From 63b2601e6758ff2ae8d8222d80b596eb76be95aa Mon Sep 17 00:00:00 2001
From: Matthew Barbour <matthew@darkholme.net>
Date: Thu, 28 May 2020 10:05:20 -0500
Subject: [PATCH] Mime type handling overhaul

Changed mime type map to deal with the reality that certain file types have multiple extensions and/or multiple mime types, as well as constants supporting all of the data. Created new functions using the updated mime type map to resolve mime types and extensions. Updated various items around the project that determine mime/extension to take advantage of the new functions.
---
 core/basethemelet.php              |   2 +-
 core/extension.php                 |  13 +-
 core/filetypes.php                 | 409 +++++++++++++++++++++++++++++
 core/imageboard/image.php          |   2 +-
 core/imageboard/misc.php           |   2 +-
 core/imageboard/tag.php            |   2 -
 core/polyfills.php                 |  97 +------
 ext/alias_editor/main.php          |   2 +-
 ext/auto_tagger/main.php           |   2 +-
 ext/autocomplete/main.php          |   2 +-
 ext/browser_search/main.php        |   2 +-
 ext/danbooru_api/main.php          |   6 +-
 ext/handle_archive/main.php        |   2 +-
 ext/handle_cbz/main.php            |   4 +-
 ext/handle_flash/main.php          |   2 +-
 ext/handle_ico/main.php            |   2 +-
 ext/handle_mp3/main.php            |   4 +-
 ext/handle_pixel/main.php          |   8 +-
 ext/handle_svg/main.php            |   6 +-
 ext/handle_video/main.php          |  13 +-
 ext/handle_video/theme.php         |  16 +-
 ext/image/main.php                 |  12 +-
 ext/media/main.php                 |  58 ++--
 ext/media/media_engine.php         |  68 ++---
 ext/random_image/main.php          |   2 +-
 ext/resize/main.php                |   2 +-
 ext/rotate/main.php                |   4 +-
 ext/rss_comments/main.php          |   2 +-
 ext/rss_comments/test.php          |   2 +-
 ext/rss_images/main.php            |   2 +-
 ext/rss_images/test.php            |  10 +-
 ext/shimmie_api/main.php           |   2 +-
 ext/sitemap/main.php               |   4 +-
 ext/static_files/main.php          |  11 +-
 ext/tag_list/main.php              |   2 +-
 ext/tagger_xml/main.php            |   2 +-
 ext/transcode/main.php             |  32 +--
 ext/update/main.php                |   2 +-
 ext/upload/main.php                |  10 +-
 ext/upload/theme.php               |  18 +-
 themes/rule34v2/themelet.class.php |   2 +-
 41 files changed, 575 insertions(+), 270 deletions(-)
 create mode 100644 core/filetypes.php

diff --git a/core/basethemelet.php b/core/basethemelet.php
index cc493bb8..bcae8d9f 100644
--- a/core/basethemelet.php
+++ b/core/basethemelet.php
@@ -53,7 +53,7 @@ class BaseThemelet
         $h_tip = html_escape($image->get_tooltip());
         $h_tags = html_escape(strtolower($image->get_tag_list()));
 
-        $extArr = array_flip(['swf', 'svg', 'mp3']); //List of thumbless filetypes
+        $extArr = array_flip([EXTENSION_FLASH, EXTENSION_SVG, EXTENSION_MP3]); //List of thumbless filetypes
         if (!isset($extArr[$image->ext])) {
             $tsize = get_thumbnail_size($image->width, $image->height);
         } else {
diff --git a/core/extension.php b/core/extension.php
index a0060fb0..37d6cad9 100644
--- a/core/extension.php
+++ b/core/extension.php
@@ -275,7 +275,7 @@ abstract class FormatterExtension extends Extension
  */
 abstract class DataHandlerExtension extends Extension
 {
-    protected $SUPPORTED_EXT = [];
+    protected $SUPPORTED_MIME = [];
 
     protected function move_upload_to_archive(DataUploadEvent $event)
     {
@@ -403,7 +403,7 @@ abstract class DataHandlerExtension extends Extension
         $image->hash = $metadata['hash'];
         $image->filename = (($pos = strpos($metadata['filename'], '?')) !== false) ? substr($metadata['filename'], 0, $pos) : $metadata['filename'];
         if ($config->get_bool("upload_use_mime")) {
-            $image->ext = get_extension(getMimeType($filename));
+            $image->ext = get_extension_for_file($filename);
         } else {
             $image->ext = (($pos = strpos($metadata['extension'], '?')) !== false) ? substr($metadata['extension'], 0, $pos) : $metadata['extension'];
         }
@@ -419,15 +419,20 @@ abstract class DataHandlerExtension extends Extension
 
     protected function supported_ext(string $ext): bool
     {
-        return in_array(strtolower($ext), $this->SUPPORTED_EXT);
+        return in_array(get_mime_for_extension($ext), $this->SUPPORTED_MIME);
     }
 
     public static function get_all_supported_exts(): array
     {
         $arr = [];
         foreach (getSubclassesOf("DataHandlerExtension") as $handler) {
-            $arr = array_merge($arr, (new $handler())->SUPPORTED_EXT);
+            $handler = (new $handler());
+
+            foreach($handler->SUPPORTED_MIME as $mime) {
+                $arr = array_merge($arr, get_all_extension_for_mime($mime));
+            }
         }
+        $arr = array_unique($arr);
         return $arr;
     }
 }
diff --git a/core/filetypes.php b/core/filetypes.php
new file mode 100644
index 00000000..169ba58e
--- /dev/null
+++ b/core/filetypes.php
@@ -0,0 +1,409 @@
+<?php
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
+* MIME types and extension information and resolvers                        *
+\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+class MimeTypeMap {
+
+}
+
+const EXTENSION_ANI = 'ani';
+const EXTENSION_ASC = 'asc';
+const EXTENSION_ASF = 'asf';
+const EXTENSION_AVI = 'avi';
+const EXTENSION_BMP = 'bmp';
+const EXTENSION_BZIP = 'bz';
+const EXTENSION_BZIP2 = 'bz2';
+const EXTENSION_CBR = 'cbr';
+const EXTENSION_CBZ = 'cbz';
+const EXTENSION_CBT = 'cbt';
+const EXTENSION_CBA = 'cbA';
+const EXTENSION_CB7 = 'cb7';
+const EXTENSION_CSS = 'css';
+const EXTENSION_CSV = 'csv';
+const EXTENSION_CUR = 'cur';
+const EXTENSION_FLASH = 'swf';
+const EXTENSION_FLASH_VIDEO = 'flv';
+const EXTENSION_GIF = 'gif';
+const EXTENSION_GZIP = 'gz';
+const EXTENSION_HTML = 'html';
+const EXTENSION_HTM = 'htm';
+const EXTENSION_ICO = 'ico';
+const EXTENSION_JFIF = 'jfif';
+const EXTENSION_JFI = 'jfi';
+const EXTENSION_JPEG = 'jpeg';
+const EXTENSION_JPG = 'jpg';
+const EXTENSION_JS = 'js';
+const EXTENSION_JSON = 'json';
+const EXTENSION_MKV = 'mkv';
+const EXTENSION_MP3 = 'mp3';
+const EXTENSION_MP4 = 'mp4';
+const EXTENSION_M4V = 'm4v';
+const EXTENSION_M4A = 'm4a';
+const EXTENSION_MPEG = 'mpeg';
+const EXTENSION_MPG = 'mpg';
+const EXTENSION_OGG = 'ogg';
+const EXTENSION_OGG_VIDEO = 'ogv';
+const EXTENSION_OGG_AUDIO = 'oga';
+const EXTENSION_PDF = 'pdf';
+const EXTENSION_PHP = 'php';
+const EXTENSION_PHP5 = 'php5';
+const EXTENSION_PNG = 'png';
+const EXTENSION_PSD = 'psd';
+const EXTENSION_MOV = 'mov';
+const EXTENSION_RSS = 'rss';
+const EXTENSION_SVG = 'svg';
+const EXTENSION_TAR = 'tar';
+const EXTENSION_TEXT = 'txt';
+const EXTENSION_TIFF = 'tiff';
+const EXTENSION_TIF = 'tif';
+const EXTENSION_WAV = 'wav';
+const EXTENSION_WEBM = 'webm';
+const EXTENSION_WEBP = 'webp';
+const EXTENSION_WMA = 'wma';
+const EXTENSION_WMV = 'wmv';
+const EXTENSION_XML = 'xml';
+const EXTENSION_XSL = 'xsl';
+const EXTENSION_ZIP = 'zip';
+
+
+// Couldn't find a mimetype for ani, so made one up based on it being a riff container
+const MIME_TYPE_ANI = 'application/riff+ani';
+const MIME_TYPE_ASF = 'video/x-ms-asf';
+const MIME_TYPE_AVI = 'video/x-msvideo';
+// Went with mime types from http://fileformats.archiveteam.org/wiki/Comic_Book_Archive
+const MIME_TYPE_COMIC_ZIP = 'application/vnd.comicbook+zip';
+const MIME_TYPE_COMIC_RAR = 'application/vnd.comicbook-rar';
+const MIME_TYPE_BMP = 'image/x-ms-bmp';
+const MIME_TYPE_BZIP = 'application/x-bzip';
+const MIME_TYPE_BZIP2 = 'application/x-bzip2';
+const MIME_TYPE_CSS = 'text/css';
+const MIME_TYPE_CSV = 'text/csv';
+const MIME_TYPE_FLASH = 'application/x-shockwave-flash';
+const MIME_TYPE_FLASH_VIDEO = 'video/x-flv';
+const MIME_TYPE_GIF = 'image/gif';
+const MIME_TYPE_GZIP = 'application/x-gzip';
+const MIME_TYPE_HTML = 'text/html';
+const MIME_TYPE_ICO = 'image/x-icon';
+const MIME_TYPE_JPEG = 'image/jpeg';
+const MIME_TYPE_JS = 'text/javascript';
+const MIME_TYPE_JSON = 'application/json';
+const MIME_TYPE_MKV = 'video/x-matroska';
+const MIME_TYPE_MP3 = 'audio/mpeg';
+const MIME_TYPE_MP4_AUDIO = 'audio/mp4';
+const MIME_TYPE_MP4_VIDEO = 'video/mp4';
+const MIME_TYPE_MPEG = 'video/mpeg';
+const MIME_TYPE_OCTET_STREAM = 'application/octet-stream';
+const MIME_TYPE_OGG = 'application/ogg';
+const MIME_TYPE_OGG_VIDEO = 'video/ogg';
+const MIME_TYPE_OGG_AUDIO = 'audio/ogg';
+const MIME_TYPE_PDF = 'application/pdf';
+const MIME_TYPE_PHP = 'text/x-php';
+const MIME_TYPE_PNG = 'image/png';
+const MIME_TYPE_PSD = 'image/vnd.adobe.photoshop';
+const MIME_TYPE_QUICKTIME = 'video/quicktime';
+const MIME_TYPE_RSS = 'application/rss+xml';
+const MIME_TYPE_SVG = 'image/svg+xml';
+const MIME_TYPE_TAR = 'application/x-tar';
+const MIME_TYPE_TEXT = 'text/plain';
+const MIME_TYPE_TIFF = 'image/tiff';
+const MIME_TYPE_WAV = 'audio/x-wav';
+const MIME_TYPE_WEBM = 'video/webm';
+const MIME_TYPE_WEBP = 'image/webp';
+const MIME_TYPE_WIN_BITMAP = 'image/x-win-bitmap';
+const MIME_TYPE_XML = 'text/xml';
+const MIME_TYPE_XML_APPLICATION = 'application/xml';
+const MIME_TYPE_XSL = 'application/xsl+xml';
+const MIME_TYPE_ZIP = 'application/zip';
+
+const MIME_TYPE_MAP_EXT = 'ext';
+const MIME_TYPE_MAP_MIME = 'mime';
+
+// Mime type map. Each entry in the MIME_TYPE_ARRAY represents a kind of file, identified by the "correct" mimetype as the key.
+// The value for each entry is a map of twokeys, ext and mime.
+// ext's value is an array of all of the extensions that the file type can use, with the "correct" one being first.
+// mime's value is an array of all mime types that the file type is known to use, with the current "correct" one being first.
+
+const MIME_TYPE_MAP = [
+    MIME_TYPE_ANI => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_ANI],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_ANI],
+    ],
+    MIME_TYPE_AVI => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_AVI],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_AVI,'video/avi','video/msvideo'],
+    ],
+    MIME_TYPE_ASF => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_ASF,EXTENSION_WMA,EXTENSION_WMV],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_ASF,'audio/x-ms-wma','video/x-ms-wmv'],
+    ],
+    MIME_TYPE_BMP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_BMP],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_BMP],
+    ],
+    MIME_TYPE_BZIP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_BZIP],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_BZIP],
+    ],
+    MIME_TYPE_BZIP2 => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_BZIP2],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_BZIP2],
+    ],
+    MIME_TYPE_COMIC_ZIP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_CBZ],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_COMIC_ZIP],
+    ],
+    MIME_TYPE_CSS => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_CSS],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_CSS],
+    ],
+    MIME_TYPE_CSV => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_CSV],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_CSV],
+    ],
+    MIME_TYPE_FLASH => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_FLASH],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_FLASH],
+    ],
+    MIME_TYPE_FLASH_VIDEO => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_FLASH_VIDEO],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_FLASH_VIDEO,'video/flv'],
+    ],
+    MIME_TYPE_GIF => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_GIF],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_GIF],
+    ],
+    MIME_TYPE_GZIP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_GZIP],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_TAR],
+    ],
+    MIME_TYPE_HTML => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_HTM, EXTENSION_HTML],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_HTML],
+    ],
+    MIME_TYPE_ICO => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_ICO, EXTENSION_CUR],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_ICO, MIME_TYPE_WIN_BITMAP],
+    ],
+    MIME_TYPE_JPEG => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_JPG, EXTENSION_JPEG, EXTENSION_JFIF, EXTENSION_JFI],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_JPEG],
+    ],
+    MIME_TYPE_JS => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_JS],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_JS],
+    ],
+    MIME_TYPE_JSON => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_JSON],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_JSON],
+    ],
+    MIME_TYPE_MKV => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_MKV],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_MKV],
+    ],
+    MIME_TYPE_MP3 => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_MP3],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_MP3],
+    ],
+    MIME_TYPE_MP4_AUDIO => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_M4A],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_MP4_AUDIO,"audio/m4a"],
+    ],
+    MIME_TYPE_MP4_VIDEO => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_MP4,EXTENSION_M4V],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_MP4_VIDEO,'video/x-m4v'],
+    ],
+    MIME_TYPE_MPEG => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_MPG,EXTENSION_MPEG],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_MPEG],
+    ],
+    MIME_TYPE_PDF => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_PDF],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_PDF],
+    ],
+    MIME_TYPE_PHP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_PHP,EXTENSION_PHP5],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_PHP],
+    ],
+    MIME_TYPE_PNG => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_PNG],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_PNG],
+    ],
+    MIME_TYPE_PSD => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_PSD],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_PSD],
+    ],
+    MIME_TYPE_OGG_AUDIO => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_OGG_AUDIO,EXTENSION_OGG],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_OGG_AUDIO,MIME_TYPE_OGG],
+    ],
+    MIME_TYPE_OGG_VIDEO => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_OGG_VIDEO],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_OGG_VIDEO],
+    ],
+    MIME_TYPE_QUICKTIME => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_MOV],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_QUICKTIME],
+    ],
+    MIME_TYPE_RSS => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_RSS],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_RSS],
+    ],
+    MIME_TYPE_SVG => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_SVG],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_SVG],
+    ],
+    MIME_TYPE_TAR => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_TAR],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_TAR],
+    ],
+    MIME_TYPE_TEXT => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_TEXT, EXTENSION_ASC],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_TEXT],
+    ],
+    MIME_TYPE_TIFF => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_TIF,EXTENSION_TIFF],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_TIFF],
+    ],
+    MIME_TYPE_WAV => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_WAV],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_WAV],
+    ],
+    MIME_TYPE_WEBM => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_WEBM],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_WEBM],
+    ],
+    MIME_TYPE_WEBP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_WEBP],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_WEBP],
+    ],
+    MIME_TYPE_XML => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_XML],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_XML,MIME_TYPE_XML_APPLICATION],
+    ],
+    MIME_TYPE_XSL => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_XSL],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_XSL],
+    ],
+    MIME_TYPE_ZIP => [
+        MIME_TYPE_MAP_EXT => [EXTENSION_ZIP],
+        MIME_TYPE_MAP_MIME => [MIME_TYPE_ZIP],
+    ],
+];
+
+/**
+ * Returns the mimetype that matches the provided extension.
+ */
+function get_mime_for_extension(string $ext): ?string
+{
+    $ext = strtolower($ext);
+
+    foreach (MIME_TYPE_MAP as $key=>$value) {
+        if(in_array($ext,$value[MIME_TYPE_MAP_EXT])) {
+            return $key;
+        }
+    }
+    return null;
+}
+
+/**
+ * Returns the mimetype for the specified file, trying file inspection methods before falling back on extension-based detection.
+ * @param String $file
+ * @param String $ext The files extension, for if the current filename somehow lacks the extension
+ * @return String The extension that was found.
+ */
+function get_mime(string $file, string $ext=""): string
+{
+    if(!file_exists($file)) {
+        throw new SCoreException("File not found: ".$file);
+    }
+
+    $type = false;
+
+    if (extension_loaded('fileinfo')) {
+        $finfo = finfo_open(FILEINFO_MIME_TYPE);
+        try {
+            $type = finfo_file($finfo, $file);
+        } finally {
+            finfo_close($finfo);
+        }
+    } elseif (function_exists('mime_content_type')) {
+        // If anyone is still using mime_content_type()
+        $type = trim(mime_content_type($file));
+    }
+
+    if($type===false || empty($type)) {
+        // Checking by extension is our last resort
+        if($ext==null||strlen($ext) == 0)
+            $ext = pathinfo($file, PATHINFO_EXTENSION);
+
+        $type = get_mime_for_extension($ext);
+    }
+
+    if ($type !== false && strlen($type) > 0) {
+        return $type;
+    }
+
+    return MIME_TYPE_OCTET_STREAM;
+}
+
+/**
+ * Returns the file extension associated with the specified mimetype.
+ */
+function get_extension(?string $mime_type): ?string
+{
+    if (empty($mime_type)) {
+        return null;
+    }
+
+    if($mime_type==MIME_TYPE_OCTET_STREAM) {
+        return null;
+    }
+
+    foreach (MIME_TYPE_MAP as $key=>$value) {
+        if(in_array($mime_type,$value[MIME_TYPE_MAP_MIME])) {
+            return $value[MIME_TYPE_MAP_EXT][0];
+        }
+    }
+    return null;
+}
+
+/**
+ * Returns all of the file extensions associated with the specified mimetype.
+ */
+function get_all_extension_for_mime(?string $mime_type): array
+{
+    $output = [];
+    if (empty($mime_type)) {
+        return $output;
+    }
+
+    foreach (MIME_TYPE_MAP as $key=>$value) {
+        if(in_array($mime_type,$value[MIME_TYPE_MAP_MIME])) {
+            $output = array_merge($output, $value[MIME_TYPE_MAP_EXT]);
+        }
+    }
+    return $output;
+}
+
+/**
+ * Gets an the extension defined in MIME_TYPE_MAP for a file.
+ *
+ * @param String $file_path
+ * @return String The extension that was found, or null if one can not be found.
+ */
+function get_extension_for_file(String $file_path): ?String
+{
+    $mime = get_mime($file_path);
+    if (!empty($mime)) {
+        if($mime==MIME_TYPE_OCTET_STREAM) {
+            return null;
+        } else {
+            $ext = get_extension($mime);
+        }
+        if (!empty($ext)) {
+            return $ext;
+        }
+    }
+    return null;
+}
diff --git a/core/imageboard/image.php b/core/imageboard/image.php
index 513ddbc1..6b786472 100644
--- a/core/imageboard/image.php
+++ b/core/imageboard/image.php
@@ -570,7 +570,7 @@ class Image
      */
     public function get_mime_type(): string
     {
-        return getMimeType($this->get_image_filename(), $this->get_ext());
+        return get_mime($this->get_image_filename(), $this->get_ext());
     }
 
     /**
diff --git a/core/imageboard/misc.php b/core/imageboard/misc.php
index 393e0f94..2fe18795 100644
--- a/core/imageboard/misc.php
+++ b/core/imageboard/misc.php
@@ -142,7 +142,7 @@ function create_scaled_image(string $inname, string $outname, array $tsize, stri
     }
 
     $output_format = $config->get_string(ImageConfig::THUMB_TYPE);
-    if ($output_format=="webp") {
+    if ($output_format==EXTENSION_WEBP) {
         $output_format = Media::WEBP_LOSSY;
     }
 
diff --git a/core/imageboard/tag.php b/core/imageboard/tag.php
index 6b10de46..129bdc39 100644
--- a/core/imageboard/tag.php
+++ b/core/imageboard/tag.php
@@ -116,8 +116,6 @@ class Tag
 
         for ($i = 0; $i < count($tags1); $i++) {
             if ($tags1[$i]!==$tags2[$i]) {
-                var_dump($tags1);
-                var_dump($tags2);
                 return false;
             }
         }
diff --git a/core/polyfills.php b/core/polyfills.php
index 0b733987..38c82baf 100644
--- a/core/polyfills.php
+++ b/core/polyfills.php
@@ -3,6 +3,9 @@
 * Things which should be in the core API                                    *
 \* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
+require_once "filetypes.php";
+
+
 /**
  * Return the unique elements of an array, case insensitively
  */
@@ -253,99 +256,6 @@ if (!function_exists('mb_strlen')) {
     }
 }
 
-const MIME_TYPE_MAP = [
-    'jpg' => 'image/jpeg',
-    'gif' => 'image/gif',
-    'png' => 'image/png',
-    'tif' => 'image/tiff',
-    'tiff' => 'image/tiff',
-    'ico' => 'image/x-icon',
-    'swf' => 'application/x-shockwave-flash',
-    'flv' => 'video/x-flv',
-    'svg' => 'image/svg+xml',
-    'pdf' => 'application/pdf',
-    'zip' => 'application/zip',
-    'gz' => 'application/x-gzip',
-    'tar' => 'application/x-tar',
-    'bz' => 'application/x-bzip',
-    'bz2' => 'application/x-bzip2',
-    'txt' => 'text/plain',
-    'asc' => 'text/plain',
-    'htm' => 'text/html',
-    'html' => 'text/html',
-    'css' => 'text/css',
-    'js' => 'text/javascript',
-    'xml' => 'text/xml',
-    'xsl' => 'application/xsl+xml',
-    'ogg' => 'application/ogg',
-    'mp3' => 'audio/mpeg',
-    'wav' => 'audio/x-wav',
-    'avi' => 'video/x-msvideo',
-    'mpg' => 'video/mpeg',
-    'mpeg' => 'video/mpeg',
-    'mov' => 'video/quicktime',
-    'php' => 'text/x-php',
-    'mp4' => 'video/mp4',
-    'ogv' => 'video/ogg',
-    'webm' => 'video/webm',
-    'webp' => 'image/webp',
-    'bmp' =>'image/x-ms-bmp',
-    'psd' => 'image/vnd.adobe.photoshop',
-    'mkv' => 'video/x-matroska'
-];
-
-/**
- * Get MIME type for file
- *
- * The contents of this function are taken from the __getMimeType() function
- * from the "Amazon S3 PHP class" which is Copyright (c) 2008, Donovan Schönknecht
- * and released under the 'Simplified BSD License'.
- */
-function getMimeType(string $file, string $ext=""): string
-{
-    // Static extension lookup
-    $ext = strtolower($ext);
-
-    if (array_key_exists($ext, MIME_TYPE_MAP)) {
-        return MIME_TYPE_MAP[$ext];
-    }
-
-    $type = false;
-    // Fileinfo documentation says fileinfo_open() will use the
-    // MAGIC env var for the magic file
-    if (extension_loaded('fileinfo') && isset($_ENV['MAGIC']) &&
-        ($finfo = finfo_open(FILEINFO_MIME, $_ENV['MAGIC'])) !== false) {
-        if (($type = finfo_file($finfo, $file)) !== false) {
-            // Remove the charset and grab the last content-type
-            $type = explode(' ', str_replace('; charset=', ';charset=', $type));
-            $type = array_pop($type);
-            $type = explode(';', $type);
-            $type = trim(array_shift($type));
-        }
-        finfo_close($finfo);
-
-    // If anyone is still using mime_content_type()
-    } elseif (function_exists('mime_content_type')) {
-        $type = trim(mime_content_type($file));
-    }
-
-    if ($type !== false && strlen($type) > 0) {
-        return $type;
-    }
-
-    return 'application/octet-stream';
-}
-
-function get_extension(?string $mime_type): ?string
-{
-    if (empty($mime_type)) {
-        return null;
-    }
-
-    $ext = array_search($mime_type, MIME_TYPE_MAP);
-    return ($ext ? $ext : null);
-}
-
 /** @noinspection PhpUnhandledExceptionInspection */
 function getSubclassesOf(string $parent)
 {
@@ -860,3 +770,4 @@ function stringer($s)
     }
     return (string)$s;
 }
+
diff --git a/ext/alias_editor/main.php b/ext/alias_editor/main.php
index e8a3a678..f3d4f979 100644
--- a/ext/alias_editor/main.php
+++ b/ext/alias_editor/main.php
@@ -96,7 +96,7 @@ class AliasEditor extends Extension
                 $this->theme->display_aliases($t->table($t->query()), $t->paginator());
             } elseif ($event->get_arg(0) == "export") {
                 $page->set_mode(PageMode::DATA);
-                $page->set_type("text/csv");
+                $page->set_type(MIME_TYPE_CSV);
                 $page->set_filename("aliases.csv");
                 $page->set_data($this->get_alias_csv($database));
             } elseif ($event->get_arg(0) == "import") {
diff --git a/ext/auto_tagger/main.php b/ext/auto_tagger/main.php
index da32789a..8f8d16b9 100644
--- a/ext/auto_tagger/main.php
+++ b/ext/auto_tagger/main.php
@@ -98,7 +98,7 @@ class AutoTagger extends Extension
                 $this->theme->display_auto_tagtable($t->table($t->query()), $t->paginator());
             } elseif ($event->get_arg(0) == "export") {
                 $page->set_mode(PageMode::DATA);
-                $page->set_type("text/csv");
+                $page->set_type(MIME_TYPE_CSV);
                 $page->set_filename("auto_tag.csv");
                 $page->set_data($this->get_auto_tag_csv($database));
             } elseif ($event->get_arg(0) == "import") {
diff --git a/ext/autocomplete/main.php b/ext/autocomplete/main.php
index 843c8536..4d459651 100644
--- a/ext/autocomplete/main.php
+++ b/ext/autocomplete/main.php
@@ -20,7 +20,7 @@ class AutoComplete extends Extension
             }
 
             $page->set_mode(PageMode::DATA);
-            $page->set_type("application/json");
+            $page->set_type(MIME_TYPE_JSON);
 
             $s = strtolower($_GET["s"]);
             if (
diff --git a/ext/browser_search/main.php b/ext/browser_search/main.php
index d29326e0..c3965896 100644
--- a/ext/browser_search/main.php
+++ b/ext/browser_search/main.php
@@ -42,7 +42,7 @@ class BrowserSearch extends Extension
 
             // And now to send it to the browser
             $page->set_mode(PageMode::DATA);
-            $page->set_type("text/xml");
+            $page->set_type(MIME_TYPE_XML);
             $page->set_data($xml);
         } elseif ($event->page_matches("browser_search")) {
             $suggestions = $config->get_string("search_suggestions_results_order");
diff --git a/ext/danbooru_api/main.php b/ext/danbooru_api/main.php
index 4eadd66c..0892e3fd 100644
--- a/ext/danbooru_api/main.php
+++ b/ext/danbooru_api/main.php
@@ -10,13 +10,13 @@ class DanbooruApi extends Extension
 
             if ($event->page_matches("api/danbooru/add_post") || $event->page_matches("api/danbooru/post/create.xml")) {
                 // No XML data is returned from this function
-                $page->set_type("text/plain");
+                $page->set_type(MIME_TYPE_TEXT);
                 $this->api_add_post();
             } elseif ($event->page_matches("api/danbooru/find_posts") || $event->page_matches("api/danbooru/post/index.xml")) {
-                $page->set_type("application/xml");
+                $page->set_type(MIME_TYPE_XML_APPLICATION);
                 $page->set_data($this->api_find_posts());
             } elseif ($event->page_matches("api/danbooru/find_tags")) {
-                $page->set_type("application/xml");
+                $page->set_type(MIME_TYPE_XML_APPLICATION);
                 $page->set_data($this->api_find_tags());
             }
 
diff --git a/ext/handle_archive/main.php b/ext/handle_archive/main.php
index 04937c90..d493d354 100644
--- a/ext/handle_archive/main.php
+++ b/ext/handle_archive/main.php
@@ -2,7 +2,7 @@
 
 class ArchiveFileHandler extends DataHandlerExtension
 {
-    protected $SUPPORTED_EXT = ["zip"];
+    protected $SUPPORTED_MIME = [MIME_TYPE_ZIP];
 
     public function onInitExt(InitExtEvent $event)
     {
diff --git a/ext/handle_cbz/main.php b/ext/handle_cbz/main.php
index b9011c52..c6ce429e 100644
--- a/ext/handle_cbz/main.php
+++ b/ext/handle_cbz/main.php
@@ -2,7 +2,7 @@
 
 class CBZFileHandler extends DataHandlerExtension
 {
-    public $SUPPORTED_EXT = ["cbz"];
+    public $SUPPORTED_MIME = [MIME_TYPE_COMIC_ZIP];
 
     protected function media_check_properties(MediaCheckPropertiesEvent $event): void
     {
@@ -27,7 +27,7 @@ class CBZFileHandler extends DataHandlerExtension
             $cover,
             warehouse_path(Image::THUMBNAIL_DIR, $hash),
             get_thumbnail_max_size_scaled(),
-            get_extension(getMimeType($cover)),
+            get_extension(get_mime($cover)),
             null
         );
         return true;
diff --git a/ext/handle_flash/main.php b/ext/handle_flash/main.php
index 2f8fd1aa..2bad8e3e 100644
--- a/ext/handle_flash/main.php
+++ b/ext/handle_flash/main.php
@@ -2,7 +2,7 @@
 
 class FlashFileHandler extends DataHandlerExtension
 {
-    protected $SUPPORTED_EXT = ["swf"];
+    protected $SUPPORTED_MIME = [MIME_TYPE_FLASH];
 
     protected function media_check_properties(MediaCheckPropertiesEvent $event): void
     {
diff --git a/ext/handle_ico/main.php b/ext/handle_ico/main.php
index f80555d3..50e570fd 100644
--- a/ext/handle_ico/main.php
+++ b/ext/handle_ico/main.php
@@ -2,7 +2,7 @@
 
 class IcoFileHandler extends DataHandlerExtension
 {
-    protected $SUPPORTED_EXT = ["ico", "ani", "cur"];
+    protected $SUPPORTED_MIME = [MIME_TYPE_ICO, MIME_TYPE_ANI];
 
     protected function media_check_properties(MediaCheckPropertiesEvent $event): void
     {
diff --git a/ext/handle_mp3/main.php b/ext/handle_mp3/main.php
index 1d943b62..17123bff 100644
--- a/ext/handle_mp3/main.php
+++ b/ext/handle_mp3/main.php
@@ -2,7 +2,7 @@
 
 class MP3FileHandler extends DataHandlerExtension
 {
-    protected $SUPPORTED_EXT = ["mp3"];
+    protected $SUPPORTED_MIME = [MIME_TYPE_MP3];
 
     protected function media_check_properties(MediaCheckPropertiesEvent $event): void
     {
@@ -23,6 +23,6 @@ class MP3FileHandler extends DataHandlerExtension
 
     protected function check_contents(string $tmpname): bool
     {
-        return getMimeType($tmpname) == 'audio/mpeg';
+        return get_mime($tmpname) === MIME_TYPE_MP3;
     }
 }
diff --git a/ext/handle_pixel/main.php b/ext/handle_pixel/main.php
index c44f7bd0..0ba5c73e 100644
--- a/ext/handle_pixel/main.php
+++ b/ext/handle_pixel/main.php
@@ -2,13 +2,13 @@
 
 class PixelFileHandler extends DataHandlerExtension
 {
-    protected $SUPPORTED_EXT = ["jpg", "jpeg", "gif", "png", "webp"];
+    protected $SUPPORTED_MIME = [MIME_TYPE_JPEG, MIME_TYPE_GIF, MIME_TYPE_PNG, MIME_TYPE_WEBP];
 
     protected function media_check_properties(MediaCheckPropertiesEvent $event): void
     {
         if (in_array($event->ext, Media::LOSSLESS_FORMATS)) {
             $event->image->lossless = true;
-        } elseif ($event->ext=="webp") {
+        } elseif ($event->ext==EXTENSION_WEBP) {
             $event->image->lossless = Media::is_lossless_webp($event->file_name);
         }
 
@@ -17,10 +17,10 @@ class PixelFileHandler extends DataHandlerExtension
         }
         $event->image->audio = false;
         switch ($event->ext) {
-            case "gif":
+            case EXTENSION_GIF:
                 $event->image->video = Media::is_animated_gif($event->file_name);
                 break;
-            case "webp":
+            case EXTENSION_WEBP:
                 $event->image->video = Media::is_animated_webp($event->file_name);
                 break;
             default:
diff --git a/ext/handle_svg/main.php b/ext/handle_svg/main.php
index 84eb19a6..7b366a4a 100644
--- a/ext/handle_svg/main.php
+++ b/ext/handle_svg/main.php
@@ -3,7 +3,7 @@ use enshrined\svgSanitize\Sanitizer;
 
 class SVGFileHandler extends DataHandlerExtension
 {
-    protected $SUPPORTED_EXT = ["svg"];
+    protected $SUPPORTED_MIME = [MIME_TYPE_SVG];
 
     /** @var SVGFileHandlerTheme */
     protected $theme;
@@ -16,7 +16,7 @@ class SVGFileHandler extends DataHandlerExtension
             $image = Image::by_id($id);
             $hash = $image->hash;
 
-            $page->set_type("image/svg+xml");
+            $page->set_type(MIME_TYPE_SVG);
             $page->set_mode(PageMode::DATA);
 
             $sanitizer = new Sanitizer();
@@ -67,7 +67,7 @@ class SVGFileHandler extends DataHandlerExtension
 
     protected function check_contents(string $file): bool
     {
-        if (getMimeType($file)!="image/svg+xml") {
+        if (get_mime($file)!==MIME_TYPE_SVG) {
             return false;
         }
 
diff --git a/ext/handle_video/main.php b/ext/handle_video/main.php
index 5b5b3beb..cd3d5453 100644
--- a/ext/handle_video/main.php
+++ b/ext/handle_video/main.php
@@ -3,13 +3,12 @@
 class VideoFileHandler extends DataHandlerExtension
 {
     protected $SUPPORTED_MIME = [
-        'video/webm',
-        'video/mp4',
-        'video/ogg',
-        'video/flv',
-        'video/x-flv'
+        MIME_TYPE_WEBM,
+        MIME_TYPE_MP4_VIDEO,
+        MIME_TYPE_OGG_VIDEO,
+        MIME_TYPE_FLASH_VIDEO,
     ];
-    protected $SUPPORTED_EXT = ["flv", "mp4", "m4v", "ogv", "webm"];
+    protected $SUPPORTED_EXT = [EXTENSION_FLASH_VIDEO, EXTENSION_MP4, EXTENSION_M4V, EXTENSION_OGG_VIDEO, EXTENSION_WEBM];
 
     public function onInitExt(InitExtEvent $event)
     {
@@ -87,6 +86,6 @@ class VideoFileHandler extends DataHandlerExtension
 
     protected function check_contents(string $tmpname): bool
     {
-        return in_array(getMimeType($tmpname), $this->SUPPORTED_MIME);
+        return in_array(get_mime($tmpname), $this->SUPPORTED_MIME);
     }
 }
diff --git a/ext/handle_video/theme.php b/ext/handle_video/theme.php
index 24619e0c..f0e7b71e 100644
--- a/ext/handle_video/theme.php
+++ b/ext/handle_video/theme.php
@@ -2,6 +2,9 @@
 
 class VideoFileHandlerTheme extends Themelet
 {
+
+    const SUPPORTED_TYPES = [MIME_TYPE_MP4_VIDEO, MIME_TYPE_OGG_VIDEO, MIME_TYPE_WEBM, MIME_TYPE_FLASH_VIDEO];
+
     public function display_image(Page $page, Image $image)
     {
         global $config;
@@ -16,10 +19,11 @@ class VideoFileHandlerTheme extends Themelet
         $html = "Video not playing? <a href='$ilink'>Click here</a> to download the file.<br/>";
 
         //Browser media format support: https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
-        $supportedExts = ['mp4' => 'video/mp4', 'm4v' => 'video/mp4', 'ogv' => 'video/ogg', 'webm' => 'video/webm', 'flv' => 'video/flv'];
-        if (array_key_exists($ext, $supportedExts)) {
+        $mime = get_mime_for_extension($ext);
+
+        if (in_array($mime, self::SUPPORTED_TYPES)) {
             //FLV isn't supported by <video>, but it should always fallback to the flash-based method.
-            if ($ext == "webm") {
+            if ($mime == MIME_TYPE_WEBM) {
                 //Several browsers still lack WebM support sadly: https://caniuse.com/#feat=webm
                 $html .= "<!--[if IE]><p>To view webm files with IE, please <a href='https://tools.google.com/dlpage/webmmf/' target='_blank'>download this plugin</a>.</p><![endif]-->";
             }
@@ -40,7 +44,7 @@ class VideoFileHandlerTheme extends Themelet
 							<img alt='thumb' src=\"{$thumb_url}\" />
 						</object>";
 
-            if ($ext == "flv") {
+            if ($mime == MIME_TYPE_FLASH_VIDEO) {
                 //FLV doesn't support <video>.
                 $html .= $html_fallback;
             } else {
@@ -50,7 +54,7 @@ class VideoFileHandlerTheme extends Themelet
                 $html .= "
 					<video controls class='shm-main-image' id='main_image' alt='main image' poster='$thumb_url' {$autoplay} {$loop}
 					style='max-width: 100%'>
-						<source src='{$ilink}' type='{$supportedExts[$ext]}'>
+						<source src='{$ilink}' type='{$mime}'>
 
 						<!-- If browser doesn't support filetype, fallback to flash -->
 						{$html_fallback}
@@ -60,7 +64,7 @@ class VideoFileHandlerTheme extends Themelet
             }
         } else {
             //This should never happen, but just in case let's have a fallback..
-            $html = "Video type '$ext' not recognised";
+            $html = "Video type '$mime' not recognised";
         }
         $page->add_block(new Block("Video", $html, "main", 10));
     }
diff --git a/ext/image/main.php b/ext/image/main.php
index e4091141..197b7444 100644
--- a/ext/image/main.php
+++ b/ext/image/main.php
@@ -21,8 +21,8 @@ class ImageIO extends Extension
     ];
 
     const THUMBNAIL_TYPES = [
-        'JPEG' => "jpg",
-        'WEBP (Not IE/Safari compatible)' => "webp"
+        'JPEG' => EXTENSION_JPG,
+        'WEBP (Not IE/Safari compatible)' => EXTENSION_WEBP
     ];
 
     public function onInitExt(InitExtEvent $event)
@@ -32,7 +32,7 @@ class ImageIO extends Extension
         $config->set_default_int(ImageConfig::THUMB_HEIGHT, 192);
         $config->set_default_int(ImageConfig::THUMB_SCALING, 100);
         $config->set_default_int(ImageConfig::THUMB_QUALITY, 75);
-        $config->set_default_string(ImageConfig::THUMB_TYPE, 'jpg');
+        $config->set_default_string(ImageConfig::THUMB_TYPE, EXTENSION_JPG);
 
         if (function_exists(self::EXIF_READ_FUNCTION)) {
             $config->set_default_bool(ImageConfig::SHOW_META, false);
@@ -271,11 +271,7 @@ class ImageIO extends Extension
         if (!is_null($image)) {
             if ($type == "thumb") {
                 $ext = $config->get_string(ImageConfig::THUMB_TYPE);
-                if (array_key_exists($ext, MIME_TYPE_MAP)) {
-                    $page->set_type(MIME_TYPE_MAP[$ext]);
-                } else {
-                    $page->set_type("image/jpeg");
-                }
+                $page->set_type(get_mime_for_extension($ext));
 
                 $file = $image->get_thumb_filename();
             } else {
diff --git a/ext/media/main.php b/ext/media/main.php
index e98da9b0..81e3b24b 100644
--- a/ext/media/main.php
+++ b/ext/media/main.php
@@ -26,26 +26,26 @@ class Media extends Extension
 
     const LOSSLESS_FORMATS = [
         self::WEBP_LOSSLESS,
-        "png",
-        "psd",
-        "bmp",
-        "ico",
-        "cur",
-        "ani",
-        "gif"
+        EXTENSION_PNG,
+        EXTENSION_PSD,
+        EXTENSION_BMP,
+        EXTENSION_ICO,
+        EXTENSION_CUR,
+        EXTENSION_ANI,
+        EXTENSION_GIF
 
     ];
 
     const ALPHA_FORMATS = [
         self::WEBP_LOSSLESS,
         self::WEBP_LOSSY,
-        "webp",
-        "png",
+        EXTENSION_WEBP,
+        EXTENSION_PNG,
     ];
 
     const FORMAT_ALIASES = [
-        "tif" => "tiff",
-        "jpeg" => "jpg",
+        EXTENSION_TIF => EXTENSION_TIFF,
+        EXTENSION_JPEG => EXTENSION_JPG,
     ];
 
 
@@ -363,7 +363,7 @@ class Media extends Extension
 
         $codec = "mjpeg";
         $quality = $config->get_int(ImageConfig::THUMB_QUALITY);
-        if ($config->get_string(ImageConfig::THUMB_TYPE) == "webp") {
+        if ($config->get_string(ImageConfig::THUMB_TYPE) == EXTENSION_WEBP) {
             $codec = "libwebp";
         } else {
             // mjpeg quality ranges from 2-31, with 2 being the best quality.
@@ -436,7 +436,7 @@ class Media extends Extension
         switch ($format) {
             case self::WEBP_LOSSLESS:
             case self::WEBP_LOSSY:
-                return "webp";
+                return EXTENSION_WEBP;
             default:
                 return $format;
         }
@@ -445,7 +445,7 @@ class Media extends Extension
 //    private static function image_save_imagick(Imagick $image, string $path, string $format, int $output_quality = 80, bool $minimize)
 //    {
 //        switch ($format) {
-//            case "png":
+//            case EXTENSION_PNG:
 //                $result = $image->setOption('png:compression-level', 9);
 //                if ($result !== true) {
 //                    throw new GraphicsException("Could not set png compression option");
@@ -555,7 +555,7 @@ class Media extends Extension
             return true;
         }
         switch ($format) {
-            case "webp":
+            case EXTENSION_WEBP:
                 return self::is_lossless_webp($filename);
                 break;
         }
@@ -586,7 +586,7 @@ class Media extends Extension
             $output_type = $input_type;
         }
 
-        if ($output_type=="webp" && self::is_lossless($input_path, $input_type)) {
+        if ($output_type==EXTENSION_WEBP && self::is_lossless($input_path, $input_type)) {
             $output_type = self::WEBP_LOSSLESS;
         }
 
@@ -612,7 +612,7 @@ class Media extends Extension
             case Media::WEBP_LOSSLESS:
                 $args .= '-define webp:lossless=true';
                 break;
-            case "png":
+            case EXTENSION_PNG:
                 $args .= '-define png:compression-level=9';
                 break;
         }
@@ -668,19 +668,19 @@ class Media extends Extension
             /* If not specified, output to the same format as the original image */
             switch ($info[2]) {
                 case IMAGETYPE_GIF:
-                    $output_type = "gif";
+                    $output_type = EXTENSION_GIF;
                     break;
                 case IMAGETYPE_JPEG:
-                    $output_type = "jpeg";
+                    $output_type = EXTENSION_JPEG;
                     break;
                 case IMAGETYPE_PNG:
-                    $output_type = "png";
+                    $output_type = EXTENSION_PNG;
                     break;
                 case IMAGETYPE_WEBP:
-                    $output_type = "webp";
+                    $output_type = EXTENSION_WEBP;
                     break;
                 case IMAGETYPE_BMP:
-                    $output_type = "bmp";
+                    $output_type = EXTENSION_BMP;
                     break;
                 default:
                     throw new MediaException("Failed to save the new image - Unsupported image type.");
@@ -776,21 +776,21 @@ class Media extends Extension
             }
 
             switch ($output_type) {
-                case "bmp":
+                case EXTENSION_BMP:
                     $result = imagebmp($image_resized, $output_filename, true);
                     break;
-                case "webp":
+                case EXTENSION_WEBP:
                 case Media::WEBP_LOSSY:
                     $result = imagewebp($image_resized, $output_filename, $output_quality);
                     break;
-                case "jpg":
-                case "jpeg":
+                case EXTENSION_JPG:
+                case EXTENSION_JPEG:
                     $result = imagejpeg($image_resized, $output_filename, $output_quality);
                     break;
-                case "png":
+                case EXTENSION_PNG:
                     $result = imagepng($image_resized, $output_filename, 9);
                     break;
-                case "gif":
+                case EXTENSION_GIF:
                     $result = imagegif($image_resized, $output_filename);
                     break;
                 default:
@@ -904,7 +904,7 @@ class Media extends Extension
      */
     public static function normalize_format(string $format, ?bool $lossless = null): ?string
     {
-        if ($format == "webp") {
+        if ($format == EXTENSION_WEBP) {
             if ($lossless === true) {
                 $format = Media::WEBP_LOSSLESS;
             } else {
diff --git a/ext/media/media_engine.php b/ext/media/media_engine.php
index 62e56e05..43dc74f4 100644
--- a/ext/media/media_engine.php
+++ b/ext/media/media_engine.php
@@ -15,63 +15,63 @@ abstract class MediaEngine
     ];
     public const OUTPUT_SUPPORT = [
         MediaEngine::GD => [
-            "gif",
-            "jpg",
-            "png",
-            "webp",
+            EXTENSION_GIF,
+            EXTENSION_JPG,
+            EXTENSION_PNG,
+            EXTENSION_WEBP,
             Media::WEBP_LOSSY,
         ],
         MediaEngine::IMAGICK => [
-            "gif",
-            "jpg",
-            "png",
-            "webp",
+            EXTENSION_GIF,
+            EXTENSION_JPG,
+            EXTENSION_PNG,
+            EXTENSION_WEBP,
             Media::WEBP_LOSSY,
             Media::WEBP_LOSSLESS,
         ],
         MediaEngine::FFMPEG => [
-            "jpg",
-            "webp",
-            "png",
+            EXTENSION_JPG,
+            EXTENSION_WEBP,
+            EXTENSION_PNG,
         ],
         MediaEngine::STATIC => [
-            "jpg",
+            EXTENSION_JPG,
         ],
     ];
     public const INPUT_SUPPORT = [
         MediaEngine::GD => [
-            "bmp",
-            "gif",
-            "jpg",
-            "png",
-            "webp",
+            EXTENSION_BMP,
+            EXTENSION_GIF,
+            EXTENSION_JPG,
+            EXTENSION_PNG,
+            EXTENSION_WEBP,
             Media::WEBP_LOSSY,
             Media::WEBP_LOSSLESS,
         ],
         MediaEngine::IMAGICK => [
-            "bmp",
-            "gif",
-            "jpg",
-            "png",
-            "psd",
-            "tiff",
-            "webp",
+            EXTENSION_BMP,
+            EXTENSION_GIF,
+            EXTENSION_JPG,
+            EXTENSION_PNG,
+            EXTENSION_PSD,
+            EXTENSION_TIFF,
+            EXTENSION_WEBP,
             Media::WEBP_LOSSY,
             Media::WEBP_LOSSLESS,
-            "ico",
+            EXTENSION_ICO,
         ],
         MediaEngine::FFMPEG => [
-            "avi",
-            "mkv",
-            "webm",
-            "mp4",
-            "mov",
-            "flv",
+            EXTENSION_AVI,
+            EXTENSION_MKV,
+            EXTENSION_WEBM,
+            EXTENSION_MP4,
+            EXTENSION_MOV,
+            EXTENSION_FLASH_VIDEO,
         ],
         MediaEngine::STATIC => [
-            "jpg",
-            "gif",
-            "png",
+            EXTENSION_JPG,
+            EXTENSION_GIF,
+            EXTENSION_PNG,
         ],
     ];
 }
diff --git a/ext/random_image/main.php b/ext/random_image/main.php
index b33fe4b8..fee4f418 100644
--- a/ext/random_image/main.php
+++ b/ext/random_image/main.php
@@ -35,7 +35,7 @@ class RandomImage extends Extension
                 send_event(new DisplayingImageEvent($image));
             } elseif ($action === "widget") {
                 $page->set_mode(PageMode::DATA);
-                $page->set_type("text/html");
+                $page->set_type(MIME_TYPE_HTML);
                 $page->set_data($this->theme->build_thumb_html($image));
             }
         }
diff --git a/ext/resize/main.php b/ext/resize/main.php
index b43d9ee8..ea03abe4 100644
--- a/ext/resize/main.php
+++ b/ext/resize/main.php
@@ -84,7 +84,7 @@ class ResizeImage extends Extension
                 $height = $config->get_int(ResizeConfig::DEFAULT_HEIGHT);
             }
             $isanigif = 0;
-            if ($image_obj->ext == "gif") {
+            if ($image_obj->ext == EXTENSION_GIF) {
                 $image_filename = warehouse_path(Image::IMAGE_DIR, $image_obj->hash);
                 if (($fh = @fopen($image_filename, 'rb'))) {
                     //check if gif is animated (via https://www.php.net/manual/en/function.imagecreatefromgif.php#104473)
diff --git a/ext/rotate/main.php b/ext/rotate/main.php
index 42ce6304..9b1bfbfa 100644
--- a/ext/rotate/main.php
+++ b/ext/rotate/main.php
@@ -15,7 +15,7 @@ class RotateImage extends Extension
     /** @var RotateImageTheme */
     protected $theme;
 
-    const SUPPORTED_EXT = ["jpg","jpeg","png","gif","webp"];
+    const SUPPORTED_MIME = [MIME_TYPE_JPEG, MIME_TYPE_PNG, MIME_TYPE_GIF, MIME_TYPE_WEBP];
 
     public function onInitExt(InitExtEvent $event)
     {
@@ -28,7 +28,7 @@ class RotateImage extends Extension
     {
         global $user, $config;
         if ($user->can(Permissions::EDIT_FILES) && $config->get_bool("rotate_enabled")
-                && in_array($event->image->ext, self::SUPPORTED_EXT)) {
+                && in_array(get_mime_for_extension($event->image->ext), self::SUPPORTED_MIME)) {
             /* Add a link to rotate the image */
             $event->add_part($this->theme->get_rotate_html($event->image->id));
         }
diff --git a/ext/rss_comments/main.php b/ext/rss_comments/main.php
index cb9f4ab7..77dfb08a 100644
--- a/ext/rss_comments/main.php
+++ b/ext/rss_comments/main.php
@@ -16,7 +16,7 @@ class RSSComments extends Extension
         global $config, $database, $page;
         if ($event->page_matches("rss/comments")) {
             $page->set_mode(PageMode::DATA);
-            $page->set_type("application/rss+xml");
+            $page->set_type(MIME_TYPE_RSS);
 
             $comments = $database->get_all("
 				SELECT
diff --git a/ext/rss_comments/test.php b/ext/rss_comments/test.php
index 2d812f8f..83936ca6 100644
--- a/ext/rss_comments/test.php
+++ b/ext/rss_comments/test.php
@@ -9,7 +9,7 @@ class RSSCommentsTest extends ShimmiePHPUnitTestCase
         send_event(new CommentPostingEvent($image_id, $user, "ASDFASDF"));
 
         $this->get_page('rss/comments');
-        //$this->assert_mime("application/rss+xml");
+        //$this->assert_mime(MIME_TYPE_RSS);
         $this->assert_no_content("Exception");
         $this->assert_content("ASDFASDF");
     }
diff --git a/ext/rss_images/main.php b/ext/rss_images/main.php
index f72b54d3..e0ca5d48 100644
--- a/ext/rss_images/main.php
+++ b/ext/rss_images/main.php
@@ -43,7 +43,7 @@ class RSSImages extends Extension
         global $page;
         global $config;
         $page->set_mode(PageMode::DATA);
-        $page->set_type("application/rss+xml");
+        $page->set_type(MIME_TYPE_RSS);
 
         $data = "";
         foreach ($images as $image) {
diff --git a/ext/rss_images/test.php b/ext/rss_images/test.php
index 00021b77..a3aa9323 100644
--- a/ext/rss_images/test.php
+++ b/ext/rss_images/test.php
@@ -8,26 +8,26 @@ class RSSImagesTest extends ShimmiePHPUnitTestCase
         $this->log_out();
 
         $this->get_page('rss/images');
-        //$this->assert_mime("application/rss+xml");
+        //$this->assert_mime(MIME_TYPE_RSS);
         $this->assert_no_content("Exception");
 
         $this->get_page('rss/images/1');
-        //$this->assert_mime("application/rss+xml");
+        //$this->assert_mime(MIME_TYPE_RSS);
         $this->assert_no_content("Exception");
 
         # FIXME: test that the image is actually found
         $this->get_page('rss/images/computer/1');
-        //$this->assert_mime("application/rss+xml");
+        //$this->assert_mime(MIME_TYPE_RSS);
         $this->assert_no_content("Exception");
 
         # valid tag, invalid page
         $this->get_page('rss/images/computer/2');
-        //$this->assert_mime("application/rss+xml");
+        //$this->assert_mime(MIME_TYPE_RSS);
         $this->assert_no_content("Exception");
 
         # not found
         $this->get_page('rss/images/waffle/2');
-        //$this->assert_mime("application/rss+xml");
+        //$this->assert_mime(MIME_TYPE_RSS);
         $this->assert_no_content("Exception");
     }
 }
diff --git a/ext/shimmie_api/main.php b/ext/shimmie_api/main.php
index 31923d46..ecada937 100644
--- a/ext/shimmie_api/main.php
+++ b/ext/shimmie_api/main.php
@@ -36,7 +36,7 @@ class ShimmieApi extends Extension
 
         if ($event->page_matches("api/shimmie")) {
             $page->set_mode(PageMode::DATA);
-            $page->set_type("text/plain");
+            $page->set_type(MIME_TYPE_TEXT);
 
             if ($event->page_matches("api/shimmie/get_tags")) {
                 if ($event->count_args() > 0) {
diff --git a/ext/sitemap/main.php b/ext/sitemap/main.php
index afa60714..02ef3ccc 100644
--- a/ext/sitemap/main.php
+++ b/ext/sitemap/main.php
@@ -155,7 +155,7 @@ class XMLSitemap extends Extension
         // Generate new sitemap
         file_put_contents($this->sitemap_filepath, $xml);
         $page->set_mode(PageMode::DATA);
-        $page->set_type("application/xml");
+        $page->set_type(MIME_TYPE_XML_APPLICATION);
         $page->set_data($xml);
     }
 
@@ -191,7 +191,7 @@ class XMLSitemap extends Extension
         $xml = file_get_contents($this->sitemap_filepath);
 
         $page->set_mode(PageMode::DATA);
-        $page->set_type("application/xml");
+        $page->set_type(MIME_TYPE_XML_APPLICATION);
         $page->set_data($xml);
     }
 }
diff --git a/ext/static_files/main.php b/ext/static_files/main.php
index 5715f9d4..fd541e37 100644
--- a/ext/static_files/main.php
+++ b/ext/static_files/main.php
@@ -21,15 +21,8 @@ class StaticFiles extends Extension
                 $page->add_http_header('Expires: ' . gmdate('D, d M Y H:i:s', time() + 600) . ' GMT');
                 $page->set_mode(PageMode::DATA);
                 $page->set_data(file_get_contents($filename));
-                if (endsWith($filename, ".ico")) {
-                    $page->set_type("image/x-icon");
-                }
-                if (endsWith($filename, ".png")) {
-                    $page->set_type("image/png");
-                }
-                if (endsWith($filename, ".txt")) {
-                    $page->set_type("text/plain");
-                }
+
+                $page->set_type(get_mime($filename));
             }
         }
     }
diff --git a/ext/tag_list/main.php b/ext/tag_list/main.php
index f7c4f537..9071ded7 100644
--- a/ext/tag_list/main.php
+++ b/ext/tag_list/main.php
@@ -77,7 +77,7 @@ class TagList extends Extension
             }
 
             $page->set_mode(PageMode::DATA);
-            $page->set_type("text/plain");
+            $page->set_type(MIME_TYPE_TEXT);
             $page->set_data(implode("\n", $res));
         }
     }
diff --git a/ext/tagger_xml/main.php b/ext/tagger_xml/main.php
index 8a8165dd..32fc62be 100644
--- a/ext/tagger_xml/main.php
+++ b/ext/tagger_xml/main.php
@@ -30,7 +30,7 @@ class TaggerXML extends Extension
             "</tags>";
 
             $page->set_mode(PageMode::DATA);
-            $page->set_type("text/xml");
+            $page->set_type(MIME_TYPE_XML);
             $page->set_data($xml);
         }
     }
diff --git a/ext/transcode/main.php b/ext/transcode/main.php
index 44062aaf..27c1eb8c 100644
--- a/ext/transcode/main.php
+++ b/ext/transcode/main.php
@@ -17,20 +17,20 @@ class TranscodeImage extends Extension
     const ACTION_BULK_TRANSCODE = "bulk_transcode";
 
     const INPUT_FORMATS = [
-        "BMP" => "bmp",
-        "GIF" => "gif",
-        "ICO" => "ico",
-        "JPG" => "jpg",
-        "PNG" => "png",
-        "PSD" => "psd",
-        "TIFF" => "tiff",
-        "WEBP" => "webp",
+        "BMP" => EXTENSION_BMP,
+        "GIF" => EXTENSION_GIF,
+        "ICO" => EXTENSION_ICO,
+        "JPG" => EXTENSION_JPG,
+        "PNG" => EXTENSION_PNG,
+        "PSD" => EXTENSION_PSD,
+        "TIFF" => EXTENSION_TIFF,
+        "WEBP" => EXTENSION_WEBP,
     ];
 
     const OUTPUT_FORMATS = [
         "" => "",
-        "JPEG (lossy)" => "jpg",
-        "PNG (lossless)" => "png",
+        "JPEG (lossy)" => EXTENSION_JPG,
+        "PNG (lossless)" => EXTENSION_PNG,
         "WEBP (lossy)" => Media::WEBP_LOSSY,
         "WEBP (lossless)" => Media::WEBP_LOSSLESS,
     ];
@@ -102,7 +102,7 @@ class TranscodeImage extends Extension
 
             $ext = Media::normalize_format($ext);
 
-            if ($event->type=="gif"&&Media::is_animated_gif($event->tmpname)) {
+            if ($event->type==EXTENSION_GIF&&Media::is_animated_gif($event->tmpname)) {
                 return;
             }
 
@@ -314,14 +314,14 @@ class TranscodeImage extends Extension
         try {
             $result = false;
             switch ($target_format) {
-                case "webp":
+                case EXTENSION_WEBP:
                 case Media::WEBP_LOSSY:
                     $result = imagewebp($image, $tmp_name, $q);
                     break;
-                case "png":
+                case EXTENSION_PNG:
                     $result = imagepng($image, $tmp_name, 9);
                     break;
-                case "jpg":
+                case EXTENSION_JPG:
                     // In case of alpha channels
                     $width = imagesx($image);
                     $height = imagesy($image);
@@ -376,7 +376,7 @@ class TranscodeImage extends Extension
             case Media::WEBP_LOSSY:
                 $args .= '';
                 break;
-            case "png":
+            case EXTENSION_PNG:
                 $args .= '-define png:compression-level=9';
                 break;
             default:
@@ -387,7 +387,7 @@ class TranscodeImage extends Extension
 
         $source_type = "";
         switch ($source_format) {
-            case "ico":
+            case EXTENSION_ICO:
                 $source_type = "ico:";
         }
 
diff --git a/ext/update/main.php b/ext/update/main.php
index 15ea9434..bd562bb8 100644
--- a/ext/update/main.php
+++ b/ext/update/main.php
@@ -67,7 +67,7 @@ class Update extends Extension
 
         log_info("update", "Attempting to download Shimmie commit:  ".$commitSHA);
         if ($headers = transload($url, $filename)) {
-            if (($headers['Content-Type'] !== "application/zip") || ((int) $headers['Content-Length'] !== filesize($filename))) {
+            if (($headers['Content-Type'] !== MIME_TYPE_ZIP) || ((int) $headers['Content-Length'] !== filesize($filename))) {
                 unlink("./data/update_{$commitSHA}.zip");
                 log_warning("update", "Download failed: not zip / not same size as remote file.");
                 return false;
diff --git a/ext/upload/main.php b/ext/upload/main.php
index 9616dd90..8581d225 100644
--- a/ext/upload/main.php
+++ b/ext/upload/main.php
@@ -45,14 +45,18 @@ class DataUploadEvent extends Event
         $this->set_tmpname($tmpname);
 
         if ($config->get_bool("upload_use_mime")) {
-            $this->set_type(get_extension(getMimeType($tmpname)));
-        } else {
+            $filetype = get_extension_for_file($tmpname);
+        }
+
+        if(empty($filetype)) {
             if (array_key_exists('extension', $metadata) && !empty($metadata['extension'])) {
-                $this->type = strtolower($metadata['extension']);
+                $filetype = strtolower($metadata['extension']);
             } else {
                 throw new UploadException("Could not determine extension for file " . $metadata["filename"]);
             }
         }
+
+        $this->set_type($filetype);
     }
 
     public function set_type(String $type)
diff --git a/ext/upload/theme.php b/ext/upload/theme.php
index f8e74712..a512b744 100644
--- a/ext/upload/theme.php
+++ b/ext/upload/theme.php
@@ -123,22 +123,8 @@ class UploadTheme extends Themelet
         $html .= ' (Drag &amp; drop onto your bookmarks toolbar, then click when looking at an image)';
 
         // Bookmarklet checks if shimmie supports ext. If not, won't upload to site/shows alert saying not supported.
-        $supported_ext = "jpg jpeg gif png webp";
-        if (class_exists("FlashFileHandler")) {
-            $supported_ext .= " swf";
-        }
-        if (class_exists("ICOFileHandler")) {
-            $supported_ext .= " ico ani cur";
-        }
-        if (class_exists("MP3FileHandler")) {
-            $supported_ext .= " mp3";
-        }
-        if (class_exists("SVGFileHandler")) {
-            $supported_ext .= " svg";
-        }
-        if (class_exists("VideoFileHandler")) {
-            $supported_ext .= " flv mp4 ogv webm m4v";
-        }
+        $supported_ext = join(" ", DataHandlerExtension::get_all_supported_exts());
+
         $title = "Booru to " . $config->get_string(SetupConfig::TITLE);
         // CA=0: Ask to use current or new tags | CA=1: Always use current tags | CA=2: Always use new tags
         $html .= '<p><a href="javascript:
diff --git a/themes/rule34v2/themelet.class.php b/themes/rule34v2/themelet.class.php
index 6f2b7aeb..54556b1b 100644
--- a/themes/rule34v2/themelet.class.php
+++ b/themes/rule34v2/themelet.class.php
@@ -19,7 +19,7 @@ class Themelet extends BaseThemelet
         $h_ext = strtolower($image->ext);
 
         // If file is flash or svg then sets thumbnail to max size.
-        if ($image->ext === 'swf' || $image->ext === 'svg') {
+        if ($image->ext === EXTENSION_FLASH || $image->ext === EXTENSION_SVG) {
             $tsize = get_thumbnail_size($config->get_int('thumb_width'), $config->get_int('thumb_height'));
         } else {
             $tsize = get_thumbnail_size($image->width, $image->height);