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@branneman
Last active Dec 16, 2021
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Racket: How to do HTTP requests
#lang racket/base
(require
net/http-easy)
(define (base-url path)
(string-append "https://httpbin.org" path))
; request: GET
; response: plain string body
(response-body
(get (base-url "/html")))
; request: GET
; response: json body
(response-json
(get (base-url "/json")))
; request: GET
; response: ignore body, take headers
(response-headers
(get (base-url "/json")))
; request: GET auth bearer request header
; response: ignore body, validate http status code, take set-cookie response header
(let ([res (get (base-url "/bearer")
#:auth (bearer-auth "secret"))])
(when (not (= 200 (response-status-code res)))
(error "not 200!"))
(response-headers-ref res 'server))
; request: POST form fields body
; response: ignore body, validate http status code
(response-status-code
(post (base-url "/post")
#:form '((k1 . "v1")
(k2 . "v2"))))
; request: POST json body
; response: json body
(response-json
(post (base-url "/post")
#:json (hasheq 'foo "bar")))
#lang racket/base
(require
racket/port
net/uri-codec
net/url
net/url-connect
http/head
json)
(define (base-url path)
(string->url (string-append "https://httpbin.org" path)))
(define (heads-string->dict-downcase heads-string)
(for/hash ([(k v) (heads-string->dict heads-string)])
(values (string->symbol (string-downcase (symbol->string k))) v)))
; Don't ignore (a potentially) invalid tls certificate
(current-https-protocol 'secure)
; request: GET
; response: plain string body
(call/input-url
(base-url "/html")
get-pure-port
port->string)
; request: GET
; response: json body
(call/input-url
(base-url "/json")
get-pure-port
read-json)
; request: GET
; response: ignore body, take headers
(call/input-url
(base-url "/json")
get-impure-port
(λ (in) (heads-string->dict-downcase (purify-port in))))
; request: GET auth bearer request header
; response: ignore body, validate http status code, take set-cookie response header
(call/input-url
(base-url "/bearer")
(λ (url) (get-impure-port
url
'("authorization: Bearer secret")))
(λ (in)
(let ([heads-string (purify-port in)])
(when (not (= 200 (extract-http-code heads-string)))
(error "not 200!"))
(hash-ref (heads-string->dict-downcase heads-string) 'server))))
; request: POST form fields body
; response: ignore body, validate http status code
(call/input-url
(base-url "/post")
(λ (url) (post-impure-port
url
(string->bytes/utf-8 (alist->form-urlencoded
(list (cons 'k1 "v1") (cons 'k2 "v2"))))
'("content-type: application/x-www-form-urlencoded; charset=utf-8")))
(compose extract-http-code purify-port))
; request: POST json body
; response: json body
(call/input-url
(base-url "/post")
(λ (url) (post-pure-port
url
#"{\"foo\":\"bar\"}"
'("content-type: application/json; charset=utf-8")))
read-json)
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