Activity Logger part 1

Your task is to create a proof of concept solution for a site where people can log their fitness activities. More precisely for walking, jogging og cycling. Many advanced systems exist on the market today, like Stava, Garmin Connect, Endomondo, Nike+, but for many people these apps are overly complicated. So we go simple.

The idea is that a user can log an exercise activity on a website and then the system will enrich the data from two external APIs. Namely with weather info from the current day and a few data about the city in which the exercise took place. See illustration below:

You will be able to build a real solution with a frontend later this semester. But for now we will focus on the backend. In this exercise, we will focus on getting the data from the APIs, storing the data in memory in DTOs. Later we might want to add the data to a database with JPA. But not today.

All data will be held in an ActivityDTO. The ActivityDTO will contain / reference a WeatherInfoDTO and a CityInfoDTO. The content of WeatherInfoDTO and CityInfoDTO can be obtained from two external APIs. The domain model may look like this:

We will be using two example APIs to get data from. Both are free to use and does not require any authentication.

• CityInfo: https://open-meteo.com/en/docs/geocoding-api
• WeatherInfo: https://open-meteo.com/en/docs

To get info about the city of Roskilde:

• https://geocoding-api.open-meteo.com/v1/search?name=Roskilde&count=1&language=en&format=json&countryCode=DK

To get the current weather in Roskilde:

• https://api.open-meteo.com/v1/forecast?latitude=55.64152&longitude=12.08035&current_weather=true

HttpRequest request = HttpRequest
                    .newBuilder()
                    .uri(new URI(encodedURL))
                    .GET()
                    .build();

1. Take a close look at the domain model and the external APIs. What data do you need to get from the APIs? What data do you need to store in the ActivityDTO?

2. Create a WeatherInfoDTO and a CityInfoDTO that can hold the data from the external APIs.

3. Create an ActivityDTO that can hold the data from the external APIs + extra data that you might want to add.

4. Create a WeatherService and a CityService that can fetch data from the external APIs and return the data in the form of a WeatherInfoDTO and a CityInfoDTO. You will need to get the latitude and longitude from the CityService to be able to get the weather data from the WeatherService.

5. Create a ActivityService that can create an ActivityDTO and enrich it with data from the WeatherService and the CityService.

6. Create a integration test that can test the ActivityService and the WeatherService and the CityService.