An HTTP client, taking inspiration from Ruby's faraday and Python's requests
Package API:
HttpClient
- Main interface to making HTTP requests. Synchronous requests only.HttpResponse
- HTTP response object, used for all responses across the different clients.Paginator
- Auto-paginate through requests - supports a subset of all possible pagination scenarios - will fill out more scenarios soonAsync
- Asynchronous HTTP requests - a simple interface for many URLS - whose interface is similar toHttpClient
- all URLs are treated the same.AsyncVaried
- Asynchronous HTTP requests - accepts any number ofHttpRequest
objects - with a different interface thanHttpClient
/Async
due to the nature of handling requests with different HTTP methods, options, etc.HttpRequest
- HTTP request object, used forAsyncVaried
mock()
- Turn on/off mocking, viawebmockr
auth()
- Simple authentication helperproxy()
- Proxy helperupload()
- File upload helper- set curl options globally:
set_auth()
,set_headers()
,set_opts()
,set_proxy()
, andcrul_settings()
- Writing to disk and streaming: available with both synchronous requests as well as async requests
- Hooks on requests and responses are available in the
HttpClient
method only, and allow you to trigger functions to run on requests or responses, or both. See?hooks
for the details and examples
Mocking:
crul
now integrates with webmockr to mock
HTTP requests. Checkout the http testing book
Caching:
crul
also integrates with vcr to cache http requests/responses. Checkout the http testing book
CRAN version
install.packages("crul")
Dev version
devtools::install_github("ropensci/crul")
library("crul")
HttpClient
is where to start
(x <- HttpClient$new(
url = "https://httpbin.org",
opts = list(
timeout = 1
),
headers = list(
a = "hello world"
)
))
#> <crul connection>
#> url: https://httpbin.org
#> curl options:
#> timeout: 1
#> proxies:
#> auth:
#> headers:
#> a: hello world
#> progress: FALSE
#> hooks:
Makes an R6 class, that has all the bits and bobs you'd expect for doing HTTP requests. When it prints, it gives any defaults you've set. As you update the object you can see what's been set
x$opts
#> $timeout
#> [1] 1
x$headers
#> $a
#> [1] "hello world"
You can also pass in curl options when you make HTTP requests, see below for examples.
The client object created above has http methods that you can call, and pass paths to, as well as query parameters, body values, and any other curl options.
Here, we'll do a GET request on the route /get
on our base url
https://httpbin.org
(the full url is then https://httpbin.org/get
)
res <- x$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$status_code
#> [1] 200
Status information
res$status_http()
#> <Status code: 200>
#> Message: OK
#> Explanation: Request fulfilled, document follows
The content
res$content
#> [1] 7b 0a 20 20 22 61 72 67 73 22 3a 20 7b 7d 2c 20 0a 20 20 22 68 65 61
#> [24] 64 65 72 73 22 3a 20 7b 0a 20 20 20 20 22 41 22 3a 20 22 68 65 6c 6c
#> [47] 6f 20 77 6f 72 6c 64 22 2c 20 0a 20 20 20 20 22 41 63 63 65 70 74 22
#> [70] 3a 20 22 61 70 70 6c 69 63 61 74 69 6f 6e 2f 6a 73 6f 6e 2c 20 74 65
#> [93] 78 74 2f 78 6d 6c 2c 20 61 70 70 6c 69 63 61 74 69 6f 6e 2f 78 6d 6c
#> [116] 2c 20 2a 2f 2a 22 2c 20 0a 20 20 20 20 22 41 63 63 65 70 74 2d 45 6e
#> [139] 63 6f 64 69 6e 67 22 3a 20 22 67 7a 69 70 2c 20 64 65 66 6c 61 74 65
#> [162] 22 2c 20 0a 20 20 20 20 22 48 6f 73 74 22 3a 20 22 68 74 74 70 62 69
#> [185] 6e 2e 6f 72 67 22 2c 20 0a 20 20 20 20 22 55 73 65 72 2d 41 67 65 6e
#> [208] 74 22 3a 20 22 6c 69 62 63 75 72 6c 2f 37 2e 35 34 2e 30 20 72 2d 63
#> [231] 75 72 6c 2f 33 2e 33 20 63 72 75 6c 2f 30 2e 37 2e 34 22 0a 20 20 7d
#> [254] 2c 20 0a 20 20 22 6f 72 69 67 69 6e 22 3a 20 22 36 35 2e 31 39 37 2e
#> [277] 31 34 36 2e 31 38 2c 20 36 35 2e 31 39 37 2e 31 34 36 2e 31 38 22 2c
#> [300] 20 0a 20 20 22 75 72 6c 22 3a 20 22 68 74 74 70 73 3a 2f 2f 68 74 74
#> [323] 70 62 69 6e 2e 6f 72 67 2f 67 65 74 22 0a 7d 0a
HTTP method
res$method
#> [1] "get"
Request headers
res$request_headers
#> $`User-Agent`
#> [1] "libcurl/7.54.0 r-curl/3.3 crul/0.7.4"
#>
#> $`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"
#>
#> $`access-control-allow-credentials`
#> [1] "true"
#>
#> $`access-control-allow-origin`
#> [1] "*"
#>
#> $`content-encoding`
#> [1] "gzip"
#>
#> $`content-type`
#> [1] "application/json"
#>
#> $date
#> [1] "Wed, 27 Mar 2019 23:58:45 GMT"
#>
#> $server
#> [1] "nginx"
#>
#> $`content-length`
#> [1] "228"
#>
#> $connection
#> [1] "keep-alive"
All response headers - e.g., intermediate headers
res$response_headers_all
And you can parse the content with parse()
res$parse()
#> No encoding supplied: defaulting to UTF-8.
#> [1] "{\n \"args\": {}, \n \"headers\": {\n \"A\": \"hello world\", \n \"Accept\": \"application/json, text/xml, application/xml, */*\", \n \"Accept-Encoding\": \"gzip, deflate\", \n \"Host\": \"httpbin.org\", \n \"User-Agent\": \"libcurl/7.54.0 r-curl/3.3 crul/0.7.4\"\n }, \n \"origin\": \"65.197.146.18, 65.197.146.18\", \n \"url\": \"https://httpbin.org/get\"\n}\n"
jsonlite::fromJSON(res$parse())
#> No encoding supplied: defaulting to UTF-8.
#> $args
#> named list()
#>
#> $headers
#> $headers$A
#> [1] "hello world"
#>
#> $headers$Accept
#> [1] "application/json, text/xml, application/xml, */*"
#>
#> $headers$`Accept-Encoding`
#> [1] "gzip, deflate"
#>
#> $headers$Host
#> [1] "httpbin.org"
#>
#> $headers$`User-Agent`
#> [1] "libcurl/7.54.0 r-curl/3.3 crul/0.7.4"
#>
#>
#> $origin
#> [1] "65.197.146.18, 65.197.146.18"
#>
#> $url
#> [1] "https://httpbin.org/get"
res <- HttpClient$new(url = "http://api.gbif.org/v1/occurrence/search")
res$get(query = list(limit = 100), timeout_ms = 100)
#> Error in curl::curl_fetch_memory(x$url$url, handle = x$url$handle) :
#> Timeout was reached
The simpler interface allows many requests (many URLs), but they all get the same options/headers, etc. and you have to use the same HTTP method on all of them:
(cc <- Async$new(
urls = c(
'https://httpbin.org/',
'https://httpbin.org/get?a=5',
'https://httpbin.org/get?foo=bar'
)
))
res <- cc$get()
lapply(res, function(z) z$parse("UTF-8"))
The AsyncVaried
interface accepts any number of HttpRequest
objects, which
can define any type of HTTP request of any HTTP method:
req1 <- HttpRequest$new(
url = "https://httpbin.org/get",
opts = list(verbose = TRUE),
headers = list(foo = "bar")
)$get()
req2 <- HttpRequest$new(url = "https://httpbin.org/post")$post()
out <- AsyncVaried$new(req1, req2)
Execute the requests
out$request()
Then functions get applied to all responses:
out$status()
#> [[1]]
#> <Status code: 200>
#> Message: OK
#> Explanation: Request fulfilled, document follows
#>
#> [[2]]
#> <Status code: 200>
#> Message: OK
#> Explanation: Request fulfilled, document follows
out$parse()
#> [1] "{\n \"args\": {}, \n \"headers\": {\n \"Accept\": \"application/json, text/xml, application/xml, */*\", \n \"Accept-Encoding\": \"gzip, deflate\", \n \"Foo\": \"bar\", \n \"Host\": \"httpbin.org\", \n \"User-Agent\": \"R (3.5.3 x86_64-apple-darwin15.6.0 x86_64 darwin15.6.0)\"\n }, \n \"origin\": \"65.197.146.18, 65.197.146.18\", \n \"url\": \"https://httpbin.org/get\"\n}\n"
#> [2] "{\n \"args\": {}, \n \"data\": \"\", \n \"files\": {}, \n \"form\": {}, \n \"headers\": {\n \"Accept\": \"application/json, text/xml, application/xml, */*\", \n \"Accept-Encoding\": \"gzip, deflate\", \n \"Content-Length\": \"0\", \n \"Content-Type\": \"application/x-www-form-urlencoded\", \n \"Host\": \"httpbin.org\", \n \"User-Agent\": \"libcurl/7.54.0 r-curl/3.3 crul/0.7.4\"\n }, \n \"json\": null, \n \"origin\": \"65.197.146.18, 65.197.146.18\", \n \"url\": \"https://httpbin.org/post\"\n}\n"
library(httr)
x <- HttpClient$new(
url = "https://httpbin.org/bytes/102400",
progress = progress()
)
z <- x$get()
|==============================================| 100%
- ...
- Please report any issues or bugs.
- License: MIT
- Get citation information for
crul
in R doingcitation(package = 'crul')
- Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.