AEM 6550 - Modify the Filename on Upload Before Executing DAM Update Asset Workflow

 

Adjust the filename on upload (organization standards?), before executing DAM Update Asset workflow. The sample in this post adds a filter executing prior to com.day.cq.dam.core.impl.servlet.CreateAssetServlet, intercepting the file upload stream 

Code in this post was not production harnessed, make sure you test (and improve it) for large files, small files, binaries, text files etc..

For validating file names on client side check this post

For handling files uploaded using Web Interface & Asset Link - Demo | Package Install | Github

For handling files uploaded using Web Interface  - Demo | Package Install | Github

Uploaded using Web Interface

Uploaded using Asset Link

Solution

Add a filter eg. apps.experienceaem.assets.EAEMChangeFileNameFilter intercepting the file name stream and adjust the name (here it replaces spaces with hyphens)

package apps.experienceaem.assets;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.osgi.service.component.annotations.Component;
import org.osgi.framework.Constants;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.Part;

import javax.servlet.*;
import java.io.*;
import java.util.*;

@Component(
        immediate = true,
        service = Filter.class,
        name = "Experience AEM Request Name Change Filter for CreateAssetServlet Streaming Requests",
        property = {
                Constants.SERVICE_RANKING + ":Integer=-99",
                "sling.filter.scope=REQUEST"
        })
public class EAEMChangeFileNameFilter implements Filter {
    private static Logger log = LoggerFactory.getLogger(EAEMChangeFileNameFilter.class);

    private static final String STRING_MATCH = " ";

    public void init(FilterConfig filterConfig) throws ServletException {
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        if (!(request instanceof SlingHttpServletRequest) || !(response instanceof SlingHttpServletResponse)) {
            chain.doFilter(request, response);
            return;
        }

        final SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;

        if (!StringUtils.equals("POST", slingRequest.getMethod()) || !isCreateAssetRequest(slingRequest) ) {
            chain.doFilter(request, response);
            return;
        }

        Iterator parts = (Iterator)request.getAttribute("request-parts-iterator");

        if( (parts == null) || !parts.hasNext()){
            chain.doFilter(request, response);
            return;
        }

        List<Part> otherParts = new ArrayList<Part>();
        Part part = null;

        while(parts.hasNext()) {
            part = (Part) parts.next();

            otherParts.add(new EAEMFileNameRequestPart(part));
        }

        request.setAttribute("request-parts-iterator", otherParts.iterator());

        chain.doFilter(request, response);
    }

    private boolean isCreateAssetRequest(SlingHttpServletRequest slingRequest){
        String[] selectors = slingRequest.getRequestPathInfo().getSelectors();

        if(ArrayUtils.isEmpty(selectors) || (selectors.length > 1)){
            return false;
        }

        return selectors[0].equals("createasset");
    }

    public void destroy() {
    }

    //code copied form https://svn.apache.org/repos/asf/sling/trunk/bundles/engine/src/main/java/org/apache/sling/engine/impl/parameters/RequestPartsIterator.java
    private static class EAEMFileNameRequestPart implements Part {
        private final Part part;
        private final InputStream inputStream;

        public EAEMFileNameRequestPart(Part part) throws IOException {
            this.part = part;

            if(!isFileNamePart(part)){
                this.inputStream = new ByteArrayInputStream(IOUtils.toByteArray(part.getInputStream()));
            }else{
                this.inputStream = this.getFileNameAdjustedStream(part);
            }
        }

        private InputStream getFileNameAdjustedStream(Part part) throws IOException{
            String fileName = null;

            try{
                fileName = IOUtils.toString(part.getInputStream(), "UTF-8");
            }catch(Exception e){
                log.error("Error reading filename from stream...");
            }

            if(fileName == null){
                fileName = "";
            }

            if(!fileName.contains(STRING_MATCH)){
                log.debug("Return unprocessed file name : " + fileName);
                return new ByteArrayInputStream(fileName.getBytes());
            }

            fileName = fileName.trim().replaceAll(STRING_MATCH, "-");

            log.debug("Uploaded file name changed to : " + fileName);

            return new ByteArrayInputStream(fileName.getBytes());
        }

        private boolean isFileNamePart(Part part){
            return ("fileName".equals(part.getName()));
        }

        public InputStream getInputStream() throws IOException {
            return inputStream;
        }

        public  String getContentType() {
            return part.getContentType();
        }

        public String getName() {
            return part.getName();
        }

        public long getSize() {
            return 0;
        }

        public  void write(String s) throws IOException {
            throw new UnsupportedOperationException("Writing parts directly to disk is not supported by this implementation, use getInputStream instead");
        }

        public  void delete() throws IOException {
        }

        public  String getHeader(String headerName) {
            return part.getHeader(headerName);
        }

        public  Collection<String> getHeaders(String headerName) {
            return part.getHeaders(headerName);
        }

        public  Collection<String> getHeaderNames() {
            return part.getHeaderNames();
        }

        public String getSubmittedFileName() {
            return part.getSubmittedFileName();
        }

        private <T> Collection<T> toCollection(Iterator<T> i) {
            if ( i == null ) {
                return Collections.emptyList();
            } else {
                List<T> c = new ArrayList<T>();
                while(i.hasNext()) {
                    c.add(i.next());
                }
                return c;
            }
        }
    }
}