>
#>   Locked objects: TRUE
#>   Locked class: FALSE
#>   Portable: TRUE

Which returns the matching error class object, with which you can initialize a new object:

x$new()
#> <HTTPTeaPot>
#>   behavior: stop
#>   message_template: {{reason}} (HTTP {{status}})
#>   message_template_verbose: {{reason}} (HTTP {{status}}).\n - {{message}}

If you pass it a status code it doesn’t know about it errors

find_error_class(999)
#> Error in find_error_class(999) : no method found for 999

Use fauxpas with HTTP clients

crul

library("crul")
cli <- HttpClient$new("https://httpbin.org/status/414")
res <- cli$get()
http(res)
#> Error: Request-URI Too Long (HTTP 414).
http414(res)
#> Error: Request-URI Too Long (HTTP 414).
x <- HTTPRequestURITooLong$new()
x$do_verbose(res)
#> Error: Request-URI Too Long (HTTP 414).
#> - The server is refusing to service the request because the Request-URI is
#>    longer than the server is willing to interpret. This rare condition is only likely
#>    to occur when a client has improperly converted a POST request to a GET request
#>    with long query information, when the client has descended into a URI black hole
#>    of redirection (e.g., a redirected URI prefix that points to a suffix of itself),
#>    or when the server is under attack by a client attempting to exploit security
#>    holes present in some servers using fixed-length buffers for reading or
#>    manipulating the Request-URI.

curl

library("curl")
h <- curl::new_handle()
curl::handle_setopt(h)
resp <- curl::curl_fetch_memory("https://httpbin.org/status/404", h)
http(resp)
#> Error: Not Found (HTTP 404).
http404(resp)
#> Error: Not Found (HTTP 404).
x <- HTTPNotFound$new()
x$do_verbose(resp)
#> Error:  Not Found (HTTP 404).
#>  - The server has not found anything matching the Request-URI. No indication is
#> given of whether the condition is temporary or permanent. The 410 (Gone) status
#> code SHOULD be used if the server knows, through some internally configurable
#> mechanism, that an old resource is permanently unavailable and has no forwarding
#> address. #> This status code is commonly used when the server does not wish to
#> reveal exactly why the request has been refused, or when no other response is
#> applicable.

httr

library("httr")
res <- GET("https://httpbin.org/status/405")
http405(res)
#> Error: Method Not Allowed (HTTP 405).
x <- HTTPMethodNotAllowed$new()
x$do_verbose(res)
#> Error: Method Not Allowed (HTTP 405).
#>  - The method specified in the Request-Line is not allowed for the resource
#> identified by the Request-URI. The response MUST include an Allow header
#> containing a list of valid methods for the requested resource.