Added support for MongoDB

README_MONGO.md

@@ -0,0 +1,27 @@
+## Connecting a MongoDB Database
+
+You'll need access to a MongoDB instance. The below steps outline how to do this:
+
+1. Sign in to your IBM Cloud Console, and select the 'Create Resource' button in the top right of the page.
+2. Type 'MongoDB' in the search field and select 'Compose for MongoDB' under the 'Data & Analytics' section.
+3. Check that the name/region/organization/pricing fields are accurate.
+4. Select the 'Create' button in the botton left of the page.
+5. Return to the IBM Cloud dashboard and select the newly created service.
+6. In the sidebar on the left side of the page, select 'Service Credentials'
+7. Select the 'New Credential' button, and then the 'Add' button in the page that appears.
+
+You will also need to run `pip install -r requirements.txt` again to install the required [MongoDB driver](https://github.com/mongodb/mongo-python-driver).
+
+To prepare the application for use in a local environment, use the below steps. Otherwise, skip the steps to move on to deploying the application to IBM Cloud:
+
+1. Make a copy of the 'vcap-local.template.json' file (in the application root directory) as 'vcap-local.json' in the same directory.
+2. Copy the contents of the 'uri' field in the credentials generated from earlier into the field (replacing "MONGO_DATABASE_URI").
+3. Run the application using `python hello.py`.
+
+Before deploying the application, make sure that it builds successfully by running `python hello.py` from the root directory of the project (where this README document is located). If no errors are shown, run `cf push` to deploy the application. Once the deployment process completes, run `cf bind-service GetStartedPython [SERVICE_NAME]`, where [SERVICE_NAME] is the name of your MongoDB service. Finally, run `cf retage GetStartedPytohon`. Once this finishes, you can access the application using the URL provided in the output from the 'cf push' command from earlier.
+
+## Additional Notes on Changes
+
+The application may work with either Cloudant or MongoDB. However, if both services are available (and at most one is user-provided), **the application will default to MongoDB**. If both services are available as user-provided services, this behavior is **not** guaranteed, and the application may default to either service.
+
+When deployed on IBM Cloud, this application **does** require bound MongoDB services to have some permutation of 'mongodb' in the name. User-provided services (as created with the cf utility) are also acceptable.

hello.py

@@ -1,38 +1,99 @@
+###############################################################################
+# Copyright IBM Corporation 2018                                              #
+#                                                                             #
+# 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.                                              #
+###############################################################################
 from cloudant import Cloudant
 from flask import Flask, render_template, request, jsonify
 import atexit
 import os
 import json
+import ssl
+import re
+from pymongo import MongoClient
 
 app = Flask(__name__, static_url_path='')
 
 db_name = 'mydb'
+collection_name = 'mycollection' # MongoDB requires a collection name.
 client = None
 db = None
+vendor_name = None # Record DB vendor to determine which methods are used.
+
+# Allow for any service with some permutation of a vendor name to be used
+# (this is mostly to provide a general solution for user-provided services).
+mongo_re = re.compile(r'.*[Mm][Oo][Nn][Gg][Oo].*')
+cloudant_re = re.compile(r'.*[Cc][Ll][Oo][Uu][Dd][Aa][Nn][Tt].*')
 
 if 'VCAP_SERVICES' in os.environ:
     vcap = json.loads(os.getenv('VCAP_SERVICES'))
     print('Found VCAP_SERVICES')
-    if 'cloudantNoSQLDB' in vcap:
-        creds = vcap['cloudantNoSQLDB'][0]['credentials']
+
+    mongo_result = next(iter(filter(lambda key: mongo_re.search(key) != None, vcap)), None)
+    cloudant_result = next(iter(filter(lambda key: cloudant_re.search(key) != None, vcap)), None)
+    user_provided_result = next(iter(filter(lambda key: key == 'user-provided', vcap)), None)
+
+    # Allow for user-provided services to be used.
+    if user_provided_result:
+        if mongo_re.search(vcap[user_provided_result][0]['name']):
+            mongo_result = user_provided_result
+        elif cloudant_re.search(vcap[user_provided_result][0]['name']):
+            cloudant_result = user_provided_result
+
+    if mongo_result:
+        creds = vcap[mongo_result][0]['credentials']
+        uri = creds['uri']
+        client = MongoClient(uri, ssl_cert_reqs=ssl.CERT_NONE)
+        db = client[db_name][collection_name]
+        vendor_name = 'mongo'
+    elif cloudant_result:
+        creds = vcap[cloudant_result][0]['credentials']
         user = creds['username']
         password = creds['password']
         url = 'https://' + creds['host']
         client = Cloudant(user, password, url=url, connect=True)
         db = client.create_database(db_name, throw_on_exists=False)
+        vendor_name = 'cloudant'
+
 elif "CLOUDANT_URL" in os.environ:
     client = Cloudant(os.environ['CLOUDANT_USERNAME'], os.environ['CLOUDANT_PASSWORD'], url=os.environ['CLOUDANT_URL'], connect=True)
     db = client.create_database(db_name, throw_on_exists=False)
+    vendor_name = 'cloudant'
+
 elif os.path.isfile('vcap-local.json'):
     with open('vcap-local.json') as f:
         vcap = json.load(f)
         print('Found local VCAP_SERVICES')
-        creds = vcap['services']['cloudantNoSQLDB'][0]['credentials']
-        user = creds['username']
-        password = creds['password']
-        url = 'https://' + creds['host']
-        client = Cloudant(user, password, url=url, connect=True)
-        db = client.create_database(db_name, throw_on_exists=False)
+
+        mongo_result = next(iter(filter(lambda key: mongo_re.search(key) != None, vcap['services'])), None)
+        cloudant_result = next(iter(filter(lambda key: cloudant_re.search(key) != None, vcap['services'])), None)
+
+        if mongo_result:
+            #creds = vcap['services']['compose-for-mongodb'][0]['credentials']
+            creds = vcap['services'][mongo_result][0]['credentials']
+            uri = creds['uri']
+            client = MongoClient(uri, ssl_cert_reqs=ssl.CERT_NONE)
+            db = client[db_name][collection_name]
+            vendor_name = 'mongo'
+        elif cloudant_result:
+            #creds = vcap['services']['cloudantNoSQLDB'][0]['credentials']
+            creds = vcap['services'][cloudant_result][0]['credentials']
+            user = creds['username']
+            password = creds['password']
+            url = 'https://' + creds['host']
+            client = Cloudant(user, password, url=url, connect=True)
+            db = client.create_database(db_name, throw_on_exists=False)
+            vendor_name = 'cloudant'
 
 # On IBM Cloud Cloud Foundry, get the port number from the environment variable PORT
 # When running this app on the local machine, default the port to 8000
@@ -42,6 +103,12 @@
 def root():
     return app.send_static_file('index.html')
 
+def get_visitor_cloudant():
+    return list(map(lambda doc: doc['name'], db))
+
+def get_visitor_mongo():
+    return list(map(lambda doc: doc['name'], db.find(projection={"_id": False, "count": False})))
+
 # /* Endpoint to greet and add a new visitor to database.
 # * Send a POST request to localhost:8000/api/visitors with body
 # * {
@@ -51,11 +118,21 @@ def root():
 @app.route('/api/visitors', methods=['GET'])
 def get_visitor():
     if client:
-        return jsonify(list(map(lambda doc: doc['name'], db)))
+        # Call vendor-specific handler.
+        return jsonify(globals()['get_visitor_' + vendor_name]())
     else:
         print('No database')
         return jsonify([])
 
+def add_visitor_cloudant(data):
+    my_document = db.create_document(data)
+    data['_id'] = my_document['_id']
+    return data
+
+def add_visitor_mongo(data):
+    data['_id'] = str(db.insert_one(data).inserted_id)
+    return data
+
 # /**
 #  * Endpoint to get a JSON array of all the visitors in the database
 #  * REST API example:
@@ -72,8 +149,8 @@ def put_visitor():
     user = request.json['name']
     data = {'name':user}
     if client:
-        my_document = db.create_document(data)
-        data['_id'] = my_document['_id']
+        # Call vendor-specific handler.
+        data = globals()['add_visitor_' + vendor_name](data)
         return jsonify(data)
     else:
         print('No database')

requirements.txt

@@ -1,2 +1,3 @@
 Flask==0.12.2
 cloudant==2.4.0
+pymongo[tls]==3.7.0

vcap-local.template.json

@@ -9,6 +9,14 @@
           },
           "label": "cloudantNoSQLDB"
         }
+      ],
+      "compose-for-mongodb": [
+        {
+          "credentials": {
+            "uri": "MONGO_DATABASE_URI"
+          },
+          "label": "compose-for-mongodb"
+        }
       ]
     }
-  }
+}