title: api platform - Unable to generate an IRI for the item
body: <p>I'm starting with API Platform and I'm using the example entity "Foo":</p>
  
  <p>
  
  <pre><code>namespace AppBundle\Entity;
  
  use ApiPlatform\Core\Annotation\ApiResource;
  use Doctrine\ORM\Mapping as ORM;
  
  
  /**
   * Foo
   *
   * @ORM\Table(name="foo")
   * @ApiResource
   * @ORM\Entity
   */
  class Foo
  {
      /**
       * @var string
       *
       * @ORM\Column(name="bar", type="string", length=255, nullable=false)
       */
      private $bar;
  
      /**
       * @var integer
       *
       * @ORM\Column(name="id", type="integer")
       * @ORM\Id
       * @ORM\GeneratedValue(strategy="IDENTITY")
       */
      private $id;
  
  
  }
  </code></pre>
  
  <p>I succesfully see the new Entity in dashboard (See image):</p>
  
  <p><a href="https://i.stack.imgur.com/aQUj0.png" rel="noreferrer">API Platform Dhasboard</a></p>
  
  <p>And I had the following error when I try to get all Foo collection:</p>
  
  <pre><code>curl -X GET "http://127.0.0.1:8000/foos" -H "accept: application/json"
  
      {
    "type": "https://tools.ietf.org/html/rfc2616#section-10",
    "title": "An error occurred",
    "detail": "Unable to generate an IRI for the item of type \"AppBundle\\Entity\\Foo\"",
    "trace": [
      {
        "namespace": "",
        "short_class": "",
        "class": "",
        "type": "",
        "function": "",
        "file": "/home/xxxx/api/vendor/api-platform/core/src/Bridge/Symfony/Routing/IriConverter.php",
        "line": 107,
        "args": []
      },
  </code></pre>
  
  <p>I tried different formats and check the the routes too:</p>
  
  <pre><code> julian@js:~/xxxxx/api$ ./bin/console debug:router
   ------------------------------- -------- -------- ------ ----------------------------------- 
    Name                            Method   Scheme   Host   Path                               
   ------------------------------- -------- -------- ------ ----------------------------------- 
    _wdt                            ANY      ANY      ANY    /_wdt/{token}                      
    _profiler_home                  ANY      ANY      ANY    /_profiler/                        
    _profiler_search                ANY      ANY      ANY    /_profiler/search                  
    _profiler_search_bar            ANY      ANY      ANY    /_profiler/search_bar              
    _profiler_phpinfo               ANY      ANY      ANY    /_profiler/phpinfo                 
    _profiler_search_results        ANY      ANY      ANY    /_profiler/{token}/search/results  
    _profiler_open_file             ANY      ANY      ANY    /_profiler/open                    
    _profiler                       ANY      ANY      ANY    /_profiler/{token}                 
    _profiler_router                ANY      ANY      ANY    /_profiler/{token}/router          
    _profiler_exception             ANY      ANY      ANY    /_profiler/{token}/exception       
    _profiler_exception_css         ANY      ANY      ANY    /_profiler/{token}/exception.css   
    _twig_error_test                ANY      ANY      ANY    /_error/{code}.{_format}           
    api_entrypoint                  ANY      ANY      ANY    /{index}.{_format}                 
    api_doc                         ANY      ANY      ANY    /docs.{_format}                    
    api_jsonld_context              ANY      ANY      ANY    /contexts/{shortName}.{_format}            
    api_foos_get_collection         GET      ANY      ANY    /foos.{_format}                    
    api_foos_post_collection        POST     ANY      ANY    /foos.{_format}                    
    api_foos_get_item               GET      ANY      ANY    /foos/{id}.{_format}               
    api_foos_put_item               PUT      ANY      ANY    /foos/{id}.{_format}               
    api_foos_delete_item            DELETE   ANY      ANY    /foos/{id}.{_format}               
  
   ------------------------------- -------- -------- ------ ----------------------------------- 
  </code></pre>
  
  <p>It's possible what I need some special library in my server? What I'm doing wrong?</p>
  
  <p>Thanks in advance!</p>