From cb2247c9da68ea06d5bf48d0b9eb54078178e55d Mon Sep 17 00:00:00 2001
From: Yasuhiro Matsumoto <mattn.jp@gmail.com>
Date: Thu, 25 Dec 2025 16:44:30 +0900
Subject: [PATCH] implement blossom mirror

---
 blossom.go | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 122 insertions(+), 3 deletions(-)

diff --git a/blossom.go b/blossom.go
index 45a5eaa..7df0015 100644
--- a/blossom.go
+++ b/blossom.go
@@ -3,10 +3,15 @@ package main
 import (
 	"bytes"
 	"context"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
 	"fmt"
 	"io"
+	"net/http"
 	"os"
 
+	"fiatjaf.com/nostr"
 	"fiatjaf.com/nostr/keyer"
 	"fiatjaf.com/nostr/nipb0/blossom"
 	"github.com/urfave/cli/v3"
@@ -230,11 +235,46 @@ if any of the files are not found the command will fail, otherwise it will succe
 		},
 		{
 			Name:                      "mirror",
-			Usage:                     "",
-			Description:               ``,
+			Usage:                     "mirrors blobs from source server to target server",
+			Description:               `lists all blobs from the source server and mirrors them to the target server using BUD-04. requires --sec to sign the authorization event.`,
 			DisableSliceFlagSeparator: true,
-			ArgsUsage:                 "",
 			Action: func(ctx context.Context, c *cli.Command) error {
+				targetClient, err := getBlossomClient(ctx, c)
+				if err != nil {
+					return err
+				}
+
+				// Create client for source server
+				sourceServer := c.Args().First()
+				keyer, _, err := gatherKeyerFromArguments(ctx, c)
+				if err != nil {
+					return err
+				}
+				sourceClient := blossom.NewClient(sourceServer, keyer)
+
+				// Get list of blobs from source server
+				bds, err := sourceClient.List(ctx)
+				if err != nil {
+					return fmt.Errorf("failed to list blobs from source server: %w", err)
+				}
+
+				// Mirror each blob to target server
+				hasError := false
+				for _, bd := range bds {
+					mirrored, err := mirrorBlob(ctx, targetClient, bd.URL)
+					if err != nil {
+						fmt.Fprintf(os.Stderr, "failed to mirror %s: %s\n", bd.SHA256, err)
+						hasError = true
+						continue
+					}
+
+					j, _ := json.Marshal(mirrored)
+					stdout(string(j))
+				}
+
+				if hasError {
+					os.Exit(3)
+				}
 				return nil
 			},
 		},
@@ -248,3 +288,82 @@ func getBlossomClient(ctx context.Context, c *cli.Command) (*blossom.Client, err
 	}
 	return blossom.NewClient(c.String("server"), keyer), nil
 }
+
+// mirrorBlob mirrors a blob from a URL to the mediaserver using BUD-04
+func mirrorBlob(ctx context.Context, client *blossom.Client, url string) (*blossom.BlobDescriptor, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, fmt.Errorf("failed to download blob from URL: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to download blob: HTTP %d", resp.StatusCode)
+	}
+
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read blob content: %w", err)
+	}
+
+	hash := sha256.Sum256(data)
+	hashHex := hex.EncodeToString(hash[:])
+
+	signer := client.GetSigner()
+	pubkey, _ := signer.GetPublicKey(ctx)
+
+	evt := nostr.Event{
+		Kind:      24242,
+		CreatedAt: nostr.Now(),
+		Tags: nostr.Tags{
+			{"t", "upload"},
+			{"x", hashHex},
+			{"expiration", fmt.Sprintf("%d", nostr.Now()+60)},
+		},
+		Content: "blossom stuff",
+		PubKey:  pubkey,
+	}
+
+	if err := signer.SignEvent(ctx, &evt); err != nil {
+		return nil, fmt.Errorf("failed to sign authorization event: %w", err)
+	}
+
+	evtj, err := json.Marshal(evt)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal authorization event: %w", err)
+	}
+	auth := base64.StdEncoding.EncodeToString(evtj)
+
+	mediaserver := client.GetMediaServer()
+	mirrorURL := mediaserver + "mirror"
+
+	requestBody := map[string]string{"url": url}
+	requestJSON, _ := json.Marshal(requestBody)
+
+	req, err := http.NewRequestWithContext(ctx, "PUT", mirrorURL, bytes.NewReader(requestJSON))
+	if err != nil {
+		return nil, fmt.Errorf("failed to create mirror request: %w", err)
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Nostr "+auth)
+
+	httpClient := &http.Client{}
+	mirrorResp, err := httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to send mirror request: %w", err)
+	}
+	defer mirrorResp.Body.Close()
+
+	if mirrorResp.StatusCode < 200 || mirrorResp.StatusCode >= 300 {
+		body, _ := io.ReadAll(mirrorResp.Body)
+		return nil, fmt.Errorf("mirror request failed with HTTP %d: %s", mirrorResp.StatusCode, string(body))
+	}
+
+	var bd blossom.BlobDescriptor
+	if err := json.NewDecoder(mirrorResp.Body).Decode(&bd); err != nil {
+		return nil, fmt.Errorf("failed to decode blob descriptor: %w", err)
+	}
+
+	return &bd, nil
+}