request
request is DSL for http requests for R, and is inspired by the CLI tool httpie.
request is built on httr, though may allow using the R packages RCurl or curl as optional backends at some point.
I gave a poster at User2016, its in my talks repo
Philosophy
- The web is increasingly a JSON world, so we assume
applications/jsonby default, but give back other types if not - The workflow follows logically, or at least should, from, hey, I got this url, to i need to add some options, to execute request
- Whenever possible, we transform output to data.frame's - facilitating downstream manipulation via
dplyr, etc. - We do
GETrequests by default. Specify a different type if you don't wantGET - You can use non-standard evaluation to easily pass in query parameters without worrying about
&'s, URL escaping, etc. (seeapi_query()) - Same for body params (see
api_body())
All of the defaults just mentioned can be changed.
Auto execute http requests with pipes
When using pipes, we autodetect that a pipe is being used within the function calls, and automatically do the appropriate http request on the last piped function call. When you call a function without using pipes, you have to use the http() function explicitly to make the http request.
low level http
Low level access is available with http_client(), which returns an R6 class with various methods for inspecting http request results.
Peek at a request
The function peep() let's you peek at a request without performing the http request.
Install
From CRAN
install.packages("request")Development version from GitHub
devtools::install_github("sckott/request")library("request")NSE and SE
NSE is supported
api('https://api.github.com/') %>%
api_path(repos, ropensci, rgbif, issues)as well as SE
api('https://api.github.com/') %>%
api_path_('repos', 'ropensci', 'rgbif', 'issues')Building API routes
Works with full or partial URLs
api('https://api.github.com/')
#> URL: https://api.github.com/
api('http://api.gbif.org/v1')
#> URL: http://api.gbif.org/v1
api('api.gbif.org/v1')
#> URL: api.gbif.org/v1Works with ports, full or partial
api('http://localhost:9200')
#> URL: http://localhost:9200
api('localhost:9200')
#> URL: http://localhost:9200
api(':9200')
#> URL: http://localhost:9200
api('9200')
#> URL: http://localhost:9200
api('9200/stuff')
#> URL: http://localhost:9200/stuffMake HTTP requests
The above examples with api() are not passed through a pipe, so only define a URL, but don't do an HTTP request. To make an HTTP request, you can either pipe a url or partial url to e.g., api(), or call http() at the end of a string of function calls:
'https://api.github.com/' %>% api()
#> $current_user_url
#> [1] "https://api.github.com/user"
#>
#> $current_user_authorizations_html_url
#> [1] "https://github.com/settings/connections/applications{/client_id}"
#>
#> $authorizations_url
#> [1] "https://api.github.com/authorizations"
#>
#> $code_search_url
...Or
api('https://api.github.com/') %>% http()
#> $current_user_url
#> [1] "https://api.github.com/user"
#>
#> $current_user_authorizations_html_url
#> [1] "https://github.com/settings/connections/applications{/client_id}"
#>
#> $authorizations_url
#> [1] "https://api.github.com/authorizations"
#>
#> $code_search_url
...http() is called at the end of a chain of piped commands, so no need to invoke it. However, you can if you like.
Templating
repo_info <- list(username = 'craigcitro', repo = 'r-travis')
api('https://api.github.com/') %>%
api_template(template = 'repos/{{username}}/{{repo}}/issues', data = repo_info) %>%
peep
#> <http request>
#> url: https://api.github.com/
#> paths:
#> query:
#> body:
#> paging:
#> headers:
#> rate limit:
#> retry (n/delay (s)): /
#> error handler:
#> config:Set paths
api_path() adds paths to the base URL (see api_query()) for query parameters
api('https://api.github.com/') %>%
api_path(repos, ropensci, rgbif, issues) %>%
peep
#> <http request>
#> url: https://api.github.com/
#> paths: repos/ropensci/rgbif/issues
#> query:
#> body:
#> paging:
#> headers:
#> rate limit:
#> retry (n/delay (s)): /
#> error handler:
#> config:Query
api("http://api.plos.org/search") %>%
api_query(q = ecology, wt = json, fl = 'id,journal') %>%
peep
#> <http request>
#> url: http://api.plos.org/search
#> paths:
#> query: q=ecology, wt=json, fl=id,journal
#> body:
#> paging:
#> headers:
#> rate limit:
#> retry (n/delay (s)): /
#> error handler:
#> config:ToDo
See the issues for discussion of these
- Paging
- Retry
- Rate limit
Meta
- 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.
