Tcl

REST Asynchronous Streaming Upload File

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Demonstrates how to asynchronous streaming upload a file to cloud storage. This particular example demonstrates an upload to the Azure Cloud Storage service. The same concepts apply to S3, Google Cloud, and Google Drive. Tcl

load ./chilkat.dll

set success 0

# 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.blob.core.windows.net" $port $bTls $bAutoReconnect]
if {$success != 1} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    exit
}

# Provide Azure Cloud credentials for the REST call.
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 "Blob"
# This causes the "x-ms-version: 2021-08-06" header to be automatically added.
CkAuthAzureStorage_put_XMsVersion $azAuth "2021-08-06"
set success [CkRest_SetAuthAzureStorage $rest $azAuth]

# Set some request headers.
set success [CkRest_AddHeader $rest "x-ms-blob-content-disposition" "attachment; filename=\"thisIsATest.txt\""]
set success [CkRest_AddHeader $rest "x-ms-blob-type" "BlockBlob"]
set success [CkRest_AddHeader $rest "x-ms-meta-m1" "v1"]
set success [CkRest_AddHeader $rest "x-ms-meta-m2" "v2"]

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

set sendStream [new_CkStream]

# Define the source data for the stream to be a file.
CkStream_put_SourceFile $sendStream "qa_data/hamlet.xml"

# Create a background thread task to upload from the stream
# The name of the Azure storage container is "test".
# task is a CkTask
set task [CkRest_FullRequestStreamAsync $rest "PUT" "/test/thisIsATest.txt" $sendStream]

# Start the task. 
set success [CkTask_Run $task]

# In this example, we'll simply sleep and periodically
# check to see if the REST upload if finished.
set curPctDone 0
while {[CkTask_get_Finished $task] != 1} {
    CkTask_SleepMs $task 100
}

# Check to see if the call to FullRequestStream in the background thread pool succeeded.
if {[CkTask_get_TaskSuccess $task] != 1} then {
    # Show what would've been the LastErrorText had FullRequestStream been called synchronously
    puts [CkTask_resultErrorText $task]
    delete_CkTask $task

    delete_CkRest $rest
    delete_CkAuthAzureStorage $azAuth
    delete_CkStream $sendStream
    exit
}

set responseStatusCode [CkRest_get_ResponseStatusCode $rest]

# When successful, the Azure Storage service will respond with a 201 response code,
# with an empty body.  Therefore, in the success condition, the responseStr is empty.
if {$responseStatusCode == 201} then {
    puts "File uploaded."
} else {
    # It failed, so examine the response body, if one was returned:
    # Given that FullRequestStream returns a string, the return value is obtained via GetResultString.
    set responseBodyStr [CkTask_getResultString $task]
    puts "response body (if any): $responseBodyStr"

    # 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 "---"
    puts "LastRequestStartLine: [CkRest_lastRequestStartLine $rest]"
    puts "LastRequestHeader: [CkRest_lastRequestHeader $rest]"
}

delete_CkTask $task


delete_CkRest $rest
delete_CkAuthAzureStorage $azAuth
delete_CkStream $sendStream