Overview

• This repository serves as a Shared Backend for Symptom Checker application.

• Shared Backend is responsible for handling :

  • ICD API authentication for symptoms-related diagnosis data,
  • connection to MongoDB,
  • authentication and authorization of users and admins,
  • authentication of user requests and admin requests,
  • communication with ICD API for user's symptoms-related diagnosis data,
  • communication with MongoDB to retrieve specific data for admin,
  • cleaning and transformation of JSON response from ICD API for relevancy to MongoDB (mongoose ODM) schema,
  • encryption and saving the processed diagnosis data in MongoDB,
  • encryption and sending the processed diagnosis data as JSON response to Client-side (Web, Mobile or Admin),

• Architected and developed using Node.js, Express.js, and MongoDB.

• Employed a layered architecture with clear separation of concerns for maintainability and scalability.

• Prototype, plan and implementation of the Symptom Checker application are defined in the prototype README

• Tools and Technologies used :

  • express
  • node

Workflow

• All diagrams rendered using Mermaid

• Refer Frontend Workflow

• Database Schema represented in Class Diagram

classDiagram
    class User {
        +String username
        +String passwordHash
        +List~ObjectId~ diagnosis
    }

    class Diagnosis {
        +List~DiagnosisData~ diagnosis
        +ObjectId user
    }

    class DiagnosisData {
        +String symptom
        +TopResult topResult
        +OtherResults includedResults
        +OtherResults excludedResults
    }

    class TopResult {
        +String label
        +Number score
        +String title
        +String detail
        +String url
    }

    class OtherResults {
        +List~String~ label
        +List~Number~ score
        +List~String~ url
    }

    User --> Diagnosis : diagnosis
    Diagnosis --> User : user
    Diagnosis --> DiagnosisData : diagnosis
    DiagnosisData --> TopResult : topResult
    DiagnosisData --> OtherResults : includedResults
    DiagnosisData --> OtherResults : excludedResults

Loading

---

• Backend Workflows represented in Sequence Diagram

  sequenceDiagram
      box Blue CLIENT
      participant FRONTEND
      end
  
      box Purple SERVER
      participant BACKEND
      participant ICD11 API
      participant DATABASE
      end
  
      critical Establish Database connection
          BACKEND-->DATABASE: Mongoose ODM connects to MongoDB
      option Network Timeout
          BACKEND-->BACKEND: Log Timeout Error
      option MongoDB Error
          BACKEND-->BACKEND: Log Validation Error
      end
      critical Authorize ICD API Access
          loop Scheduled Renewal of Auth Token every hour
              BACKEND->>+ICD11 API: Auth Controller : POST /token-endpoint/client-credentials
              ICD11 API-->>-BACKEND: Auth Token : Bearer, 3600 seconds validity
          end
      option Network Timeout
          BACKEND-->BACKEND: Log Timeout Error
      option API Error
          BACKEND-->BACKEND: Log Server Error    
      end
  
      alt Valid Registration
          Note over FRONTEND: <Signup /> validation - PASSED
          FRONTEND->>+BACKEND: Auth Service : POST /public/auth/signup
          Note over BACKEND, DATABASE: Backend-Database validation - PASSED        
          BACKEND-->+DATABASE: Auth Controller : User Information {username: '', passwordHash: ''}
          DATABASE-->>-BACKEND: Database Server : User {username: '', symptom: [] }
          BACKEND-->>-FRONTEND: Auth Controller : return User {username: '', symptom: []}
          Note over FRONTEND: <AlertProvider /> state success
      else Backend-Database Validation Error
          Note over FRONTEND: <Signup /> validation - PASSED
          FRONTEND->>+BACKEND: Auth Service : POST /public/auth/signup
          Note over BACKEND, DATABASE: Backend-Database validation - FAILED
          BACKEND-->>-FRONTEND: Auth Controller : ErrorHandler forwards response
          Note over FRONTEND: Display error notification
      end
      alt Valid Login
          Note over FRONTEND: <Login /> validation - PASSED
          FRONTEND->>+BACKEND: Auth Service : POST /public/auth/login
          BACKEND->>+DATABASE: Auth Controller : verify User login credentials
          DATABASE-->>-BACKEND: Database Server : User exists
          Note over BACKEND, DATABASE: Backend-Database validation - PASSED
          BACKEND-->>-FRONTEND: Auth Controller : sessionStorage created<br>'auth_token' packed in Request Header
          Note over FRONTEND: <AlertProvider /> state success
      else Backend-Database Validation Error
          Note over FRONTEND: <Login /> validation - PASSED
          FRONTEND->>+BACKEND: Auth Service : POST /public/auth/login
          BACKEND->>+DATABASE: Auth Controller : verify User Information {username: '', password: ''}
          DATABASE-->>-BACKEND: Auth Controller : User does not exist
          Note over BACKEND, DATABASE: Backend-Database validation - FAILED
          BACKEND-->>-FRONTEND: Auth Controller : ErrorHandler forwards response
          Note over FRONTEND: Display error notification
      end
  
      alt General Symptoms search
          Note over FRONTEND: <SymptomForm /> validation - PASSED
          FRONTEND->>+BACKEND: POST /api/protected/symptoms/general
      Note over BACKEND: Sanitize and Validate User input
          loop Search request for each symptom  
              BACKEND->>+ICD11 API: SymptomChecker Controller : GET /icd/release/11/2024-01/mms/search
              ICD11 API-->>-BACKEND: External Server : multiple search results {}<br> {'label': [''], 'score': [''], 'foundationUri': ['']}
              loop Lookup request for each foundationUri 
                  BACKEND->>+ICD11 API: SymptomChecker Controller : GET /icd/release/11/2024-01/mms/lookup 
                  ICD11 API-->>-BACKEND: External Server : lookup results {}<br>locate {'title': '', 'definition': '', 'browserUrl': ''}
              end
          end
          BACKEND-->>-FRONTEND: SymptomChecker Controller: diagnosisData {'topResult': {}, 'includedResults': {}, 'excludedResults': {}}
          par
              BACKEND->>+DATABASE: SymptomChecker Controller : encrypt and store symptoms, diagnosisData
          and
              Note over FRONTEND: <SymptomForm /> render diagnosisData
          end
  
      else Specific Symptoms search
          Note over FRONTEND: <SymptomForm /> validation - PASSED
          FRONTEND->>+BACKEND: POST /api/protected/symptoms/specific
      Note over BACKEND: Sanitize and Validate User input 
          loop GET request for each symptom   
              BACKEND->>+ICD11 API: SymptomChecker Controller : GET /icd/release/11/2024-01/mms/autocode
              ICD11 API-->>-BACKEND: External Server : single search result {}<br>locate {'label': '', 'score': '', 'foundationUri': ''} 
              BACKEND->>+ICD11 API: SymptomChecker Controller : GET /icd/release/11/2024-01/mms/lookup 
              ICD11 API-->>-BACKEND: External Server : lookup results {}<br>locate {'title': '', 'definition': '', 'browserUrl': ''}
          end
          BACKEND-->>-FRONTEND: SymptomChecker Controller: diagnosisData {'topResult': {}, 'includedResults': {}, 'excludedResults': {}}
          par
              BACKEND->>+DATABASE: SymptomChecker Controller : encrypt and store symptoms, diagnosisData
          and
              Note over FRONTEND: <SymptomForm /> render diagnosisData
          end
      end
  

  Loading

---

Usage

• Make sure you have node(v20.11.0) and npm(v10.5.0) installed on your machine before running these commands.

• Clone the project

    git clone https://github.com/prak112/Symptom-Checker-backend.git

• Install dependencies using npm

    cd Symptom-Checker-backend/symptom-checker-backend
    npm install

• Run the development server

    npm run dev

---

Credits

• Coding Assistants :
  • GitHub Copilot
  • Pieces Copilot
• Documentation Tool : Mermaid

---

---