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POHow to handle delete in Google App Engine (Python)
 

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  1. POHow to handle delete in Google App Engine (Python)
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    <p>I'm a newbie programmer and new to Google App Engine and webapp2 etc. So this may be a very basic question.</p> <p>I am creating an application to store images into BlobStore. My model stores description, blob_key, image url and date.</p> <p>I am able to save everything, so that bit is okay. </p> <p>But now I want to create a delete button which will not only delete an item from the datastore, but also delete the image saved in the blobstore.</p> <p>I have created a DeleteHandler, and in the html I have a form, passing the key for the item I want to delete. In the DeleteHandler, I am using the posted key to delete the item from the datastore. I am also trying to use the key to use it delete the image saved in the blobstore.</p> <p>So far I'm getting a 404 on the delete form post, and even if I get past that, I'm not sure if my DeleteHandler is correct to handle the functionality I am looking for.</p> <p>Any help would be much appreciated..</p> <p>Main.py:</p> <pre><code>import os import urllib import webapp2 from google.appengine.ext.webapp import template from google.appengine.ext import blobstore from google.appengine.ext.webapp import blobstore_handlers from google.appengine.api import images #Models from google.appengine.ext import db class ImageItem(db.Model): description = db.StringProperty(required=True) img_url = db.StringProperty() blob_key = blobstore.BlobReferenceProperty() when = db.DateTimeProperty(auto_now_add=True) #Handlers (Views) class MainHandler(webapp2.RequestHandler): def get(self): upload_url = blobstore.create_upload_url('/upload') imgs = db.GqlQuery( 'SELECT * FROM ImageItem ' 'ORDER BY when DESC') imgs_dict = {'imgs': imgs} self.response.out.write( template.render( 'main.html',locals() ) ) class UploadHandler(blobstore_handlers.BlobstoreUploadHandler): def post(self): f = self.get_uploads('file')[0] # 'file' is file upload field in the form img =ImageItem(description=self.request.get('description')) img.blob_key = f.key() img.img_url = images.get_serving_url( f.key() ) img.put() self.redirect('/') class DeleteHandler(webapp2.RequestHandler): def post(self): key = self.request.get('k') item = db.get(key) images.delete( item.blob_key ) item.delete() self.response.out.write(key) #URL Routing happens here app = webapp2.WSGIApplication([('/', MainHandler), ('/upload', UploadHandler), ('/delete', DeleteHandler)], debug=True) </code></pre> <p>Main.html:</p> <pre><code>&lt;form action="{{upload_url}}" method="POST" enctype="multipart/form-data"&gt; &lt;p&gt; &lt;label for="file"&gt;Upload File&lt;/label&gt; &lt;input type="file" name="file" id="file"&gt; &lt;/p&gt; &lt;p&gt; &lt;label for="description"&gt;Description&lt;/label&gt; &lt;input type="text" id="description" name="description"&gt; &lt;/p&gt; &lt;input type="submit" name="submit" value="Submit"&gt; &lt;/form&gt; &lt;ul&gt; {% for i in imgs %} &lt;li&gt; &lt;img src="{{i.img_url}}=s400-c" alt=""&gt; {{i.description }} &lt;/li&gt; &lt;li&gt;{{i.when }}&lt;/li&gt; &lt;li&gt; &lt;form action="/delete" method="POST" enctype="multipart/form-data"&gt; &lt;input type="text" name="k" value="{{i.key}}" /&gt; &lt;input type="submit" value="delete"&gt; &lt;/form&gt; &lt;/li&gt; {% endfor %} &lt;/ul&gt; </code></pre>
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