Visual FoxPro

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. Visual FoxPro

LOCAL lnSuccess
LOCAL loRest
LOCAL lnBTls
LOCAL lnPort
LOCAL lnBAutoReconnect
LOCAL loAzAuth
LOCAL lcResponseStr

lnSuccess = 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.

loRest = CreateObject('Chilkat.Rest')

* Connect to the Azure Storage Blob Service
lnBTls = 1
lnPort = 443
lnBAutoReconnect = 1
* In this example, the storage account name is "chilkat".
lnSuccess = loRest.Connect("chilkat.blob.core.windows.net",lnPort,lnBTls,lnBAutoReconnect)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

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

* 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.
lnSuccess = loRest.AddHeader("Origin","www.contoso.com")
* The Access-Control-Request-Method is the HTTP method (such as GET, POST, PUT, etc.) of the actual request.
lnSuccess = loRest.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.)
lcResponseStr = loRest.FullRequestNoBody("OPTIONS","/test")
IF (loRest.LastMethodSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loAzAuth
    CANCEL
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 (loRest.ResponseStatusCode <> 200) THEN
    * Examine the request/response to see what happened.
    ? "response status code = " + STR(loRest.ResponseStatusCode)
    ? "response status text = " + loRest.ResponseStatusText
    ? "response header: " + loRest.ResponseHeader
    ? "response body (if any): " + lcResponseStr
    ? "---"
    ? "LastRequestStartLine: " + loRest.LastRequestStartLine
    ? "LastRequestHeader: " + loRest.LastRequestHeader
    RELEASE loRest
    RELEASE loAzAuth
    CANCEL
ENDIF

? "Success: Preflight Blob Request is accepted."

RELEASE loRest
RELEASE loAzAuth