Xbase++

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. Xbase++

LOCAL nSuccess
LOCAL oRest
LOCAL nBTls
LOCAL nPort
LOCAL nBAutoReconnect
LOCAL oAzAuth
LOCAL cResponseStr

nSuccess := 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.

oRest := CreateObject("Chilkat.Rest")

//  Connect to the Azure Storage Blob Service
nBTls := 1
nPort := 443
nBAutoReconnect := 1
//  In this example, the storage account name is "chilkat".
nSuccess := oRest:Connect("chilkat.blob.core.windows.net", nPort, nBTls, nBAutoReconnect)
IF (nSuccess != 1)
    ? oRest:LastErrorText
    oRest:destroy()
    RETURN
ENDIF

//  Provide Azure Cloud credentials for the REST call.
oAzAuth := CreateObject("Chilkat.AuthAzureStorage")
oAzAuth:AccessKey := "AZURE_ACCESS_KEY"
//  The account name used here should match the 1st part of the domain passed in the call to Connect (above).
oAzAuth:Account := "chilkat"
oAzAuth:Scheme := "SharedKey"
oAzAuth:Service := "Blob"
//  This causes the "x-ms-version: 2021-08-06" header to be automatically added.
oAzAuth:XMsVersion := "2021-08-06"
nSuccess := oRest:SetAuthAzureStorage(oAzAuth)

//  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.
nSuccess := oRest:AddHeader("Origin", "www.contoso.com")
//  The Access-Control-Request-Method is the HTTP method (such as GET, POST, PUT, etc.) of the actual request.
nSuccess := oRest:AddHeader("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.)
cResponseStr := oRest:FullRequestNoBody("OPTIONS", "/test")
IF (oRest:LastMethodSuccess != 1)
    ? oRest:LastErrorText
    oRest:destroy()
    oAzAuth:destroy()
    RETURN
ENDIF

//  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 (oRest:ResponseStatusCode != 200)
    //  Examine the request/response to see what happened.
    ? "response status code = " + Str(oRest:ResponseStatusCode)
    ? "response status text = " + oRest:ResponseStatusText
    ? "response header: " + oRest:ResponseHeader
    ? "response body (if any): " + cResponseStr
    ? "---"
    ? "LastRequestStartLine: " + oRest:LastRequestStartLine
    ? "LastRequestHeader: " + oRest:LastRequestHeader
    oRest:destroy()
    oAzAuth:destroy()
    RETURN
ENDIF

? "Success: Preflight Blob Request is accepted."

oRest:destroy()
oAzAuth:destroy()