PureBasic

Azure Service Bus - Read Queued Message

See more Azure Service Bus Examples

Demonstrates read a message from an Azure Service Bus Queue. The message is received and removed from the queue. PureBasic

IncludeFile "CkRest.pb"
IncludeFile "CkStringBuilder.pb"

Procedure ChilkatExample()

    success.i = 0

    ; Note: Requires Chilkat v9.5.0.65 or greater.

    ; This requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    ; Make the initial connection.
    ; A single REST object, once connected, can be used for many Azure Service Bus REST API calls.
    ; The auto-reconnect indicates that if the already-established HTTPS connection is closed,
    ; then it will be automatically re-established as needed.
    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    bAutoReconnect.i = 1
    success = CkRest::ckConnect(rest,"<yournamespace>.servicebus.windows.net",443,1,bAutoReconnect)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; ----------------------------------------------------------------------------------------------
    ; The code above this comment could be placed inside a function/subroutine within the application
    ; because the connection does not need to be made for every request.  Once the connection is made
    ; the app may send many requests..
    ; ----------------------------------------------------------------------------------------------

    ; Receive and delete a message from a queue named "gila";
    queueName.s = "gila"

    ; Let's load a previously computed SAS token and use it.
    ; See Azure Shared Access Signature for an example to genenerate an Azure SAS token.
    sbToken.i = CkStringBuilder::ckCreate()
    If sbToken.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckLoadFile(sbToken,"qa_data/tokens/serviceBusSas.txt","utf-8")

    ; Tell the REST object to use the Azure Shared Access Signature for authorization.
    CkStringBuilder::ckPrepend(sbToken,"SharedAccessSignature ")
    CkRest::ckAddHeader(rest,"Authorization",CkStringBuilder::ckGetAsString(sbToken))

    ; Build the path..
    sbPath.i = CkStringBuilder::ckCreate()
    If sbPath.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbPath,"/")
    CkStringBuilder::ckAppend(sbPath,queueName)
    CkStringBuilder::ckAppend(sbPath,"/messages/head")

    ; Add timeout and api-version query parameters.
    CkRest::ckAddQueryParam(rest,"timeout","20")
    CkRest::ckAddQueryParam(rest,"api-version","2013-08")

    ; Use the DELETE HTTP verb to read the message at the head of the queue and remove it.
    sbResponseBody.i = CkStringBuilder::ckCreate()
    If sbResponseBody.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkRest::ckFullRequestNoBodySb(rest,"DELETE",CkStringBuilder::ckGetAsString(sbPath),sbResponseBody)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkStringBuilder::ckDispose(sbToken)
        CkStringBuilder::ckDispose(sbPath)
        CkStringBuilder::ckDispose(sbResponseBody)
        ProcedureReturn
    EndIf

    Debug "Response Status Code = " + Str(CkRest::ckResponseStatusCode(rest))

    ; Check for a success response.
    If CkRest::ckResponseStatusCode(rest) <> 200
        Debug CkRest::ckLastRequestStartLine(rest)
        Debug CkRest::ckLastRequestHeader(rest)
        Debug CkStringBuilder::ckGetAsString(sbResponseBody)
        Debug "Failed."
        CkRest::ckDispose(rest)
        CkStringBuilder::ckDispose(sbToken)
        CkStringBuilder::ckDispose(sbPath)
        CkStringBuilder::ckDispose(sbResponseBody)
        ProcedureReturn
    EndIf

    ; If successful, the message is the contents of the response body.
    message.s = CkStringBuilder::ckGetAsString(sbResponseBody)
    Debug "Dequeued message: " + message

    Debug "Success."


    CkRest::ckDispose(rest)
    CkStringBuilder::ckDispose(sbToken)
    CkStringBuilder::ckDispose(sbPath)
    CkStringBuilder::ckDispose(sbResponseBody)


    ProcedureReturn
EndProcedure