Swagger Authorization - Simple Guide

Step-by-Step Process & Entities

Entities Involved

1. Developer/Tester (Browser)

Person accessing Swagger UI for API testing
Can be a developer, QA tester, or technical user
Uses their Microsoft credentials to authenticate with Swagger

2. Swagger UI (Interactive API Documentation)

Web-based API documentation and testing interface
Built into both ApiService and IntegrationServiceAPI
Location: /swagger endpoint (e.g., http://localhost:7532/swagger)
Allows developers to test API endpoints interactively
Uses Scalar UI for enhanced API documentation

3. Microsoft Entra ID (Azure AD Tenant)

Microsoft's cloud identity service
Stores developer credentials and profiles
Tenant ID: 6073ce8b-73f3-4df4-9b80-5e40cdc6965f
Issues JWT tokens after successful authentication
Hosted by Microsoft (external service)

4. Swagger Client Application

Azure AD app registration specifically for Swagger UI
Client ID: 84c38b43-12e4-4c26-8292-8910d79aa532
Type: Single Page Application (SPA) with PKCE enabled
Registered in the same Azure AD tenant

5. ApiService (Backend REST API)

Core backend API
Location: Source/EGU.PartnerPortal.ApiService
Swagger URL: http://localhost:7532/swagger (local)
Client ID: 4dad5d62-dc8c-4378-8bd0-ae736a4d73fe
Scope: api://4dad5d62-dc8c-4378-8bd0-ae736a4d73fe/access_as_user

6. IntegrationServiceAPI (Integration REST API)

External system integration API
Location: Source/EGU.PartnerPortal.IntegrationServiceAPI
Swagger URL: http://localhost:7098/swagger (local)
Client ID: bd5100ee-af63-4880-8c60-47d4207d60c1
Scope: api://bd5100ee-af63-4880-8c60-47d4207d60c1/access_as_user

High-Level Authorization Flows

Flow 1: Developer Opens Swagger & Authenticates (Steps 1-6)

┌─────────────────────────────────────────────────────────────────┐
│         SWAGGER AUTHENTICATION FLOW (Steps 1-6)                 │
└─────────────────────────────────────────────────────────────────┘

    ┌──────────────┐
    │  Developer   │
    │   Browser    │
    └──────┬───────┘
           │
           │ Step 1: Navigate to Swagger UI
           │ (http://localhost:7532/swagger)
           ▼
    ┌──────────────────────┐
    │   Swagger UI Page    │
    │   (Unauthenticated)  │
    └──────┬───────────────┘
           │
           │ Step 2: Click "Authorize" button
           │ Select oauth2 security scheme
           ▼
    ┌──────────────────────────────┐
    │  Swagger Authorization Modal │
    │  Shows required scopes       │
    └──────┬───────────────────────┘
           │
           │ Step 3: Click "Authorize"
           │ → Redirect to Microsoft login
           ▼
    ┌──────────────────────────────┐
    │  Microsoft Entra ID          │
    │  Login Page                  │
    └──────┬───────────────────────┘
           │
           │ Step 4: User enters
           │ email + password + MFA
           ▼
    ┌──────────────────────────────┐
    │  Microsoft Entra ID          │
    │  Validates Credentials       │
    └──────┬───────────────────────┘
           │
           │ ✅ Valid credentials
           │
           │ Step 5: Returns
           │ authorization code
           ▼
    ┌──────────────────────┐
    │  Swagger UI          │
    │  (PKCE exchange)     │
    └──────┬───────────────┘
           │
           │ Step 6: Exchange code
           │ for access token
           ▼
    ┌──────────────────────────────┐
    │  Microsoft Entra ID          │
    │  Token Endpoint              │
    └──────┬───────────────────────┘
           │
           │ Returns access token (1h)
           ▼
    ┌────────────────────────────────┐
    │   ✅ SWAGGER AUTHORIZED         │
    │   Can test API endpoints       │
    └────────────────────────────────┘

Flow 2: Testing API Endpoint with Token (Steps 7-8)

┌─────────────────────────────────────────────────────────────────┐
│          API TEST & VALIDATION FLOW (Steps 7-8)                 │
└─────────────────────────────────────────────────────────────────┘

    ┌────────────────────────────────┐
    │   Developer clicks "Try it out"│
    │   on an API endpoint           │
    └────────────┬───────────────────┘
                 │
                 │ Step 7: Swagger adds token to request
                 ▼
    ┌──────────────────────────────────┐
    │  HTTP Request                    │
    │  GET /api/v1/WorkOrder/Overview  │
    │  Authorization: Bearer eyJ...    │
    └──────┬───────────────────────────┘
           │
           │ Step 8: Request received
           ▼
    ┌──────────────────────────────────────┐
    │  ApiService/IntegrationServiceAPI    │
    │  JWT Authentication Middleware       │
    └──────┬───────────────────────────────┘
           │
           │ Token Validation:
           │ ✓ Issuer (Azure AD tenant)
           │ ✓ Audience (this API)
           │ ✓ Signature (Azure AD keys)
           │ ✓ Expiration (not expired)
           │
           ├─── ✅ Valid ────┐    ❌ Invalid ───┐
           │                 │                   │
           ▼                 ▼                   ▼
    ┌──────────────┐  ┌──────────────┐  ┌──────────────┐
    │  Controller  │  │  200 OK      │  │  401/403     │
    │  Executes    │  │  Returns     │  │  Unauthorized│
    │  Endpoint    │  │  Data        │  │  Forbidden   │
    └──────────────┘  └──────────────┘  └──────────────┘

Step-by-Step Authorization Process

Step 1: Developer Opens Swagger UI

What happens:

Developer navigates to Swagger UI endpoint
- ApiService: http://localhost:7532/swagger (local dev)
- IntegrationServiceAPI: http://localhost:7098/swagger (local dev)
Swagger UI loads, showing all available API endpoints
All endpoints show a lock icon 🔒 indicating authorization required

Who's involved:

Developer (Browser)
Swagger UI

What you see:

List of all API endpoints organized by controller
Open lock icons (grayed out) indicating authentication required
"Authorize" button in the top-right corner

Result:

Swagger UI is loaded but cannot test endpoints yet
Need to authenticate first

Step 2: Click "Authorize" Button

What happens:

Developer clicks the "Authorize" button (or clicks a lock icon)
Modal dialog appears showing available security schemes
Shows OAuth2 (Authorization Code with PKCE) security scheme
Displays the required scope for the API

Who's involved:

Developer
Swagger UI

Authorization modal shows:

For ApiService:

oauth2 (OAuth2, authorizationCode with PKCE)
Scopes:
  api://4dad5d62-dc8c-4378-8bd0-ae736a4d73fe/access_as_user - Access API as user

For IntegrationServiceAPI:

oauth2 (OAuth2, authorizationCode with PKCE)
Scopes:
  api://bd5100ee-af63-4880-8c60-47d4207d60c1/access_as_user - Access Integration API as user

Result:

Developer sees what permissions will be requested
Ready to start OAuth2 flow

Step 3: Initiate OAuth2 Flow

What happens:

Developer clicks "Authorize" in the modal
Swagger UI starts the OAuth2 Authorization Code flow
Browser redirects to Microsoft Entra ID login page
Security code (PKCE) generated automatically

Who's involved:

Swagger UI
Microsoft Entra ID

What's sent to Microsoft:

Swagger client ID
Which API scope is needed
Security challenge code (PKCE)
Where to redirect back after login

Result:

Browser redirected to Microsoft login page

Step 4: Developer Enters Credentials

What happens:

Developer sees Microsoft login page
Enters email (e.g., developer@example.com)
Enters password
Completes MFA challenge (required)
(First time only) Consents to app permissions

Who's involved:

Developer
Microsoft Entra ID

What Microsoft validates:

User credentials are correct
User has access to the tenant
User consents to requested scope

Result:

Microsoft Entra ID validates credentials
If valid → Proceed to Step 5
If invalid → Show error, retry

Step 5: Authorization Code Returned

What happens:

Microsoft Entra ID generates a one-time authorization code
Redirects browser back to Swagger's callback page
Code is valid for 10 minutes

Who's involved:

Microsoft Entra ID
Swagger UI

Result:

Swagger UI receives authorization code
Ready to exchange code for access token

Step 6: Exchange Code for Access Token

What happens:

Swagger UI automatically exchanges authorization code for access token
Sends code + PKCE verifier to Microsoft token endpoint
Microsoft validates code and PKCE verifier
Returns access token

Who's involved:

Swagger UI
Microsoft Entra ID

What's in the access token:

Who issued it (Microsoft Entra ID)
Who it's for (ApiService or IntegrationServiceAPI)
Developer's identity (name and email)
What permissions are granted
When it expires (1 hour)

Result:

Swagger UI now has access token (valid for 1 hour)
Authorization modal closes
Lock icons change to closed locks (black) indicating authorized
Developer can now test endpoints

Step 7: Testing an API Endpoint

What happens (every time developer tests an endpoint):

Developer selects an endpoint (e.g., GET /api/v1/WorkOrder/Overview)
Clicks "Try it out"
Fills in any required parameters
Clicks "Execute"
Swagger UI automatically adds the access token to the request
Request sent to the API

Who's involved:

Developer
Swagger UI
ApiService or IntegrationServiceAPI

Result:

API receives authenticated request with token
Token proves developer's identity and permissions

Step 8: API Validates Token

What happens (on ApiService/IntegrationServiceAPI):

API receives request with token
Authentication middleware examines the token
Checks who issued the token (Azure AD)
Validates token is authentic:
- Signature is valid (proves token came from Azure AD)
- Issuer matches (correct Azure AD tenant)
- Audience matches (token is for this specific API)
- Not expired (within 1-hour lifetime)
If all checks pass → Request continues to controller
If any check fails → Return 401 Unauthorized

Who's involved:

ApiService or IntegrationServiceAPI
JWT Authentication Middleware
Microsoft Entra ID (public keys used for validation)

What's validated:

Token signature: Proves it's authentic and not forged
Issuer: Confirms it came from Azure AD
Audience: Ensures it's for the correct API
Expiration: Checks it hasn't expired

Result:

✅ Valid token → Controller executes, returns response (200 OK)
❌ Invalid token → Authentication fails, returns 401 Unauthorized
Swagger UI displays the response