refactor(preconditions): move file

Author: TomokiMiyauci

etag.ts

@@ -0,0 +1,22 @@
+// Copyright 2023-latest the httpland authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+// TODO(miyauci): External Packaging
+
+import { type ETag } from "./deps.ts";
+
+export interface StrongETag extends ETag {
+  readonly weak: false;
+}
+
+export function matchWeak(left: ETag, right: ETag): boolean {
+  return left.tag === right.tag;
+}
+
+export function matchStrong(left: ETag, right: ETag): boolean {
+  return isStrongETag(left) && isStrongETag(right) && left.tag === right.tag;
+}
+
+export function isStrongETag(etag: ETag): etag is StrongETag {
+  return !etag.weak;
+}

preconditions/if_modified_since.ts

@@ -12,7 +12,8 @@ import {
   Status,
   unsafe,
 } from "../deps.ts";
-import { ifModifiedSince, isBannedHeader } from "./utils.ts";
+import { isBannedHeader } from "../utils.ts";
+import { ifModifiedSince } from "./utils.ts";
 import type { Precondition } from "../types.ts";
 
 /** `If-Modified-Since` header field precondition. */

preconditions/if_none_match.ts

@@ -14,7 +14,8 @@ import {
   unsafe,
 } from "../deps.ts";
 import type { Precondition } from "../types.ts";
-import { ifNoneMatch, isBannedHeader } from "./utils.ts";
+import { ifNoneMatch } from "./utils.ts";
+import { isBannedHeader } from "../utils.ts";
 
 /** `If-None-Match` header field precondition. */
 export class IfNoneMatch implements Precondition {

preconditions/utils.ts

@@ -1,15 +1,14 @@
 // Copyright 2023-latest the httpland authors. All rights reserved. MIT license.
 // This module is browser compatible.
 
-import {
-  ETag,
-  isString,
-  isValidDate,
-  parseETag,
-  parseHttpDate,
-  RepresentationHeader,
-} from "../deps.ts";
+import { isString, isValidDate, parseETag, parseHttpDate } from "../deps.ts";
 import { parse } from "../if_match.ts";
+import { matchStrong, matchWeak } from "../etag.ts";
+
+const enum Msg {
+  InvalidField = "field value is invalid <HTTP-date> format.",
+  InvalidLastModified = "last-modified is invalid <HTTP-date> format.",
+}
 
 /** Match `If-Match` field and `ETag` field.
  * @throws {SyntaxError} If the input is invalid syntax.
@@ -38,37 +37,23 @@ export function ifNoneMatch(fieldValue: string, etag: string): boolean {
   return ifNoneMatch.every((tag) => !matchWeak(tag, etagObj));
 }
 
-export function matchWeak(left: ETag, right: ETag): boolean {
-  return left.tag === right.tag;
-}
-
-export function matchStrong(left: ETag, right: ETag): boolean {
-  return isStrong(left) && isStrong(right) && left.tag === right.tag;
-}
-
-export function isStrong(etag: ETag): boolean {
-  return !etag.weak;
-}
-
 /**
  * @throws {SyntaxError} If the input is invalid.
  */
 export function ifModifiedSince(
   fieldValue: string,
   lastModified: string,
 ): boolean {
-  // A recipient MUST ignore the If-Modified-Since header field if the
-  // received field-value is not a valid HTTP-date
   const date = parseHttpDate(fieldValue.trim());
 
   if (!isValidDate(date)) {
-    throw TypeError("field value is invalid <HTTP-date> format.");
+    throw TypeError(Msg.InvalidField);
   }
 
   const lastMod = parseHttpDate(lastModified.trim());
 
   if (!isValidDate(lastMod)) {
-    throw TypeError("last-modified is invalid <HTTP-date> format.");
+    throw TypeError(Msg.InvalidLastModified);
   }
 
   // The origin server SHOULD NOT perform the requested
@@ -84,18 +69,16 @@ export function ifUnmodifiedSince(
   fieldValue: string,
   lastModified: string,
 ): boolean {
-  // A recipient MUST ignore the If-Modified-Since header field if the
-  // received field-value is not a valid HTTP-date
   const date = parseHttpDate(fieldValue.trim());
 
   if (!isValidDate(date)) {
-    throw TypeError("field value is invalid <HTTP-date> format.");
+    throw TypeError(Msg.InvalidField);
   }
 
   const lastMod = parseHttpDate(lastModified.trim());
 
   if (!isValidDate(lastMod)) {
-    throw TypeError("last-modified is invalid <HTTP-date> format.");
+    throw TypeError(Msg.InvalidLastModified);
   }
 
   // The origin server MUST NOT perform the requested method
@@ -128,13 +111,13 @@ export function ifRange(fieldValue: string, headers: IfRangeHeaders): boolean {
   const left = parseHttpDate(fieldValue);
 
   if (!isValidDate(left)) {
-    throw TypeError("field value is invalid <HTTP-date> format.");
+    throw TypeError(Msg.InvalidField);
   }
 
   const right = parseHttpDate(lastModified);
 
   if (!isValidDate(right)) {
-    throw TypeError("last-modified is invalid <HTTP-date> format.");
+    throw TypeError(Msg.InvalidLastModified);
   }
 
   return left.getTime() === right.getTime();
@@ -149,13 +132,4 @@ function isStar(input: unknown): input is Star {
   return input === "*";
 }
 
-export function isBannedHeader(fieldName: string): boolean {
-  return ([
-    RepresentationHeader.ContentEncoding,
-    RepresentationHeader.ContentLanguage,
-    RepresentationHeader.ContentLength,
-    RepresentationHeader.ContentType,
-  ] as string[]).includes(fieldName);
-}
-
 export type Star = "*";

utils.ts

@@ -8,6 +8,7 @@ import {
   isNull,
   isSuccessfulStatus,
   Method,
+  RepresentationHeader,
   Status,
   SuccessfulStatus,
 } from "./deps.ts";
@@ -79,3 +80,12 @@ export async function applyPrecondition(
 
   return precondition.respond(request, response, evalResult);
 }
+
+export function isBannedHeader(fieldName: string): boolean {
+  return ([
+    RepresentationHeader.ContentEncoding,
+    RepresentationHeader.ContentLanguage,
+    RepresentationHeader.ContentLength,
+    RepresentationHeader.ContentType,
+  ] as string[]).includes(fieldName);
+}