(Tcl) 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.

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load ./chilkat.dll

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

# Note: This example requires Chilkat v9.5.0.66 or greater.

set http [new_CkHttp]

CkHttp_put_AwsAccessKey $http "AWS_ACCESS_KEY"
CkHttp_put_AwsSecretKey $http "AWS_SECRET_KEY"

# Make sure to set your AWS region correctly
CkHttp_put_AwsRegion $http "us-east-1"

set bucketName "chilkat100"
set objectName "starfish/starfish.jpg"
set localFilePath "qa_output/starfish.jpg"
set awsService "s3"

# The signed URL will be valid for this number of seconds:
set numSecondsValid 86400

# Choose between a URL beginning with "http://" or "https://"...
set bUseHttps 0

# Generate the pre-signed URL
set preSignedUrl [CkHttp_s3_GenerateUrlV4 $http $bUseHttps $bucketName $objectName $numSecondsValid $awsService]
if {[CkHttp_get_LastMethodSuccess $http] != 1} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkHttp $http
    exit
}

# The following URL can be copy-and-pasted into a browser..
puts "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.
set success [CkHttp_Download $http $preSignedUrl "qa_output/starfish.jpg"]
if {$success != 1} then {
    puts [CkHttp_lastErrorText $http]
} else {
    puts "Success."
}


delete_CkHttp $http