crul
is an HTTP client for R.
Stable CRAN version
install.packages("crul")
Dev version
install.packages("pak") pak::pkg_install("ropensci/crul")
library("crul")
HttpClient
is where to start
(x <- HttpClient$new( url = "https://hb.opencpu.org", opts = list( timeout = 1 ), headers = list( a = "hello world" ) )) #> <crul connection> #> url: https://hb.opencpu.org #> curl options: #> timeout: 1 #> proxies: #> auth: #> headers: #> a: hello world #> progress: FALSE #> hooks:
Makes a R6 class, that has all the bits and bobs you'd expect for doing HTTP requests. When it prints, it gives any defaults you've set. As you update the object you can see what's been set
x$opts #> $timeout #> [1] 1
x$headers #> $a #> [1] "hello world"
The client object created above has http methods that you can call, and pass paths to, as well as query parameters, body values, and any other curl options.
Here, we'll do a GET request on the route /get
on our base url
https://hb.opencpu.org
(the full url is then https://hb.opencpu.org/get
)
res <- x$get("get")
The response from a http request is another R6 class HttpResponse
, which
has slots for the outputs of the request, and some functions to deal with
the response:
Status code
res$status_code #> [1] 200
The content
res$content #> [1] 7b 0a 20 20 22 61 72 67 73 22 3a 20 7b 7d 2c 20 0a 20 20 22 68 65 61 64 65 #> [26] 72 73 22 3a 20 7b 0a 20 20 20 20 22 41 22 3a 20 22 68 65 6c 6c 6f 20 77 6f #> [51] 72 6c 64 22 2c 20 0a 20 20 20 20 22 41 63 63 65 70 74 22 3a 20 22 61 70 70 #> [76] 6c 69 63 61 74 69 6f 6e 2f 6a 73 6f 6e 2c 20 74 65 78 74 2f 78 6d 6c 2c 20 #> [101] 61 70 70 6c 69 63 61 74 69 6f 6e 2f 78 6d 6c 2c 20 2a 2f 2a 22 2c 20 0a 20 #> [126] 20 20 20 22 41 63 63 65 70 74 2d 45 6e 63 6f 64 69 6e 67 22 3a 20 22 67 7a #> [151] 69 70 2c 20 64 65 66 6c 61 74 65 22 2c 20 0a 20 20 20 20 22 43 6f 6e 6e 65 #> [176] 63 74 69 6f 6e 22 3a 20 22 63 6c 6f 73 65 22 2c 20 0a 20 20 20 20 22 48 6f #> [201] 73 74 22 3a 20 22 68 74 74 70 62 69 6e 3a 38 30 38 30 22 2c 20 0a 20 20 20 #> [226] 20 22 55 73 65 72 2d 41 67 65 6e 74 22 3a 20 22 6c 69 62 63 75 72 6c 2f 37 #> [251] 2e 38 37 2e 30 20 72 2d 63 75 72 6c 2f 35 2e 30 2e 30 20 63 72 75 6c 2f 31 #> [276] 2e 33 2e 39 31 30 30 22 0a 20 20 7d 2c 20 0a 20 20 22 6f 72 69 67 69 6e 22 #> [301] 3a 20 22 31 37 32 2e 31 38 2e 30 2e 34 22 2c 20 0a 20 20 22 75 72 6c 22 3a #> [326] 20 22 68 74 74 70 3a 2f 2f 68 74 74 70 62 69 6e 3a 38 30 38 30 2f 67 65 74 #> [351] 22 0a 7d 0a
HTTP method
res$method #> [1] "get"
Request headers
res$request_headers #> $`User-Agent` #> [1] "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100" #> #> $`Accept-Encoding` #> [1] "gzip, deflate" #> #> $Accept #> [1] "application/json, text/xml, application/xml, */*" #> #> $a #> [1] "hello world"
Response headers
res$response_headers #> $status #> [1] "HTTP/1.1 200 OK" #> #> $server #> [1] "nginx/1.20.2" #> #> $date #> [1] "Wed, 10 May 2023 21:55:58 GMT" #> #> $`content-type` #> [1] "application/json" #> #> $`content-length` #> [1] "354" #> #> $connection #> [1] "keep-alive" #> #> $`access-control-allow-origin` #> [1] "*" #> #> $`access-control-allow-credentials` #> [1] "true" #> #> $`x-powered-by` #> [1] "Flask" #> #> $`x-processed-time` #> [1] "0"
All response headers, including intermediate headers, if any
res$response_headers_all #> [[1]] #> [[1]]$status #> [1] "HTTP/1.1 200 OK" #> #> [[1]]$server #> [1] "nginx/1.20.2" #> #> [[1]]$date #> [1] "Wed, 10 May 2023 21:55:58 GMT" #> #> [[1]]$`content-type` #> [1] "application/json" #> #> [[1]]$`content-length` #> [1] "354" #> #> [[1]]$connection #> [1] "keep-alive" #> #> [[1]]$`access-control-allow-origin` #> [1] "*" #> #> [[1]]$`access-control-allow-credentials` #> [1] "true" #> #> [[1]]$`x-powered-by` #> [1] "Flask" #> #> [[1]]$`x-processed-time` #> [1] "0"
And you can parse the content with a provided function:
res$parse() #> [1] "{\n \"args\": {}, \n \"headers\": {\n \"A\": \"hello world\", \n \"Accept\": \"application/json, text/xml, application/xml, */*\", \n \"Accept-Encoding\": \"gzip, deflate\", \n \"Connection\": \"close\", \n \"Host\": \"httpbin:8080\", \n \"User-Agent\": \"libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100\"\n }, \n \"origin\": \"172.18.0.4\", \n \"url\": \"http://httpbin:8080/get\"\n}\n" jsonlite::fromJSON(res$parse()) #> $args #> named list() #> #> $headers #> $headers$A #> [1] "hello world" #> #> $headers$Accept #> [1] "application/json, text/xml, application/xml, */*" #> #> $headers$`Accept-Encoding` #> [1] "gzip, deflate" #> #> $headers$Connection #> [1] "close" #> #> $headers$Host #> [1] "httpbin:8080" #> #> $headers$`User-Agent` #> [1] "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100" #> #> #> $origin #> [1] "172.18.0.4" #> #> $url #> [1] "http://httpbin:8080/get"
With the HttpClient
object, which holds any configuration stuff
we set, we can make other HTTP verb requests. For example, a HEAD
request:
x$post( path = "post", body = list(hello = "world") )
x <- HttpClient$new(url = "https://hb.opencpu.org") f <- tempfile() res <- x$get(disk = f) # when using write to disk, content is a path res$content #> [1] "/var/folders/vw/4nm3x1ld0_jgmqy6_yf6pz3c0000gn/T//RtmpZ9O9vQ/file17033155d5263"
Read lines
readLines(res$content, n = 10) #> [1] "<!DOCTYPE html>" #> [2] "<html>" #> [3] "<head>" #> [4] " <meta http-equiv='content-type' value='text/html;charset=utf8'>" #> [5] " <meta name='generator' value='Ronn/v0.7.3 (http://github.com/rtomayko/ronn/tree/0.7.3)'>" #> [6] " <title>httpbin(1): HTTP Client Testing Service</title>" #> [7] " <style type='text/css' media='all'>" #> [8] " /* style: man */" #> [9] " body#manpage {margin:0}" #> [10] " .mp {max-width:100ex;padding:0 9ex 1ex 4ex}"
(x <- HttpClient$new(url = "https://hb.opencpu.org")) #> <crul connection> #> url: https://hb.opencpu.org #> curl options: #> proxies: #> auth: #> headers: #> progress: FALSE #> hooks: res <- x$get('stream/5', stream = function(x) cat(rawToChar(x))) #> {"url": "http://httpbin:8080/stream/5", "headers": {"Connection": "close", "Host": "httpbin:8080", "Accept-Encoding": "gzip, deflate", "Accept": "application/json, text/xml, application/xml, */*", "User-Agent": "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100"}, "args": {}, "id": 0, "origin": "172.18.0.4"} #> {"url": "http://httpbin:8080/stream/5", "headers": {"Connection": "close", "Host": "httpbin:8080", "Accept-Encoding": "gzip, deflate", "Accept": "application/json, text/xml, application/xml, */*", "User-Agent": "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100"}, "args": {}, "id": 1, "origin": "172.18.0.4"} #> {"url": "http://httpbin:8080/stream/5", "headers": {"Connection": "close", "Host": "httpbin:8080", "Accept-Encoding": "gzip, deflate", "Accept": "application/json, text/xml, application/xml, */*", "User-Agent": "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100"}, "args": {}, "id": 2, "origin": "172.18.0.4"} #> {"url": "http://httpbin:8080/stream/5", "headers": {"Connection": "close", "Host": "httpbin:8080", "Accept-Encoding": "gzip, deflate", "Accept": "application/json, text/xml, application/xml, */*", "User-Agent": "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100"}, "args": {}, "id": 3, "origin": "172.18.0.4"} #> {"url": "http://httpbin:8080/stream/5", "headers": {"Connection": "close", "Host": "httpbin:8080", "Accept-Encoding": "gzip, deflate", "Accept": "application/json, text/xml, application/xml, */*", "User-Agent": "libcurl/7.87.0 r-curl/5.0.0 crul/1.3.9100"}, "args": {}, "id": 4, "origin": "172.18.0.4"} # when streaming, content is NULL res$content #> NULL
Learn more with the other vignettes:
Any scripts or data that you put into this service are public.
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.