From 3862333dfaad2b71909d4727109624a6b07f4284 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Wed, 19 Jun 2024 19:54:40 -0300
Subject: [PATCH] nip11: always return a struct from Fetch() with URL filled.

---
 nip11/fetch.go      | 23 +++++++++++++++--------
 nip11/nip11_test.go | 25 ++++++++++++++++---------
 nip11/types.go      |  2 ++
 3 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/nip11/fetch.go b/nip11/fetch.go
index 4627f05..b230a98 100644
--- a/nip11/fetch.go
+++ b/nip11/fetch.go
@@ -10,8 +10,12 @@ import (
 	"github.com/nbd-wtf/go-nostr"
 )
 
-// Fetch fetches the NIP-11 RelayInformationDocument.
-func Fetch(ctx context.Context, u string) (info *RelayInformationDocument, err error) {
+// Fetch fetches the NIP-11 metadata for a relay.
+//
+// It will always return `info` with at least `URL` filled -- even if we can't connect to the
+// relay or if it doesn't have a NIP-11 handler -- although in that case it will also return
+// an error.
+func Fetch(ctx context.Context, u string) (info RelayInformationDocument, err error) {
 	if _, ok := ctx.Deadline(); !ok {
 		// if no timeout is set, force it to 7 seconds
 		var cancel context.CancelFunc
@@ -20,10 +24,14 @@ func Fetch(ctx context.Context, u string) (info *RelayInformationDocument, err e
 	}
 
 	// normalize URL to start with http://, https:// or without protocol
-	u = "http" + nostr.NormalizeURL(u)[2:]
+	u = nostr.NormalizeURL(u)
+
+	info = RelayInformationDocument{
+		URL: u,
+	}
 
 	// make request
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	req, err := http.NewRequestWithContext(ctx, "GET", "http"+u[2:], nil)
 
 	// add the NIP-11 header
 	req.Header.Add("Accept", "application/nostr+json")
@@ -31,13 +39,12 @@ func Fetch(ctx context.Context, u string) (info *RelayInformationDocument, err e
 	// send the request
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
-		return nil, fmt.Errorf("request failed: %w", err)
+		return info, fmt.Errorf("request failed: %w", err)
 	}
 	defer resp.Body.Close()
 
-	info = &RelayInformationDocument{}
-	if err := json.NewDecoder(resp.Body).Decode(info); err != nil {
-		return nil, fmt.Errorf("invalid json: %w", err)
+	if err := json.NewDecoder(resp.Body).Decode(&info); err != nil {
+		return info, fmt.Errorf("invalid json: %w", err)
 	}
 
 	return info, nil
diff --git a/nip11/nip11_test.go b/nip11/nip11_test.go
index 9e4e6dd..cda76de 100644
--- a/nip11/nip11_test.go
+++ b/nip11/nip11_test.go
@@ -3,6 +3,8 @@ package nip11
 import (
 	"context"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAddSupportedNIP(t *testing.T) {
@@ -34,15 +36,20 @@ func TestAddSupportedNIP(t *testing.T) {
 
 func TestFetch(t *testing.T) {
 	res, err := Fetch(context.Background(), "wss://relay.nostr.bg")
-	if err != nil || res.Name == "" {
-		t.Errorf("failed to fetch from wss")
-	}
+	assert.Equal(t, res.URL, "wss://relay.nostr.bg")
+	assert.Nil(t, err, "failed to fetch from wss")
+	assert.NotEmpty(t, res.Name)
+
 	res, err = Fetch(context.Background(), "https://relay.nostr.bg")
-	if err != nil || res.Name == "" {
-		t.Errorf("failed to fetch from https")
-	}
+	assert.Nil(t, err, "failed to fetch from https")
+	assert.NotEmpty(t, res.Name)
+
 	res, err = Fetch(context.Background(), "relay.nostr.bg")
-	if err != nil || res.Name == "" {
-		t.Errorf("failed to fetch without protocol")
-	}
+	assert.Nil(t, err, "failed to fetch without protocol")
+	assert.NotEmpty(t, res.Name)
+
+	res, err = Fetch(context.Background(), "wlenwqkeqwe.asjdaskd")
+	assert.Error(t, err)
+	assert.NotNil(t, res)
+	assert.Equal(t, res.URL, "wss://wlenwqkeqwe.asjdaskd")
 }
diff --git a/nip11/types.go b/nip11/types.go
index 1894893..7fa3873 100644
--- a/nip11/types.go
+++ b/nip11/types.go
@@ -3,6 +3,8 @@ package nip11
 import "slices"
 
 type RelayInformationDocument struct {
+	URL string `json:"-"`
+
 	Name          string `json:"name"`
 	Description   string `json:"description"`
 	PubKey        string `json:"pubkey"`