Commit abstracted AuthTokenGenerator

Author: lauzadis

aws-runtime/aws-config/common/src/aws/sdk/kotlin/runtime/auth/AuthTokenGenerator.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package aws.sdk.kotlin.runtime.auth
+
+import aws.sdk.kotlin.runtime.auth.credentials.DefaultChainCredentialsProvider
+import aws.smithy.kotlin.runtime.auth.awscredentials.Credentials
+import aws.smithy.kotlin.runtime.auth.awssigning.AwsSignatureType
+import aws.smithy.kotlin.runtime.auth.awssigning.AwsSigningConfig
+import aws.smithy.kotlin.runtime.auth.awssigning.AwsSigningConfig.Companion.invoke
+import aws.smithy.kotlin.runtime.auth.awssigning.DefaultAwsSigner
+import aws.smithy.kotlin.runtime.http.HttpMethod
+import aws.smithy.kotlin.runtime.http.request.HttpRequest
+import aws.smithy.kotlin.runtime.net.url.Url
+import aws.smithy.kotlin.runtime.time.Clock
+import kotlinx.coroutines.runBlocking
+import kotlin.time.Duration
+
+/**
+ * Generates an authentication token, which is a SigV4-signed URL with the HTTP scheme removed.
+ * @param service The name of the service the token is being generated for
+ * @param credentials The credentials to use when generating the auth token, defaults to resolving credentials from the [DefaultChainCredentialsProvider]
+ */
+public class AuthTokenGenerator(
+    public val service: String,
+    public val credentials: Credentials? = runBlocking { DefaultChainCredentialsProvider().resolve() },
+) {
+    private fun String.trimScheme() = removePrefix("http://").removePrefix("https://")
+
+    public suspend fun generateAuthToken(endpoint: Url, region: String, expiration: Duration): String {
+        val req = HttpRequest(HttpMethod.GET, endpoint)
+
+        val creds = credentials
+        val serv = service
+
+        val config = AwsSigningConfig {
+            credentials = creds
+            this.region = region
+            service = serv
+            signingDate = Clock.System.now()
+            expiresAfter = expiration
+            signatureType = AwsSignatureType.HTTP_REQUEST_VIA_QUERY_PARAMS
+        }
+
+        return DefaultAwsSigner.sign(req, config).output.url.toString().trimScheme()
+    }
+}