Add Python 3 version of Module 15 sample.

googlecodelabs · Mar 23, 2023 · 8997c2c · 8997c2c
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diff --git a/mod15b-blobstore/README.md b/mod15b-blobstore/README.md
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+# Module 15b - Usage of App Engine `blobstore` with Flask framework in Python 3
+
+This repo folder is the corresponding Python 3 version of the Module 15 app.
+
+- All files in this folder are identical to the _Python 2_ code in the [Module 15 repo folder](/mod15-blobstore) **except**:
+    1. `app.yaml` was modified for the Python 3 runtime.
+    1. `appengine_config.py` is unused and thus deleted.
+- The _Python 3_ version of the Module 15 app ([Module 15 repo folder](/mod15-blobstore)) features the use of [Blobstore handlers classes](https://cloud.google.com/appengine/docs/standard/python3/services/blobstore).
diff --git a/mod15b-blobstore/app.yaml b/mod15b-blobstore/app.yaml
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+runtime: python310
+app_engine_apis: true
diff --git a/mod15b-blobstore/main.py b/mod15b-blobstore/main.py
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+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import io
+from flask import Flask, abort, redirect, request
+from google.appengine.api import wrap_wsgi_app
+from google.appengine.ext import blobstore, ndb
+
+app = Flask(__name__)
+app.wsgi_app = wrap_wsgi_app(app.wsgi_app, use_deferred=True)
+
+
+class Visit(ndb.Model):
+    'Visit entity registers visitor IP address & timestamp'
+    visitor   = ndb.StringProperty()
+    timestamp = ndb.DateTimeProperty(auto_now_add=True)
+    blob_key = ndb.BlobKeyProperty()
+
+
+def store_visit(remote_addr, user_agent, upload_key):
+    'create new Visit entity in Datastore'
+    Visit(visitor='{}: {}'.format(remote_addr, user_agent),
+            file_blob = upload_key).put()
+
+
+def fetch_visits(limit):
+    'get most recent visits'
+    return Visit.query().order(-Visit.timestamp).fetch(limit)
+
+
+class UploadHandler(blobstore.BlobstoreUploadHandler):
+    'Upload blob (POST) handler'
+    def post(self):
+        uploads = self.get_uploads(request.environ)
+        blob_id = uploads[0].key() if uploads else None
+        store_visit(self.request.remote_addr, self.request.user_agent, blob_id)
+        return redirect('/', code=307)
+
+class ViewBlobHandler(blobstore.BlobstoreDownloadHandler):
+    'view uploaded blob (GET) handler'
+    def get(self, blob_key):
+        if not blobstore.get(blob_key):
+            return "Blobg key not found", 404
+        else:
+            headers = self.send_blob(request.environ, blob_key) 
+
+        # Prevent Flask from setting a default content-type.
+        # GAE sets it to a guessed type if the header is not set.
+            headers['Content-Type'] = None
+            return '', headers
+
+@app.route('/view_photo/<photo_key>')
+def view_photo(photo_key):
+    """View photo given a key."""
+    return ViewBlobHandler().get(photo_key)
+
+
+@app.route('/upload_photo', methods=['POST'])
+def upload_photo():
+    """Upload handler called by blobstore when a blob is uploaded in the test."""
+    return UploadHandler().post()
+
+@app.route('/', methods=['GET', 'POST'])
+def root():
+    'main application (GET/POST) handler'
+    context = {}
+    if request.method == 'GET':
+        context['upload_url'] = url_for('upload')
+    else:
+        context['visits'] = fetch_visits(10)
+    return render_template('index.html', **context)
diff --git a/mod15b-blobstore/requirements.txt b/mod15b-blobstore/requirements.txt
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+Flask==2.0.1
+appengine-python-standard>=1.0.0
diff --git a/mod15b-blobstore/templates/index.html b/mod15b-blobstore/templates/index.html
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+<!doctype html>
+<html>
+<head>
+<title>VisitMe Example</title>
+</head>
+<body>
+
+<h1>VisitMe example</h1>
+{% if upload_url %}
+
+<h3>Welcome... upload a file? (optional)</h3>
+<form action="{{ upload_url }}" method="POST" enctype="multipart/form-data">
+    <input type="file" name="file"><p></p>
+    <input type="submit"> <input type="submit" value="Skip">
+</form>
+
+{% else %}
+
+<h3>Last 10 visits</h3>
+<ul>
+{% for visit in visits %}
+<li>{{ visit.timestamp.ctime() }}
+    <i><code>
+    {% if visit.file_blob %}
+        (<a href="/view/{{ visit.file_blob }}" target="_blank">view</a>)
+    {% else %}
+        (none)
+    {% endif %}
+    </code></i>
+    from {{ visit.visitor }}
+</li>
+{% endfor %}
+</ul>
+
+{% endif %}
+
+</body>
+</html>