The article represents different tools and framework that were found to be used in the android version of Instagram mobile app. Please give a shout if you disagree with one or more entries listed below.

Tools & Frameworks

Following represents a list of tools & frameworks, mostly, open-source that have been used to build android version of Instagram app:

Oauth signpost library is used to handle oAuth communication. Signpost is the easy and intuitive solution for signing HTTP messages on the Java platform such as Android in conformance with the OAuth Core 1.0a standard. Signpost exposes a minimalistic API designed for two purposes: Signing HTTP messages and requesting tokens from an OAuth service provider.

The article on this page explains on how to use OAuth Signpost API to authenticate and retrieve the data from OAuth Service Provider such as Google. A sample use case is to retrieve all of the contacts from your Google account and display on the screen for further processing. This is where OAuth-Signpost API would help. One could read more details on the Singpost author’s page at brainflush.wordpress.com.

HttpClientAndroidLib (Http Resources Handling)

HttpClientAndroidLib is simply a repackaging of HttpClient 4.3.1 for Android. The library simplifies the aspect related with handling Http requests and accessing HTTP resources on web. Instagram does have lot to do with accessing Http resources and this is where this library comes very handy.

MP4Parser is a set of Java API that could be used to parse MP4 files. MP4 (MPEG-4 Part 14) is a digital multimedia format most commonly used to store video and audio, but can also be used to store other data such as subtitles and still images. The ISOParser API, which is a part of the project, primarily provides a way to read and write the MP4 file structure. It is a low level tool dealing with the so called boxes but it is as well as dealing with structure like tracks and movies. One could check examples here for a quick start with ISOParser in their project.

This is one of the most widely used framework for processing JSON data. This suggests that data seems to be exchanged in JSON format (no surprises though given the widespread adoption of JSON as data exchange format). At the framework level, one could choose different models for processing JSON data such as following:

Streaming API for incremental parsing and generation. This is the best performing out of all three models.

Tree Model that provides mutable in-memory tree representation of JSON

Data binding converst JSON to and from POJOs. This is most convenient of all.

Android Cloud to Device Messaging (C2DM) is a service that helps in sending data from servers to Instagram app on Android devices. The service provides a simple, lightweight mechanism that servers can use to tell Instagram app to contact the server directly and fetch updated user data.

Custom Components

Following represents different custom components that were written to take care of some of the key functionality in the app: