Iron Router / Meteor - Publish information with username in url

I am relatively new to Meteor (especially Iron Router) and am stuck with the next release ...

I have a route that displays the details of a single post:

    this.route('singlePost',{
      path:'/posts/:_id',
      data:function(){
        return Posts.findOne(this.params._id);
      }
    });

      

        
        
        
      

    

This works great, but I would like to show the username for the owner of the post in the url, not the static path "/ posts /" like:

    this.route('singlePost',{
      path:'/:username/:_id',
      data:function(){
        return Posts.findOne(this.params._id);
      }
    });

      

        
        
        
      

    

The post object includes the owner's user ID but not the username (the username is in the Meteor.users collection).

When I try to set a route with two dynamic values ​​(username, post Id), the pathFor link disappears (I assume because it cannot find the "username" in the returned post object).

How can I get the route to recognize the username? I am guessing some search functionality for the Users collection, but I'm not sure when / where. Also, how can I check the route to make sure the message belongs to the correct username?

Edit - here is the code:

router.js

    Router.configure({
      layoutTemplate: 'layout',
      loadingTemplate: 'loading',
      waitOn:function(){
        return Meteor.subscribe('posts') && Meteor.subscribe('users');
      }
    });

    Router.map(function() {
      this.route('home', {
        path: '/',
        data:function(){
          Session.set('pageView','list');
          return Posts.find();
        }
      });
      this.route('singlePost',{
        path:'/:username/:_id',
        data:function(){
          Session.set('pageView','single');
          return Posts.findOne(this.params._id);
        }
      });
    });

    Router.onBeforeAction('loading');

      

        
        
        
      

    

home.html

    <template name="home">
      {{> postsList}}
    </template>

      

        
        
        
      

    

posts_list.html

    <template name="postsList">
      <ul>
        {{#each posts}}
          {{> postBlock}}
        {{/each}}
      </ul>
    </template>

      

        
        
        
      

    

single_post.html

    <template name="singlePost">
      {{> postBlock}}
    </template>

      

        
        
        
      

    

post_block.html

    <template name="postBlock">

      {{#if pageView "list"}}
        <li>
          <a href="{{pathFor 'singlePost'}}">{{title}}</a><br/>
          Author: {{username}}
        </li>
      {{/if}}

      {{#if pageView "single"}}
        <h1>{{title}}</h1>
        <p>{{description}}</p>
        <p>Author: {{username}}</p>
      {{/if}}
    </template>

      

        
        
        
      

    

post_block.js

    Template.postBlock.helpers({
      username:function(){
        var user = getUserInfo(this.owner);
        return user.username;
      },
      pageView:function(type){
        return Session.get('pageView') == type;
      }
    });

      

        
        
        
      

    

functions.js

    getUserInfo = function(id){
      return Meteor.users.findOne(id);
    }

      

        
        
        
      

    

The username is displayed correctly in both list and detail views, however I am unable to get the path reference for the username reference.