Lua

Azure File Service: Upload Large File

See more Azure Cloud Storage Examples

Sample code to upload a large file to a directory in a share in the Azure File Service. A file is uploaded by first creating the file in the Azure share and then writing ranges of bytes to the file. Azure imposes a 4MB limit for each PUT to write a range. Files larger than 4MB need to be uploaded by making multiple "Put Range" calls. This example uploads a large file requiring multiple "Put Range" calls. Lua

local chilkat = require("chilkat")

-- Azure File Service Example: Upload a large file.
-- See:  https://docs.microsoft.com/en-us/rest/api/storageservices/create-share
-- also see: https://docs.microsoft.com/en-us/rest/api/storageservices/put-range

-- 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.file.core.windows.net", port, bTls, bAutoReconnect)
if not success then
    print(rest.last_error_text)
    return
end

-- This example will upload a larger file.
local localFilePath = "qa_data/zips/somethingBig.zip"
local fac = chilkat.FileAccess.new()
-- Note: The FileSize method returns a signed 32-bit integer.  If the file is potentially larger than 2GB, call FileSizeStr instead to return
-- the size of the file as a string, then convert to an integer value.
local szLocalFile = fac:file_size(localFilePath)
if szLocalFile < 0 then
    print(fac.last_error_text)
    return
end

-- Provide Azure Cloud credentials for the REST calls.
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 = "File"
-- 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: x-ms-date, Authorization.  These headers
-- are automatically set by Chilkat.

-- However, a few additional headers are required for the "Create File" operation:
rest:add_header("x-ms-type", "file")

-- This required header specifies the final size of the file (or the maximum size it can be).
local sbFileSize = chilkat.StringBuilder.new()
sbFileSize:append_int(szLocalFile)
rest:add_header("x-ms-content-length", sbFileSize:get_as_string())

-- Send a PUT request to create the file (or replace the file if it already exists).
-- This will initialize the file in the Azure file storage.  To upload content, we'll need
-- to do the "Put Range" operation one or more times.

-- The following will create the file "somethingBig.zip" in the share "pip"
local responseStr = rest:full_request_no_body("PUT", "/pip/somethingBig.zip")
if not rest.last_method_success then
    print(rest.last_error_text)
    return
end

-- When successful, the Azure File Service will respond with a 201 (Created) response status code,
-- with no XML response body.  If an error response is returned, there will be an XML 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("Successfully created somethingBig.zip")

-- --------------------------------------------------------------------------------
-- Upload the file data...

-- Make sure the headers from the "Create File" operation are removed.
rest:clear_all_headers()

-- The x-ms-write header is required for each "Put Range" request.
rest:add_header("x-ms-write", "update")

local sbRange = chilkat.StringBuilder.new()
local sbResponseBody = chilkat.StringBuilder.new()
local bdFileData = chilkat.BinData.new()

-- Open the file.  We'll be reading and uploading in chunks..
success = fac:open_for_read(localFilePath)
if not success then
    print(fac.last_error_text)
    return
end

local numBytesLeft = szLocalFile
local curIndex = 0
while numBytesLeft > 0 do
    local chunkSize = numBytesLeft
    -- Azure allows for 4MB max chunks  (4 x 1024 x 1024 = 4194304)
    if chunkSize > 4194304 then
        chunkSize = 4194304
    end

    -- The only tricky part here is to correctly add the x-ms-range header.
    -- It will be formatted like this:
    -- x-ms-range: bytes=0-759623
    sbRange:clear()
    sbRange:append("bytes=")
    sbRange:append_int(curIndex)
    sbRange:append("-")
    sbRange:append_int(curIndex + chunkSize - 1)

    -- This replaces the header if it already exists..
    rest:add_header("x-ms-range", sbRange:get_as_string())

    -- Read the next chunk from the local file.
    bdFileData:clear()
    success = fac:file_read_bd(chunkSize, bdFileData)

    success = rest:full_request_bd("PUT", "/pip/somethingBig.zip?comp=range", bdFileData, sbResponseBody)
    if not success then
        -- This would indicate a failure where no response was received.
        print(rest.last_error_text)
        return
    end

    -- A 201 response indicates the chunk was uploaded.
    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("Uploaded chunk from " .. curIndex .. " to " .. (curIndex + chunkSize - 1))

    curIndex = curIndex + chunkSize
    numBytesLeft = numBytesLeft - chunkSize
end

fac:file_close()

print("success.")