refactor: remove std/encoding/hex dep (#17)

Author: lucacasonato

deps.ts

@@ -1,7 +1,7 @@
-import { hex } from "./deps.ts";
 import { toAmz, toDateStamp } from "./src/date.ts";
 export { toAmz, toDateStamp };
 import { getSignatureKey, signAwsV4 } from "./src/signing.ts";
+import { sha256Hex } from "./src/util.ts";
 
 /**
  * Generic AWS Signer interface
@@ -96,15 +96,13 @@ export class AWSSignerV4 implements Signer {
     const body = request.body
       ? new Uint8Array(await request.arrayBuffer())
       : null;
-    const payloadHash = await sha256(body ?? new Uint8Array(0));
+    const payloadHash = await sha256Hex(body ?? new Uint8Array(0));
 
     const { awsAccessKeyId, awsSecretKey } = this.credentials;
 
     const canonicalRequest =
       `${request.method}\n${pathname}\n${canonicalQuerystring}\n${canonicalHeaders}\n${signedHeaders}\n${payloadHash}`;
-    const canonicalRequestDigest = await sha256(
-      new TextEncoder().encode(canonicalRequest),
-    );
+    const canonicalRequestDigest = await sha256Hex(canonicalRequest);
 
     const algorithm = "AWS4-HMAC-SHA256";
     const credentialScope =
@@ -159,9 +157,3 @@ export class AWSSignerV4 implements Signer {
     return AWS_REGION;
   };
 }
-
-async function sha256(data: Uint8Array): Promise<string> {
-  const hash = await crypto.subtle.digest("SHA-256", data);
-  const hexBytes = hex.encode(new Uint8Array(hash));
-  return new TextDecoder().decode(hexBytes);
-}

mod.ts

@@ -1,4 +1,4 @@
-import { hex } from "../deps.ts";
+import { hex, hmacSha256 } from "./util.ts";
 
 const AWS4: Uint8Array = new TextEncoder().encode("AWS4");
 
@@ -12,8 +12,7 @@ export async function signAwsV4(
   msg: string,
 ): Promise<string> {
   const hash = await hmacSha256(key, msg);
-  const hexBytes = hex.encode(hash);
-  return new TextDecoder().decode(hexBytes);
+  return hex(hash);
 }
 
 /**
@@ -46,28 +45,3 @@ export async function getSignatureKey(
 
   return new Uint8Array(mac);
 }
-
-async function hmacSha256(
-  key: string | Uint8Array,
-  msg: string,
-): Promise<Uint8Array> {
-  if (typeof key === "string") {
-    key = new TextEncoder().encode(key);
-  }
-
-  const hash = await crypto.subtle.importKey(
-    "raw",
-    key,
-    { name: "HMAC", hash: { name: "SHA-256" } },
-    false,
-    ["sign"],
-  );
-
-  const mac = await crypto.subtle.sign(
-    { name: "HMAC", hash: { name: "SHA-256" } },
-    hash,
-    new TextEncoder().encode(msg),
-  );
-
-  return new Uint8Array(mac);
-}

src/signing.ts

@@ -0,0 +1,38 @@
+export function hex(data: Uint8Array): string {
+  return [...data]
+    .map((b) => b.toString(16).padStart(2, "0"))
+    .join("");
+}
+
+export async function sha256Hex(data: string | Uint8Array): Promise<string> {
+  if (typeof data === "string") {
+    data = new TextEncoder().encode(data);
+  }
+  const hash = await crypto.subtle.digest("SHA-256", data);
+  return hex(new Uint8Array(hash));
+}
+
+export async function hmacSha256(
+  keyData: string | Uint8Array,
+  data: string,
+): Promise<Uint8Array> {
+  if (typeof keyData === "string") {
+    keyData = new TextEncoder().encode(keyData);
+  }
+
+  const key = await crypto.subtle.importKey(
+    "raw",
+    keyData,
+    { name: "HMAC", hash: "SHA-256" },
+    false,
+    ["sign"],
+  );
+
+  const mac = await crypto.subtle.sign(
+    { name: "HMAC", hash: "SHA-256" },
+    key,
+    new TextEncoder().encode(data),
+  );
+
+  return new Uint8Array(mac);
+}