Create Rest Web Service to receive an Image

Question

How would you design a REST based web service that receives an image file in the form of an InputStream? If the InputStream is posted to a REST end point, how does that end point receive it so that it can create an image file?

Answer 1

Example REST Web Service Java Class to Recieve Image

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.ws.rs.Consumes;
import javax.ws.rs.FormParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;

import com.sun.jersey.core.header.FormDataContentDisposition;
import com.sun.jersey.multipart.FormDataParam;
import com.sun.org.apache.xml.internal.security.exceptions.Base64DecodingException;
import com.sun.org.apache.xml.internal.security.utils.Base64;


@Path("/upload")
public class Upload_Documents {


    private static final String UPLOAD_FOLDER = "c:/uploadedFiles/";

    @Context
    private UriInfo context;
    /**
     * Returns text response to caller containing uploaded file location
     * 
     * @return error response in case of missing parameters an internal
     *         exception or success response if file has been stored
     *         successfully
     */
    @POST
    @Path("/pic")
    @Consumes(MediaType.MULTIPART_FORM_DATA)
    public Response uploadFile(
            @FormDataParam("file") InputStream uploadedInputStream,
            @FormDataParam("file") FormDataContentDisposition fileDetail) {

        System.out.println("Called Upload Image");
        // check if all form parameters are provided
        if (uploadedInputStream == null || fileDetail == null)
            return Response.status(400).entity("Invalid form data").build();
        // create our destination folder, if it not exists
        try {
            createFolderIfNotExists(UPLOAD_FOLDER);
        } catch (SecurityException se) {
            return Response.status(500)
                    .entity("Can not create destination folder on server")
                    .build();
        }
        String uploadedFileLocation = UPLOAD_FOLDER + fileDetail.getFileName();
        try {
            saveToFile(uploadedInputStream, uploadedFileLocation);
        } catch (IOException e) {
            return Response.status(500).entity("Can not save file").build();
        }
        return Response.status(200)
                .entity("File saved to " + uploadedFileLocation).build();
    }
    /**
     * Utility method to save InputStream data to target location/file
     * 
     * @param inStream
     *            - InputStream to be saved
     * @param target
     *            - full path to destination file
     */
    private void saveToFile(InputStream inStream, String target)
            throws IOException {
        OutputStream out = null;
        int read = 0;
        byte[] bytes = new byte[1024];
        out = new FileOutputStream(new File(target));
        while ((read = inStream.read(bytes)) != -1) {
            out.write(bytes, 0, read);
        }
        out.flush();
        out.close();
    }
    /**
     * Creates a folder to desired location if it not already exists
     * 
     * @param dirName
     *            - full path to the folder
     * @throws SecurityException
     *             - in case you don't have permission to create the folder
     */
    private void createFolderIfNotExists(String dirName)
            throws SecurityException {
        File theDir = new File(dirName);
        if (!theDir.exists()) {
            theDir.mkdir();
        }
}
}