Lua

Upload File in Blocks (with Content-MD5 header) and Commit the Block List

See more Azure Cloud Storage Examples

Demonstrates how to upload a file in blocks and then commit the block list. This example includes a Content-MD5 header for each block. Lua

local chilkat = require("chilkat")

-- Azure Blob Service Example: Upload a file in blocks, and then commit the block list.
-- See also: https://msdn.microsoft.com/en-us/library/azure/dd135726.aspx

-- 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 Azure Storage Blob Service
local bTls = true
local port = 443
local bAutoReconnect = true
-- In this example, the storage account name is "chilkat".
local success = rest:connect("chilkat.blob.core.windows.net", port, bTls, bAutoReconnect)
if not success then
    print(rest.last_error_text)
    return
end

-- Provide Azure Cloud credentials for the REST call.
local azAuth = chilkat.AuthAzureStorage.new()
azAuth.access_key = "AZURE_ACCESS_KEY"
-- The account name used here should match the 1st part of the domain passed in the call to Connect (above).
azAuth.account = "chilkat"
azAuth.scheme = "SharedKey"
azAuth.service = "Blob"
-- This causes the "x-ms-version: 2021-08-06" header to be automatically added.
azAuth.xms_version = "2021-08-06"
success = rest:set_auth_azure_storage(azAuth)

-- Note: The application does not need to explicitly set the following
-- headers: Content-Length, x-ms-date, Authorization.  These headers
-- are automatically set by Chilkat.

-- As the blocks are uploaded, we'll keep an XML block list for the subsequent commit..
local xml = chilkat.Xml.new()
xml.tag = "BlockList"

-- Any type of file can be uploaded in this way.  It can a text file, binary file, anything...
-- This example will upload an XML file that is approximately 275K in size.  It can be downloaded
-- at http://www.chilkatsoft.com/hamlet.xml
local fac = chilkat.FileAccess.new()
success = fac:open_for_read("qa_data/xml/hamlet.xml")
-- Assuming success for the example..

-- We'll upload in 16K blocks (normally a program would upload in larger block sizes than this,
-- but this is just an example...)
local blockSize = 16384

-- How many 16K blocks?  (Including 1 for the last partial block)
local numBlocks = fac:get_num_blocks(blockSize)

local crypt = chilkat.Crypt2.new()
crypt.hash_algorithm = "md5"

local sbResponseBody = chilkat.StringBuilder.new()
local uriPath = chilkat.StringBuilder.new()
local blockId = ""
local dataBlock = chilkat.BinData.new()
local contentMd5 = ""
local i = 0
while i < numBlocks do
    dataBlock:clear()
    success = fac:read_block_bd(i, blockSize, dataBlock)
    if not success then
        print(fac.last_error_text)
        return
    end

    -- Generate a base64 block ID.
    -- (Chilkat provides a helper method named GenBlockId to make this easy)
    -- A pre-base64 encoded block ID length of 4 is sufficient in this case because
    -- this file certainly won't have more than 99,999 blocks..
    blockId = fac:gen_block_id(i, 4, "base64")

    -- Add this blockId to the list of blocks to be committed.
    xml:new_child2("Latest", blockId)

    -- Build the URI path
    uriPath:clear()
    success = uriPath:append("/mycontainer/hamlet.xml?comp=block&blockId=")
    success = uriPath:append(blockId)

    contentMd5 = crypt:hash_bd_enc(dataBlock)
    rest:add_header("Content-MD5", contentMd5)

    -- Upload this block..
    sbResponseBody:clear()
    success = rest:full_request_bd("PUT", uriPath:get_as_string(), dataBlock, sbResponseBody)
    if not success then
        print(rest.last_error_text)
        return
    end

    -- Verify that we received a 201 status code.
    if rest.response_status_code ~= 201 then
        -- Examine the request/response to see what happened.
        print("response status code = " .. rest.response_status_code)
        print("response status text = " .. rest.response_status_text)
        print("response header: " .. rest.response_header)
        print("response body (if any): " .. sbResponseBody:get_as_string())
        print("---")
        print("LastRequestStartLine: " .. rest.last_request_start_line)
        print("LastRequestHeader: " .. rest.last_request_header)
        return
    end

    i = i + 1
end

fac:file_close()

-- Now commit the blocks.
-- Let's have a look at the XML that will commit the blocks:
local xmlStr = xml:get_xml()
print(xmlStr)

-- The XML will look like this:

-- <?xml version="1.0" encoding="utf-8" ?>
-- <BlockList>
--     <Latest>MDAwMA==</Latest>
--     <Latest>MDAwMQ==</Latest>
--     <Latest>MDAwMg==</Latest>
--     <Latest>MDAwMw==</Latest>
--     <Latest>MDAwNA==</Latest>
--     <Latest>MDAwNQ==</Latest>
--     <Latest>MDAwNg==</Latest>
--     <Latest>MDAwNw==</Latest>
--     <Latest>MDAwOA==</Latest>
--     <Latest>MDAwOQ==</Latest>
--     <Latest>MDAxMA==</Latest>
--     <Latest>MDAxMQ==</Latest>
--     <Latest>MDAxMg==</Latest>
--     <Latest>MDAxMw==</Latest>
--     <Latest>MDAxNA==</Latest>
--     <Latest>MDAxNQ==</Latest>
--     <Latest>MDAxNg==</Latest>
--     <Latest>MDAxNw==</Latest>
-- </BlockList>

-- --------------------------------------------------------------------------
-- IMPORTANT: Remove the Content-MD5 header previously set in the loop above.
-- --------------------------------------------------------------------------
rest:remove_header("Content-MD5")

-- Send the PUT Block List...
local responseStr = rest:full_request_string("PUT", "/mycontainer/hamlet.xml?comp=blocklist", xmlStr)
if not rest.last_method_success then
    print(rest.last_error_text)
    return
end

-- When successful, the Azure Storage service will respond with a 201 response status code,
-- with no response body.

if rest.response_status_code ~= 201 then
    -- Examine the request/response to see what happened.
    print("response status code = " .. rest.response_status_code)
    print("response status text = " .. rest.response_status_text)
    print("response header: " .. rest.response_header)
    print("response body (if any): " .. responseStr)
    print("---")
    print("LastRequestStartLine: " .. rest.last_request_start_line)
    print("LastRequestHeader: " .. rest.last_request_header)
    return
end

print("Success.")