(Visual FoxPro) Generate an AWS (S3) Pre-Signed URL using Signature V4

Demonstrates how to generate a pre-signed URL using AWS Signature Version 4. This example generates a pre-signed URL for the Amazon S3 service.

Note: this example requires Chilkat v9.5.0.66 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loHttp
LOCAL lcBucketName
LOCAL lcObjectName
LOCAL lcLocalFilePath
LOCAL lcAwsService
LOCAL lnNumSecondsValid
LOCAL lnBUseHttps
LOCAL lcPreSignedUrl
LOCAL lnSuccess

* This example assumes the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Http')
loHttp = CreateObject('Chilkat.Http')

loHttp.AwsAccessKey = "AWS_ACCESS_KEY"
loHttp.AwsSecretKey = "AWS_SECRET_KEY"

* Make sure to set your AWS region correctly
loHttp.AwsRegion = "us-east-1"

lcBucketName = "chilkat100"
lcObjectName = "starfish/starfish.jpg"
lcLocalFilePath = "qa_output/starfish.jpg"
lcAwsService = "s3"

* The signed URL will be valid for this number of seconds:
lnNumSecondsValid = 86400

* Choose between a URL beginning with "http://" or "https://"...
lnBUseHttps = 0

* Generate the pre-signed URL
lcPreSignedUrl = loHttp.S3_GenerateUrlV4(lnBUseHttps,lcBucketName,lcObjectName,lnNumSecondsValid,lcAwsService)
IF (loHttp.LastMethodSuccess <> 1) THEN
    ? loHttp.LastErrorText
    RELEASE loHttp
    CANCEL
ENDIF

* The following URL can be copy-and-pasted into a browser..
? "Pre-Signed AWS S3 URL: " + lcPreSignedUrl

* Here's an example of a pre-signed URL. 
* This URL will only work within 1 day (86400 seconds) after the time this example was published.
* 
*     http://chilkat100.s3.amazonaws.com/starfish/starfish.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=16QXXDGY83AJJR6RVQ02%2F20170111%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20170111T161959Z&X-Amz-Expires=86400&X-Amz-SignedHeaders=host&X-Amz-Signature=72bf4fd9a15d7bbcdd313a3318d937a778905f62a3fbff9b789d8dc28acd9232

* Now try to do an HTTP Download using the signed URL.
lnSuccess = loHttp.Download(lcPreSignedUrl,"qa_output/starfish.jpg")
IF (lnSuccess <> 1) THEN
    ? loHttp.LastErrorText
ELSE
    ? "Success."
ENDIF

RELEASE loHttp