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(define-module (atom)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-19)
#:use-module (sxml simple)
#:use-module (ice-9 binary-ports)
#:use-module (rnrs bytevectors)
#:export (feed
entry
person
media
render))
; ATOM Explanation: http://www.atomenabled.org/developers/syndication/
; ATOM Validator: https://validator.w3.org/feed/check.cgi
(define mime-types
'(("3gp" . "audio/3gpp")
("3gpp" . "audio/3gpp")
("3g2" . "audio/3gpp2")
("3gpp2" . "audio/3gpp2")
("aac" . "audio/aac")
("adts" . "audio/aac")
("loas" . "audio/aac")
("ass" . "audio/aac")
("au" . "audio/basic")
("snd" . "audio/basic")
("mp3" . "audio/mpeg")
("mp2" . "audio/mpeg")
("opus" . "audio/opus")
("oga" . "audio/ogg")
("aif" . "audio/x-aiff")
("aifc" . "audio/x-aiff")
("aiff" . "audio/x-aiff")
("ra" . "audio/x-pn-realaudio")
("wav" . "audio/x-wav")
("avif" . "image/avif")
("bmp" . "image/bmp")
("gif" . "image/gif")
("ief" . "image/ief")
("jpg" . "image/jpeg")
("jpe" . "image/jpeg")
("jpeg" . "image/jpeg")
("heic" . "image/heic")
("heif" . "image/heif")
("png" . "image/png")
("svg" . "image/svg+xml")
("tiff" . "image/tiff")
("tif" . "image/tiff")
("ico" . "image/vnd.microsoft.icon")
("ras" . "image/x-cmu-raster")
("pnm" . "image/x-portable-anymap")
("pbm" . "image/x-portable-bitmap")
("pgm" . "image/x-portable-graymap")
("ppm" . "image/x-portable-pixmap")
("rgb" . "image/x-rgb")
("xbm" . "image/x-xbitmap")
("xpm" . "image/x-xpixmap")
("xwd" . "image/x-xwindowdump")
("ogv" . "video/ogv")
("mp4" . "video/mp4")
("mpeg" . "video/mpeg")
("m1v" . "video/mpeg")
("mpa" . "video/mpeg")
("mpe" . "video/mpeg")
("mpg" . "video/mpeg")
("mov" . "video/quicktime")
("qt" . "video/quicktime")
("webm" . "video/webm")
("avi" . "video/x-msvideo")
("movie" . "video/x-sgi-movie")))
;; Entities
(define-record-type <feed>
(make-feed id title subtitle uri date entries)
feed?
(id feed-id)
(title feed-title)
(subtitle feed-subtitle)
(uri feed-uri)
(date feed-date set-feed-date!)
(entries feed-entries set-feed-entries!))
(define-record-type <entry>
(make-entry id title published updated authors summary content categories contributors media)
entry?
(id entry-id set-entry-id!)
(title entry-title)
(published _entry-published)
(updated _entry-updated)
(authors entry-authors)
(summary entry-summary)
(content entry-content)
(categories entry-categories)
(contributors entry-contributors)
(media entry-media))
(define (date->string/RFC3339 date)
(date->string date "~4"))
(define (entry-published entry)
(date->string/RFC3339 (_entry-published entry)))
(define (entry-updated entry)
(date->string/RFC3339 (_entry-updated entry)))
(define (string->date/ISO string)
(string->date string "~Y-~m-~d"))
(define-record-type <media>
(make-media title type length uri path contents)
media?
(title media-title)
(type media-type)
(length media-length)
(uri media-uri)
(path media-path)
(contents media-contents))
(define-record-type <person>
(make-person name email uri)
person?
(name person-name)
(email person-email)
(uri person-uri))
(define zero-date (string->date/ISO "1970-01-01"))
(define (newest a b) (if (time>? (date->time-utc a) (date->time-utc b)) a b))
(define (find-newest dates) (reduce newest zero-date dates))
(define* (feed #:key (title "")
(subtitle "")
(uri "")
(entries '()))
(make-feed uri
title
subtitle
uri
(find-newest (map entry-updated entries))
entries))
(define* (register-entry! feed entry)
(let ((entries (feed-entries feed)))
(set-entry-id! entry (string-append
(feed-uri feed) "/"
(number->string (length entries)))) ;; TODO: is this enough
(set-feed-entries! feed (append entries (list entry))))
(set-feed-date! feed (find-newest (map entry-updated
(feed-entries feed)))))
(define* (entry feed #:key (title "")
(published "1970-01-01")
(updated "1970-01-01")
(authors '())
(summary-html '())
(content-html '())
(categories '())
(contributors '())
(media '()))
(register-entry! feed
(make-entry #f
title
(string->date/ISO published)
(find-newest (map string->date/ISO
(list published updated)))
authors
summary-html
content-html
categories
contributors
media)))
(define* (person name #:key (email "")
(uri ""))
(make-person name email uri))
(define* (media path #:key (title "")
(uri ""))
(define (type path)
(let* ((extension (car (last-pair (string-split path #\.))))
(type (assoc-ref mime-types extension)))
(if (string? type) type (throw "Unknown mime-type"))))
(let ((contents (call-with-input-file path get-bytevector-all #:binary #t)))
(make-media title
(type path)
(bytevector-length contents)
uri
path
contents)))
;; Rendering
(define (render-person tag person)
`(,tag
(name ,(person-name person))
(uri ,(or (person-uri person) ""))
(email ,(or (person-email person) ""))))
(define (partial f . set)
(lambda (. args) (apply f (append set args))))
(define render-author (partial render-person 'author))
(define render-contributor (partial render-person 'contributor))
(define (render-media med)
`(link (@(rel enclosure)
(href ,(media-uri med))
(type ,(media-type med))
(title ,(media-title med))
(length ,(media-length med)))))
(define (render-category cat)
`(category (@(term ,cat))))
(define (render-entry ent)
`(entry
(id ,(entry-id ent))
(title ,(entry-title ent))
(published ,(entry-published ent))
(updated ,(entry-updated ent))
,@(map render-author (entry-authors ent))
(summary (@(type html)) ,(entry-summary ent))
(content (@(type html)) ,(entry-content ent))
,@(map render-category (entry-categories ent))
,@(map render-contributor (entry-contributors ent))
,@(map render-media (entry-media ent))))
(define (render-feed fe)
`(feed (@(xmlns "http://www.w3.org/2005/Atom"))
(id ,(feed-id fe))
(title ,(feed-title fe))
(link (@(href ,(feed-uri fe))
(rel "self")))
(updated ,(feed-date fe))
(subtitle ,(feed-subtitle fe))
,@(map render-entry (feed-entries fe))))
(define* (render feed #:optional (port (current-output-port)))
(display "<?xml version=\"1.0\" encoding=\"utf-8\"?>" port)
(sxml->xml (render-feed feed)) port)
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