support running nak with multiple lines of stdin sequentially.

event.go

@@ -90,15 +90,16 @@ example:
 	},
 	ArgsUsage: "[relay...]",
 	Action: func(c *cli.Context) error {
+		for stdinEvent := range getStdinLinesOrBlank() {
 			evt := nostr.Event{
 				Tags: make(nostr.Tags, 0, 3),
 			}
 
 			mustRehashAndResign := false
-
+			if stdinEvent != "" {
-		if stdinEvent := getStdin(); stdinEvent != "" {
 				if err := json.Unmarshal([]byte(stdinEvent), &evt); err != nil {
-				return fmt.Errorf("invalid event received from stdin: %w", err)
+					lineProcessingError(c, "invalid event received from stdin: %s", err)
+					continue
 				}
 			}
 
@@ -198,7 +199,9 @@ example:
 				}
 				fmt.Println(result)
 			}
+		}
 
+		exitIfLineProcessingError(c)
 		return nil
 	},
 }

helpers.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"bufio"
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"net/url"
@@ -11,7 +13,36 @@ import (
 	"github.com/urfave/cli/v2"
 )
 
-func getStdin() string {
+const (
+	LINE_PROCESSING_ERROR = iota
+)
+
+func getStdinLinesOrBlank() chan string {
+	ch := make(chan string)
+	go func() {
+		r := bufio.NewReader(os.Stdin)
+		if _, err := r.Peek(1); err != nil {
+			ch <- ""
+			close(ch)
+		} else {
+			scanner := bufio.NewScanner(r)
+			for scanner.Scan() {
+				ch <- scanner.Text()
+			}
+			close(ch)
+		}
+	}()
+	return ch
+}
+
+func getStdinOrFirstArgument(c *cli.Context) string {
+	// try the first argument
+	target := c.Args().First()
+	if target != "" {
+		return target
+	}
+
+	// try the stdin
 	stat, _ := os.Stdin.Stat()
 	if (stat.Mode() & os.ModeCharDevice) == 0 {
 		read := bytes.NewBuffer(make([]byte, 0, 1000))
@@ -23,14 +54,6 @@ func getStdin() string {
 	return ""
 }
 
-func getStdinOrFirstArgument(c *cli.Context) string {
-	target := c.Args().First()
-	if target != "" {
-		return target
-	}
-	return getStdin()
-}
-
 func validateRelayURLs(wsurls []string) error {
 	for _, wsurl := range wsurls {
 		u, err := url.Parse(wsurl)
@@ -49,3 +72,14 @@ func validateRelayURLs(wsurls []string) error {
 
 	return nil
 }
+
+func lineProcessingError(c *cli.Context, msg string, args ...any) {
+	c.Context = context.WithValue(c.Context, LINE_PROCESSING_ERROR, true)
+	fmt.Fprintf(os.Stderr, msg+"\n", args...)
+}
+
+func exitIfLineProcessingError(c *cli.Context) {
+	if val := c.Context.Value(LINE_PROCESSING_ERROR); val != nil && val.(bool) {
+		os.Exit(123)
+	}
+}

req.go

@@ -95,10 +95,12 @@ example:
 	},
 	ArgsUsage: "[relay...]",
 	Action: func(c *cli.Context) error {
+		for stdinFilter := range getStdinLinesOrBlank() {
 			filter := nostr.Filter{}
-		if stdinFilter := getStdin(); stdinFilter != "" {
+			if stdinFilter != "" {
 				if err := json.Unmarshal([]byte(stdinFilter), &filter); err != nil {
-				return fmt.Errorf("invalid filter received from stdin: %w", err)
+					lineProcessingError(c, "invalid filter received from stdin: %s", err)
+					continue
 				}
 			}
 
@@ -175,7 +177,9 @@ example:
 
 				fmt.Println(result)
 			}
+		}
 
+		exitIfLineProcessingError(c)
 		return nil
 	},
 }

verify.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"encoding/json"
-	"fmt"
 
 	"github.com/nbd-wtf/go-nostr"
 	"github.com/urfave/cli/v2"
@@ -17,21 +16,27 @@ var verify = &cli.Command{
 it outputs nothing if the verification is successful.
 `,
 	Action: func(c *cli.Context) error {
+		for stdinEvent := range getStdinLinesOrBlank() {
 			evt := nostr.Event{}
-		if stdinEvent := getStdin(); stdinEvent != "" {
+			if stdinEvent != "" {
 				if err := json.Unmarshal([]byte(stdinEvent), &evt); err != nil {
-				return fmt.Errorf("invalid JSON: %w", err)
+					lineProcessingError(c, "invalid event: %s", err)
+					continue
 				}
 			}
 
 			if evt.GetID() != evt.ID {
-			return fmt.Errorf("invalid .id, expected %s, got %s", evt.GetID(), evt.ID)
+				lineProcessingError(c, "invalid .id, expected %s, got %s", evt.GetID(), evt.ID)
+				continue
 			}
 
 			if ok, err := evt.CheckSignature(); !ok {
-			return fmt.Errorf("invalid signature: %w", err)
+				lineProcessingError(c, "invalid signature: %s", err)
+				continue
+			}
 		}
 
+		exitIfLineProcessingError(c)
 		return nil
 	},
 }