Recent Karma

recentkarma.go

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
)

const userJSON = "https://www.reddit.com/user/%s.json"

type RedditUser struct {
	Data struct {
		Children []struct {
			Data struct {
				Score     int    `json:"score"`
				LinkTitle string `json:"link_title"`
				Subreddit string `json:"subreddit"`
			} `json:"data"`
		} `json:"children"`
	} `json:"data"`
}

func main() {
	un1, un2 := os.Args[1], os.Args[2]
	user1, user2 := fetchUser(un1), fetchUser(un2)
	if user1.Data.Children[0].Data.Score > user2.Data.Children[0].Data.Score {
		fmt.Printf("%s has more likes than %s\n", un1, un2)
	} else if user1.Data.Children[0].Data.Score < user2.Data.Children[0].Data.Score {
		fmt.Printf("%s has more likes than %s\n", un2, un1)
	} else {
		fmt.Printf("%s and %s are tied!\n", un1, un2)
	}
}

// Returns the karma on the most recent post for the given username
func fetchUser(username string) *RedditUser {
	// Form HTTP request
	c := &http.Client{}
	req, err := http.NewRequest("GET", fmt.Sprintf(userJSON, username), nil)
	if err != nil {
		log.Fatalf("failed to create http request: %v", err)
	}
	req.Header.Add("User-Agent", "go:recentkarma:v0.0.0 (by /u/expiredmcat)")

	// Request JSON
	resp, err := c.Do(req)
	if err != nil {
		log.Fatalf("unable to fetch user: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode == 429 {
		log.Println("too many requests, trying again")
		return fetchUser(username)
	}

	// Decode JSON
	var user RedditUser
	err = json.NewDecoder(resp.Body).Decode(&user)
	if err != nil {
		log.Fatalf("unable to decode json: %v", err)
	}

	return &user
}