From aa3a73a170b8f2aa0036939d5a425c35c05f69b4 Mon Sep 17 00:00:00 2001
From: Daniel Arthur Gallagher
 <8526031+DanArthurGallagher@users.noreply.github.com>
Date: Fri, 24 Apr 2020 14:42:21 +0200
Subject: [PATCH] feat: add CORS support (#1)

Adds a CORS header if the flag is set.
---
 README.md | 9 +++++----
 main.go   | 7 +++++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 7499a47..c553d0c 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,8 @@ By default, serves the current working directory on port 8000. If `$GOPATH/bin`
 
 ### Command-line Arguments
 
-| Flag | Default | Description |
-| --- | --- | --- |
-| -port | `8000` | port to listen on |
-| -dir | `"."` | directory to serve |
+| Flag  | Default | Description                                                  |
+| ----- | ------- | ------------------------------------------------------------ |
+| -port | `8000`  | port to listen on                                            |
+| -dir  | `"."`   | directory to serve                                           |
+| -cors | `false` | `true` to enable CORS (via `Access-Control-Allow-Origin: *`) |
diff --git a/main.go b/main.go
index 1b70f57..912b06d 100644
--- a/main.go
+++ b/main.go
@@ -9,10 +9,12 @@ import (
 
 var Port int
 var Dir string
+var UseCors bool
 
 func init() {
 	flag.IntVar(&Port, "port", 8000, "port to listen on")
 	flag.StringVar(&Dir, "dir", ".", "directory to serve")
+	flag.BoolVar(&UseCors, "cors", false, "Set true to enable 'Access-Control-Allow-Origin: *' on all requests")
 }
 
 // ResponseWriter wraps http.ResponseWriter to capture the HTTP status code
@@ -23,6 +25,11 @@ type ResponseWriter struct {
 
 func (w *ResponseWriter) WriteHeader(statusCode int) {
 	w.StatusCode = statusCode
+
+	if UseCors {
+		w.ResponseWriter.Header().Add("Access-Control-Allow-Origin", "*")
+	}
+
 	w.ResponseWriter.WriteHeader(statusCode)
 }