Lua

REST Stream Response to File (Streaming Download) (Amazon S3)

See more Amazon S3 (new) Examples

Demonstrates how to stream the response body directly to a file. (The example shows how to stream a JPG from the Amazon S3 service.) 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
local success = rest:connect("s3.amazonaws.com", port, bTls, bAutoReconnect)

-- ----------------------------------------------------------------------------
-- Important: For buckets created in regions outside us-east-1,
-- there are three important changes that need to be made.
-- See Working with S3 Buckets in Non-us-east-1 Regions for the details.
-- ----------------------------------------------------------------------------

-- 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"
success = rest:set_auth_aws(authAws)

-- Set the bucket name via the HOST header.
-- In this case, the bucket name is "chilkat100".
rest.host = "chilkat100.s3.amazonaws.com"

-- 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