1	# ezhttp/src/client: fetch a URL. URL and HTTP parsing joined to the wire effect.
2	# Answers a structured Response (status + headers + body), not a hub-style
3	# "0\n…" string contract.
4	import Base
5	import ./url.bend as Url
6	import ./http.bend as Http
7	import ./body.bend as Body
8	import ./wire.bend as Wire
9	import ./wirespec.bend as Spec
10	import ./redirect.bend as Redirect
11	import ./auth.bend as Auth
12	
13	# structured client result: transport/parse error, or an HTTP response
14	type Response is Data:
15	  Err{why: String}
16	  Response{status: U32, headers: List<&2, Http.Header>, body: String}
17	
18	# a torn or successful HTTP parse as a client Response
19	def from.reply(r: Http.Reply) -> Response:
20	  match r:
21	    case Http.Torn{why}:
22	      Err{why}
23	    case Http.Reply{status, headers, body}:
24	      Response{status, headers, body}
25	
26	# a finished exchange; a failed one keeps its reason, marked when it was a
27	# timeout (wirespec.bend wire.why)
28	def from.raw(+raw: String, ok: Bool) -> Response:
29	  match ok:
30	    case False{}:
31	      Err{Spec.wire.why(Spec.wire.code(raw), Spec.wire.text(raw))}
32	    case True{}:
33	      from.reply(Http.parse(Spec.wire.text(raw)))
34	
35	# an exchange's answer as a client Response
36	def http.heard(+raw: String) -> Response:
37	  from.raw(raw, Spec.wire.ok(raw))
38	
39	# an exchange as wirespec.bend wrote it: sent and read by its own method, or
40	# the URL's reason
41	def http.send(ex: Spec.Exchange) -> IO(Response):
42	  match ex:
43	    case Spec.NoUrl{why}:
44	      IO.pure(Response, Err{why})
45	    case Spec.Exchange{secure, host, port, method, req}:
46	      do IO<Response>:
47	        +raw : String <- Wire.wire.talk(secure, host, port, method, req)
48	        IO.pure(Response, http.heard(raw))
49	
50	# a URL that came apart (or not) into an HTTP exchange
51	def http.loc(method: String, l: Url.Loc, headers: List<&2, Http.Header>,
52	  body: String) -> IO(Response):
53	  http.send(Spec.wire.exchange(method, l, headers, body))
54	
55	# an exchange as wirespec.bend wrote it, bounded by a timeout, sent and read
56	# by its own method
57	def http.send.timed(ms: U32, ex: Spec.Exchange) -> IO(Response):
58	  match ex:
59	    case Spec.NoUrl{why}:
60	      IO.pure(Response, Err{why})
61	    case Spec.Exchange{secure, host, port, method, req}:
62	      do IO<Response>:
63	        +raw : String <- Wire.wire.talk.timed(secure, ms, host, port, method,
64	          req)
65	        IO.pure(Response, http.heard(raw))
66	
67	# a request with this method, headers and body, bounded by a timeout in
68	# milliseconds
69	def client.timed(method: String, url: String, headers: List<&2, Http.Header>,
70	  body: String, ms: U32) -> IO(Response):
71	  http.send.timed(ms, Spec.wire.exchange(method, Url.parse(url), headers, body))
72	
73	# GET bounded by a timeout in milliseconds
74	def client.get.timed(url: String, headers: List<&2, Http.Header>, ms: U32)
75	  -> IO(Response):
76	  client.timed("GET", url, headers, "", ms)
77	
78	# the next hop after a response (redirect.bend); a failed exchange stops
79	def client.hop(left: Nat, url: String, r: Response) -> Redirect.Hop:
80	  match r:
81	    case Err{why}:
82	      Redirect.Stop{}
83	    case Response{status, headers, body}:
84	      Redirect.redirect.plan(left, url, status, headers)
85	
86	# a response, or the GET its hop asks for
87	def client.after(hop: Redirect.Hop, r: Response, go: String -> IO(Response))
88	  -> IO(Response):
89	  match hop:
90	    case Redirect.Stop{}:
91	      IO.pure(Response, r)
92	    case Redirect.Go{next}:
93	      go(next)
94	
95	# GET, following redirects while `left` hops remain; `body` goes with this
96	# hop only. The answer is the last response, which is a redirect only when
97	# the hops ran out or its Location is not one redirect.bend follows
98	def client.follow(+left: Nat, +url: String, +headers: List<&2, Http.Header>,
99	  body: String, +ms: U32) -> IO(Response):
100	  match left:
101	    case 0n:
102	      client.timed("GET", url, headers, body, ms)
103	    case 1n+p:
104	      do IO<Response>:
105	        +r : Response <- client.timed("GET", url, headers, body, ms)
106	        client.after(client.hop(left, url, r), r,
107	          next => client.follow(p, next, headers, "", ms))
108	
109	# a request once it is known whether it follows redirects
110	def client.request.go(go: Bool, method: String, url: String,
111	  headers: List<&2, Http.Header>, body: String, ms: U32) -> IO(Response):
112	  match go:
113	    case True{}:
114	      client.follow(Redirect.redirect.max(), url, headers, body, ms)
115	    case False{}:
116	      client.timed(method, url, headers, body, ms)
117	
118	# a request with a method, headers, body and timeout; it follows redirects
119	# when `follow` is set and the method is GET (redirect.bend
120	# redirect.follows), and answers its first response otherwise
121	def client.request.opts(+method: String, url: String,
122	  headers: List<&2, Http.Header>, body: String, ms: U32, follow: Bool)
123	  -> IO(Response):
124	  client.request.go(Redirect.redirect.follows(method, follow), method, url,
125	    headers, body, ms)
126	
127	# GET with headers and a timeout, following redirects when `follow` is set
128	def client.get.opts(url: String, headers: List<&2, Http.Header>, ms: U32,
129	  follow: Bool) -> IO(Response):
130	  client.request.opts("GET", url, headers, "", ms, follow)
131	
132	# whether a response is the failure of an exchange that ran out of time
133	def client.timed_out(r: Response) -> Bool:
134	  match r:
135	    case Err{why}:
136	      Spec.wire.timed_out(why)
137	    case Response{status, headers, body}:
138	      False{}
139	
140	# GET
141	def client.get(url: String, headers: List<&2, Http.Header>) -> IO(Response):
142	  http.loc("GET", Url.parse(url), headers, "")
143	
144	# HEAD (RFC 9110 §9.3.2)
145	def client.head(url: String, headers: List<&2, Http.Header>) -> IO(Response):
146	  http.loc("HEAD", Url.parse(url), headers, "")
147	
148	# POST
149	def client.post(url: String, headers: List<&2, Http.Header>, body: Body.Body)
150	  -> IO(Response):
151	  http.loc("POST", Url.parse(url), headers, Body.body.payload(body))
152	
153	# PUT
154	def client.put(url: String, headers: List<&2, Http.Header>, body: Body.Body)
155	  -> IO(Response):
156	  http.loc("PUT", Url.parse(url), headers, Body.body.payload(body))
157	
158	# DELETE
159	def client.delete(url: String, headers: List<&2, Http.Header>, body: Body.Body)
160	  -> IO(Response):
161	  http.loc("DELETE", Url.parse(url), headers, Body.body.payload(body))
162	
163	# OPTIONS
164	def client.options(url: String, headers: List<&2, Http.Header>) -> IO(Response):
165	  http.loc("OPTIONS", Url.parse(url), headers, "")
166	
167	# Authorization: Bearer … (auth.bend)
168	def client.bearer(token: String) -> Http.Header:
169	  Auth.auth.bearer(token)
170	
171	# Authorization: Basic … (auth.bend; RFC 7617, RFC 4648 Base64)
172	def client.basic(user: String, password: String) -> Http.Header:
173	  Auth.auth.basic(user, password)