Started to implement server

vendor/deno.land/x/oak@v12.1.0/headers.ts

@@ -0,0 +1,78 @@
+// Copyright 2018-2022 the oak authors. All rights reserved. MIT license.
+
+import type { BufReader } from "./buf_reader.ts";
+import { errors } from "./deps.ts";
+
+const COLON = ":".charCodeAt(0);
+const HTAB = "\t".charCodeAt(0);
+const SPACE = " ".charCodeAt(0);
+
+const decoder = new TextDecoder();
+
+/** With a provided attribute pattern, return a RegExp which will match and
+ * capture in the first group the value of the attribute from a header value. */
+export function toParamRegExp(
+  attributePattern: string,
+  flags?: string,
+): RegExp {
+  // deno-fmt-ignore
+  return new RegExp(
+    `(?:^|;)\\s*${attributePattern}\\s*=\\s*` +
+    `(` +
+      `[^";\\s][^;\\s]*` +
+    `|` +
+      `"(?:[^"\\\\]|\\\\"?)+"?` +
+    `)`,
+    flags
+  );
+}
+
+/** Asynchronously read the headers out of body request and resolve with them as
+ * a `Headers` object. */
+export async function readHeaders(
+  body: BufReader,
+): Promise<Record<string, string>> {
+  const headers: Record<string, string> = {};
+  let readResult = await body.readLine();
+  while (readResult) {
+    const { bytes } = readResult;
+    if (!bytes.length) {
+      return headers;
+    }
+    let i = bytes.indexOf(COLON);
+    if (i === -1) {
+      throw new errors.BadRequest(
+        `Malformed header: ${decoder.decode(bytes)}`,
+      );
+    }
+    const key = decoder.decode(bytes.subarray(0, i)).trim().toLowerCase();
+    if (key === "") {
+      throw new errors.BadRequest("Invalid header key.");
+    }
+    i++;
+    while (i < bytes.byteLength && (bytes[i] === SPACE || bytes[i] === HTAB)) {
+      i++;
+    }
+    const value = decoder.decode(bytes.subarray(i)).trim();
+    headers[key] = value;
+    readResult = await body.readLine();
+  }
+  throw new errors.BadRequest("Unexpected end of body reached.");
+}
+
+/** Unquotes attribute values that might be pass as part of a header. */
+export function unquote(value: string): string {
+  if (value.startsWith(`"`)) {
+    const parts = value.slice(1).split(`\\"`);
+    for (let i = 0; i < parts.length; ++i) {
+      const quoteIndex = parts[i].indexOf(`"`);
+      if (quoteIndex !== -1) {
+        parts[i] = parts[i].slice(0, quoteIndex);
+        parts.length = i + 1; // Truncates and stops the loop
+      }
+      parts[i] = parts[i].replace(/\\(.)/g, "$1");
+    }
+    value = parts.join(`"`);
+  }
+  return value;
+}