update readme

### NGSI-LD Entity Types

| Entity Type           | Description                                                              |

| ------------------- | ---------------------------------------------------------- |

| ``WeatherObserved`` | Real-time weather conditions (temperature, humidity, etc.) |

Additional entity types can be added dynamically by extending the Type Mapping Configuration.

| --------------------- | ------------------------------------------------------------------------ |

| ``DeviceMeasurement`` | Device measurements which include records of all the sensors registered. |

To support more NGSI-LD models:

1. Add a new type mapping in ``typeMaps/``

1. Add a new type mapping in ``typeMaps/``. See the DeviceMeasurement typemap for the base structure.

2. Extend NGSITranslator.js to handle the new entity type

3. Modify generalControllers.js to process the new queries

## Testing 

## Queries & Testing 

You can view the structure of HTTP queries and test the broker/bridge by using the following Postman workspace:

**https://www.postman.com/retr0dev/workspace/uowm-depe-http-bridge**

Clone the workspace into your own account and modify it to your needs.

**Setting up Postman**

In order to test the broker and the http bridge you can use the sample queries provided at the following Postman workspace:

1. Setup the env variables.

   - `broker-ip` : localhost if running locally otherwise the IP of your Scorpio broker

   - `broker-port` : the port of the Scorpio broker

   - `http-bridge-ip` : the IP address of the bridge - **CANNOT BE LOCALHOST** - If you are running the bridge on the same machine as your broker then you need to set the bridge IP to the machine IP.

   - `http-bridge-port` : the port of the HTTP bridge

2. Register Context Source

   - In the `Scorpio-Registration` POST request you need to add any new entity types you have implemented.

3. Test the broker

    - If everything was setup correctly, you can use any of the GET requests to fetch data according to the request you selected.

    The format the requests are following (where 'XYZ' is the entity type to fetch ) is:

        - XYZ-Realtime : Latest data from the specific type.

        - XYZ-Realtime-Attrs : Latest data from the specific type and the specific attribute listed in the params.

        - XYZ-Temporal : Data from a specific date range.

        - XYZ-Temporal-Attrs : Data from a specific date range and a specific attribute listed in the params.

**https://www.postman.com/payload-geoscientist-32828968/scorpio-broker-registration/overview**

*Note:*

The reason all Realtime requests have a limit on the database entries it will return is because we cannot fetch millions of records from a single query. The server cannot handle that.

## **Overview**

The **HTTP Bridge** serves as a middleware between the **Scorpio Broker** and the **Smart City Heraklion API**. It is responsible for **fetching data from the API**, **translating it into the NGSI-LD format**, and **returning a structured response** that conforms to the **NGSI-LD data model**.

The **HTTP Bridge** serves as a middleware between the **Scorpio Broker** and a **API**. It is responsible for **fetching data from the API**, **translating it into the NGSI-LD format**, and **returning a structured response** that conforms to the **NGSI-LD data model**.

---

## **Getting Started**

### **1. Prerequisites**

Ensure you have the following installed:

- **Docker** 

- **Node.js** (v14 or higher, if running locally)

- **npm** (Node Package Manager)

---

### **2. Configuration**

Before running the application, configure the necessary environment variables.

### **Using `.env` File (Recommended)**

Create a `.env` file in the project root with the following content:

```

PORT=9010 # Http Bridge Port

HOST="0.0.0.0" # Http Bridge Host (DONT CHANGE id running with Docker)

API_URL=https://smartcity.heraklion.gr/open-data-api # Base URL of the API

```

### **3. Running the HTTP Bridge**

1. Install npm packages

```

npm install

```

2. Build the Docker Image

```

docker build -t http-bridge .

```

3. Run the Container

```

docker run -d --name http-bridge -p 8080:8080 --env-file .env http-bridge

```

The bridge will be accessible at: **{HOST}:{PORT}**

Default: **http://localhost:8080**

---

### **4. Stopping & Removing the Container**

1. To stop the running container:

```

docker stop http-bridge

```

2. To remove the container:

```

docker rm http-bridge

```

---

## **Supported NGSI-LD Entity Types**

| **Entity Type**      | **Description**                                        |

|----------------------|--------------------------------------------------------|

| `WeatherObserved`    | Real-time weather conditions (temperature, humidity, etc.) |

Additional entity types can be added dynamically by extending the **Type Mapping Configuration**.

---

## **Extending the Bridge**

To support more NGSI-LD models, simply:

1. **Add a new type mapping** in `typeMaps/`

2. **Extend `NGSITranslator.js`** to handle the new entity type

3. **Modify `generalControllers.js`** to process the new queries

---

## **Extra Links**

[Scorpio Broker](https://github.com/efntallaris/scorpioBroker)

[Postman Workplace](https://www.postman.com/payload-geoscientist-32828968/workspace/scorpio-broker-registration)

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**See the README on the root of this repository for instructions on how to install and setup.**