Swift

HTTP GET -- Read Response from Stream

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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Swift


func chilkatTest() {
    var success: Bool = false

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

    let rest = CkoRest()!

    // 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:
    let url = CkoUrl()!
    url.parse(url: "http://www.nytimes.com/pages/business/index.html")

    var bAutoReconnect: Bool = true
    success = rest.connect(hostname: url.host, port: url.port.intValue, tls: url.ssl, autoReconnect: bAutoReconnect)

    // Send the GET request (This sends the GET request, but does not read the response.)
    success = rest.sendReqNoBody(httpVerb: "GET", uriPath: url.path)
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    // Read the response header.
    var responseStatusCode: Int = rest.readResponseHeader().intValue
    if responseStatusCode < 0 {
        print("\(rest.lastErrorText!)")
        return
    }

    print("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
        var errResponse: String? = rest.readRespBodyString()
        if rest.lastMethodSuccess != true {
            print("\(rest.lastErrorText!)")
        }
        else {
            print("\(errResponse!)")
        }

        return
    }

    let bodyStream = CkoStream()!
    // Set a 10 second read timeout for the stream. 
    // (Give up if no data arrives within 10 seconds after calling a read method.)
    bodyStream.readTimeoutMs = 10000

    // Create a background thread task to read the response body (which feeds
    // it to the bodyStream object.)
    var readResponseBodyTask: CkoTask? = rest.readRespBodyStreamAsync(stream: bodyStream, autoSetStreamCharset: true)

    // Start the task. 
    success = readResponseBodyTask!.run()

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

    let sbBody = CkoStringBuilder()!
    var exitLoop: Bool = false
    while !exitLoop && (bodyStream.endOfStream != true) {

        var bodyText: String? = bodyStream.readString()
        if bodyStream.lastMethodSuccess == true {
            sbBody.append(value: bodyText)
            if sbBody.contains(str: "</head>", caseSensitive: false) {
                exitLoop = true
            }

        }
        else {
            exitLoop = true
        }

    }

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

    readResponseBodyTask = nil

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

    print("----")
    print("\(sbBody.getAsString()!)")
    print("----")
    print("Successfully received the body up to the desired point.")

}