import { ifNoneMatch } from "https://deno.land/std@0.208.0/http/mod.ts";
A helper function that takes the value from the If-None-Match
header and
a calculated etag for the target entity and returns false
if the etag for
the entity matches the supplied value, otherwise true
.
See MDN's If-None-Match
article for more information on how to use this function.
import {
calculate,
ifNoneMatch,
} from "https://deno.land/std@0.208.0/http/etag.ts";
import { assert } from "https://deno.land/std@0.208.0/assert/assert.ts"
const body = "hello deno!";
Deno.serve(async (req) => {
const ifNoneMatchValue = req.headers.get("if-none-match");
const etag = await calculate(body);
assert(etag);
if (!ifNoneMatch(ifNoneMatchValue, etag)) {
return new Response(null, { status: 304, headers: { etag } });
} else {
return new Response(body, { status: 200, headers: { etag } });
}
});