DataFlex

Receive Text until CRLF

Demonstrates receiving text on a socket connection up to and including when an expected CRLF arrives. The example sends an HTTP HEAD request to an HTTP server and then reads the response header using ReceiveToCRLF and ReceiveUntilMatch. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSocket
    Boolean iUseTls
    Integer iMaxWaitMillisec
    String sResponseStatusLine
    String sResponseHeaderLine
    String sRemainderOfHeader
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatSocket)) To hoSocket
    If (Not(IsComObjectCreated(hoSocket))) Begin
        Send CreateComObject of hoSocket
    End

    // Connect using TLS to www.chilkatsoft.com
    // We could also use a normal TCP connection also by specifying port 80 with useTls = False.
    Move True To iUseTls
    Move 20000 To iMaxWaitMillisec
    Get ComConnect Of hoSocket "www.chilkatsoft.com" 443 iUseTls iMaxWaitMillisec To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoSocket To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Tell the socket object that all text is to be sent in the utf-8 encoding,
    // and the text received is assumed to be utf-8.
    Set ComStringCharset Of hoSocket To "utf-8"

    // Send an HTTP HEAD request:
    Get ComSendString Of hoSocket "HEAD / HTTP/1.1" + (character(13)) + (character(10)) + "Host: www.chilkatsoft.com" + (character(13)) + (character(10)) + (character(13)) + (character(10)) To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoSocket To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Wait a maximum of 4 seconds while no data is forthcoming:
    Set ComMaxReadIdleMs Of hoSocket To 4000

    // To explain MaxReadIdleMs further:  In Chilkat, a max "idle timeout" is the max time to wait
    // while no additional data arrives on the socket.  Imagine if 10MB of data will be received
    // where the 1st CRLF occurs at the very end.  As long as the data continues arriving and does not
    // halt for more than 4000ms, then the ReceiveToCRLF will continue receiving.  It is only after
    // the connection becomes idle for more than 4000ms that the app will giveup and fail the read.

    // Get the 1st response line, which should be "HTTP/1.1 200 OK"
    Get ComReceiveToCRLF Of hoSocket To sResponseStatusLine
    Get ComLastMethodSuccess Of hoSocket To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoSocket To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "StatusLine: " sResponseStatusLine

    // Now get the 1st line of the response header:
    Get ComReceiveToCRLF Of hoSocket To sResponseHeaderLine
    Get ComLastMethodSuccess Of hoSocket To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoSocket To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "HeaderLine: " sResponseHeaderLine

    // Now read the remainder of the response header by reading until a double CRLF is seen:
    Get ComReceiveUntilMatch Of hoSocket (character(13)) + (character(10)) + (character(13)) + (character(10)) To sRemainderOfHeader
    Get ComLastMethodSuccess Of hoSocket To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoSocket To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Remainder: " sRemainderOfHeader

    // Close the connection with the server
    // Wait a max of 20 seconds (20000 millsec)
    Get ComClose Of hoSocket 20000 To iSuccess


End_Procedure