Getting started - running a Node.js sample application

This "Getting Started" document shows you how to build and run the simple_sample_http.js Node.js sample application.

Prerequisites

Before you get started, you should:

Prepare your development environment.
Set up your IoT hub.
Use the iothub-explorer utility to connect your device to an IoT hub. You'll use iothub-explorer again in a moment to monitor the messages you send from the sample application; leave your shell (Linux) or Node.js command prompt (Windows) open.
Make note of the connection string for your device from the previous step.

Get the following sample files from https://github.com/Azure/azure-iot-sdks/node/device/samples
- package.json
- simple_sample_http.js
Place the files in the folder of your choice on the target machine/device
Open the file simple_sample_http.js in a text editor.

Locate the following code in the file:

var connectionString = '[IoT Device Connection String]';

Replace [IoT Device Connection String] with the connection string for your device. Save the changes.
From the shell or command prompt you used earlier to run the iothub-explorer utility, use the following command to receive device-to-cloud messages from the sample application (replace with the ID you assigned your device earlier):
```
node iothub-explorer.js "<iothub-connection-string>" monitor-events <device-id>
```
Open a new shell or Node.js command prompt and navigate to the folder where you placed the sample files. Run the sample application using the following commands:
```
npm install
node .
```
The sample application will send messages to your IoT hub, and the iothub-explorer utility will display the messages as your IoT hub receives them.