106 lines
2.4 KiB
Go
106 lines
2.4 KiB
Go
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package hn
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import (
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"encoding/json"
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"errors"
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"fmt"
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"log"
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"net/http"
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"regexp"
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"strconv"
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)
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type Item struct {
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ID int
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By string // username of author
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Time int // UNIX timestamp
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Descendants int // number of comments
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Kids []int
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Score int
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Title string
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Url string
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}
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var (
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hnUrl = "https://news.ycombinator.com"
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hnFirebaseUrl = "https://hacker-news.firebaseio.com/v0"
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hnLinkRegexp = regexp.MustCompile(`(?:https?:\/\/)?news\.ycombinator\.com\/item\?id=([0-9]+)`)
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)
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func FetchTopItems() ([]Item, error) {
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log.Println("[hn] fetch top items ...")
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// API docs: https://github.com/HackerNews/API
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url := fmt.Sprintf("%s/topstories.json", hnFirebaseUrl)
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resp, err := http.Get(url)
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if err != nil {
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return nil, fmt.Errorf("error fetching HN top stories %w:", err)
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}
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defer resp.Body.Close()
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var ids []int
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err = json.NewDecoder(resp.Body).Decode(&ids)
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if err != nil {
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return nil, fmt.Errorf("error decoding HN top stories JSON: %w", err)
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}
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// we are only interested in the first page of top stories
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const limit = 30
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ids = ids[:limit]
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var stories [limit]Item
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for i, id := range ids {
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var item Item
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err := FetchItemById(id, &item)
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if err != nil {
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return nil, err
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}
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stories[i] = item
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}
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log.Println("[hn] fetch top items ... OK")
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// Can't return [30]Item as []Item so we copy the array
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return stories[:], nil
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}
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func FetchItemById(id int, hnItem *Item) error {
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// log.Printf("[hn] fetch HN item %d ...\n", id)
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url := fmt.Sprintf("https://hacker-news.firebaseio.com/v0/item/%d.json", id)
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resp, err := http.Get(url)
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if err != nil {
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err = fmt.Errorf("error fetching HN item %d: %w", id, err)
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return err
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}
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defer resp.Body.Close()
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err = json.NewDecoder(resp.Body).Decode(&hnItem)
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if err != nil {
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err := fmt.Errorf("error decoding JSON for HN item %d: %w", id, err)
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return err
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}
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// log.Printf("[hn] fetch HN item %d ... OK\n", id)
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return nil
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}
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func ParseLink(link string) (int, error) {
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match := hnLinkRegexp.FindStringSubmatch(link)
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if len(match) == 0 {
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return -1, errors.New("not a hacker news link")
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}
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id, err := strconv.Atoi(match[1])
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if err != nil {
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return -1, errors.New("integer conversion to string failed")
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}
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return id, nil
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}
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func UserLink(user string) string {
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return fmt.Sprintf("%s/user?id=%s", hnUrl, user)
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}
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func ItemLink(id int) string {
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return fmt.Sprintf("%s/item?id=%d", hnUrl, id)
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}
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