B4X Requires Chilkat v11.0.0+

Generate an AWS (S3) Pre-Signed URL to Download File

See more Amazon S3 (new) Examples

Demonstrates how to generate a pre-signed URL to download a file from the Amazon S3 service. B4X

Dim success As Boolean = False

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

Dim http As ChilkatHttp
http.Initialize("http")

http.AwsAccessKey = "AWS_ACCESS_KEY"
http.AwsSecretKey = "AWS_SECRET_KEY"

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

Dim bucketName As String = "chilkat100"
Dim objectName As String = "starfish/starfish.jpg"
Dim localFilePath As String = "qa_output/starfish.jpg"
Dim awsService As String = "s3"

'  The signed URL will be valid for this number of seconds:
Dim numSecondsValid As Int = 86400

'  Choose between a URL beginning with "http://" or "https://"...
Dim bUseHttps As Boolean = False

'  Generate the pre-signed URL
Dim preSignedUrl As String = http.S3_GenPresignedUrl("GET", bUseHttps, bucketName, objectName, numSecondsValid, awsService)
If http.LastMethodSuccess = False Then
    Log(http.LastErrorText)
    Return
End If


'  The following URL can be copy-and-pasted into a browser..
Log("Pre-Signed AWS S3 URL: " & preSignedUrl)

'  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.
success = http.Download(preSignedUrl, "c:/temp/qa_output/starfish.jpg")
If success = False Then
    Log(http.LastErrorText)
    Return
End If


Log("Success.")