Timestamp microservice

User stories

• I can pass a string as a parameter, and it will check to see whether that string contains either a unix timestamp or a natural language date (example: January 1, 2016)
• If it does, it returns both the Unix timestamp and the natural language form of that date.
• If it does not contain a date or Unix timestamp, it returns null for those properties.

Example usage

/api/time/December%2015,%202015
/api/time/1450137600

Example output

{ "unix": 1450137600, "natural": "December 15, 2015" }

Solution

package main

import (
    "encoding/json"
    "log"
    "net/http"
    "strconv"

    "time"

    "github.com/gorilla/mux"
)

var dateFormats = []string{
    "January 2 2006",
    "Jan 2 2006",
    "2 Jan 2006",
    "2 January 2006",

    "January 2, 2006",
    "Jan 2, 2006",
    "2 Jan, 2006",
    "2 January, 2006",

    "2006 January 2",
    "2006 Jan 2",
    "2006 2 Jan",
    "2006 2 January",

    "2006, January 2",
    "2006, Jan 2",
    "2006, 2 Jan",
    "2006, 2 January",
}

type response struct {
    Unix    string `json:"unix,omitempty"`
    Natural string `json:"natural,omitempty"`
}

func main() {
    r := mux.NewRouter()
    r.HandleFunc("/api/time/{date}", handleString).Methods("GET")
    log.Fatal(http.ListenAndServe(":8000", r))
}

func handleString(w http.ResponseWriter, r *http.Request) {
    enc := json.NewEncoder(w)
    date := mux.Vars(r)["date"]
    i, err := strconv.ParseInt(date, 10, 64)
    if err == nil {
        tm := time.Unix(i, 0)
        enc.Encode(response{
            Unix:    date,
            Natural: tm.Format("January 2, 2006"),
        })
        return
    }
    var resp response
    for _, dateFormat := range dateFormats {
        if tm, err := time.Parse(dateFormat, date); err == nil {
            resp = response{
                Unix:    strconv.FormatInt(tm.UTC().Unix(), 10),
                Natural: tm.Format("January 2, 2006"),
            }
        }
    }

    enc.Encode(resp)
}