Full Stack Web Development with Raspberry Pi 3

Adding the required APIs

Just like in the previous section, we will need to start by adding the APIs to get the readings and their average for a certain time period:

    app.get('/temperature/range', function (req, res) {
      /**
       * Here, the "start" and "end" datetimes for the range     of readings are
       * expected to be received through the query parameters.     This is spllied as part
       * of the URL request
       */
      const {start, end} = req.query

      /**
       * The "fetchReadingsBetweenTime" method is called,     which returns an array of results, which we return as     JSON to the client side
       */
      databaseOperations.fetchReadingsBetweenTime    ('temperature', start, end, (err, results) => {
        if (err) {
          console.error(err)
          return res.status(500).end()
        }
       res.json(results)
      })
    })

    app.get ...