UV

Introduction

UV is a command line application written in Go that checks the current level of UV radiation expressed on the UV Index scale. Additionally, it displays a set of times related to the Sun's position in the sky and an estimation of safe sunlight exposure for different skin types.

Setup

Binary files are released from time to time. However, users are encouraged to build the application on their own. The only requirement is a Go compiler and building scripts are provided for Linux and Windows operating systems. The application's directory should be appended to PATH environmental variable.

For the core functionality, OpenUV API key is required. If the user wants to specify location by city and country instead of latitude and longitude, OpenWeather API key is needed as well.

Settings

Settings are stored in a file under ./settings/uv.json. If the file is not found, a new one is generated. With the help of this file the user provides their API keys and, optionally, a default location of choice (may be left as null). Specifying a default location allows to omit the passage of the same name over and over again. The default location may also be set with an appropriate flag. The request limit allows to track the number of daily requests left on OpenUV API account. Setting it to -1 disables tracking.

The settings file is structured as follows:

{
    "open_weather_key": "key1",
    "open_uv_key":      "key2",

    "default_location": {
        "name":    "London",
        "state":   "England",
        "country": "GB",
        "lat":     51.50732,
        "lon":     -0.1276474
    },

    "request_limit": 50
}

Note that southern latitude and western longitude are negative.

Usage

Flags

Flag	Description
-d	make the location specified with the -l or -f flags the new default location
-f	search online by city and (optionally) country
-h	display help
-l	specify your own location by hand (without using the API)
-u	unset the current default location

OpenWeather Geocoding API (-f) may return multiple matching locations. In such case, the user will be prompted to choose one from the list.

If the city name has more than one word in it, wrap it in quotes. If you want to specify a country name as well, separate it from the city name with a comma and put the whole thing in quotes.

Using the -l flag requires proper structure. See the examples below. If you need to use spaces, wrap the whole location data in quotes.

Examples

Syntax	Meaning
uv -f London	query the API with city name only as the location
uv -f "Rio de Janeiro"	query the API with a multi-word city name
uv -f "London, GB"	query the API by specifying city and country
uv -f London -d	query the API and make London the default location
uv -l London,GB,51.508,-0.128	specify your own location (comma-separated)
uv	query the API using the default location
uv -u	unset the current default location

Output

Structure

The description of most elements is based on the OpenUV API Documentation. Time is expressed in UTC.

Element	Description
Header	Location name and coordinates, generation time, [requests left]
UV Index block	UV index - current, daily maximum (value and time) and ozone level [du]
Sunrise	Sunrise time
Solar Noon	Sun's zenith time
Sunset	Sunset time
Night	Night becomes dark enough for astronomical observations
Golden Hour	Evening golden hour's start time
Morning GH ends	Morning golden hour's end time
Safe Exposure block	Safe sunlight exposure time for skin types on Fitzpatrick scale

Example

This is the example report for the city of London.

London, GB    51.507 -0.128    2022-08-17 07:43 UTC    [43]

UV Index:
  Current:   1.27
  Max:       5.59 (12:06)
  Ozone:   332.50

Sunrise:           04:50
Solar Noon:        12:06
Sunset:            19:21
Night:             21:43
Golden Hour:       18:35
Morning GH ends:   05:36

Safe Exposure Time [min]:
  1:   131   |   4:   262
  2:   157   |   5:   420
  3:   210   |   6:   787

Resources

• UV Index

• Fizpatrick scale

• OpenUV

• OpenWeather

License

This software is available under MIT License.