Handle PDF Submission
In this part we will create a simple servlet that runs on AEM Publish to handle the PDF submission from Acrobat/Reader. This servlet will in turn, make an HTTP POST request to a servlet running in an AEM author instanceresponsible for saving the submitted data as a nt:file
node in AEM Author’s repository.
The following is the code of the servlet which handles the PDF submission. In this servlet we make a POST call to a servlet mounted on /bin/startworkflow in a AEM Author instance. This servlet saves the form data in the AEM Author’s repository.
AEM Publish servlet
package com.aemforms.handlepdfsubmission.core.servlets;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.Servlet;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingAllMethodsServlet;
import org.osgi.service.component.annotations.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@Component(
service={Servlet.class},
property={
"sling.servlet.methods=post",
"sling.servlet.paths=/bin/handlepdfsubmit"
}
)
public class HandlePDFSubmission extends SlingAllMethodsServlet {
private static Logger logger = LoggerFactory.getLogger(HandlePDFSubmission.class);
protected void doPost(SlingHttpServletRequest request,SlingHttpServletResponse response) {
ByteArrayOutputStream result = new ByteArrayOutputStream();
try {
ServletInputStream is = request.getInputStream();
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) != -1) {
result.write(buffer, 0, length);
}
logger.debug(result.toString(StandardCharsets.UTF_8.name()));
} catch (IOException e1) {
logger.error("An error occurred", e1);
}
HttpPost postReq = new HttpPost("http://localhost:4502/bin/startworkflow");
// This is the base64 encoding of the admin credetnials. This call should be made over HTTPS in production scenarios to avoid leaking credentials.
postReq.addHeader("Authorization", "Basic YWRtaW46YWRtaW4=");
CloseableHttpClient httpClient = HttpClients.createDefault();
List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
logger.debug("added url parameters");
try {
urlParameters.add(new BasicNameValuePair("xmlData", result.toString(StandardCharsets.UTF_8.name())));
postReq.setEntity(new UrlEncodedFormEntity(urlParameters));
httpClient.execute(postReq);
logger.debug("Sent request to author instance");
ServletOutputStream sout = response.getOutputStream();
sout.print("Your form was successfully submitted");
} catch (UnsupportedEncodingException | ClientProtocolException | IOException e) {
logger.error("An error occurred", e)
}
}
AEM Author servlet
The next step is to store the submitted data in the AEM Author’s repository. The servlet mounted on /bin/startworkflow
saves the submitted data.
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.UUID;
import javax.jcr.Binary;
import javax.jcr.Node;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.servlet.Servlet;
import javax.servlet.ServletOutputStream;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.servlets.SlingAllMethodsServlet;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.mergeandfuse.getserviceuserresolver.GetResolver;
@Component(
service = {Servlet.class},
property = {
"sling.servlet.methods=get",
"sling.servlet.paths=/bin/startworkflow"
}
)
public class StartWorkflow extends SlingAllMethodsServlet {
private static Logger logger = LoggerFactory.getLogger(StartWorkflow.class);
@Reference
private GetResolver getResolver;
protected void doPost(SlingHttpServletRequest request, SlingHttpServletResponse response) {
String xmlData = null;
System.out.println("in start workflow");
response.setContentType("text/html;charset=UTF-8");
if (request.getParameter("xmlData") != null) {
logger.debug("The form was submitted from Acrobat/Reader");
xmlData = request.getParameter("xmlData");
System.out.println("in start workflow" + xmlData);
} else {
logger.debug("Mobile Form submission");
StringBuffer stringBuffer = new StringBuffer();
String line = null;
try {
InputStreamReader isReader = new InputStreamReader(request.getInputStream(), "UTF-8");
BufferedReader reader = new BufferedReader(isReader);
while ((line = reader.readLine()) != null)
stringBuffer.append(line);
} catch (Exception e) {
logger.debug("Error" + e.getMessage());
}
xmlData = new String(stringBuffer);
}
Resource r = getResolver.getFormsServiceResolver().getResource("/content/pdfsubmissions");
Session session = r.getResourceResolver().adaptTo(Session.class);
logger.debug("Got reosurce pdfsubmissions" + r.getPath());
UUID uidName = UUID.randomUUID();
Node xmlDataFilesNode = r.adaptTo(Node.class);
InputStream is = new ByteArrayInputStream(xmlData.getBytes());
Binary binary;
try {
Node xmlFileNode = xmlDataFilesNode.addNode(uidName.toString(), "nt:file");
logger.debug("Added nt file node");
Node jcrContent = xmlFileNode.addNode("jcr:content", "nt:resource");
logger.debug("Added jcr content");
binary = session.getValueFactory().createBinary(is);
jcrContent.setProperty("jcr:data", binary);
session.save();
} catch (RepositoryException e) {
logger.error("Unable to store data to JCR", e);
}
response.setContentType("text/plain;charset=UTF-8");
try {
ServletOutputStream sout = response.getOutputStream();
sout.print("Your form was successfully submitted");
} catch (IOException e) {
logger.error("Unable write response", e);
}
}
}
An AEM workflow launcher is configured to trigger every time a new resource of type nt:file
is created under the /content/pdfsubmissions
node. This workflow will create non-interactive or a static PDF by merging the submitted data with the xdp template. The generated pdf is then assigned to a user for review and approval.
To store the submitted data under /content/pdfsubmissions
node, we make use of GetResolver
OSGi service allows us to save the submitted data using the fd-service
system user which is available in every AEM Forms installation.