AppEngine上动态加载BlobProperty图像

首先，我非常新的编码和自学成才的，所以模型/聋子的耳朵（但愿意学习！）AppEngine上动态加载BlobProperty图像

所以我保存的图像到的意见/ DOM秋天数据库作为blob（BlobProperty），现在试图为它们服务。

相关代码：（我拿出一吨为了便于阅读）

class Mentors(db.Model): 
    id = db.StringProperty() 
    mentor_id = db.StringProperty() 
    name = db.StringProperty() 
    img_file = db.BlobProperty()

class ImageHandler (webapp2.RequestHandler): 
    def get(self): 

    mentor_id=self.request.get('mentor_id') 
    mentor = db.GqlQuery("SELECT * FROM Mentors WHERE mentor_id = :1 LIMIT 1", mentor_id) 
    if mentor.img_file: 
     self.response.headers['Content-Type'] = "image/jpg" 
     self.response.out.write(mentor.img_file) 
    else: 
     self.error(404)

application = webapp2.WSGIApplication([ 
    routes.DomainRoute('medhack.prebacked.com', medhack_pages), 
    webapp2.Route(r'/', handler=HomepageHandler, name='home-main'), 
    webapp2.Route(r'/imageit', handler=ImageHandler, name='image-handler') 
    ], 
     debug=True)

class MedHackHandler(webapp2.RequestHandler): 
    def get(self, url="/"): 
     # ... bunch of code to serve template etc. 

     mentors_events = db.GqlQuery("SELECT * FROM Mentors_Events WHERE event_id = :1 ORDER BY mentor_type DESC, mentor_id ASC", current_event_id) 
     mentors = mentors_events

HTML：

{% for m in mentors %} 
     #here 'mentors' refers to mentors_event query, and 'mentor' refers to the mentors table above. 
     <img src="imageit?mentor_id={{m.mentor.mentor_id}}" alt="{{m.mentor.name}} headshot"/> 
{% endfor %}

它似乎imageit实际上没有被调用或路径错误，或者......我不知道。如此多的尝试和失败。

资源我做过尝试，但不明白：
https://developers.google.com/appengine/articles/python/serving_dynamic_images
show images on the templates of django using google app engine
https://sites.google.com/site/usfcomputerscience/storing-and-serving-images

这似乎是宕接近，但我无法弄清楚如何实施。需要一个“傻瓜”翻译。 How to load Blobproperty image in Google App Engine?

来源

2013-07-11 MrDunham