From 19890c33cafbaede2bde55f11ca7539ae8a814a2 Mon Sep 17 00:00:00 2001
From: Robin Verton <hello@robinverton.de>
Date: Tue, 29 Sep 2020 13:14:45 +0200
Subject: [PATCH] Allow redirects from http to https on the same host, fixes
 #38

---
 webanalyze.go | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/webanalyze.go b/webanalyze.go
index bf2a64d..07c56bd 100644
--- a/webanalyze.go
+++ b/webanalyze.go
@@ -61,7 +61,6 @@ func NewWebAnalyzer(apps io.Reader, client *http.Client) (*WebAnalyzer, error) {
 		return nil, err
 	}
 
-
 	wa.client = client
 
 	return wa, nil
@@ -108,7 +107,17 @@ func fetchHost(host string, client *http.Client) (*http.Response, error) {
 				Proxy:           http.ProxyFromEnvironment,
 			},
 			CheckRedirect: func(req *http.Request, via []*http.Request) error {
-				return http.ErrUseLastResponse
+				url, err := url.Parse(host)
+				if err != nil {
+					return http.ErrUseLastResponse
+				}
+
+				// allow redirects from http -> https on the same host
+				if url.Host != via[len(via)-1].URL.Host {
+					return http.ErrUseLastResponse
+				}
+
+				return nil
 			},
 		}
 	}