1 files changed, 149 insertions, 0 deletions
diff --git a/std/media_types/mod.ts b/std/media_types/mod.ts
new file mode 100644
index 000000000..b7c75fb22
--- /dev/null
+++ b/std/media_types/mod.ts
@@ -0,0 +1,149 @@
+/*!
+ * Ported from: https://github.com/jshttp/mime-types and licensed as:
+ *
+ * (The MIT License)
+ *
+ * Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+ * Copyright (c) 2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+ * Copyright (c) 2019 the Deno authors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * 'Software'), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+import { db, extname } from "./deps.ts";
+
+const EXTRACT_TYPE_REGEXP = /^\s*([^;\s]*)(?:;|\s|$)/;
+const TEXT_TYPE_REGEXP = /^text\//i;
+
+/** A map of extensions for a given media type */
+export const extensions = new Map<string, string[]>();
+
+/** A map of the media type for a given extension */
+export const types = new Map<string, string>();
+
+/** Internal function to populate the maps based on the Mime DB */
+function populateMaps(
+  extensions: Map<string, string[]>,
+  types: Map<string, string>
+): void {
+  const preference = ["nginx", "apache", undefined, "iana"];
+
+  for (const type of Object.keys(db)) {
+    const mime = db[type];
+    const exts = mime.extensions;
+
+    if (!exts || !exts.length) {
+      continue;
+    }
+
+    extensions.set(type, exts);
+
+    for (const ext of exts) {
+      if (types.has(ext)) {
+        const current = types.get(ext)!;
+        const from = preference.indexOf(db[current].source);
+        const to = preference.indexOf(mime.source);
+
+        if (
+          current !== "application/octet-stream" &&
+          (from > to ||
+            (from === to && current.substr(0, 12) === "application/"))
+        ) {
+          continue;
+        }
+      }
+
+      types.set(ext, type);
+    }
+  }
+}
+
+// Populate the maps upon module load
+populateMaps(extensions, types);
+
+/** Given a media type return any default charset string.  Returns `undefined`
+ * if not resolvable.
+ */
+export function charset(type: string): string | undefined {
+  const m = EXTRACT_TYPE_REGEXP.exec(type);
+  if (!m) {
+    return;
+  }
+  const [match] = m;
+  const mime = db[match.toLowerCase()];
+
+  if (mime && mime.charset) {
+    return mime.charset;
+  }
+
+  if (TEXT_TYPE_REGEXP.test(match)) {
+    return "UTF-8";
+  }
+}
+
+/** Given an extension, lookup the appropriate media type for that extension.
+ * Likely you should be using `contentType()` though instead.
+ */
+export function lookup(path: string): string | undefined {
+  const extension = extname("x." + path)
+    .toLowerCase()
+    .substr(1);
+
+  return types.get(extension);
+}
+
+/** Given an extension or media type, return the full `Content-Type` header
+ * string.  Returns `undefined` if not resolvable.
+ */
+export function contentType(str: string): string | undefined {
+  let mime = str.includes("/") ? str : lookup(str);
+
+  if (!mime) {
+    return;
+  }
+
+  if (!mime.includes("charset")) {
+    const cs = charset(mime);
+    if (cs) {
+      mime += `; charset=${cs.toLowerCase()}`;
+    }
+  }
+
+  return mime;
+}
+
+/** Given a media type, return the most appropriate extension or return
+ * `undefined` if there is none.
+ */
+export function extension(type: string): string | undefined {
+  const match = EXTRACT_TYPE_REGEXP.exec(type);
+
+  if (!match) {
+    return;
+  }
+
+  const exts = extensions.get(match[1].toLowerCase());
+
+  if (!exts || !exts.length) {
+    return;
+  }
+
+  return exts[0];
+}