---
product: Chilkat
product_version: 11.7.0
language: pascal
language_label: Lazarus Pascal
class: AuthAws
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/pascal_AuthAwsRef.html
---
# Chilkat AuthAws — Lazarus Pascal — v11.7.0

> Chilkat 11.7.0 · language=pascal · 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/pascal/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

**Create / Free**

```pascal
uses
  Chilkat.AuthAws;

var
  obj: TAuthAws;
begin
  obj := TAuthAws.Create;
  try
    if not obj.IsValid then
      raise Exception.Create('Failed to create a TAuthAws instance.');

    // ... use obj ...

  finally
    obj.Free;
  end;
end;
```

`constructor Create;`

Allocates the underlying CkAuthAws object and returns a new TAuthAws instance. Simply adding **Chilkat.AuthAws** to the unit's `uses` clause is enough to locate and bind to the Chilkat shared library (DLL / .so / .dylib) at runtime — no separate load step is required. Check `obj.IsValid` after calling `Create`; it is `False` if the underlying library could not be found/loaded or the object could not be allocated (for example, when unlicensed).

`destructor Destroy; override;`

Every TAuthAws created by calling `Create` should eventually be released by calling `.Free` (inherited from `TObject`). The destructor automatically disposes the underlying CkAuthAws handle. A native (unmanaged) memory leak occurs if the object is never freed.

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 Lazarus Pascal.

## 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` | `property DebugLogFilePath: string read GetDebugLogFilePath write SetDebugLogFilePath;` | 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` | `property LastErrorHtml: string read GetLastErrorHtml;` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `property LastErrorText: string read GetLastErrorText;` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `property LastErrorXml: string read GetLastErrorXml;` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `property LastMethodSuccess: Boolean read GetLastMethodSuccess write SetLastMethodSuccess;` | read/write | Indicates the success or failure of the most recent method call: `True` means success, `False` means failure. |
| `VerboseLogging` | `property VerboseLogging: Boolean read GetVerboseLogging write SetVerboseLogging;` | read/write | If set to `True`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `property Version: string read GetVersion;` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AccessKey` | property, read/write | `property AccessKey: string read GetAccessKey write SetAccessKey;` |
| `CanonicalizedResourceV2` | property, read/write | `property CanonicalizedResourceV2: string read GetCanonicalizedResourceV2 write SetCanonicalizedResourceV2;` |
| `EnableSecrets` | property, read/write | `property EnableSecrets: Boolean read GetEnableSecrets write SetEnableSecrets;` |
| `PrecomputedMd5` | property, read/write | `property PrecomputedMd5: string read GetPrecomputedMd5 write SetPrecomputedMd5;` |
| `PrecomputedSha256` | property, read/write | `property PrecomputedSha256: string read GetPrecomputedSha256 write SetPrecomputedSha256;` |
| `Region` | property, read/write | `property Region: string read GetRegion write SetRegion;` |
| `SecretKey` | property, read/write | `property SecretKey: string read GetSecretKey write SetSecretKey;` |
| `ServiceName` | property, read/write | `property ServiceName: string read GetServiceName write SetServiceName;` |
| `SignatureVersion` | property, read/write | `property SignatureVersion: Integer read GetSignatureVersion write SetSignatureVersion;` |
| `GenPresignedUrl` | method | `function GenPresignedUrl(const httpVerb: string;     useHttps: Boolean;     const domain: string;     const path: string;     numSecondsValid: Integer;     const awsService: string): string;` |

## Properties

### AuthAws.AccessKey

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

```pascal
property AccessKey: string read GetAccessKey write SetAccessKey;
```

The AWS access key.

### AuthAws.CanonicalizedResourceV2

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

```pascal
property CanonicalizedResourceV2: string read GetCanonicalizedResourceV2 write SetCanonicalizedResourceV2;
```

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 · pascal · AuthAws · EnableSecrets · property · read/write · since 11.5.0`

```pascal
property EnableSecrets: Boolean read GetEnableSecrets write SetEnableSecrets;
```

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 · pascal · AuthAws · PrecomputedMd5 · property · read/write · since 9.5.0.58`

```pascal
property PrecomputedMd5: string read GetPrecomputedMd5 write SetPrecomputedMd5;
```

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 · pascal · AuthAws · PrecomputedSha256 · property · read/write · since 9.5.0.58`

```pascal
property PrecomputedSha256: string read GetPrecomputedSha256 write SetPrecomputedSha256;
```

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 · pascal · AuthAws · Region · property · read/write · since 9.5.0.58`

```pascal
property Region: string read GetRegion write SetRegion;
```

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 · pascal · AuthAws · SecretKey · property · read/write · since 9.5.0.58`

```pascal
property SecretKey: string read GetSecretKey write SetSecretKey;
```

The AWS secret key.

### AuthAws.ServiceName

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

```pascal
property ServiceName: string read GetServiceName write SetServiceName;
```

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 · pascal · AuthAws · SignatureVersion · property · read/write · since 9.5.0.58`

```pascal
property SignatureVersion: Integer read GetSignatureVersion write SetSignatureVersion;
```

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 · pascal · AuthAws · GenPresignedUrl · method · since 9.5.0.85`

```pascal
function  GenPresignedUrl(const httpVerb: string;
    useHttps: Boolean;
    const domain: string;
    const path: string;
    numSecondsValid: Integer;
    const awsService: string): 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 True for success, False for failure.