Question

With Apache HttpClient, it’s possible to manipulate the retrieved content by adding a HttpResponseIntercepter. With this it is quite easy to add header attributes. But how to manipulate the content of the retrieved HttpEntitys?

As example I like to convert all Text to Uppercase.

@Test
public void shoudConvertEverythingToUpperCase() throws ClientProtocolException, IOException
{
    final DefaultHttpClient defaultHttpClient = new DefaultHttpClient();

    defaultHttpClient.addResponseInterceptor(new HttpResponseInterceptor() {

        @Override
        public void process(final HttpResponse response, final HttpContext context) throws HttpException, IOException
        {
            final HttpEntity entity = response.getEntity();

            final HttpEntity upperCaseEntity = makeAllUppercase(entity);

            response.setEntity(upperCaseEntity);
        }

        private HttpEntity makeAllUppercase(final HttpEntity entity)
        {
            // how to uppercase everything and return the cloned HttpEntity
            return null;
        }
    });

    final HttpResponse httpResponse = defaultHttpClient.execute(new HttpGet("http://stackoverflow.com"));

    assertTrue(StringUtils.isAllUpperCase(EntityUtils.toString(httpResponse.getEntity())));
}

Answer 1

private HttpEntity makeAllUppercase(final HttpEntity entity)
{
    Header h = entity.getContentType();
    ContentType contentType = h != null ? ContentType.parse(h.getValue()) : ContentType.DEFAULT_TEXT;
    String content = EntityUtils.toString(entity, contentType.getCharset());
    return new StringEntity(content.toUpperCase(Locale.US), contentType);
}

This is not the most efficient due to intermediate buffering of content in memory but the most concise implementation.