add nipb0/blossom helpers.

nipb0/blossom/check.go

@@ -0,0 +1,22 @@
+package blossom
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+// Check checks if a file exists on the media server by its hash
+func (c *Client) Check(ctx context.Context, hash string) error {
+	if !nostr.IsValid32ByteHex(hash) {
+		return fmt.Errorf("%s is not a valid 32-byte hex string", hash)
+	}
+
+	err := c.httpCall(ctx, "HEAD", c.mediaserver+"/"+hash, "", nil, nil, 0, nil)
+	if err != nil {
+		return fmt.Errorf("failed to check for %s: %w", hash, err)
+	}
+
+	return nil
+}