Lua

(using AWS Signature Version 2) Streaming Download to File

See more Amazon S3 (new) Examples

The main purpose of this example is to demonstrate how to use the older Signature Version 2 authentication w/ S3. It uses V2 authentication to download a file. Lua

local chilkat = require("chilkat")

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

local rest = chilkat.Rest.new()

-- Connect to the Amazon AWS REST server.
local bTls = true
local port = 443
local bAutoReconnect = true
-- The file is located in the bucket named "chilkat100", which becomes part of the domain:
local success = rest:connect("chilkat100.s3.amazonaws.com", port, bTls, bAutoReconnect)

-- Provide AWS credentials for the REST call.
local authAws = chilkat.AuthAws.new()
authAws.access_key = "AWS_ACCESS_KEY"
authAws.secret_key = "AWS_SECRET_KEY"
authAws.service_name = "s3"

-- For AWS Signature Version 2, the following two properties need to be set:
authAws.signature_version = 2
-- See http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement
authAws.canonicalized_resource_v2 = "/chilkat100/starfish.jpg"

success = rest:set_auth_aws(authAws)

-- Send the request to download the JPG.
success = rest:send_req_no_body("GET", "/starfish.jpg")
if not success then
    print(rest.last_error_text)
    return
end

-- Read the response header.
local responseStatusCode = rest:read_response_header()
if responseStatusCode < 0 then
    print(rest.last_error_text)
    return
end

print("Response status code = " .. responseStatusCode)

-- We expect a 200 response status if the JPG data is coming.
-- Otherwise, we'll get a string response body with an error message(or no response body).
if responseStatusCode == 200 then
    local bodyStream = chilkat.Stream.new()

    -- The stream's sink will be a file.
    bodyStream.sink_file = "qa_output/starfish.jpg"

    -- Read the response body to the stream.  Given that we've
    -- set the stream's sink to a file, it will stream directly
    -- to the file.
    success = rest:read_resp_body_stream(bodyStream, true)
    if not success then
        print(rest.last_error_text)
        return
    end

    print("Successfully received the JPG file.")
else
    local errResponse = rest:read_resp_body_string()
    if not rest.last_method_success then
        print(rest.last_error_text)
    else
        print(errResponse)
    end
end