Amazon S3 file download through curl by using IAM user credentials - shell

Question

I have created an IAM user with access to only one bucket. I have tested the credentials and permissions through web and python boto. Its working fine.
Now I have requirement to use these credentials and download the private file from that bucket through curl.
signature="$(echo -n "GET" | openssl sha1 -hmac "f/rHQ8yCvPthxxxxxxxXxxxx" -binary | base64)"
date="$(LC_ALL=C date -u +"%a, %d %b %Y %X %z")"
curl -H "Host: my-bucket.s3.amazonaws.com" -H "Date: $date" -H "Authorization: AWS 'XXXAJX2NY3QXXX35XXX':$signature" -H "Content-Type: 'text/plain'" https://my-bucket.s3.amazonaws.com/path/to_file.txt
but i am getting the following error:
InvalidAccessKeyIdThe AWS Access Key Id you provided does not exist in our records.
Please help, how do I download the file using curl ? Is there anything am I missing or its not possible through curl command?
Thanks!

Answer 1

Following is the example on how you can download with s3 curl script,
#!/bin/sh
file=path/to/file
bucket=your-bucket
resource="/${bucket}/${file}"
contentType="application/x-compressed-tar"
dateValue="`date +'%a, %d %b %Y %H:%M:%S %z'`"
stringToSign="GET
${contentType}
${dateValue}
${resource}"
s3Key=xxxxxxxxxxxxxxxxxxxx
s3Secret=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
signature=`/bin/echo -en "$stringToSign" | openssl sha1 -hmac ${s3Secret} -binary | base64`
curl -H "Host: ${bucket}.s3.amazonaws.com" \
-H "Date: ${dateValue}" \
-H "Content-Type: ${contentType}" \
-H "Authorization: AWS ${s3Key}:${signature}" \
https://${bucket}.s3.amazonaws.com/${file}
Hope it helps.