Upload file to app engine and generate public url for dmprof visualizer.

tools/deep_memory_profiler/visualizer/app.py

+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import jinja2
+import os
+import services
+import urllib
+import webapp2
+
+from google.appengine.ext import blobstore
+from google.appengine.ext.webapp import blobstore_handlers
+
+
+JINJA_ENVIRONMENT = jinja2.Environment(
+  loader=jinja2.FileSystemLoader(os.path.dirname(__file__)),
+  extensions=['jinja2.ext.autoescape'])
+
+
+class MainPage(webapp2.RequestHandler):
+  """Show breakdown with received profiler-id and template-id. If nothing was
+  received, show blank page waiting user to upload file."""
+  def get(self):
+    page_template = JINJA_ENVIRONMENT.get_template('index.html')
+    upload_url = blobstore.create_upload_url('/upload')
+
+    # Get profiler id and template id from url query.
+    run_id = self.request.get('run_id')
+    tmpl_id = self.request.get('tmpl_id')
+
+    template_values = {'upload_url': upload_url}
+
+    if not run_id or not tmpl_id:
+      self.response.write(page_template.render(template_values))
+    else:
+      template_values['json'] = services.GetProfiler(run_id)
+      template_values['template'] = services.GetTemplate(tmpl_id)
+
+      # TODO(junjianx): Return error page when no json or template found.
+      self.response.write(page_template.render(template_values))
+
+
+class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):
+  """Handle file uploading with BlobstoreUploadHandler. BlobstoreUploadHandler
+  can deal with files overweighing size limitation within one HTTP connection so
+  that user can upload large json file."""
+  def post(self):
+    blob_info = self.get_uploads('file')[0]
+
+    run_id = services.CreateProfiler(blob_info)
+    default_key = services.CreateTemplates(blob_info)

[sullivan, 2013/09/20 13:59:51]

Reading the code, right now I think if there is no default_key, the Profile and
Templates will be created, and then services.CreateTemplates will raise an
exception and the user will get a 500 error. It would probably be better to give
the user a helpful response in this case. Also, should any data be stored in the
datastore if there is no default_key (probably a sign that there's something
wrong with the data, isn't it?)

[junjianx, 2013/09/24 05:53:53]

Done.
I think validation of uploaded file should be done separately. Temporarily, only
default_template attribute is validated in main logic. 

+
+    # Jump to new graph page using default template.
+    query_params = {
+      'run_id': run_id,
+      'tmpl_id': default_key.urlsafe()
+    }
+    # TODO(junjianx): Return error page when no default template indicated.
+    self.redirect('/?' + urllib.urlencode(query_params))
+
+
+application = webapp2.WSGIApplication([
+  ('/', MainPage),
+  ('/upload', UploadHandler)
+], debug=True)