ContentRetrievalProcessor.java

package edu.columbia.biology.processors;

import java.io.IOException;

import javax.servlet.http.HttpServletResponse;

import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponents;

import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.model.S3ObjectInputStream;

import edu.columbia.biology.RestTemplateFactory;

@Component
public class ContentRetrievalProcessor {
	
	private static final Logger LOGGER = LoggerFactory.getLogger(ContentRetrievalProcessor.class);

	@Autowired
	private AmazonS3 amazonS3Client;

	@Autowired
	private RestTemplateFactory restTemplateFactory;
	
	public <T> T retrieveResponseFromUri(UriComponents uriComponents, Class<T> clazz) {
		LOGGER.info("Retrieving resource from {}", uriComponents.toUriString());
		RestTemplate restTemplate = restTemplateFactory.getObject();
		ResponseEntity<T> responseEntity = restTemplate.exchange(uriComponents.toUriString(), HttpMethod.GET,
				new HttpEntity<T>(restTemplateFactory.createHeaders()), clazz);

		return responseEntity.getBody();
	}
	
	public void sendImageToClient(String imageUUID, HttpServletResponse response) throws IOException{
		S3Object object = amazonS3Client.getObject("cellx-files-test", imageUUID);
		S3ObjectInputStream inputStream = object.getObjectContent();
		response.setContentType(MediaType.IMAGE_PNG_VALUE);
		response.setHeader("Cache-Control", "public, max-age=1210000");
		IOUtils.copy(inputStream, response.getOutputStream());
		response.flushBuffer();
	}
}

S3ContentDeliveryController.java

package edu.columbia.biology.controller;

import java.io.IOException;

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.core.Authentication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import edu.columbia.biology.processors.CellxPrincipalProcessor;
import edu.columbia.biology.processors.ContentRetrievalProcessor;
import edu.columbia.biology.service.ImageService;

/*
 * Test cases
 * Access: image/3d12b0a7-7604-5935-a862-84f306b28ff8.png
 * Access controlled: image/abb47011-1f4f-5ae4-a4dd-5e8b834527d2.png
 */
@RestController
public class S3ContentDeliveryController {
	private static final Logger LOGGER = LoggerFactory.getLogger(S3ContentDeliveryController.class);

	@Autowired
	private ImageService imageService;
	
	@Autowired
	private ContentRetrievalProcessor contentRetrievalProcessor;
	
	@Autowired
	private CellxPrincipalProcessor cellxPrincipalProcessor;
	
	@RequestMapping(value = "/s3/image", method = RequestMethod.GET) 
	public void retrieveS3ImagesObjectWithUUID(@RequestParam("imageUUID") String imageUUID,
			Authentication authentication, HttpServletResponse response) throws IOException {
		if (imageService.imageIsUserAccessible(authentication, imageUUID)) {
			contentRetrievalProcessor.sendImageToClient(imageUUID, response);
		} else {
			if (authentication != null) {
				LOGGER.info("User {} does not have access to image {}", cellxPrincipalProcessor.retrieveUserIdFromPrincipal(authentication),
						imageUUID);
			} else {
				LOGGER.info("Guest user does not have access to image {}", imageUUID);
			}
			throw new AccessDeniedException("User does not have access to the image resouorce");
		}
	}
}