▼Net:   Networking Libraries
►1 HTTP Client
On this page:
http-conn?
http-conn-live?
http-conn
http-conn-open!
http-conn-open
http-conn-close!
http-conn-abandon!
http-conn-send!
http-conn-recv!
http-conn-sendrecv!
http-sendrecv
data-procedure/  c
1.1 Troubleshooting and Tips
1.1.1 How do I send properly formatted POST form requests?
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1 HTTP Client

 (require net/http-client) package: base
The net/http-client library provides utilities to use the HTTP protocol.

procedure

(http-conn? x) → boolean?

  x : any/c
Identifies an HTTP connection.

procedure

(http-conn-live? x) → boolean?

  x : any/c
Identifies an HTTP connection that is "live", i.e. one for which http-conn-send! is valid.

procedure

(http-conn) → http-conn?

Returns a fresh HTTP connection.

procedure

(http-conn-open! hc    
  host    
  [#:ssl? ssl?    
  #:port port]) → void?
  hc : http-conn?
  host : (or/c bytes? string?)
  ssl? : (or/c boolean? ssl-client-context? symbol?) = #f
  port : (between/c 1 65535) = (if ssl? 443 80)
Uses hc to connect to host on port port using SSL if ssl? is not #f (using ssl? as an argument to ssl-connect to, for example, check certificates.)

If hc is live, the connection is closed.

procedure

(http-conn-open host    
  [#:ssl? ssl?    
  #:port port]) → http-conn?
  host : (or/c bytes? string?)
  ssl? : (or/c boolean? ssl-client-context? symbol?) = #f
  port : (between/c 1 65535) = (if ssl? 443 80)
Calls http-conn-open! with a fresh connection, which is returned.

procedure

(http-conn-close! hc) → void?

  hc : http-conn?
Closes hc if it is live.

procedure

(http-conn-abandon! hc) → void?

  hc : http-conn?
Closes the output side of hc, if it is live.

procedure

(http-conn-send! hc    
  uri    
  [#:version version    
  #:method method    
  #:close? close?    
  #:headers headers    
  #:content-decode decodes    
  #:data data]) → void?
  hc : http-conn-live?
  uri : (or/c bytes? string?)
  version : (or/c bytes? string?) = #"1.1"
  method : (or/c bytes? string? symbol?) = #"GET"
  close? : boolean? = #f
  headers : (listof (or/c bytes? string?)) = empty
  decodes : (listof symbol?) = '(gzip)
  data : (or/c false/c bytes? string? data-procedure/c) = #f
Sends an HTTP request to hc to the URI uri using HTTP version version, the method method, and the additional headers given in headers and the additional data data. If method is #"HEAD" (or "HEAD" or 'HEAD), provide the same method when calling http-conn-recv! to avoid attempting to receive content.

If data is a procedure, it will be called once with a procedure of one argument, which is a string or byte string to be written to the request body using chunked transfer encoding.

If headers does not contain an Accept-Encoding header, then a header indicating that encodings from decodes are accepted is automatically added.

If close? is #t and headers does not contain a Connection header, then a Connection: close header will be added.

This function does not support requests that expect 100 (Continue) responses.

procedure

(http-conn-recv! hc 
  [#:content-decode decodes 
  #:method method 
  #:close? close?]) 
 → 
bytes? (listof bytes?) input-port?
  hc : http-conn-live?
  decodes : (listof symbol?) = '(gzip)
  method : (or/c bytes? string? symbol?) = #"GET"
  close? : boolean? = #f
Parses an HTTP response from hc for the method method while decoding the encodings listed in decodes.

Returns the status line, a list of headers, and an port which contains the contents of the response. The port’s content must be consumed before the connection is used further.

If close? is #t, then the connection will be closed following the response parsing. If close? is #f, then the connection is only closed if the server instructs the client to do so.

Changed in version 6.1.1.6 of package base: Added the #:method argument.

procedure

(http-conn-sendrecv! hc 
  uri 
  [#:version version 
  #:method method 
  #:headers headers 
  #:data data 
  #:content-decode decodes 
  #:close? close?]) 
 → 
bytes? (listof bytes?) input-port?
  hc : http-conn-live?
  uri : (or/c bytes? string?)
  version : (or/c bytes? string?) = #"1.1"
  method : (or/c bytes? string? symbol?) = #"GET"
  headers : (listof (or/c bytes? string?)) = empty
  data : (or/c false/c bytes? string? data-procedure/c) = #f
  decodes : (listof symbol?) = '(gzip)
  close? : boolean? = #f
Calls http-conn-send! and http-conn-recv! in sequence.

procedure

(http-sendrecv host 
  uri 
  [#:ssl? ssl? 
  #:port port 
  #:version version 
  #:method method 
  #:headers headers 
  #:data data 
  #:content-decode decodes]) 
 → 
bytes? (listof bytes?) input-port?
  host : (or/c bytes? string?)
  uri : (or/c bytes? string?)
  ssl? : (or/c boolean? ssl-client-context? symbol?) = #f
  port : (between/c 1 65535) = (if ssl? 443 80)
  version : (or/c bytes? string?) = #"1.1"
  method : (or/c bytes? string? symbol?) = #"GET"
  headers : (listof (or/c bytes? string?)) = empty
  data : (or/c false/c bytes? string? data-procedure/c) = #f
  decodes : (listof symbol?) = '(gzip)
Calls http-conn-send! and http-conn-recv! in sequence on a fresh HTTP connection produced by http-conn-open.

The HTTP connection is not returned, so it is always closed after one response, which is why there is no #:closed? argument like http-conn-recv!.

value

data-procedure/c : chaperone-contract?

Contract for a procedure that accepts a procedure of one argument, which is a string or byte string: (-> (-> (or/c bytes? string?) void?) any).

1.1 Troubleshooting and Tips

1.1.1 How do I send properly formatted POST form requests?

You should send a Content-Type header with the value application/x-www-form-urlencoded and send the data formatted by net/uri-codec’s form-urlencoded-encode function. For example,

(http-send!
   hc "/login"
   #:method "POST"
   #:data
   (alist->form-urlencoded
    (list (cons 'username "Ryu")
          (cons 'password "Sheng Long")))
   #:headers (list "Content-Type: application/x-www-form-urlencoded"))
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