Initial commit

internal/feed/hacker-news.go

@@ -0,0 +1,89 @@
+package feed
+
+import (
+	"fmt"
+	"log/slog"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+type hackerNewsPostResponseJson struct {
+	Id           int    `json:"id"`
+	Score        int    `json:"score"`
+	Title        string `json:"title"`
+	TargetUrl    string `json:"url,omitempty"`
+	CommentCount int    `json:"descendants"`
+	TimePosted   int64  `json:"time"`
+}
+
+func getHackerNewsTopPostIds() ([]int, error) {
+	request, _ := http.NewRequest("GET", "https://hacker-news.firebaseio.com/v0/topstories.json", nil)
+	response, err := decodeJsonFromRequest[[]int](defaultClient, request)
+
+	if err != nil {
+		return nil, fmt.Errorf("%w: could not fetch list of post IDs", ErrNoContent)
+	}
+
+	return response, nil
+}
+
+func getHackerNewsPostsFromIds(postIds []int) (ForumPosts, error) {
+	requests := make([]*http.Request, len(postIds))
+
+	for i, id := range postIds {
+		request, _ := http.NewRequest("GET", fmt.Sprintf("https://hacker-news.firebaseio.com/v0/item/%d.json", id), nil)
+		requests[i] = request
+	}
+
+	task := decodeJsonFromRequestTask[hackerNewsPostResponseJson](defaultClient)
+	job := newJob(task, requests).withWorkers(30)
+	results, errs, err := workerPoolDo(job)
+
+	if err != nil {
+		return nil, err
+	}
+
+	posts := make(ForumPosts, 0, len(postIds))
+
+	for i := range results {
+		if errs[i] != nil {
+			slog.Error("Failed to fetch or parse hacker news post", "error", errs[i], "url", requests[i].URL)
+			continue
+		}
+
+		posts = append(posts, ForumPost{
+			Title:           results[i].Title,
+			DiscussionUrl:   "https://news.ycombinator.com/item?id=" + strconv.Itoa(results[i].Id),
+			TargetUrl:       results[i].TargetUrl,
+			TargetUrlDomain: extractDomainFromUrl(results[i].TargetUrl),
+			CommentCount:    results[i].CommentCount,
+			Score:           results[i].Score,
+			TimePosted:      time.Unix(results[i].TimePosted, 0),
+		})
+	}
+
+	if len(posts) == 0 {
+		return nil, ErrNoContent
+	}
+
+	if len(posts) != len(postIds) {
+		return posts, fmt.Errorf("%w could not fetch some hacker news posts", ErrPartialContent)
+	}
+
+	return posts, nil
+}
+
+func FetchHackerNewsTopPosts(limit int) (ForumPosts, error) {
+	postIds, err := getHackerNewsTopPostIds()
+
+	if err != nil {
+		return nil, err
+	}
+
+	if len(postIds) > limit {
+		postIds = postIds[:limit]
+	}
+
+	return getHackerNewsPostsFromIds(postIds)
+}