feat: add user received direct messages retrieval

Signed-off-by: r3drun3 <simone.ragonesi@sighup.io>

.gitignore

@@ -7,4 +7,5 @@
 #dev
 example_output.json
 user_tagged_notes.json
-user_reposted_notes.json
+user_reposted_notes.json
+user_received_direct_messages.json

README.md

@@ -54,6 +54,7 @@ Usage:
 
 Available Commands:
   completion  Generate the autocompletion script for the specified shell
+  dm          Operations on direct messages
   help        Help about any command
   notes       Operations on notes
   relay       Operations on relays
@@ -99,6 +100,19 @@ PAYMENTSURL:  https://relay.nostrview.com/invoices
 ```  
 </details>  
 
+
+<details>
+  <summary>Retrieve from the specified relay the last 300 direct messages that the specified user received</summary>
+
+```console
+nostro dm --userreceived npub1rusgp3upyrtpsy2pcqznl6e8hejg9ne8u2eg05gzc4n2cctsugksvcx2np nostr.wine
+returned events saved to user_received_direct_messages.json
+```
+</details>  
+
+
+
+
 <details>
   <summary>Retrieve from the specified relay the last 300 notes in which the specified user has been tagged</summary>
 

cmd/root.go

@@ -22,6 +22,7 @@ var rootCmd = &cobra.Command{
 func init() {
 	rootCmd.AddCommand(commands.RelayCmd)
 	rootCmd.AddCommand(commands.NotesCmd)
+	rootCmd.AddCommand(commands.DirectMessagesCmd)
 }
 
 func Execute() {

internal/commands/dm.go

@@ -0,0 +1,84 @@
+package commands
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip19"
+	"github.com/spf13/cobra"
+)
+
+var userReceivedDm bool
+
+var DirectMessagesCmd = &cobra.Command{
+	Use:   "dm",
+	Short: "Operations on direct messages",
+	Long:  `Search and retrieve direct messages on nostr`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		if userReceivedDm {
+			if len(args) != 2 {
+				return fmt.Errorf("user npbu key and relay name are required")
+			}
+			npub := args[0]
+			url := args[1]
+			// connect to relay
+			ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+			relay, err := nostr.RelayConnect(ctx, url)
+			if err != nil {
+				panic(err)
+			}
+			// create filters
+			var filters nostr.Filters
+			if _, v, err := nip19.Decode(npub); err == nil {
+				t := make(map[string][]string)
+				// making a "p" tag for the above public key.
+				// this filters for messages tagged with the user, mainly replies.
+				t["p"] = []string{v.(string)}
+				filters = []nostr.Filter{{
+					Kinds: []int{int(nostr.KindEncryptedDirectMessage)},
+					Tags:  t,
+					Limit: 300,
+				}}
+			} else {
+				panic("not a valid npub!")
+			}
+			// create a subscription and submit to relay
+			// results will be returned on the sub.Events channel
+			sub, _ := relay.Subscribe(ctx, filters)
+
+			// we will append the returned events to this slice
+			evs := make([]nostr.Event, 0)
+
+			go func() {
+				<-sub.EndOfStoredEvents
+				cancel()
+			}()
+			for ev := range sub.Events {
+				evs = append(evs, *ev)
+			}
+
+			filename := "user_received_direct_messages.json"
+			if f, err := os.Create(filename); err == nil {
+				fmt.Fprintf(os.Stderr, "returned events saved to %s\n", filename)
+				// encode the returned events in a file
+				enc := json.NewEncoder(f)
+				enc.SetIndent("", " ")
+				enc.Encode(evs)
+				f.Close()
+			} else {
+				panic(err)
+			}
+		} else {
+			cmd.Help()
+		}
+		return nil
+	},
+}
+
+func init() {
+	DirectMessagesCmd.Flags().BoolVarP(&userReceivedDm, "userreceived", "", false, "Retrieve from the specified relay the last 300 direct messages that the specified user received.")
+}