Tcl

Azure Storage: CORS Preflight Blob Request

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Azure Storage Blob Service REST API: Sample code to send a CORS pre-flight blob request. Tcl

load ./chilkat.dll

set success 0

# Azure Blob Service Example: CORS Preflight Blob Request
# See also: https://msdn.microsoft.com/en-us/library/azure/dn535599.aspx

# 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]

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

# The preflight blob request requires the following two HTTP headers.
# The Origin is the domain from which the actual request will be issued.
set success [CkRest_AddHeader $rest "Origin" "www.contoso.com"]
# The Access-Control-Request-Method is the HTTP method (such as GET, POST, PUT, etc.) of the actual request.
set success [CkRest_AddHeader $rest "Access-Control-Request-Method" "PUT"]

# The expected response is a 202 response status code with no response body.
# The name of the container or blob resource in this example is "test". (Replace "test" with your container name.)
set responseStr [CkRest_fullRequestNoBody $rest "OPTIONS" "/test"]
if {[CkRest_get_LastMethodSuccess $rest] != 1} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkAuthAzureStorage $azAuth
    exit
}

# When successful, the Azure Storage service will respond with a 200 response code,
# with no response body.

# If CORS is not enabled or no matching rule is found for the request, 
# then a 403 status code is returned, with the following status text:
# "CORS not enabled or no matching rule found for this request."
if {[CkRest_get_ResponseStatusCode $rest] != 200} 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_CkAuthAzureStorage $azAuth
    exit
}

puts "Success: Preflight Blob Request is accepted."

delete_CkRest $rest
delete_CkAuthAzureStorage $azAuth