Mobile application architecture

Is there such a thing as architecture design for mobile applications?

Christos Matskas

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HelloI’m Christos

christosmatskas cmatskas https://cmatskas.com




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architectureˈɑːkɪtɛktʃə/noun: architecture1.the art or practice of designing and constructing buildings."schools of architecture and design“

• the style in which a building is designed and constructed, especially with regard to a specific period, place, or culture.plural noun: architectures"Georgian architecture" 2. the complex or carefully designed structure of something."the chemical architecture of the human brain"• the conceptual structure and logical organization of a computer or computer-based system.


What is Software Architecture?


Refactoring?


Refactoring?


Big Ball Of Mud ™



Confident?


Why does it matter?

• Quality• Performance• Maintainability


Refactoring


Speed


Cost


Mob App Development Platforms

3 MADPs for building apps:• Native• Web• Hybrid


Native DropBox


Hybrid

Uber


Mobile Web

Google Maps


Native Apps - Assessment

Pros• Best performance• Fast, fluid UI • Full access to the platform's capabilities• Monetization – App StoreCons• High cost of development• Updates require full deployment on each platform


Hybrid Apps - Assessment

Pros• Good performance but not as good as hybrid• Fast development cycle as it's easy to create cross platform

apps• Allows monetization as they can be deployed in the app storeCons• Occasionally connected Internet access is required• Updates require deployment on each platform• Mostly full compatibility through the use of plugins (not

100%)


Web Apps - AssessmentPros• Good performance - it's a web page• Very fast development cycle• Consistent UI across all platforms• Easy to deployCons• Very hard to monetize - no app store option• Requires internet access• Web browsers may have different behaviour and performance• No access to the underlying hardware issues


Development Tools

Native• xCode, Android Studio, Eclipse, Visual Studio etc

Native & Hybrid• Ionic, AppBuilder, Cordova, Silver, FuseTools,

Xamarin Studio etc

Platform agnostic tools• Sublime, Visual Studio Code, Web Developer tools


Architecture principles

Sound familiar?

• Meet best practices• Minimize costs• Minimize maintenance requirements• Usability• Extensibility


Separation of Concerns


Single Responsibility


Principle of Least Knoweldge


Don’t Repeat Yourself


No Bid Design Upfront (BDUF)


Composition over Inheritance


Suggestions

• Logical layers• No mixing of components in same layer• Strict vs relaxed layering• Abstraction for loose coupling• Don’t overload component functionality• Consistency of data formats• Abstract Cross-cutting code• Consistent naming conventions• Exception handling standards








Mobile Architecture Design


Authentication & Authorization• Occasionally connected scenarios • 3rd party authentication services• Authentication and authorization over a

virtual private network (VPN) • Security Model Differences


Caching

• Caching unnecessary data• Cached data in occasionally connected scenarios • Inappropriate cache locations and formats • Caching sensitive data in unencrypted form • Failing to choose an appropriate caching

technology• Failing to implement caching alltogether


Communications• Failing to protect sensitive data over the air (HTTPS anyone?)• Failing to secure web service communication• Failing to secure communication over a VPN • Performance impact of communication security on limited-bandwidth

connections (https compression)• Not managing limited-bandwidth connections efficiently • Not managing connections to multiple network services efficiently • Not designing to work with intermittent connectivity • Not considering connection costs or allowing users to manage

connections WiFi / 3-4G• Not designing to minimize power usage when running on battery power

(this relates to managing background tasks efficiently)• Failing to use the appropriate communication protocol


Configuration Management• Failing to restore configuration state after a reset. • Failing to consider configuration management synchronization

over the air (e.g. Windows has roaming settings)• Failing to consider configuration management synchronization

with the host PC (is the application truly x-plat?)• Choosing an inappropriate format for configuration information

(using a local db file when you could be using a simple json file to store the settings)

• Failing to protect sensitive configuration information (encrypting sensitive data is of major importance)

• Failing to consider the platform differences when using configuration settings


Data Access

• Data-access mechanisms that work with intermittent connectivity

• Database access performance (especially if the data is large)

• Navigating through large datasets when not required • Failing to consider appropriate replication technologies

and techniques • Failing to consider access to device database services• Failing to consider different authentication mechanisms• Failing to consider data integrity and consistency


Hardware - Devices

• Failing to consider device heterogeneity, such as screen size, CPU power and RAM

• Not presenting user-friendly error messages consistent with the platform

• Failure to consider the processing power of the device


Exception Management

• Not recovering application state after an exception • Revealing sensitive information to the end user • Not logging sufficient details about the exception • Using exceptions to control application flow


Logging

• Not considering remote logging instead of logging on the device (plenty of 3rd party services)

• Not considering how to access device logs • Not considering resource constraints when logging

(connectivity, service down etc)• Failing to protect sensitive information in the log files

(common error both in desktop/web and mobile apps)

• Not considering logging for monitoring user engagement and proactive bug fixing


Synchronization

• Failing to secure synchronization when communicating

• Failing to manage synchronization options over the air (wifi, 4g, both)

• Failing to manage synchronization interruptions • Failing to handle synchronization conflicts • Failing to consider merge replication where

appropriate • Failing to consider 3rd party services for managing

data synchronization


Testing

• Failing to implement comprehensive tests• Failing to appreciate debugging costs when

choosing to support multiple device types • Failing to design with debugging in mind; for

example, using emulators instead of the actual devices

• Failing to debug in all connection scenarios • Failing to consider automated testing frameworks

and associated costs


UI/UX

• Not considering the restricted UI form factor • Not considering the single window environment • Not considering that only one application can be running • Not designing a touch-screen or stylus-driven UI for

usability • Not including support for multiple screen sizes and

orientations • Not managing device reset and resume • Not considering the limited API and reduced range of UI

controls compared to the desktop


Security

• Failure to understand the exact security requirements

• Failure to adequately secure persisted application data

• Failure to secure all communications with 3rd party services

• Failure to capture and log what constitutes unusual or suspicious activity on a device

• Failure to protect against reverse engineering









Mobile Application?


Architecture Design?