(Tcl) Azure File Service: Upload Large File

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.

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load ./chilkat.dll

# 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.

set rest [new_CkRest]

# Connect to the Azure Storage Blob Service
set bTls 1
set port 443
set bAutoReconnect 1
# In this example, the storage account name is "chilkat".
set success [CkRest_Connect $rest "chilkat.file.core.windows.net" $port $bTls $bAutoReconnect]
if {$success != 1} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    exit
}

# This example will upload a larger file.
set localFilePath "qa_data/zips/somethingBig.zip"
set fac [new_CkFileAccess]

# 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.
set szLocalFile [CkFileAccess_FileSize $fac $localFilePath]
if {$szLocalFile < 0} then {
    puts [CkFileAccess_lastErrorText $fac]
    delete_CkRest $rest
    delete_CkFileAccess $fac
    exit
}

# Provide Azure Cloud credentials for the REST calls.
set azAuth [new_CkAuthAzureStorage]

CkAuthAzureStorage_put_AccessKey $azAuth "AZURE_ACCESS_KEY"
# The account name used here should match the 1st part of the domain passed in the call to Connect (above).
CkAuthAzureStorage_put_Account $azAuth "chilkat"
CkAuthAzureStorage_put_Scheme $azAuth "SharedKey"
CkAuthAzureStorage_put_Service $azAuth "File"
# This causes the "x-ms-version: 2020-08-04" header to be automatically added.
CkAuthAzureStorage_put_XMsVersion $azAuth "2020-08-04"
set success [CkRest_SetAuthAzureStorage $rest $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:
CkRest_AddHeader $rest "x-ms-type" "file"

# This required header specifies the final size of the file (or the maximum size it can be).
set sbFileSize [new_CkStringBuilder]

CkStringBuilder_AppendInt $sbFileSize $szLocalFile
CkRest_AddHeader $rest "x-ms-content-length" [CkStringBuilder_getAsString $sbFileSize]

# 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"
set responseStr [CkRest_fullRequestNoBody $rest "PUT" "/pip/somethingBig.zip"]
if {[CkRest_get_LastMethodSuccess $rest] != 1} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkFileAccess $fac
    delete_CkAuthAzureStorage $azAuth
    delete_CkStringBuilder $sbFileSize
    exit
}

# 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 {[CkRest_get_ResponseStatusCode $rest] != 201} then {
    # Examine the request/response to see what happened.
    puts "response status code = [CkRest_get_ResponseStatusCode $rest]"
    puts "response status text = [CkRest_responseStatusText $rest]"
    puts "response header: [CkRest_responseHeader $rest]"
    puts "response body (if any): $responseStr"
    puts "---"
    puts "LastRequestStartLine: [CkRest_lastRequestStartLine $rest]"
    puts "LastRequestHeader: [CkRest_lastRequestHeader $rest]"
    delete_CkRest $rest
    delete_CkFileAccess $fac
    delete_CkAuthAzureStorage $azAuth
    delete_CkStringBuilder $sbFileSize
    exit
}

puts "Successfully created somethingBig.zip"

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

# Make sure the headers from the "Create File" operation are removed.
CkRest_ClearAllHeaders $rest

# The x-ms-write header is required for each "Put Range" request.
CkRest_AddHeader $rest "x-ms-write" "update"

set sbRange [new_CkStringBuilder]

set sbResponseBody [new_CkStringBuilder]

set bdFileData [new_CkBinData]

# Open the file.  We'll be reading and uploading in chunks..
set success [CkFileAccess_OpenForRead $fac $localFilePath]
if {$success != 1} then {
    puts [CkFileAccess_lastErrorText $fac]
    delete_CkRest $rest
    delete_CkFileAccess $fac
    delete_CkAuthAzureStorage $azAuth
    delete_CkStringBuilder $sbFileSize
    delete_CkStringBuilder $sbRange
    delete_CkStringBuilder $sbResponseBody
    delete_CkBinData $bdFileData
    exit
}

set numBytesLeft $szLocalFile
set curIndex 0
while {$numBytesLeft > 0} {

    set chunkSize $numBytesLeft
    # Azure allows for 4MB max chunks  (4 x 1024 x 1024 = 4194304)
    if {$chunkSize > 4194304} then {
        set chunkSize 4194304
    }

    # 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
    CkStringBuilder_Clear $sbRange
    CkStringBuilder_Append $sbRange "bytes="
    CkStringBuilder_AppendInt $sbRange $curIndex
    CkStringBuilder_Append $sbRange "-"
    CkStringBuilder_AppendInt $sbRange [expr $curIndex + [expr $chunkSize - 1]]

    # This replaces the header if it already exists..
    CkRest_AddHeader $rest "x-ms-range" [CkStringBuilder_getAsString $sbRange]

    # Read the next chunk from the local file.
    CkBinData_Clear $bdFileData
    set success [CkFileAccess_FileReadBd $fac $chunkSize $bdFileData]

    set success [CkRest_FullRequestBd $rest "PUT" "/pip/somethingBig.zip?comp=range" $bdFileData $sbResponseBody]
    if {$success != 1} then {
        # This would indicate a failure where no response was received.
        puts [CkRest_lastErrorText $rest]
        delete_CkRest $rest
        delete_CkFileAccess $fac
        delete_CkAuthAzureStorage $azAuth
        delete_CkStringBuilder $sbFileSize
        delete_CkStringBuilder $sbRange
        delete_CkStringBuilder $sbResponseBody
        delete_CkBinData $bdFileData
        exit
    }

    # A 201 response indicates the chunk was uploaded.
    if {[CkRest_get_ResponseStatusCode $rest] != 201} then {
        # Examine the request/response to see what happened.
        puts "response status code = [CkRest_get_ResponseStatusCode $rest]"
        puts "response status text = [CkRest_responseStatusText $rest]"
        puts "response header: [CkRest_responseHeader $rest]"
        puts "response body (if any): $responseStr"
        puts "---"
        puts "LastRequestStartLine: [CkRest_lastRequestStartLine $rest]"
        puts "LastRequestHeader: [CkRest_lastRequestHeader $rest]"
        delete_CkRest $rest
        delete_CkFileAccess $fac
        delete_CkAuthAzureStorage $azAuth
        delete_CkStringBuilder $sbFileSize
        delete_CkStringBuilder $sbRange
        delete_CkStringBuilder $sbResponseBody
        delete_CkBinData $bdFileData
        exit
    }

    puts "Uploaded chunk from $curIndex to [expr $curIndex + [expr $chunkSize - 1]]"

    set curIndex [expr $curIndex + $chunkSize]
    set numBytesLeft [expr $numBytesLeft - $chunkSize]
}

CkFileAccess_FileClose $fac

puts "success."

delete_CkRest $rest
delete_CkFileAccess $fac
delete_CkAuthAzureStorage $azAuth
delete_CkStringBuilder $sbFileSize
delete_CkStringBuilder $sbRange
delete_CkStringBuilder $sbResponseBody
delete_CkBinData $bdFileData