#11 added README

README.md

@@ -1 +1,82 @@
 # AccessQueueService
+
+AccessQueueService is a microservice API for managing access to a resource with limited capacity. When a user requests access, they are either granted access immediately (if there is available capacity) or placed in a queue. The service also allows for revoking access.
+
+## API Routes
+
+### Request Access
+- **GET /access/{id}**
+  - **Description:** Request access for a user with the specified `id`.
+  - **Response:** Returns an `AccessResponse` object indicating whether access was granted or the user's position in the queue.
+
+### Revoke Access
+- **DELETE /access/{id}**
+  - **Description:** Revoke access for a user with the specified `id`. This will remove the user from the active list or queue and may allow the next user in the queue to gain access.
+  - **Response:** Returns a boolean indicating success.
+
+## Configuration Variables
+
+Configuration is set in `appsettings.json` or via environment variables. The main configuration section is `AccessQueue`:
+
+- **CapacityLimit**: The maximum number of users that can have access at the same time (default: 100).
+- **ActivitySeconds**: How long (in seconds) a user can remain active before being considered inactive (default: 900).
+- **ExpirationSeconds**: How long (in seconds) before an access ticket expires (default: 43200).
+- **RollingExpiration**: If true, the expiration timer resets on activity (default: true).
+- **CleanupIntervalSeconds**: How often (in seconds) the background cleanup runs to remove expired/inactive users (default: 60).
+
+Example `appsettings.json`:
+```json
+{
+  "AccessQueue": {
+    "CapacityLimit": 100,
+    "ActivitySeconds": 900,
+    "ExpirationSeconds": 43200,
+    "RollingExpiration": true,
+    "CleanupIntervalSeconds": 60
+  }
+}
+```
+
+## How the Service Works
+
+1. **Requesting Access:**
+   - When a user requests access, the service checks if the current number of active users is below `MaxCapacity`.
+   - If there is capacity, the user is granted access immediately.
+   - If not, the user is added to a queue and receives their position in the queue.
+
+2. **Revoking Access:**
+   - When a user revokes access (or their access times out), their slot is freed.
+
+3. **Queue Management:**
+   - Users in the queue are managed in a FIFO (first-in, first-out) order.
+   - If a user is removed from the queue but they are inactive, they are not granted access and their position in the queue is lost.
+
+## AccessResponse Object
+
+The `AccessResponse` object returned by the API contains the following properties:
+
+- **ExpiresOn** (`DateTime?`): The UTC timestamp when the user's access will expire. `null` if the user does not have access.
+- **RequestsAhead** (`int`): The number of requests ahead of the user in the queue. `0` if the user has access.
+- **HasAccess** (`bool`): Indicates whether the user currently has access (true if `ExpiresOn` is set and in the future).
+
+## Running the Service
+
+1. Build and run the project using .NET 8.0 or later:
+   ```powershell
+   dotnet run --project AccessQueueService/AccessQueueService.csproj
+   ```
+2. The API will be available at the configured host and port (see `launchSettings.json`).
+
+## Running the Tests
+
+Unit tests for the service are located in the `AccessQueueServiceTests` project. To run all tests, use the following command from the root of the repository:
+
+```powershell
+# Run all tests in the solution
+ dotnet test
+```
+
+Test results will be displayed in the terminal. You can also use Visual Studio's Test Explorer for a graphical interface.
+
+## License
+See [LICENSE.txt](../LICENSE.txt) for license information.