Android™

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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// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

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

    CkRest rest = new CkRest();

    // 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:
    CkUrl url = new CkUrl();
    url.ParseUrl("http://www.nytimes.com/pages/business/index.html");

    boolean bAutoReconnect = true;
    success = rest.Connect(url.host(),url.get_Port(),url.get_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) {
        Log.i(TAG, rest.lastErrorText());
        return;
        }

    // Read the response header.
    int responseStatusCode = rest.ReadResponseHeader();
    if (responseStatusCode < 0) {
        Log.i(TAG, rest.lastErrorText());
        return;
        }

    Log.i(TAG, "Response status code = " + String.valueOf(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
        String errResponse = rest.readRespBodyString();
        if (rest.get_LastMethodSuccess() != true) {
            Log.i(TAG, rest.lastErrorText());
            }
        else {
            Log.i(TAG, errResponse);
            }

        return;
        }

    CkStream bodyStream = new CkStream();
    // Set a 10 second read timeout for the stream. 
    // (Give up if no data arrives within 10 seconds after calling a read method.)
    bodyStream.put_ReadTimeoutMs(10000);

    // Create a background thread task to read the response body (which feeds
    // it to the bodyStream object.)
    CkTask readResponseBodyTask = rest.ReadRespBodyStreamAsync(bodyStream,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.

    CkStringBuilder sbBody = new CkStringBuilder();
    boolean exitLoop = false;
    while (!exitLoop and (bodyStream.get_EndOfStream() != true)) {

        String bodyText = bodyStream.readString();
        if (bodyStream.get_LastMethodSuccess() == true) {
            sbBody.Append(bodyText);
            if (sbBody.Contains("</head>",false)) {
                exitLoop = true;
                }

            }
        else {
            exitLoop = true;
            }

        }

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

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

    Log.i(TAG, "----");
    Log.i(TAG, sbBody.getAsString());
    Log.i(TAG, "----");
    Log.i(TAG, "Successfully received the body up to the desired point.");

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}