Design a Picture-Sharing System - System Design

In the present day, the need for good tools to exchange and organize images has never been this much higher. As for social networking, e-shopping, personal branding, and many other related purposes, users anticipate that the sites they visit provide them with fast and dependable environments with or without loads of images that enable them to interact with these images in many ways they possibly can. Thus, this article aims to explore the key aspects of designing and deploying a picture-sharing system that would fulfill these requirements.

Requirements of a Picture-Sharing System

1. Functional Requirements of a Picture-Sharing System

• User Management:
  • Authentication: Users should be able to sign up and sign in using their email and password or they should be able to use OAuth from social sites.
  • Authorization: Perform users’ management: define their types (admin, user) and privileges (upload, edit profile information, delete comments).
  • User Profiles: Collect the user’s details such as; username, email, and even the profile picture.
• Image Upload and Storage:
  • Upload Service: Safe uploading of images, file formats allowed (JPEG, PNG).
  • Metadata Management: Save some information such as the time the image was uploaded, the user’s ID, tags, and a brief description of the picture.
  • Security: Sanitize the files uploaded to avoid containing bad content, and limit the usage to avoid over-usage by users.
• Image Processing:
  • Resizing and Compression: Ability to respond to images, for example, the size of images, how many images on one page, and resize them for all view ports such as thumbnails, and full-size.
  • Thumbnail Generation: This way you need to generate thumbnails to make the loading time more efficient on the image grids.
  • Quality Control: Ensure enlargement and or reduction do not compromise the quality of the image.
• User Interaction:
  • Likes and Comments: Provide the functionality to let the users like images and offer them a chance to comment on the images.
  • Sharing: Make it easy for the users to share images either by a direct link or on their social media pages.
  • Notifications: Alert your users when they have been liked, commented on or have shared something.

2. Non-Functional Requirements of a Picture-Sharing System

• Performance:
  • Fast Loading Times: Front end and back end must be properly coded to make sure images are displayed in a fast manner in mobile, tablets, and laptops.
  • Responsive UI: It is important that the interaction and the page organization facilitate free-flowing access even at the busiest of times.
  • Scalability: Support more numbers of users and images without any problem in performances.
• Security:
  • Data Encryption: Secure all user data along with images when transfering through the web and when stored in the database.
  • Access Control: Speaking about security, it is required to apply role based access control (RBAC) to minimize the access to the critical operations and information.
  • Secure APIs: Authenticating: Use HTTPS and API keys to authenticate the API and the subsequent requests.
• Reliability:
  • High Availability: Minimize downtime through fault-tolerant architecture and redundancy.
  • Backup and Recovery: Regularly back up data and implement disaster recovery procedures.
• Usability:
  • Intuitive Interface: Design a user-friendly interface with clear navigation and minimal learning curve.
  • Accessibility: Ensure the platform is accessible to users with disabilities, following WCAG guidelines.

Use Case Diagram of a Picture-Sharing System

• Identify Actors: Define who uses/operates the system (for instance, the users and/or the administrators).
• Identify Use Cases: Enumerate all the aspects offered by the system (e. g. registration, creation of content materials).
• Draw Diagram: Draw actors as well as use cases as diagrams on the diagramming tool and join them with lines.

Use Case Diagram illustrating interactions between users and the system:

Capacity Estimation of a Picture-Sharing System

Behavior modeling is vital to define the capability of the photo-sharing system, where the necessary data is expected to be stored and the loads to be withstood by the systems. This includes predicting the traffic and storage to acquire the relevant parts and supplies.

• User Base: Initial estimation of 10,000 users, scaling to 100,000 over 1 year.
• Image Uploads: Expectation of 1 million images uploaded per month.
• Traffic: Peak load estimation of 1,000 concurrent users.

Predicting capacity is a vital process that needs to be carried out when developing a picture sharing system with the aim of arriving at a system that would be efficient in handling the current and future workload. First, a theoretical number of basic users is 10 thousand, and the expected increase to 100 thousand per year will also allow you to determine further development plans and the necessary infrastructure.

High Level Design of a Picture-Sharing System

The high-level design provides an overview of the system architecture, showing major components and their interactions. This helps in understanding the system’s structure and the flow of data between components.

1. Architecture Overview

The architecture of the picture-sharing system includes the following components:

1. User
   • Interacts with the system through the frontend.
   • Uploads pictures, views pictures, comments, likes, and shares.
2. Frontend
   • Provides the user interface for interacting with the system.
   • Handles user authentication and authorization.
   • Sends requests to the backend for data processing and retrieval.
3. Backend
   • Processes user requests and performs business logic.
   • Handles picture uploads, comments, likes, and shares.
   • Interacts with the database for data storage and retrieval.
   • Communicates with the notification service and analytics service.
4. Notification Service
   • Sends notifications to users about activities related to their pictures (likes, comments, shares).
   • Can use push notifications, emails, or in-app notifications.
5. Analytics Service
   • Collects and analyzes data related to user interactions with pictures.
   • Provides insights such as popular pictures, user engagement metrics, and system performance.

2. Entity-Relationship (E-R) Diagram

The E-R diagram for the picture-sharing system includes the following entities and relationships:

1. User
   • Attributes: UserID (PK), Username, Email, Password, ProfilePicture
2. Picture
   • Attributes: PictureID (PK), UserID (FK), ImageURL, UploadDate, Description
3. Comment
   • Attributes: CommentID (PK), PictureID (FK), UserID (FK), CommentText, CommentDate
4. Like
   • Attributes: LikeID (PK), PictureID (FK), UserID (FK), LikeDate
5. Share
   • Attributes: ShareID (PK), PictureID (FK), UserID (FK), ShareDate
6. Notification
   • Attributes: NotificationID (PK), UserID (FK), Message, NotificationDate, Status

A high-level architecture diagram would illustrate the components and their interactions:

1. User Interface (Frontend)
   • Users interact with the system through web/mobile apps.
2. Backend Services
   • API Gateway: Manages incoming requests and routes them to appropriate services.
   • User Service: Manages user-related functionalities (authentication, profile management).
   • Picture Service: Handles picture uploads, retrievals, and interactions (comments, likes, shares).
   • Notification Service: Sends notifications to users.
   • Analytics Service: Collects and analyzes user interaction data.
3. Database
   • Relational Database: Stores user data, picture metadata, comments, likes, shares, and notifications.
   • Cloud Storage: Stores the actual image files.
4. External Services
   • Notification Service Providers: Push notifications, email services.
   • Analytics Platforms: Data processing and visualization tools.

This high-level design of a picture-sharing system outlines the key components, their interactions, and the database structure necessary to support the system's functionality. The system is designed to handle user interactions, picture management, notifications, and analytics in a scalable and efficient manner.

Low Level Design of a Picture-Sharing System

The low-level design comes up with detailed written information of the various elements of a given system and especially includes information on data structures, algorithms, and the flow of work between components. This makes it easier for the developers to put up and manage the system.

1. User Service:

• Authentication: OAuth 2.0 for secure login.
• Database Schema:
  • Users Table: user_id (PK), username, email, password_hash, profile_pic_url.
• APIs:
  • POST /register
  • POST /login
  • GET /user/{id}

2. Image Upload Service:

• File Validation: Check file format, size limits.
• Database Schema:
  • Images Table: image_id (PK), uploader_id (FK), upload_time, original_url, metadata.
• APIs:
  • POST /upload
  • GET /images/{id}

3. Image Processing Service:

• Technologies: AWS Lambda, OpenCV for image processing.
• Tasks: Resize, compress, generate thumbnails.
• Event Handling: Triggered by image upload events.

4. Content Delivery Service:

• CDN Integration: AWS CloudFront or similar service.
• Cache Management: Ensure frequently accessed images are cached.

5. Notification Service:

• Real-time Notifications: WebSockets or Firebase Cloud Messaging.
• Email Notifications: SendGrid or AWS SES.

6. Search Service:

• Indexing: Elasticsearch for indexing image metadata.
• APIs: GET /search?query={keywords}

Interaction Flow of a Picture-Sharing System

1. User Registration Flow:

• User submits registration form via Web/Mobile Application.
• API Gateway forwards request to User Service.
• User Service validates and stores user data in User Database.
• User Service returns success message to client.

2. Image Upload Flow:

• User uploads image via Web/Mobile Application.
• API Gateway forwards request to Image Upload Service.
• Image Upload Service validates and stores image in Cloud Storage.
• Metadata is saved in Image Metadata Database.
• Image Processing Service is triggered for further processing.

3. Image Processing Flow:

• Image Processing Service receives event and processes the image.
• Resized images and thumbnails are stored back in Cloud Storage.
• Metadata is updated in Image Metadata Database.
• Notification Service informs the user of successful upload and processing.

4. Image Delivery Flow:

• User requests to view an image.
• API Gateway forwards request to Content Delivery Service.
• Content Delivery Service retrieves image from CDN/Cloud Storage.
• Image and metadata are sent to the client.

5. User Interaction Flow:

• User likes/comments on an image.
• API Gateway forwards request to Interaction Service.
• Interaction Service updates Comment and Interaction Database.
• Notification Service sends real-time notification to the image uploader.

6. Search Flow:

• User submits a search query.
• API Gateway forwards request to Search Service.
• Search Service queries Elasticsearch and retrieves results.
• Results are sent back to the client.

Database Design of a Picture-Sharing System

1. User Database:

CREATE TABLE users ( user_id SERIAL PRIMARY KEY, username VARCHAR(50) NOT NULL, email VARCHAR(100) UNIQUE NOT NULL, password_hash TEXT NOT NULL, profile_pic_url TEXT );

2. Image Metadata Database:

CREATE TABLE images ( image_id SERIAL PRIMARY KEY, uploader_id INT REFERENCES users(user_id), upload_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP, original_url TEXT NOT NULL, metadata JSONB );

3. Comment and Interaction Database:

CREATE TABLE interactions ( interaction_id SERIAL PRIMARY KEY, user_id INT REFERENCES users(user_id), image_id INT REFERENCES images(image_id), type VARCHAR(20), -- 'like', 'comment' comment TEXT, interaction_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP );

Important Components of the Picture-Sharing System:

1. Client-side Applications:

• Web Application: Provides the user interface for desktop users.
• Mobile Application: Provides the user interface for mobile users.

2. API Gateway:

• Acts as the entry point for all client requests.
• Routes requests to appropriate microservices.

3. Architecture Overview:

• Microservices-based architecture diagram showing components like user management, image processing, and content delivery.
• Client-side (web and mobile) interfaces interacting with backend services via APIs.

4. Server-side Components:

• API Gateway: Client requests coming through it while it forwards it to the right micro services.
• Image Processing Services: Services for rotation, scaling, and creating thumbnails outside the application.
• Storage Services: Integration of cloud computing strategy (e.g. Amazon S3) for scalability of the image storage.

5. Microservices:

• User Service: Manages user authentication, authorization, and profiles.
• Image Upload Service: Handles image uploads, storage, and metadata management.
• Image Processing Service: Resizes, compresses, and generates thumbnails for uploaded images.
• Content Delivery Service: Integrates with a CDN for fast image delivery.
• Notification Service: Manages real-time and email notifications.
• Search Service: Manages indexing and searching of images and metadata.

6. Databases:

• User Database: Stores user profiles and authentication data.
• Image Metadata Database: Stores metadata for uploaded images.
• Comment and Interaction Database: Stores likes, comments, and user interactions.

7. Storage:

Cloud Storage (e.g., Amazon S3): Stores the actual image files.

8. Load Balancer:

Distributes incoming traffic across multiple instances of microservices to ensure high availability and reliability.

Microservices and APIs Used in the Picture-Sharing System

When implementing the photo-sharing system, you will have to include the concept of using microservices in the system as it increases scalability, maintainability and flexibility in the system. Every microservice is tightly focused on one business process, and as a result, it can be built, released, and grew separately.

• Authentication Service:
  • OAuth integration for secure user authentication and authorization.
  • Token-based authentication mechanism for API requests.
• Image Processing Service:
  • AWS Lambda functions for on-demand image processing, triggered by upload events.
  • Integration with image processing libraries (e.g., OpenCV) for resizing and compression.
• Storage Service:
  • Utilization of Amazon S3 for scalable and durable storage of uploaded images.
  • Implementation of lifecycle policies to manage storage costs and optimize performance.

Scalability of the Picture-Sharing System

The efficiency of the photo-sharing system should be scalable, it means that the system has to be able to work with higher loads and demands. Below are some of the ways described to achieve this:

• Horizontal Scaling:
  • Load balancing across multiple instances of microservices to distribute traffic evenly.
  • Auto-scaling configurations based on CPU utilization or request rate to handle spikes in traffic.
• Vertical Scaling:
  • Upgrading server instances or increasing resources (CPU, memory) for individual microservices to improve performance.
  • Database: Upgrade the database server to a more powerful machine to handle more queries and larger datasets.
  • Application Servers: Enhance the resources of the application servers to improve performance under heavy loads.
• Auto-scaling:
  • AWS EC2 Auto Scaling policies configured to automatically adjust capacity based on predefined metrics (e.g., CPU utilization, network traffic).

Conclusion

Developing a picture sharing system requires the integration of numerous elements of the technology and architecture frameworks, all of which are significant to the System Quality, and hence the overall image and performance of the final product. Moreover, it is crucial to attend to functional requirements such as users’ list, images’ processing, and contents’ delivery, as well as non-functional ones like application’s performance increase, security and sustainable scalability to build the strong platform that would fulfil user expectations and correspond to new expectations in future.