initial release

This is a Stacker News bot that fetches every minute all recent posts.

If a post is a twitter link, it adds a comment with nitter links and stores the comment + item id in a sqlite3 database.

If the post already has a comment from the bot (by checking the database), it does not post a comment to prevent duplicates.

.env.template

@@ -0,0 +1 @@
+SN_AUTH_COOKIE=

.gitignore

@@ -0,0 +1,3 @@
+.env
+*.sqlite3
+unpaywall

README.md

@@ -0,0 +1,7 @@
+# unpaywall
+
+This is a [Stacker News bot](https://stacker.news/unpaywall) that fetches every minute all recent posts.
+
+If a post is a twitter link, it adds a comment with nitter links and stores the comment + item id in a sqlite3 database.
+
+If the post already has a comment from the bot (by checking the database), it does not post a comment to prevent duplicates.

db.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+
+	"github.com/ekzyis/sn-goapi"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+var (
+	db *sql.DB
+)
+
+func init() {
+	var err error
+	db, err = sql.Open("sqlite3", "unpaywall.sqlite3")
+	if err != nil {
+		log.Fatal(err)
+	}
+	migrate(db)
+}
+
+func migrate(db *sql.DB) {
+	_, err := db.Exec(`
+		CREATE TABLE IF NOT EXISTS comments (
+			id INTEGER PRIMARY KEY,
+			text TEXT NOT NULL,
+			parent_id INTEGER NOT NULL,
+			created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
+		)
+	`)
+	if err != nil {
+		err = fmt.Errorf("error during migration: %w", err)
+		log.Fatal(err)
+	}
+}
+
+func ItemHasComment(parentId int) bool {
+	var count int
+	err := db.QueryRow(`SELECT COUNT(1) FROM comments WHERE parent_id = ?`, parentId).Scan(&count)
+	if err != nil {
+		err = fmt.Errorf("error during item check: %w", err)
+		log.Fatal(err)
+	}
+	return count > 0
+}
+
+func SaveComment(comment *sn.Comment) {
+	_, err := db.Exec(`INSERT INTO comments(id, text, parent_id) VALUES (?, ?, ?)`, comment.Id, comment.Text, comment.ParentId)
+	if err != nil {
+		err = fmt.Errorf("error during item insert: %w", err)
+		log.Fatal(err)
+	}
+}

go.mod

@@ -0,0 +1,10 @@
+module git.ekzyis.com/ekzyis/unpaywall
+
+go 1.21.0
+
+require (
+	github.com/ekzyis/sn-goapi v0.3.0 // indirect
+	github.com/joho/godotenv v1.5.1 // indirect
+	github.com/mattn/go-sqlite3 v1.14.17 // indirect
+	github.com/namsral/flag v1.7.4-pre // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/ekzyis/sn-goapi v0.2.0 h1:k5YJlG+OguQEQRlbS5KghUttbfJaEkfvIfqB8B133FY=
+github.com/ekzyis/sn-goapi v0.2.0/go.mod h1:FObbYr/NXgnXNWU+EwiWKoWQy+wAaRS6AoW3NgsJ/Oo=
+github.com/ekzyis/sn-goapi v0.2.1-0.20230823005215-5fb6668b6270 h1:aVDLDhrRsxP+if+ujCOpydFapeei2YL47Cp1ghgbJ2I=
+github.com/ekzyis/sn-goapi v0.2.1-0.20230823005215-5fb6668b6270/go.mod h1:FObbYr/NXgnXNWU+EwiWKoWQy+wAaRS6AoW3NgsJ/Oo=
+github.com/ekzyis/sn-goapi v0.2.1-0.20230823015232-6a259372b331 h1:NpCmANlADOcRYxKe3GfaYcfra2fjTpW65M36Dq65LX8=
+github.com/ekzyis/sn-goapi v0.2.1-0.20230823015232-6a259372b331/go.mod h1:FObbYr/NXgnXNWU+EwiWKoWQy+wAaRS6AoW3NgsJ/Oo=
+github.com/ekzyis/sn-goapi v0.3.0 h1:pXRbD2iAMHvUC/+gZKXPRwInP4PuABEC1qQc+DWARlE=
+github.com/ekzyis/sn-goapi v0.3.0/go.mod h1:FObbYr/NXgnXNWU+EwiWKoWQy+wAaRS6AoW3NgsJ/Oo=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/mattn/go-sqlite3 v1.14.17 h1:mCRHCLDUBXgpKAqIKsaAaAsrAlbkeomtRFKXh2L6YIM=
+github.com/mattn/go-sqlite3 v1.14.17/go.mod h1:2eHXhiwb8IkHr+BDWZGa96P6+rkvnG63S2DGjv9HUNg=
+github.com/namsral/flag v1.7.4-pre h1:b2ScHhoCUkbsq0d2C15Mv+VU8bl8hAXV8arnWiOHNZs=
+github.com/namsral/flag v1.7.4-pre/go.mod h1:OXldTctbM6SWH1K899kPZcf65KxJiD7MsceFUpB5yDo=

main.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/ekzyis/sn-goapi"
+)
+
+var (
+	TwitterUrlRegexp = regexp.MustCompile(`^(?:https?:\/\/)?((www\.)?(twitter|x)\.com)\/`)
+	NitterUrls       = []string{"nitter.net", "nitter.it"}
+)
+
+func WaitUntilNext(d time.Duration) {
+	now := time.Now()
+	dur := now.Truncate(d).Add(d).Sub(now)
+	log.Println("sleeping for", dur.Round(time.Second))
+	time.Sleep(dur)
+}
+
+func CheckNotifications() {
+	var prevHasNewNotes bool
+	for {
+		log.Println("Checking notifications ...")
+		hasNewNotes, err := sn.CheckNotifications()
+		if err != nil {
+			SendToNostr(fmt.Sprint(err))
+		} else {
+			if !prevHasNewNotes && hasNewNotes {
+				// only send on "rising edge"
+				SendToNostr("new notifications")
+				log.Println("Forwarded notifications to monitoring")
+			} else if hasNewNotes {
+				log.Println("Notifications already forwarded")
+			}
+		}
+		prevHasNewNotes = hasNewNotes
+		WaitUntilNext(time.Hour)
+	}
+}
+
+func SessionKeepAlive() {
+	for {
+		log.Println("Refresh session using GET /api/auth/session ...")
+		sn.RefreshSession()
+		WaitUntilNext(time.Hour)
+	}
+}
+
+func main() {
+	go CheckNotifications()
+	go SessionKeepAlive()
+	for {
+		log.Println("fetching items ...")
+		r, err := sn.Items(&sn.ItemsQuery{Sort: "recent", Limit: 21})
+		if err != nil {
+			SendToNostr(fmt.Sprint(err))
+			WaitUntilNext(time.Minute)
+			continue
+		}
+
+		for _, item := range r.Items {
+			if m := TwitterUrlRegexp.FindStringSubmatch(item.Url); m != nil {
+				log.Printf("item %d is twitter link\n", item.Id)
+				if ItemHasComment(item.Id) {
+					log.Printf("item %d already has nitter links comment\n", item.Id)
+					continue
+				}
+				comment := "Nitter links:\n\n"
+				for _, nUrl := range NitterUrls {
+					nitterLink := strings.Replace(item.Url, m[1], nUrl, 1)
+					comment += nitterLink + "\n"
+				}
+				comment += "\n_Nitter is a free and open source alternative Twitter front-end focused on privacy and performance. "
+				comment += "Click [here](https://github.com/zedeus/nitter) for more information._"
+				cId, err := sn.CreateComment(item.Id, comment)
+				if err != nil {
+					SendToNostr(fmt.Sprint(err))
+					continue
+				}
+				log.Printf("created comment %d\n", cId)
+				SaveComment(&sn.Comment{Id: cId, Text: comment, ParentId: item.Id})
+			} else {
+				log.Printf("item %d is not twitter link\n", item.Id)
+			}
+		}
+
+		WaitUntilNext(time.Minute)
+	}
+}

nostr.go

@@ -0,0 +1,5 @@
+package main
+
+func SendToNostr(message string) {
+	// TODO send message to me on nostr
+}