NullPointerException when using HttpHead and Request/Response interceptors
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Key: HTTPCLIENT-1180
URL: https://issues.apache.org/jira/browse/HTTPCLIENT-1180
Project: HttpComponents HttpClient
Issue Type: Bug
Components: HttpClient
Affects Versions: 4.1.3
Environment: Operating System: Windows 7 64 bit, Software Platform :
JDK 1.7.0.2
Reporter: Peter Joole
When you try to execute a HttpHead object instead of a HttpGet object while
using the add request/response interceptors, you get a nullpointerexception.
I can replicate the exception when using the ClientGZipContentCompression
example that can be found at the HttpClient examples. But instead of using the
HttpGet object I execute a HttpHead object. When I comment the interceptor
parts out, I don't get the exception.
This is the error stack trace I get when executing the code in netbeans:
Exception in thread "main" java.lang.NullPointerException
at
testhttphead.ClientGZipContentCompression$2.process(ClientGZipContentCompression.java:74)
at
org.apache.http.protocol.ImmutableHttpProcessor.process(ImmutableHttpProcessor.java:116)
at
org.apache.http.protocol.HttpRequestExecutor.postProcess(HttpRequestExecutor.java:342)
at
org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:472)
at
org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
at
org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
at
org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
at
testhttphead.ClientGZipContentCompression.main(ClientGZipContentCompression.java:92)
Java Result: 1
Here is the code that gives me the error:
package testhttphead;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;
import org.apache.http.*;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.entity.HttpEntityWrapper;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;
/**
* Demonstration of the use of protocol interceptors to transparently modify
* properties of HTTP messages sent / received by the HTTP client.
* <p/>
* In this particular case HTTP client is made capable of transparent content
* GZIP compression by adding two protocol interceptors: a request interceptor
* that adds 'Accept-Encoding: gzip' header to all outgoing requests and a
* response interceptor that automatically expands compressed response entities
* by wrapping them with a uncompressing decorator class. The use of protocol
* interceptors makes content compression completely transparent to the consumer
* of the {@link org.apache.http.client.HttpClient HttpClient} interface.
*/
public class ClientGZipContentCompression {
public final static void main(String[] args) throws Exception {
DefaultHttpClient httpclient = new DefaultHttpClient();
try {
httpclient.addRequestInterceptor(new HttpRequestInterceptor() {
public void process(
final HttpRequest request,
final HttpContext context) throws HttpException,
IOException {
if (!request.containsHeader("Accept-Encoding")) {
request.addHeader("Accept-Encoding", "gzip");
}
}
});
httpclient.addResponseInterceptor(new HttpResponseInterceptor() {
public void process(
final HttpResponse response,
final HttpContext context) throws HttpException,
IOException {
HttpEntity entity = response.getEntity();
Header ceheader = entity.getContentEncoding();
if (ceheader != null) {
HeaderElement[] codecs = ceheader.getElements();
for (int i = 0; i < codecs.length; i++) {
if (codecs[i].getName().equalsIgnoreCase("gzip")) {
response.setEntity(
new
GzipDecompressingEntity(response.getEntity()));
return;
}
}
}
}
});
HttpHead httpHead = new HttpHead("http://www.howest.be";);
// Execute HTTP request
System.out.println("executing request " + httpHead.getURI());
HttpResponse response = httpclient.execute(httpHead);
System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
System.out.println(response.getLastHeader("Content-Encoding"));
System.out.println(response.getLastHeader("Content-Length"));
System.out.println("----------------------------------------");
HttpEntity entity = response.getEntity();
if (entity != null) {
String content = EntityUtils.toString(entity);
System.out.println(content);
System.out.println("----------------------------------------");
System.out.println("Uncompressed size: " + content.length());
}
} finally {
// When HttpClient instance is no longer needed,
// shut down the connection manager to ensure
// immediate deallocation of all system resources
httpclient.getConnectionManager().shutdown();
}
}
static class GzipDecompressingEntity extends HttpEntityWrapper {
public GzipDecompressingEntity(final HttpEntity entity) {
super(entity);
}
@Override
public InputStream getContent()
throws IOException, IllegalStateException {
// the wrapped entity's getContent() decides about repeatability
InputStream wrappedin = wrappedEntity.getContent();
return new GZIPInputStream(wrappedin);
}
@Override
public long getContentLength() {
// length of ungzipped content is not known
return -1;
}
}
}
With kind regards,
Peter
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