Category Archives: Open Source

Making of the Bazaarvoice SDK for Windows Phone 8

A page displaying item name, item information, and a list of reviews.

Hi, my name is Ralph Pina, I am a Summer ’13 intern and UT-Austin Computer Science student. During this summer I had the privilege of working with another intern, Devin Carr, on Bazaarvoice’s .NET SDK for Windows Phone 8 and Windows 8 Store apps. Our goal was to provide convenient access to our Conversations API and make the app development experience even better. We want our customers’ developers to spend more time figuring out how to make better use of the data in our network and innovating on ways to increase engagement with their brands, products, and services.

We currently provide SDKs for many other platforms including iOS, Android, so moving to cover the third largest mobile platform was a natural extension. As for Windows 8 Store apps, they are not as numerous or popular as traditional Windows Desktop apps, but as the install base for Windows 8+ devices grows, and developers get more accustomed to working with a touch interface on all their devices, their numbers should increase. This will provide an opportunity for first movers to grab a spot in million (billions?) of user’s Start Screen. We’ve got your back.

We tried to implement best practices in our development. Below are some of the technical challenges we experienced:

  • Networking: we used the newly ported Microsoft HttpClient. This is the most popular client in other .NET platforms and Microsoft is actively working to optimize it for Windows Phone. Our first implementation used the RestSharp library, a popular, open source Http client. However, like the Apache HttpClient in Android, this library loaded all data into a byte array before sending. While Windows Phone 8 has a higher max heap size for apps than Android, there is still a limit you may cross with a large image or video. Switching to HttpClient did not completely solve our problems however. While in other .NET platforms the library will buffer and stream content, this seems to be a limitation for Windows Phone. However, we hope this changes in the near future.
  • The getting started .NET app walks a developer through the installation of the SDK and how to make a simple http request and dump the JSON response on the screen.Windows Phone does not have a native JSON library available, so we used the Newton JSON.NET library. I especially like the array syntax to access items in the JSON hierarchy: for example JSONObj[“tag1”][“tag2”][“tag3”] will access a property named “tag3” which is inside the JSON object named “tag2”, which is itself inside the JSON object named “tag1”, etc, etc.

So you say there are better ways of doing this, or you want a specific implementation for your enterprise to use across various apps/brands/divisions? You are in luck! Our .NET SDK is open sourced and can be found on GitHub: https://github.com/bazaarvoice/bv-.net-sdk. So head over, hack it, maybe even submit a pull request to lay your claim to glory. While you are in GitHub, browse all the other awesome repos we’ve open sourced over the years.

Below I have included some screenshots of a couple of sample apps that demonstrate how to use the .NET SDK to submit and display sample data from our API.

A review details page using the title, user nickname, data, image, and review text.A example of a product page showing ratings.An example of a review submission page

Cheers,
Ralph Pina

Project Lassie: who let the dog out!

The Bazaarvoice Platform Infrastructure Team recently open sourced project Lassie. Lassie is a Java library that can manipulate the new DataDog screenboards. The Lassie library can create, get, update, and delete the DataDog screenboards via the REST API.

We use DataDog across various teams to collect metrics at both a system-wide and application level to give our teams a clearer view of what’s happening across all environments.

The project was developed by a Bazaarvoice summer intern, Mykal Thomas. Mykal is a senior at Georgia Tech.

Check out the Github for more information: https://github.com/bazaarvoice/lassie

Documentation for DataDog’s Screenboard API: http://docs.datadoghq.com/api/screenboards/

Jolt released to the world

We are pleased to announce a new open source contribution, a Java based JSON to JSON transformation tool named Jolt.

Jolt grew out of a BV Platform API project to migrate the backend from Solr/MySql to Cassandra/ElasticSearch.  As such, we were going to be doing a lot of data transformations from the new ElasticSearch JSON format to the BV Platform API JSON format.

Prior to Jolt, there were 3 general strategies for doing JSON to JSON transforms :

  1. Convert to XML, use XSLT, convert back to JSON
  2. Use your input JSON and a template language to build your output JSON
  3. Write custom code

Those options were rather unpalatable, so we went with option “4”, write reusable custom code.

The key insight was that there are actually separable concerns when doing a transform, and that part of the reason the XSLT or template approaches are unpalatable, is that they force you to deal with them all together.

Jolt tackles each separate concern individually :

  1. Identify the pieces of the input data that you care about and place them in the output JSON
    • Jolt provides a transform, “shift”, that has its own JSON based declarative DSL (domain specific language)
  2. Make sure the output JSON looks correct ( apply defaults to the output JSON )
    • Jolt provides a transform, “default”, with its own JSON based declarative DSL
  3. Handle all the JSON text formatting (comma, closing curly brackets etc)
    • Jolt operates on “hydrated” JSON data (Map<String,Object> and List<Object>) and leverages the Jackson library to handle serialization / JSON text formatting
  4. Verify the transform for data and format correctness
    • Jolt provides a test tool called Diffy so that you can unit test your transforms for data and format correctness
    • For format correctness, this is not as good of an answer as an xml dtd is, but you could pull in the JSON schema if you wanted
  5. Perform arbitrary custom data manipulations like adding fields together or performing date conversions
    • Jolt provides an interface where you can implement your own custom logic to be run in series with the other transforms

The code is now available at Github, and jar artifacts are now being published to Maven central.