HTTP GET -- Read Response from Stream

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Demonstrates how to send an HTTP GET for a web page, and then read the response from a Stream. The purpose is to fulfill a situation such as the following: "I have a URL and just want the <head> </head> portion of the HTML. This would avoid having to download a potentially enormous web page just to get at header information, such as the <styles>."

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    success := false

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

    rest := chilkat.NewRest()

    // In this example, we'll get the web page at http://www.nytimes.com/pages/business/index.html
    // The domain is "www.nytimes.com", and the path is "/pages/business/index.html"

    // If we have only the full URL to begin with, it can be loaded into the Chilkat URL object to
    // access the parts:
    url := chilkat.NewUrl()
    url.ParseUrl("http://www.nytimes.com/pages/business/index.html")

    bAutoReconnect := true
    success = rest.Connect(url.Host(),url.Port(),url.Ssl(),bAutoReconnect)

    // Send the GET request (This sends the GET request, but does not read the response.)
    success = rest.SendReqNoBody("GET",url.Path())
    if success != true {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        url.DisposeUrl()
        return
    }

    // Read the response header.
    responseStatusCode := rest.ReadResponseHeader()
    if responseStatusCode < 0 {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        url.DisposeUrl()
        return
    }

    fmt.Println("Response status code = ", responseStatusCode)

    // We expect a 200 response status.
    if responseStatusCode != 200 {

        // If the response status code is not 200, we could check for a redirect status code and 
        // then follow it, read the entire response (as shown here), or just call rest.Disconnect
        errResponse := rest.ReadRespBodyString()
        if rest.LastMethodSuccess() != true {
            fmt.Println(rest.LastErrorText())
        } else {
            fmt.Println(*errResponse)
        }

        rest.DisposeRest()
        url.DisposeUrl()
        return
    }

    bodyStream := chilkat.NewStream()
    // Set a 10 second read timeout for the stream. 
    // (Give up if no data arrives within 10 seconds after calling a read method.)
    bodyStream.SetReadTimeoutMs(10000)

    // Create a background thread task to read the response body (which feeds
    // it to the bodyStream object.)
    c := make(chan *chilkat.Task)
    go rest.ReadRespBodyStreamAsync(bodyStream,true,c)
    readResponseBodyTask := <-c

    // Start the task. 

    // Read the HTTP response body until the "</head>" is seen, or until
    // the end-of-stream is reached.

    sbBody := chilkat.NewStringBuilder()
    exitLoop := false
    for !exitLoop && (bodyStream.EndOfStream() != true) {

        bodyText := bodyStream.ReadString()
        if bodyStream.LastMethodSuccess() == true {
            sbBody.Append(*bodyText)
            if sbBody.Contains("</head>",false) {
                exitLoop = true
            }

        } else {
            exitLoop = true
        }

    }

    // Cancel the remainder of the task...
    readResponseBodyTask.Cancel()

    readResponseBodyTask.DisposeTask()

    // Ensure we're disconnected from the server.
    maxWaitMs := 50
    rest.Disconnect(maxWaitMs)

    fmt.Println("----")
    fmt.Println(*sbBody.GetAsString())
    fmt.Println("----")
    fmt.Println("Successfully received the body up to the desired point.")

    rest.DisposeRest()
    url.DisposeUrl()
    bodyStream.DisposeStream()
    readResponseBodyTask.DisposeTask()
    sbBody.DisposeStringBuilder()