OCaml library for JSONfeed parsing and creation
anil.recoil.org
1(*---------------------------------------------------------------------------
2 Copyright (c) 2024 Anil Madhavapeddy. All rights reserved.
3 SPDX-License-Identifier: ISC
4 ---------------------------------------------------------------------------*)
5
6module Rfc3339 = Rfc3339
7module Cito = Cito
8module Author = Author
9module Attachment = Attachment
10module Hub = Hub
11module Reference = Reference
12module Item = Item
13
14module Unknown = struct
15 type t = (string * Jsont.json) list
16
17 let empty = []
18 let is_empty = function [] -> true | _ -> false
19end
20
21type t = {
22 version : string;
23 title : string;
24 home_page_url : string option;
25 feed_url : string option;
26 description : string option;
27 user_comment : string option;
28 next_url : string option;
29 icon : string option;
30 favicon : string option;
31 authors : Author.t list option;
32 language : string option;
33 expired : bool option;
34 hubs : Hub.t list option;
35 items : Item.t list;
36 unknown : Unknown.t;
37}
38
39let create ~title ?home_page_url ?feed_url ?description ?user_comment
40 ?next_url ?icon ?favicon ?authors ?language ?expired ?hubs ~items
41 ?(unknown = Unknown.empty) () =
42 {
43 version = "https://jsonfeed.org/version/1.1";
44 title;
45 home_page_url;
46 feed_url;
47 description;
48 user_comment;
49 next_url;
50 icon;
51 favicon;
52 authors;
53 language;
54 expired;
55 hubs;
56 items;
57 unknown;
58 }
59
60let version t = t.version
61let title t = t.title
62let home_page_url t = t.home_page_url
63let feed_url t = t.feed_url
64let description t = t.description
65let user_comment t = t.user_comment
66let next_url t = t.next_url
67let icon t = t.icon
68let favicon t = t.favicon
69let authors t = t.authors
70let language t = t.language
71let expired t = t.expired
72let hubs t = t.hubs
73let items t = t.items
74let unknown t = t.unknown
75
76let equal a b =
77 a.title = b.title &&
78 a.items = b.items
79
80let pp ppf t =
81 Format.fprintf ppf "Feed: %s (%d items)" t.title (List.length t.items)
82
83let pp_summary ppf t =
84 Format.fprintf ppf "%s (%d items)" t.title (List.length t.items)
85
86(* Jsont type *)
87
88let jsont =
89 let kind = "JSON Feed" in
90 let doc = "A JSON Feed document" in
91 let unknown_mems : (Unknown.t, Jsont.json, Jsont.mem list) Jsont.Object.Mems.map =
92 let open Jsont.Object.Mems in
93 let dec_empty () = [] in
94 let dec_add _meta (name : string) value acc =
95 ((name, Jsont.Meta.none), value) :: acc
96 in
97 let dec_finish _meta mems =
98 List.rev_map (fun ((name, _meta), value) -> (name, value)) mems in
99 let enc = {
100 enc = fun (type acc) (f : Jsont.Meta.t -> string -> Jsont.json -> acc -> acc) unknown (acc : acc) ->
101 List.fold_left (fun acc (name, value) ->
102
103 f Jsont.Meta.none name value acc
104 ) acc unknown
105 } in
106 map ~kind:"Unknown members" Jsont.json ~dec_empty ~dec_add ~dec_finish ~enc
107 in
108
109 (* Helper constructor that sets version automatically *)
110 let make_from_json _version title home_page_url feed_url description user_comment
111 next_url icon favicon authors language expired hubs items unknown =
112 {
113 version = "https://jsonfeed.org/version/1.1";
114 title;
115 home_page_url;
116 feed_url;
117 description;
118 user_comment;
119 next_url;
120 icon;
121 favicon;
122 authors;
123 language;
124 expired;
125 hubs;
126 items;
127 unknown;
128 }
129 in
130
131 Jsont.Object.map ~kind ~doc make_from_json
132 |> Jsont.Object.mem "version" Jsont.string ~enc:version
133 |> Jsont.Object.mem "title" Jsont.string ~enc:title
134 |> Jsont.Object.opt_mem "home_page_url" Jsont.string ~enc:home_page_url
135 |> Jsont.Object.opt_mem "feed_url" Jsont.string ~enc:feed_url
136 |> Jsont.Object.opt_mem "description" Jsont.string ~enc:description
137 |> Jsont.Object.opt_mem "user_comment" Jsont.string ~enc:user_comment
138 |> Jsont.Object.opt_mem "next_url" Jsont.string ~enc:next_url
139 |> Jsont.Object.opt_mem "icon" Jsont.string ~enc:icon
140 |> Jsont.Object.opt_mem "favicon" Jsont.string ~enc:favicon
141 |> Jsont.Object.opt_mem "authors" (Jsont.list Author.jsont) ~enc:authors
142 |> Jsont.Object.opt_mem "language" Jsont.string ~enc:language
143 |> Jsont.Object.opt_mem "expired" Jsont.bool ~enc:expired
144 |> Jsont.Object.opt_mem "hubs" (Jsont.list Hub.jsont) ~enc:hubs
145 |> Jsont.Object.mem "items" (Jsont.list Item.jsont) ~enc:items
146 |> Jsont.Object.keep_unknown unknown_mems ~enc:unknown
147 |> Jsont.Object.finish
148
149(* Encoding and Decoding *)
150
151let decode ?layout ?locs ?file r =
152 Jsont_bytesrw.decode' ?layout ?locs ?file jsont r
153
154let decode_string ?layout ?locs ?file s =
155 Jsont_bytesrw.decode_string' ?layout ?locs ?file jsont s
156
157let encode ?format ?number_format feed ~eod w =
158 Jsont_bytesrw.encode' ?format ?number_format jsont feed ~eod w
159
160let encode_string ?format ?number_format feed =
161 Jsont_bytesrw.encode_string' ?format ?number_format jsont feed
162
163let of_string s =
164 decode_string s
165
166let to_string ?(minify=false) feed =
167 let format = if minify then Jsont.Minify else Jsont.Indent in
168 encode_string ~format feed
169
170(* Validation *)
171
172let validate feed =
173 let errors = ref [] in
174 let add_error msg = errors := msg :: !errors in
175
176 (* Check required fields *)
177 if feed.title = "" then
178 add_error "title is required and cannot be empty";
179
180 (* Check items have unique IDs *)
181 let ids = List.map Item.id feed.items in
182 let unique_ids = List.sort_uniq String.compare ids in
183 if List.length ids <> List.length unique_ids then
184 add_error "items must have unique IDs";
185
186 (* Validate authors *)
187 (match feed.authors with
188 | Some authors ->
189 List.iteri (fun i author ->
190 if not (Author.is_valid author) then
191 add_error (Printf.sprintf "feed author %d is invalid (needs at least one field)" i)
192 ) authors
193 | None -> ());
194
195 (* Validate items *)
196 List.iteri (fun i item ->
197 if Item.id item = "" then
198 add_error (Printf.sprintf "item %d has empty ID" i);
199
200 (* Validate item authors *)
201 (match Item.authors item with
202 | Some authors ->
203 List.iteri (fun j author ->
204 if not (Author.is_valid author) then
205 add_error (Printf.sprintf "item %d author %d is invalid" i j)
206 ) authors
207 | None -> ())
208 ) feed.items;
209
210 match !errors with
211 | [] -> Ok ()
212 | errs -> Error (List.rev errs)