title: Appengine create and export yaml file
body: <p>I´m having trouble in creating a file and export to .yaml.
  I´m using Google App Engine with Python 2.5.
  Don´t understand the Yaml doc´s, it makes me confused.</p>
  
  <p>What i want is to create a file and save it. It´s necessary to get entities from Models.</p>
  
  <pre><code>class SaveYAML(webapp.RequestHandler):
      def post(self):
          user = db.Query(models.User)
          user = user.filter('user =', users.get_current_user())
          users = user.fetch(limit = 1)
  
          for user in users:
              print(user.name, user.adress, user.phone, user.city)
  
          self.response.headers['Content-Type'] = 'application/yaml'
          self.response.headers['Content-Disposition'] = 'filename = myYaml.yaml' 
  </code></pre>
  
  <p>With this snippet i can view in a browser, when i click in a button the information retrieved from models.
  Maybe it´s because of print method, but it doesn´t create a file
  But when i upload my app to Google App Engine it doesn´t show the same info. It shows only 'Status 200 Ok'.</p>
  
  <p>Can someone point me in the right direction?
  Do i have to import pyyaml library?</p>
  
  <p>I changed some code to:</p>
  
  <pre><code>print(yaml.dump(user, sys.stdout))
  </code></pre>
  
  <p>and the result was this in a browser:</p>
  
  <pre><code>- !!binary |
    /9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRofHh0a
    HBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/2wBDAQkJCQwLDBgNDRgyIRwhMjIyMjIy
    MjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjIyMjL/wAARCAAnACgDASIA
    AhEBAxEB/8QAHwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQA
    AAF9AQIDAAQRBRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3
    ODk6Q0RFRkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWm
    p6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEA
    AwEBAQEBAQEBAQAAAAAAAAECAwQFBgcICQoL/8QAtREAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSEx
    BhJBUQdhcRMiMoEIFEKRobHBCSMzUvAVYnLRChYkNOEl8RcYGRomJygpKjU2Nzg5OkNERUZHSElK
    U1RVVldYWVpjZGVmZ2hpanN0dXZ3eHl6goOEhYaHiImKkpOUlZaXmJmaoqOkpaanqKmqsrO0tba3
    uLm6wsPExcbHyMnK0tPU1dbX2Nna4uPk5ebn6Onq8vP09fb3+Pn6/9oADAMBAAIRAxEAPwD2WxvX
    h8zzNxhEjgk87fmPI9R6+lbKsGUMpBBGQR3rAhKxRTyOyqglck9Mc1nX/iVdGb7JZr9qnlBMcCc7
    T3Psvqeg7elAG7rmv6f4esGu7+ZUXoq5+Zz6Cuc8I+ItS8X6pLqK/wCiaXbKYhbjkyuRnJOOw7Cs
    jXvC8epW0Ta5IdR1O7dTFDG5Eaeirj1xy3oG6dK7rQdGtvDuiQ2FuoCRLl2A+8x5J/OtFKKhtqZu
    MnPfQoajeXDeLtMtICfLG55cNj5Qp6/iVoqLQAb/AMQalqLDKoRBGf1NFceGqOpT9o+t/u6fgdNZ
    csuTt/T/ABMGTVb/AFu4NroW37H5rG5upEOB83AUHr9O/r2roI9DtfDsUt1GHmaTBmmc5kLdBz6d
    sdB246XrcIlpKgXaPNOOBz8wqtqkFxreoRWSKRp0ZJuJM43H+6PXPTPufw6DIytCk/0ttauQv2d8
    rbr3Ck8yKPQ9AP7oB7muk1m+S00We5VgVKfKQeDVe80yO3+eFAIO6gf6v6f7P8vpXP63lfsmnbnM
    c8ykoozhepIrlxk3Gi1Hd6L1ehrQinUV9lr92p0PhezNnoMAcfvJcyv9W5orWhKGFDEQU2jaR0xR
    XRCKhFRjsjOUnJuT6mALmOIyxujHMjE4478d6kXUUXIHnAZ/vH8e9FFUIY2roq8+dn03HH86wYby
    3bxFLduji3twYolxk5IyT196KKTipWv0GpNXsbNv4gtYZ/kEgjY/MpXoe5HP/wCv+ZRRTEf/2Q==
  _name: !!python/unicode 'Ana Ferreira'
  _parent: null
  _parent_key: null
  _adress: !!python/unicode 'Porto'
  _phone: !!python/unicode '1234569789'
  _user: *id002
  None
  Status: 200 OK
  Cache-Control: no-cache
  Content-Type: text/yaml
  Content-Disposition: filename = myYaml.yaml
  Expires: Fri, 01 Jan 1990 00:00:00 GMT
  Content-Length: 0
  </code></pre>
  
  <p>Changed the code, but the data is only presented by browser.</p>