()

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

breezewiki.rkt

@@ -19,6 +19,7 @@
 (require-reloadable "src/page-static.rkt" static-dispatcher)
 (require-reloadable "src/page-subdomain.rkt" subdomain-dispatcher)
 (require-reloadable "src/page-wiki.rkt" page-wiki)
+(require-reloadable "src/page-file.rkt" page-file)
 
 (reload!)
 
@@ -38,6 +39,7 @@
       page-proxy
       page-search
       page-wiki
+      page-file
       redirect-wiki-home
       static-dispatcher
       subdomain-dispatcher))))

dist.rkt

@@ -13,6 +13,7 @@
 (require (only-in "src/page-static.rkt" static-dispatcher))
 (require (only-in "src/page-subdomain.rkt" subdomain-dispatcher))
 (require (only-in "src/page-wiki.rkt" page-wiki))
+(require (only-in "src/page-file.rkt" page-file))
 
 (serve/launch/wait
  #:listen-ip (if (config-true? 'debug) "127.0.0.1" #f)
@@ -27,6 +28,7 @@
     page-proxy
     page-search
     page-wiki
+    page-file
     redirect-wiki-home
     static-dispatcher
     subdomain-dispatcher)))

src/application-globals.rkt

@@ -9,6 +9,8 @@
          "url-utils.rkt")
 
 (provide
+ ; header to not send referers to fandom
+ referrer-policy
  ; timeout durations for http-easy requests
  timeouts
  ; generates a consistent footer
@@ -22,6 +24,7 @@
   (require rackunit
            html-writing))
 
+(define referrer-policy (header #"Referrer-Policy" #"no-referrer"))
 (define timeouts (easy:make-timeout-config #:lease 5 #:connect 5))
 
 (define (application-footer source-url #:license [license-in #f])

src/dispatcher-tree.rkt

@@ -45,6 +45,7 @@
               (pathprocedure:make "/proxy" (hash-ref ds 'page-proxy))
               (pathprocedure:make "/search" (hash-ref ds 'page-global-search))
               (filter:make (pregexp (format "^/~a/wiki/Category:.+$" px-wikiname)) (lift:make (hash-ref ds 'page-category)))
+              (filter:make (pregexp (format "^/~a/wiki/File:.+$" px-wikiname)) (lift:make (hash-ref ds 'page-file)))
               (filter:make (pregexp (format "^/~a/wiki/.+$" px-wikiname)) (lift:make (hash-ref ds 'page-wiki)))
               (filter:make (pregexp (format "^/~a/search$" px-wikiname)) (lift:make (hash-ref ds 'page-search)))
               (filter:make (pregexp (format "^/~a(/(wiki(/)?)?)?$" px-wikiname)) (lift:make (hash-ref ds 'redirect-wiki-home)))

src/page-category.rkt

@@ -113,6 +113,7 @@
       (xexp->html body))
     (response/output
      #:code 200
+     #:headers (list referrer-policy)
      (λ (out)
        (write-html body out))))))
 (module+ test

src/page-file.rkt

@@ -0,0 +1,155 @@
+#lang racket/base
+(require racket/dict
+         racket/list
+         racket/match
+         racket/string
+         (prefix-in easy: net/http-easy)
+         ; html libs
+         html-parsing
+         html-writing
+         ; web server libs
+         net/url
+         web-server/http
+         (only-in web-server/dispatchers/dispatch next-dispatcher)
+         #;(only-in web-server/http/redirect redirect-to)
+         "application-globals.rkt"
+         "config.rkt"
+         "data.rkt"
+         "page-wiki.rkt"
+         "syntax.rkt"
+         "url-utils.rkt"
+         "xexpr-utils.rkt")
+
+(provide page-file)
+
+(module+ test
+  (require rackunit)
+  (define test-media-detail
+    '#hasheq((fileTitle . "Example file") (videoEmbedCode . "") (imageUrl . "https://static.wikia.nocookie.net/examplefile") (rawImageUrl . "https://static.wikia.nocookie.net/examplefile") (userName . "blankie") (isPostedIn . #t) (smallerArticleList . (#hasheq((title . "Example_article") (titleText . "Example article")))) (articleListIsSmaller . 0) (exists . #t) (imageDescription . #f))))
+
+(define (url-content-type url)
+  (log-outgoing url)
+  (define dest-res (easy:head url #:timeouts timeouts))
+  (easy:response-headers-ref dest-res 'content-type))
+
+(define (get-media-html url content-type)
+  (define maybe-proxied-url (if (config-true? 'strict_proxy) (u-proxy-url url) url))
+  (cond
+    [(eq? content-type #f) `""]
+    [(regexp-match? #rx"(?i:^image/)" content-type) `(img (@ (src ,maybe-proxied-url)))]
+    [(regexp-match? #rx"(?i:^audio/|^application/ogg(;|$))" content-type)
+     `(audio (@ (src ,maybe-proxied-url) (controls)))]
+    [(regexp-match? #rx"(?i:^video/)" content-type) `(video (@ (src ,maybe-proxied-url) (controls)))]
+    [else `""]))
+
+(define (generate-results-page #:source-url source-url
+                               #:wikiname wikiname
+                               #:title title
+                               #:media-detail media-detail
+                               #:image-content-type image-content-type
+                               #:license [license #f])
+  (define video-embed-code (jp "/videoEmbedCode" media-detail ""))
+  (define raw-image-url (jp "/rawImageUrl" media-detail))
+  (define image-url (jp "/imageUrl" media-detail raw-image-url))
+  (define username (jp "/userName" media-detail))
+  (define is-posted-in (jp "/isPostedIn" media-detail #f))
+  (define smaller-article-list (jp "/smallerArticleList" media-detail))
+  (define article-list-is-smaller (jp "/articleListIsSmaller" media-detail))
+  (define image-description (jp "/imageDescription" media-detail #f))
+  (define maybe-proxied-raw-image-url
+    (if (config-true? 'strict_proxy) (u-proxy-url raw-image-url) raw-image-url))
+  (generate-wiki-page
+   #:source-url source-url
+   #:wikiname wikiname
+   #:title title
+   #:license license
+   `(div
+     ,(if (non-empty-string? video-embed-code)
+          (update-tree-wiki (html->xexp (preprocess-html-wiki video-embed-code)) wikiname)
+          (get-media-html image-url image-content-type))
+     (p ,(if (non-empty-string? video-embed-code)
+             `""
+             `(span (a (@ (href ,maybe-proxied-raw-image-url)) "View original file") ". "))
+        "Added by "
+        (a (@ (href ,(format "/~a/wiki/User:~a" wikiname username))) ,username)
+        "."
+        ,(if is-posted-in
+             `(span " Posted in "
+                    ,@(map (λ (article)
+                             (define page-path (jp "/title" article))
+                             (define title (jp "/titleText" article page-path))
+                             `(span ,(if (eq? (car smaller-article-list) article) "" ", ")
+                                    (a (@ (href ,(format "/~a/wiki/~a" wikiname page-path))) ,title)))
+                           smaller-article-list)
+                    ,(if (eq? article-list-is-smaller 1) "…" "."))
+             `""))
+     ,(if (string? image-description)
+          (update-tree-wiki (html->xexp (preprocess-html-wiki image-description)) wikiname)
+          ""))))
+
+(define (page-file req)
+  (define wikiname (path/param-path (first (url-path (request-uri req)))))
+  (define prefixed-title (path/param-path (caddr (url-path (request-uri req)))))
+  (define origin (format "https://~a.fandom.com" wikiname))
+  (define source-url (format "~a/wiki/~a" origin prefixed-title))
+
+  (thread-let ([media-detail
+                (define dest-url
+                  (format "~a/wikia.php?~a"
+                          origin
+                          (params->query `(("format" . "json") ("controller" . "Lightbox")
+                                                               ("method" . "getMediaDetail")
+                                                               ("fileTitle" . ,prefixed-title)))))
+                (log-outgoing dest-url)
+                (define dest-res (easy:get dest-url #:timeouts timeouts))
+                (easy:response-json dest-res)]
+               [license (license-auto wikiname)])
+              (if (not (jp "/exists" media-detail #f))
+                  (next-dispatcher)
+                  (response-handler
+                   (define file-title (jp "/fileTitle" media-detail ""))
+                   (define title
+                     (if (non-empty-string? file-title) (format "File:~a" file-title) prefixed-title))
+                   (define image-content-type
+                     (if (non-empty-string? (jp "/videoEmbedCode" media-detail ""))
+                         #f
+                         (url-content-type (jp "/imageUrl" media-detail))))
+                   (define body
+                     (generate-results-page #:source-url source-url
+                                            #:wikiname wikiname
+                                            #:title title
+                                            #:media-detail media-detail
+                                            #:image-content-type image-content-type
+                                            #:license license))
+                   (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 (list referrer-policy)
+                                    (λ (out) (write-html body out)))))))
+(module+ test
+  (parameterize ([(config-parameter 'strict_proxy) "true"])
+    (check-equal? (get-media-html "https://static.wikia.nocookie.net/a" "image/jpeg")
+                  `(img (@ (src "/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fa"))))
+    (check-equal? (get-media-html "https://static.wikia.nocookie.net/b" "audio/mp3")
+                  `(audio (@ (src "/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fb")
+                             (controls)))))
+  (parameterize ([(config-parameter 'strict_proxy) "no"])
+    (check-equal? (get-media-html "https://static.wikia.nocookie.net/c" "application/ogg")
+                  `(audio (@ (src "/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fc")
+                             (controls))))
+    (check-equal? (get-media-html "https://static.wikia.nocookie.net/d" "video/mp4")
+                  `(video (@ (src "/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fd")
+                             (controls)))))
+  (check-equal? (get-media-html "https://example.com" "who knows") `"")
+  (check-equal? (get-media-html "https://example.com" #f) `""))
+(module+ test
+  (parameterize ([(config-parameter 'strict_proxy) "true"])
+    (check-not-false ((query-selector (attribute-selector 'src "/proxy?dest=https%3A%2F%2Fstatic.wikia.nocookie.net%2Fexamplefile")
+                                      (generate-results-page
+                                       #:source-url ""
+                                       #:wikiname "test"
+                                       #:title "File:Example file"
+                                       #:media-detail test-media-detail
+                                       #:image-content-type "image/jpeg"))))))

src/page-search.rkt

@@ -81,6 +81,7 @@
       (xexp->html body))
     (response/output
      #:code 200
+     #:headers (list referrer-policy)
      (λ (out)
        (write-html body out))))))
 (module+ test

src/page-wiki.rkt

@@ -152,15 +152,17 @@
                        (λ (v) (dict-update v 'rel (λ (s)
                                                     (list (string-append (car s) " noreferrer")))
                                            '(""))))
-                ; proxy images from inline styles
-                (curry attribute-maybe-update 'style
+                ; 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)
@@ -168,8 +170,10 @@
                               (eq? element-type 'a)
                               (has-class? "image-thumbnail" v)))
                        (λ (v) (attribute-maybe-update 'href u-proxy-url v)))
-                ; proxy images from src attributes
-                (curry attribute-maybe-update 'src u-proxy-url)
+                ; 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))
@@ -276,8 +280,8 @@
              (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)))
-                                 (list)))
+                                   (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