---
product: Chilkat
product_version: 11.7.0
language: js
language_label: JavaScript
class: AuthAws
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/jsAuthAwsRef.html
---
# Chilkat AuthAws — JavaScript — v11.7.0

> Chilkat 11.7.0 · language=js · class=AuthAws
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/AuthAws.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/js/guide.md`.

## Purpose

**Configure AWS request signing for REST calls and temporary pre-signed URLs.**

`Chilkat.AuthAws` holds the AWS authentication settings used by `Chilkat.Rest` when sending signed AWS requests. It supports AWS Signature Version 4 by default, can optionally use the older Signature Version 2 where applicable, accepts direct credential values or secure secret specifiers, and can generate temporary Signature V4 pre-signed URLs for AWS services.

**REST authentication object**

Provide AWS signing settings to `Chilkat.Rest` so outgoing requests are authenticated according to AWS requirements.

**Signature Version 4**

Sign requests using AWS Signature Version 4, including service, region, credentials, headers, and request payload details.

**Credentials and secrets**

Use access keys and secret keys directly, or use secret specifiers when credentials should be resolved from a secure credential source.

**Region and service targeting**

Configure the AWS region and service name so signatures are generated for the correct AWS endpoint.

**Temporary credentials**

Include session tokens when signing requests with temporary AWS credentials from STS, IAM roles, or similar credential flows.

**Pre-signed URLs**

Generate temporary Signature V4 pre-signed URLs when a client needs limited-time access without sending AWS credentials.

**Common pattern:** Create and configure an `AuthAws` object with the AWS access key, secret key or secret specifier, region, service name, and optional session token, then pass it to `Chilkat.Rest` before sending the request. Use `AuthAws` for AWS request signing; use service-specific Chilkat classes or `Chilkat.Http`/`Chilkat.Rest` for constructing and sending the actual API request.

For an extended overview, see [AuthAws Class Overview](https://www.chilkatsoft.com/authaws_class_overview.asp).

## Object creation, unlocking and error handling

**Object Creation**

Note: This is intended for running within a [Chilkat.Js embedded JavaScript engine](https://www.chilkatsoft.com/chilkat_javascript_engine.asp).

```
var obj = new CkAuthAws();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in JavaScript.

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `DebugLogFilePath` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `LastErrorHtml` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `LastErrorText` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `LastErrorXml` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `LastMethodSuccess` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `VerboseLogging` | `VerboseLogging` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `Version` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AccessKey` | property, read/write | `AccessKey` |
| `CanonicalizedResourceV2` | property, read/write | `CanonicalizedResourceV2` |
| `EnableSecrets` | property, read/write | `EnableSecrets` |
| `PrecomputedMd5` | property, read/write | `PrecomputedMd5` |
| `PrecomputedSha256` | property, read/write | `PrecomputedSha256` |
| `Region` | property, read/write | `Region` |
| `SecretKey` | property, read/write | `SecretKey` |
| `ServiceName` | property, read/write | `ServiceName` |
| `SignatureVersion` | property, read/write | `SignatureVersion` |
| `GenPresignedUrl` | method | `var strVal = GenPresignedUrl(httpVerb, useHttps, domain, path, numSecondsValid, awsService);` |

## Properties

### AuthAws.AccessKey

`Chilkat 11.7.0 · js · AuthAws · AccessKey · property · read/write · since 9.5.0.58`

```javascript
AccessKey
```

· `string`

The AWS access key.

### AuthAws.CanonicalizedResourceV2

`Chilkat 11.7.0 · js · AuthAws · CanonicalizedResourceV2 · property · read/write · since 9.5.0.58`

```javascript
CanonicalizedResourceV2
```

· `string`

If AWS Signature Version V2 is used, then this property must be set. The rules for setting the canonicalized resource for the V2 signature method is described here: [Constructing the CanonicalizedResource Element](http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement).

### AuthAws.EnableSecrets

`Chilkat 11.7.0 · js · AuthAws · EnableSecrets · property · read/write · since 11.5.0`

```javascript
EnableSecrets
```

· `boolean`

If `true` a secret specifier of the format "!!part1\|part2\|.." can be provided instead of the actual value for the AccessKey and SecretKey properties.

The default value is `false`.

### AuthAws.PrecomputedMd5

`Chilkat 11.7.0 · js · AuthAws · PrecomputedMd5 · property · read/write · since 9.5.0.58`

```javascript
PrecomputedMd5
```

· `string`

This property can optionally be set for AWS requests that have a non-empty request body. This should be the base64 encoding of the 16 bytes of the MD5 hash. The most common need for this is if doing an S3 upload from a stream. (If the pre-computed MD5 is not provided, then Chilkat is forced to stream the entire file into memory so that it can calculate the MD5 for authentication.)

**Note:** AWS Signature Version 2 uses the MD5, whereas Signature Version 4 uses SHA256.

### AuthAws.PrecomputedSha256

`Chilkat 11.7.0 · js · AuthAws · PrecomputedSha256 · property · read/write · since 9.5.0.58`

```javascript
PrecomputedSha256
```

· `string`

This property can optionally be set for AWS requests that have a non-empty request body. This should be the lowercase hex encoding of the 32-bytes of the SHA256 hash. The most common need for this is if doing an S3 upload from a stream. (If the pre-computed SHA-256 is not provided, then Chilkat is forced to stream the entire file into memory so that it can calculate the SHA-256 for authentication.)

**Note:** AWS Signature Version 4 uses the SHA256 hash. (AWS Signature Version 2 uses MD5)

### AuthAws.Region

`Chilkat 11.7.0 · js · AuthAws · Region · property · read/write · since 9.5.0.58`

```javascript
Region
```

· `string`

The AWS region, such as `us-east-1`, `us-west-2`, `eu-west-1`, `eu-central-1`, etc. The default is `us-east-1`. It is only used when the SignatureVersion property is set to 4. This property is unused when the SignatureVersion property is set to 2.

### AuthAws.SecretKey

`Chilkat 11.7.0 · js · AuthAws · SecretKey · property · read/write · since 9.5.0.58`

```javascript
SecretKey
```

· `string`

The AWS secret key.

### AuthAws.ServiceName

`Chilkat 11.7.0 · js · AuthAws · ServiceName · property · read/write · since 9.5.0.58`

```javascript
ServiceName
```

· `string`

The AWS service namespace, such as `s3`, `ses`, etc. See http://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html#genref-aws-service-namespaces

This property is unused when the SignatureVersion property is set to 2.

### AuthAws.SignatureVersion

`Chilkat 11.7.0 · js · AuthAws · SignatureVersion · property · read/write · since 9.5.0.58`

```javascript
SignatureVersion
```

· `int`

The AWS Signature Version to be used in authentication. The default value is 4. This can optionally be set to the value 2 to use the older V2 signature version.

## Methods

### AuthAws.GenPresignedUrl

`Chilkat 11.7.0 · js · AuthAws · GenPresignedUrl · method · since 9.5.0.85`

```javascript
var strVal = GenPresignedUrl(httpVerb, useHttps, domain, path, numSecondsValid, awsService);
```

· return: `string`  
· httpVerb: `string`  
· useHttps: `boolean`  
· domain: `string`  
· path: `string`  
· numSecondsValid: `int`  
· awsService: `string`

Generates a temporary pre-signed URL for an Amazon AWS service using AWS Signature V4. Requires that the SecretKey, AccessKey, and Region properties be set to valid values prior to calling this method.

The URL that is generated has this format:

```
https://<domain>/<path>
?X-Amz-Algorithm=AWS4-HMAC-SHA256
&X-Amz-Credential=<AccessKey>/<currentDate>/<Region>/<awsService>/aws4_request
&X-Amz-Date=<currentDateTime>
&X-Amz-Expires=<numSecondsValid>
&X-Amz-SignedHeaders=host
&X-Amz-Signature=<signature-value>
```

The `httpVerb` is the HTTP verb such as `GET`, `PUT`, `POST`, `DELETE`, etc. The `awsService` is a string naming the AWS service, such as `s3`, `execute-api`, etc. If `useHttps` is `true`, then the returned URL begins with `https://`, otherwise it begins with `http://`.

**Note:** It is generally not feasible to use pre-signed URLs for `POST` operations for any AWS service except for `S3`. See [AWS Pre-Signed URLs for POST Operations (non-S3)](https://www.chilkatsoft.com/aws_pre_signed_urls_for_post_operations.asp)

Returns `null` on failure