introducing parent-child context to experiment with properties and httpclient cleanup

httpclient/src/test/java/org/baeldung/httpclient/HttpClientUnshortenLiveTest.java

@@ -0,0 +1,161 @@
+package org.baeldung.httpclient;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import org.apache.http.Header;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpHeaders;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.params.BasicHttpParams;
+import org.apache.http.params.HttpParams;
+import org.apache.http.util.EntityUtils;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+
+public class HttpClientUnshortenLiveTest {
+
+    private CloseableHttpClient client;
+
+    // fixtures
+
+    @Before
+    public final void before() {
+        final HttpParams httpParameters = new BasicHttpParams();
+        httpParameters.setParameter("http.protocol.handle-redirects", false);
+
+        client = new DefaultHttpClient(httpParameters);
+    }
+
+    // tests
+
+    @Test
+    public final void givenShortenedOnce_whenUrlIsUnshortened_thenCorrectResult() throws IOException {
+        final String expectedResult = "http://www.baeldung.com/rest-versioning";
+        final String actualResult = expandSingleLevel("http://bit.ly/13jEoS1");
+        assertThat(actualResult, equalTo(expectedResult));
+    }
+
+    @Test
+    public final void givenShortenedMultiple_whenUrlIsUnshortened_thenCorrectResult() throws IOException {
+        final String expectedResult = "http://www.baeldung.com/rest-versioning";
+        final String actualResult = expand("http://t.co/e4rDDbnzmk");
+        assertThat(actualResult, equalTo(expectedResult));
+    }
+
+    // API
+
+    final String expand(final String urlArg) throws IOException {
+        String originalUrl = urlArg;
+        String newUrl = expandSingleLevel(originalUrl);
+        while (!originalUrl.equals(newUrl)) {
+            originalUrl = newUrl;
+            newUrl = expandSingleLevel(originalUrl);
+        }
+
+        return newUrl;
+    }
+
+    final String expandSafe(final String urlArg) throws IOException {
+        String originalUrl = urlArg;
+        String newUrl = expandSingleLevelSafe(originalUrl).getRight();
+        final List<String> alreadyVisited = Lists.newArrayList(originalUrl, newUrl);
+        while (!originalUrl.equals(newUrl)) {
+            originalUrl = newUrl;
+            final Pair<Integer, String> statusAndUrl = expandSingleLevelSafe(originalUrl);
+            newUrl = statusAndUrl.getRight();
+            final boolean isRedirect = statusAndUrl.getLeft() == 301 || statusAndUrl.getLeft() == 302;
+            if (isRedirect && alreadyVisited.contains(newUrl)) {
+                throw new IllegalStateException("Likely a redirect loop");
+            }
+            alreadyVisited.add(newUrl);
+        }
+
+        return newUrl;
+    }
+
+    final Pair<Integer, String> expandSingleLevelSafe(final String url) throws IOException {
+        HttpGet request = null;
+        HttpEntity httpEntity = null;
+        InputStream entityContentStream = null;
+
+        try {
+            request = new HttpGet(url);
+            final HttpResponse httpResponse = client.execute(request);
+
+            httpEntity = httpResponse.getEntity();
+            entityContentStream = httpEntity.getContent();
+
+            final int statusCode = httpResponse.getStatusLine().getStatusCode();
+            if (statusCode != 301 && statusCode != 302) {
+                return new ImmutablePair<Integer, String>(statusCode, url);
+            }
+            final Header[] headers = httpResponse.getHeaders(HttpHeaders.LOCATION);
+            Preconditions.checkState(headers.length == 1);
+            final String newUrl = headers[0].getValue();
+
+            return new ImmutablePair<Integer, String>(statusCode, newUrl);
+        } catch (final IllegalArgumentException uriEx) {
+            return new ImmutablePair<Integer, String>(500, url);
+        } finally {
+            if (request != null) {
+                request.releaseConnection();
+            }
+            if (entityContentStream != null) {
+                entityContentStream.close();
+            }
+            if (httpEntity != null) {
+                EntityUtils.consume(httpEntity);
+            }
+        }
+    }
+
+    final String expandSingleLevel(final String url) throws IOException {
+        HttpGet request = null;
+        HttpEntity httpEntity = null;
+        InputStream entityContentStream = null;
+
+        try {
+            request = new HttpGet(url);
+            final HttpResponse httpResponse = client.execute(request);
+
+            httpEntity = httpResponse.getEntity();
+            entityContentStream = httpEntity.getContent();
+
+            final int statusCode = httpResponse.getStatusLine().getStatusCode();
+            if (statusCode != 301 && statusCode != 302) {
+                return url;
+            }
+            final Header[] headers = httpResponse.getHeaders(HttpHeaders.LOCATION);
+            Preconditions.checkState(headers.length == 1);
+            final String newUrl = headers[0].getValue();
+
+            return newUrl;
+        } catch (final IllegalArgumentException uriEx) {
+            return url;
+        } finally {
+            if (request != null) {
+                request.releaseConnection();
+            }
+            if (entityContentStream != null) {
+                entityContentStream.close();
+            }
+            if (httpEntity != null) {
+                EntityUtils.consume(httpEntity);
+            }
+        }
+    }
+
+}