http_open/3 with method option

src/lib/http/http_open.pl

@@ -1,5 +1,5 @@
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-   Written 2020, 2021 by Markus Triska (triska@metalevel.at)
+   Written 2022 by Adrián Arroyo Calle (adrian.arroyocalle@gmail.com)
    Part of Scryer Prolog.
 
    http_open(+Address, -Stream, +Options)
@@ -7,12 +7,7 @@
 
    Yields Stream to read the body of an HTTP reply from Address.
    Address is a list of characters, and includes the method. Both HTTP
-   and HTTPS are supported. Redirects are followed.
-
-   Currently, Options must be the empty list. Options may be
-   added in the future to give more control over the connection.
-
-   We use HTTP/1.0 until we can read chunked transfer-encoding.
+   and HTTPS are supported.
 
    Example:
 
@@ -23,62 +18,21 @@
 
 :- module(http_open, [http_open/3]).
 
-:- use_module(library(sockets)).
-:- use_module(library(error)).
-:- use_module(library(format)).
-:- use_module(library(charsio)).
-:- use_module(library(dcgs)).
-:- use_module(library(lists), [member/2]).
-:- use_module(library(tls)).
+:- use_module(library(lists)).
 
-http_open(Address, Stream, Options) :-
-        must_be(list, Options),
-        must_be(list, Address),
-        once(phrase((seq(SchemeCs), "://", seq(Rest)), Address)),
-        atom_chars(Scheme, SchemeCs),
-        chars_host_url(Rest, Host, URL),
-        connect(Scheme, Host, Stream0),
-        format(Stream0, "\
-GET ~s HTTP/1.0\r\n\
-Host: ~w\r\n\
-User-Agent: Scryer Prolog\r\n\
-Connection: close\r\n\r\n\
-", [URL,Host]),
-        read_line_to_chars(Stream0, StatusLine, []),
-        once(phrase(("HTTP/1.",(['0']|['1'])," ",[D1]), StatusLine, _)),
-        read_header_lines(Stream0, HeaderLines),
-        handle_response(D1, HeaderLines, Stream0, Stream).
+http_open(Address, Response, Options) :-
+    parse_http_options(Options, OptionValues),
+    ( member(method(Method), OptionValues) -> true; Method = get),
+    '$http_open'(Address, Response, Method).
 
-handle_response('2', _, Stream, Stream).              % ok
-handle_response('3', HeaderLines, Stream0, Stream) :- % redirect
-        close(Stream0),
-        once((member(Line, HeaderLines),
-              phrase(("Location: ",seq(Location),"\r\n"), Line))),
-        http_open(Location, Stream, []).
-
-% Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF
-
-read_header_lines(Stream, Hs) :-
-        read_line_to_chars(Stream, Cs, []),
-        (   Cs == "" -> Hs = []
-        ;   Cs == "\r\n" -> Hs = []
-        ;   Hs = [Cs|Rest],
-            read_header_lines(Stream, Rest)
-        ).
-
-chars_host_url(Cs, Host, [/|Us]) :-
-        (   phrase((seq(Hs),"/",seq(Us)), Cs) ->
-            true
-        ;   Hs = Cs,
-            Us = []
-        ),
-        atom_chars(Host, Hs).
-
-connect(https, Host, Stream) :-
-        socket_client_open(Host:443, Stream0, []),
-        atom_chars(Host, HostChars),
-        tls_client_context(Context, [hostname(HostChars)]),
-        tls_client_negotiate(Context, Stream0, Stream).
-connect(http, Host, Stream) :-
-        socket_client_open(Host:80, Stream, []).
+parse_http_options(Options, OptionValues) :-
+    maplist(parse_http_options_, Options, OptionValues).
 
+parse_http_options_(method(Method), method(Method)) :-
+    (  var(Method) ->
+       throw(error(instantiation_error, http_open/3))
+    ;
+       lists:member(Method, [get, post, put, delete, patch, head]) -> true
+    ;
+       throw(error(domain_error(http_option, method(Method)), _))
+    ).