From 6b6ecff1fd48be5cb5d917cef59e51661523a3a8 Mon Sep 17 00:00:00 2001
From: William Perron <hey@wperron.io>
Date: Wed, 15 Feb 2023 15:45:42 -0500
Subject: [PATCH] initial commit

---
 .gitignore                  |  0
 example/http_client/main.go | 15 ++++++++++++
 go.mod                      |  3 +++
 http/round_tripper.go       | 46 +++++++++++++++++++++++++++++++++++++
 4 files changed, 64 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 example/http_client/main.go
 create mode 100644 go.mod
 create mode 100644 http/round_tripper.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..e69de29
diff --git a/example/http_client/main.go b/example/http_client/main.go
new file mode 100644
index 0000000..31a9a69
--- /dev/null
+++ b/example/http_client/main.go
@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	stdhttp "net/http"
+
+	"go.wperron.io/toolkit/http"
+)
+
+func main() {
+	stdclient := stdhttp.Client{}
+	stdclient.Transport = http.NewFollowRedirect(stdhttp.DefaultTransport)
+
+	fmt.Println(stdclient.Get("https://google.com"))
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..7d4f557
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module go.wperron.io/toolkit
+
+go 1.20
diff --git a/http/round_tripper.go b/http/round_tripper.go
new file mode 100644
index 0000000..7845af2
--- /dev/null
+++ b/http/round_tripper.go
@@ -0,0 +1,46 @@
+package http
+
+import (
+	"fmt"
+	stdhttp "net/http"
+	"net/url"
+)
+
+var _ stdhttp.RoundTripper = &FollowRedirect{}
+
+// FollowRedirect implements RoundTripper will follow the `location` header in
+// the case of a 300-399 status code
+type FollowRedirect struct {
+	next stdhttp.RoundTripper
+}
+
+func NewFollowRedirect(next stdhttp.RoundTripper) *FollowRedirect {
+	return &FollowRedirect{
+		next: next,
+	}
+}
+
+// RoundTrip implements http.RoundTripper.
+func (f *FollowRedirect) RoundTrip(req *stdhttp.Request) (*stdhttp.Response, error) {
+	res, err := f.next.RoundTrip(req)
+	if err != nil {
+		return nil, err
+	}
+
+	if res.StatusCode >= 300 && res.StatusCode <= 399 {
+		loc := res.Header.Get("location")
+
+		fmt.Println("==> got a redirect, following...")
+		if loc != "" {
+			u, err := url.Parse(loc)
+			if err != nil {
+				panic("got an invalid URL from the `location` header")
+			}
+			clone := req.Clone(req.Context())
+			clone.URL = u
+
+			return f.next.RoundTrip(clone)
+		}
+	}
+	return res, nil
+}