breezewiki/src/page-wiki.rkt
blankie bc07a37bf7
Set Referrer-Policy to no-referrer
Fandom sends a fake 404 to media if there's a Referer header that has an origin
that's not Fandom. However, we can choose not to send the header by setting
Referrer-Policy. See also:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy
2022-10-09 14:08:20 +07:00

293 lines
15 KiB
Racket

#lang racket/base
(require racket/dict
racket/function
racket/list
racket/match
racket/string
; libs
(prefix-in easy: net/http-easy)
; html libs
html-parsing
html-writing
; web server libs
net/url
web-server/http
web-server/dispatchers/dispatch
; my libs
"application-globals.rkt"
"config.rkt"
"data.rkt"
"pure-utils.rkt"
"syntax.rkt"
"xexpr-utils.rkt"
"url-utils.rkt")
(provide
; used by the web server
page-wiki
; used by page-category, and similar pages that are partially wiki pages
update-tree-wiki
preprocess-html-wiki)
(module+ test
(require rackunit)
(define wiki-document
'(*TOP*
(div (@ (class "mw-parser-output"))
(aside (@ (role "region") (class "portable-infobox pi-theme-wikia pi-layout-default"))
(h2 (@ (class "pi-item pi-title") (data-source "title"))
"Infobox Title")
(figure (@ (class "pi-item pi-image") (data-source "image"))
(a (@ (href "https://static.wikia.nocookie.net/nice-image.png") (class "image image-thumbnail") (title ""))
(img (@ (src "https://static.wikia.nocookie.net/nice-image-thumbnail.png") (class "pi-image-thumbnail")))))
(div (@ (class "pi-item pi-data") (data-source "description"))
(h3 (@ (class "pi-data-label"))
"Description")
(div (@ (class "pi-data-value"))
"Mystery infobox!")))
(div (@ (data-test-collapsesection) (class "collapsible collapsetoggle-inline collapsed"))
(i (b "This section is hidden for dramatic effect."))
(div (@ (class "collapsible-content"))
(p "Another page link: "
(a (@ (data-test-wikilink) (href "https://test.fandom.com/wiki/Another_Page") (title "Another Page"))
"Another Page"))))
(iframe (@ (src "https://example.com/iframe-src")))))))
(define (preprocess-html-wiki html)
(define (rr* find replace contents)
(regexp-replace* find contents replace))
((compose1
; fix navbox list nesting
; navbox on right of page has incorrect html "<td ...><li>" and the xexpr parser puts the <li> much further up the tree
; add a <ul> to make the parser happy
; usage: /fallout/wiki/Fallout:_New_Vegas_achievements_and_trophies
(curry rr* #rx"(<td[^>]*>\n?)(<li>)" "\\1<ul>\\2")
; change <figcaption><p> to <figcaption><span> to make the parser happy
(curry rr* #rx"(<figcaption[^>]*>)[ \t]*<p class=\"caption\">([^<]*)</p>" "\\1<span class=\"caption\">\\2</span>"))
html))
(module+ test
(check-equal? (preprocess-html-wiki "<td class=\"va-navbox-column\" style=\"width: 33%\">\n<li>Hey</li>")
"<td class=\"va-navbox-column\" style=\"width: 33%\">\n<ul><li>Hey</li>")
(check-equal? (preprocess-html-wiki "<figure class=\"thumb tright\" style=\"width: 150px\"><a class=\"image\"><img></a><noscript><a><img></a></noscript><figcaption class=\"thumbcaption\"> <p class=\"caption\">Caption text.</p></figcaption></figure>")
"<figure class=\"thumb tright\" style=\"width: 150px\"><a class=\"image\"><img></a><noscript><a><img></a></noscript><figcaption class=\"thumbcaption\"><span class=\"caption\">Caption text.</span></figcaption></figure>"))
(define (update-tree-wiki tree wikiname)
(update-tree
(λ (element element-type attributes children)
;; replace whole element?
(cond
; wrap tables in a div.table-scroller
[(and (eq? element-type 'table)
(has-class? "wikitable" attributes)
(not (dict-has-key? attributes 'data-scrolling)))
`(div
((class "table-scroller"))
((,element-type (@ (data-scrolling) ,@attributes)
,@children)))]
; exclude empty figcaptions
[(and (eq? element-type 'figcaption)
(or (eq? (length (filter element-is-element? children)) 0)
((query-selector (λ (element-type attributes children)
(eq? element-type 'use))
element))))
return-no-element]
; exclude infobox items that are videos, and gallery items that are videos
[(and (or (has-class? "pi-item" attributes)
(has-class? "wikia-gallery-item" attributes))
((query-selector (λ (element-type attributes children)
(has-class? "video-thumbnail" attributes))
element)))
return-no-element]
; exclude the invisible brackets after headings
[(and (eq? element-type 'span)
(has-class? "mw-editsection" attributes))
return-no-element]
; display a link instead of an iframe
[(eq? element-type 'iframe)
(define src (car (dict-ref attributes 'src null)))
`(a
((class "iframe-alternative") (href ,src))
(,(format "Embedded media: ~a" src)))]
[#t
(list element-type
;; attributes
((compose1
; uncollapsing
(curry attribute-maybe-update 'class
(λ (class)
(string-join
((compose1
; uncollapse all navbox items (bottom of page mass navigation)
(curry u
(λ (classlist) (and (eq? element-type 'table)
(member "navbox" classlist)
(member "collapsed" classlist)))
(λ (classlist) (filter (curry (negate equal?) "collapsed") classlist)))
; uncollapse portable-infobox sections
(curry u
(λ (classlist) (and (eq? element-type 'section)
(member "pi-collapse" classlist)))
(λ (classlist) (filter (λ (v)
(and (not (equal? v "pi-collapse-closed"))
(not (equal? v "pi-collapse"))))
classlist)))
; generic: includes article sections and tables, probably more
(curry u
(λ (classlist) (and (member "collapsible" classlist)
(member "collapsed" classlist)))
(λ (classlist) (filter (curry (negate equal?) "collapsed") classlist))))
(string-split class " "))
" ")))
; change links to stay on the same wiki
(curry attribute-maybe-update 'href
(λ (href)
((compose1
(λ (href) (regexp-replace #rx"^(/wiki/.*)" href (format "/~a\\1" wikiname)))
(λ (href) (regexp-replace (pregexp (format "^https://(~a)\\.fandom\\.com(/wiki/.*)" px-wikiname)) href "/\\1\\2")))
href)))
; add noreferrer to a.image
(curry u
(λ (v) (and (eq? element-type 'a)
(has-class? "image" v)))
(λ (v) (dict-update v 'rel (λ (s)
(list (string-append (car s) " noreferrer")))
'(""))))
; proxy images from inline styles, if strict_proxy is set
(curry u
(λ (v) (config-true? 'strict_proxy))
(λ (v) (attribute-maybe-update 'style
(λ (style)
(regexp-replace #rx"url\\(['\"]?(.*?)['\"]?\\)" style
(λ (whole url)
(string-append
"url("
(u-proxy-url url)
")")))) v)))
; and also their links, if strict_proxy is set
(curry u
(λ (v)
(and (config-true? 'strict_proxy)
(eq? element-type 'a)
(has-class? "image-thumbnail" v)))
(λ (v) (attribute-maybe-update 'href u-proxy-url v)))
; proxy images from src attributes, if strict_proxy is set
(curry u
(λ (v) (config-true? 'strict_proxy))
(λ (v) (attribute-maybe-update 'src u-proxy-url v)))
; don't lazyload images
(curry u
(λ (v) (dict-has-key? v 'data-src))
(λ (v) (attribute-maybe-update 'src (λ (_) (car (dict-ref v 'data-src))) v)))
; don't use srcset - TODO: use srcset?
(λ (v) (dict-remove v 'srcset)))
attributes)
;; children
((compose1
; wrap blinking animated images in a slot so they can be animated with CSS
(curry u
(λ (v) (and (has-class? "animated" attributes)
((length v) . > . 1)))
(λ (v)
`((span (@ (class "animated-slot__outer") (style ,(format "--steps: ~a" (length v))))
(span (@ (class "animated-slot__inner"))
,@v))))))
children))]))
tree))
(module+ test
(define transformed
(parameterize ([(config-parameter 'strict_proxy) "true"])
(update-tree-wiki wiki-document "test")))
; check that wikilinks are changed to be local
(check-equal? (get-attribute 'href (bits->attributes
((query-selector
(λ (t a c) (dict-has-key? a 'data-test-wikilink))
transformed))))
"/test/wiki/Another_Page")
; check that a.image has noreferrer
(check-equal? (get-attribute 'rel (bits->attributes
((query-selector
(λ (t a c) (and (eq? t 'a)
(has-class? "image" a)))
transformed))))
" noreferrer")
; check that article collapse sections become uncollapsed
(check-equal? (get-attribute 'class (bits->attributes
((query-selector
(λ (t a c) (dict-has-key? a 'data-test-collapsesection))
transformed))))
"collapsible collapsetoggle-inline")
; check that iframes are gone
(check-false ((query-selector (λ (t a c) (eq? t 'iframe)) transformed)))
(check-equal? (let* ([alternative ((query-selector (λ (t a c) (has-class? "iframe-alternative" a)) transformed))]
[link ((query-selector (λ (t a c) (eq? t 'a)) alternative))])
(get-attribute 'href (bits->attributes link)))
"https://example.com/iframe-src")
; check that images are proxied
(check-equal? (get-attribute 'src (bits->attributes
((query-selector
(λ (t a c) (eq? t 'img))
transformed))))
"/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fnice-image-thumbnail.png")
; check that links to images are proxied
(check-equal? (get-attribute 'href (bits->attributes
((query-selector
(λ (t a c) (and (eq? t 'a) (has-class? "image-thumbnail" a)))
transformed))))
"/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fnice-image.png"))
(define (page-wiki req)
(define wikiname (path/param-path (first (url-path (request-uri req)))))
(define origin (format "https://~a.fandom.com" wikiname))
(define path (string-join (map path/param-path (cddr (url-path (request-uri req)))) "/"))
(define source-url (format "https://~a.fandom.com/wiki/~a" wikiname path))
(thread-let
([dest-res (define dest-url
(format "~a/api.php?~a"
origin
(params->query `(("action" . "parse")
("page" . ,path)
("prop" . "text|headhtml|langlinks")
("formatversion" . "2")
("format" . "json")))))
(log-outgoing dest-url)
(easy:get dest-url #:timeouts timeouts)]
[license (license-auto wikiname)])
(cond
[(eq? 200 (easy:response-status-code dest-res))
(let* ([data (easy:response-json dest-res)]
[title (jp "/parse/title" data "")]
[page-html (jp "/parse/text" data "")]
[page-html (preprocess-html-wiki page-html)]
[page (html->xexp page-html)]
[head-html (jp "/parse/headhtml" data "")]
[body-class (match (regexp-match #rx"<body [^>]*class=\"([^\"]*)" head-html)
[(list _ classes) classes]
[_ ""])])
(if (equal? "missingtitle" (jp "/error/code" data #f))
(next-dispatcher)
(response-handler
(define body
(generate-wiki-page
(update-tree-wiki page wikiname)
#:source-url source-url
#:wikiname wikiname
#:title title
#:body-class body-class
#:license license))
(define redirect-msg ((query-selector (attribute-selector 'class "redirectMsg") body)))
(define headers (if redirect-msg
(let* ([dest (get-attribute 'href (bits->attributes ((query-selector (λ (t a c) (eq? t 'a)) redirect-msg))))]
[value (bytes-append #"0;url=" (string->bytes/utf-8 dest))])
(list (header #"Refresh" value) referrer-policy))
(list referrer-policy)))
(when (config-true? 'debug)
; used for its side effects
; convert to string with error checking, error will be raised if xexp is invalid
(xexp->html body))
(response/output
#:code 200
#:headers headers
(λ (out)
(write-html body out))))))])))