nunbot/reddit.go

package main

import (
	"crypto/tls"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"regexp"
	"strconv"
	"time"
)

type post struct {
	Title  string
	Link   string
	Number int
}

func getNewestPost(subreddit string) (post, error) {
	var resp redditResp
	re := regexp.MustCompile("([0-9]+)")
	// building request from scratch because reddit api is weird
	url := fmt.Sprintf("https://www.reddit.com/r/%v/new.json?sort=new&limit=1", subreddit)
	req, _ := http.NewRequest("GET", url, nil)
	req.Header.Set("User-Agent", "Custom Agent")
	req.Header.Set("Host", "reddit.com")
	defaultClient := http.Client{
		Transport: &http.Transport{
			TLSNextProto: map[string]func(authority string, c *tls.Conn) http.RoundTripper{},
		},
	}
	res, err := defaultClient.Do(req)
	if err != nil {
		time.Sleep(5 * time.Second)
		res, err = http.Get(url)
		if err != nil {
			return post{}, err
		}
	}
	defer res.Body.Close()
	body, readErr := io.ReadAll(res.Body)
	if readErr != nil {
		return post{}, err
	}
	err = json.Unmarshal(body, &resp)
	if err != nil {
		return post{}, err
	}
	if len(resp.Data.Children) < 1 {
		return post{}, errors.New("bad data from reddit")
	}
	reSearch := re.FindStringSubmatch(resp.Data.Children[0].Data.Title)
	if len(reSearch) == 0 {
		return post{}, fmt.Errorf("something strange in data from reddit")
	}
	numS := reSearch[0]
	num, err := strconv.Atoi(numS)
	if err != nil || numS == "" {
		num = -1
	}
	return post{
		Title:  resp.Data.Children[0].Data.Title,
		Link:   resp.Data.Children[0].Data.URL,
		Number: num,
	}, nil
}