From 951cf2c15b346dfa1f9bf1ecf3635e6c8ddf089a Mon Sep 17 00:00:00 2001
From: Jim McDonald <Jim@mcdee.net>
Date: Fri, 25 Oct 2024 22:02:18 +0100
Subject: [PATCH] Allow custom HTTP client.

---
 http/parameters.go | 10 ++++++++++
 http/service.go    | 27 +++++++++++++++------------
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/http/parameters.go b/http/parameters.go
index 2f91e076..ab679a5b 100644
--- a/http/parameters.go
+++ b/http/parameters.go
@@ -15,6 +15,7 @@ package http
 
 import (
 	"errors"
+	"net/http"
 	"time"
 
 	"github.com/attestantio/go-eth2-client/metrics"
@@ -34,6 +35,7 @@ type parameters struct {
 	hooks              *Hooks
 	reducedMemoryUsage bool
 	customSpecSupport  bool
+	client             *http.Client
 }
 
 // Parameter is the interface for service parameters.
@@ -134,6 +136,14 @@ func WithCustomSpecSupport(customSpecSupport bool) Parameter {
 	})
 }
 
+// WithHTTPClient provides a custom HTTP client for communication with the HTTP server.
+// If not supplied then a standard HTTP client is used.
+func WithHTTPClient(client *http.Client) Parameter {
+	return parameterFunc(func(p *parameters) {
+		p.client = client
+	})
+}
+
 // parseAndCheckParameters parses and checks parameters to ensure that mandatory parameters are present and correct.
 func parseAndCheckParameters(params ...Parameter) (*parameters, error) {
 	parameters := parameters{
diff --git a/http/service.go b/http/service.go
index 8077064c..ddf98843 100644
--- a/http/service.go
+++ b/http/service.go
@@ -95,18 +95,21 @@ func New(ctx context.Context, params ...Parameter) (client.Service, error) {
 		}
 	}
 
-	httpClient := &http.Client{
-		Transport: &http.Transport{
-			DialContext: (&net.Dialer{
-				Timeout:   parameters.timeout,
-				KeepAlive: 30 * time.Second,
-				DualStack: true,
-			}).DialContext,
-			MaxIdleConns:        64,
-			MaxConnsPerHost:     64,
-			MaxIdleConnsPerHost: 64,
-			IdleConnTimeout:     600 * time.Second,
-		},
+	httpClient := parameters.client
+	if httpClient == nil {
+		httpClient = &http.Client{
+			Transport: &http.Transport{
+				DialContext: (&net.Dialer{
+					Timeout:   parameters.timeout,
+					KeepAlive: 30 * time.Second,
+					DualStack: true,
+				}).DialContext,
+				MaxIdleConns:        64,
+				MaxConnsPerHost:     64,
+				MaxIdleConnsPerHost: 64,
+				IdleConnTimeout:     600 * time.Second,
+			},
+		}
 	}
 
 	base, address, err := parseAddress(parameters.address)