call third part y Rest service from aem as cloud using certificate

hi

after struggling  with this issue , i found the solution 

Solution overview:

1. Extract pfx information
2. Create system user.
3. Map the system user.
4. Add the certificate to this user.
5. Create Servlet that will run under that user.

Prerequisites

• Certificate file
• Know the certificate keystore password (some time call passphrase)

Step 1 - extract key alias from certificate

The certificate in our case is in pfx format.

Using java “keytool” we will extract the key alias from the keystore

keytool -v -list -keystore cert.pfx

you will be prompt for the pfx password

value of the “alias name” , we will use it later

step 2

create system user.

Navigate to http://localhost:4502/crx/explorer/index.jsp

Click “User Administration”

Click “login”. And give the admin credential

Then click “Create System User”

Give user id , in the path use  “/home/users/system”

Don’t forget to click the green V

Click “close”

Step 3 -  map

Go to http://localhost:4502/system/console/configMgr

Find Apache Sling Service User Mapper Service Amendment

Click on the +

On the service mapping you need to supply the domain (you can take it from the pom.xml )

Then “:” then user name and the permission needed

״nameoftheuserhere"=content-writer-service (in case you need to write to aem , use “content-writer-service”

Click “Save”

Step 4 – add certificate to user

Navigate to tools->security->users

http://localhost:4502/security/users.html

Find your user. “nameoftheuser”

Create new KeyStore and give it password (we won’t use this password now but log it)

Use “Add Private Key from Keystore File” option

New alias – free choice , I put the user name for better clarity

Upload the pfx file in “keyStoreFile” and set the password of the pfx

On the “private key alias “ use the alias that you extracted before ,  and private key password use the same as keystore file password

Step 5. – running the servlet with the user

import org.apache.sling.api.SlingHttpServletRequest;

import org.apache.sling.api.SlingHttpServletResponse;

import org.apache.sling.api.resource.ResourceResolver;

import org.apache.sling.api.resource.ResourceResolverFactory;

import org.apache.sling.api.servlets.SlingAllMethodsServlet;

import org.osgi.service.component.annotations.Component;

import org.osgi.service.component.annotations.Reference;

import javax.servlet.Servlet;

import javax.servlet.ServletException;

import java.io.IOException;

import java.util.HashMap;

import org.osgi.framework.Constants;

import holdings888.core.utils.HttpsClient;

@8220494(service = Servlet.class,

property = {

    Constants.SERVICE_DESCRIPTION + "=JSON Servlet to  api",

     "sling.servlet.paths=" + "/bin/readRules" })

public class RedirectionServlet extends SlingAllMethodsServlet {

    @3214626

    private ResourceResolverFactory resolverFactory;

    private static final long serialVersionUID = 1L;

    @9944223

    protected void doGet(final SlingHttpServletRequest req,

            final SlingHttpServletResponse resp) throws ServletException, IOException {

ResourceResolver resolver = null;

            HashMap<String, Object> param = new HashMap<>();

            param.put(ResourceResolverFactory.SUBSERVICE, "nameoftheuser");

            resolver = resolverFactory.getServiceResourceResolver(param);

       // make the call with any client implementation 

        String  res = _client.Get(http://urltoapi)