Support custom Content-Type header

README.md

@@ -1,12 +1,21 @@
-http-echo
-=========
+# http-echo
+
 HTTP Echo is a small go web server that serves the contents it was started with
 as an HTML page.
 
 The default port is 5678, but this is configurable via the `-listen` flag:
 
-```
+```bash
 http-echo -listen=:8080 -text="hello world"
 ```
 
-Then visit http://localhost:8080/ in your browser.
+Then visit <http://localhost:8080/> in your browser.
+
+## Configuration
+
+| Argument       | Required  | Default                     | Description                         |
+| -------------- | --------- | --------------------------- | ----------------------------------- |
+| `text`         | ✅        |                             | Text to put on the response         |
+| `listen`       | ❌        | `:5678`                     | Address and port to listen          |
+| `content-type` | ❌        | `text/plain; charset=utf-8` | The Content-Type header of response |
+| `status-code`  | ❌        | 200                         | HTTP response code, e.g.: 200       |

handlers.go

@@ -13,18 +13,20 @@ import (
 )
 
 const (
-	httpHeaderAppName    string = "X-App-Name"
-	httpHeaderAppVersion string = "X-App-Version"
+	httpHeaderAppName     string = "X-App-Name"
+	httpHeaderAppVersion  string = "X-App-Version"
+	httpHeaderContentType string = "Content-Type"
 
 	httpLogDateFormat string = "2006/01/02 15:04:05"
 	httpLogFormat     string = "%v %s %s \"%s %s %s\" %d %d \"%s\" %v\n"
 )
 
-// withAppHeaders adds application headers such as X-App-Version and X-App-Name.
-func withAppHeaders(c int, h http.HandlerFunc) http.HandlerFunc {
+// withAppHeaders adds application headers such as X-App-Version, X-App-Name and Content-Type.
+func withAppHeaders(c int, h http.HandlerFunc, t string) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set(httpHeaderAppName, version.Name)
 		w.Header().Set(httpHeaderAppVersion, version.Version)
+		w.Header().Set(httpHeaderContentType, t)
 		w.WriteHeader(c)
 		h(w, r)
 	}

main.go

@@ -18,10 +18,11 @@ import (
 )
 
 var (
-	listenFlag  = flag.String("listen", ":5678", "address and port to listen")
-	textFlag    = flag.String("text", "", "text to put on the webpage")
-	versionFlag = flag.Bool("version", false, "display version information")
-	statusFlag  = flag.Int("status-code", 200, "http response code, e.g.: 200")
+	contentTypeFlag = flag.String("content-type", "text/plain; charset=utf-8", "the Content-Type header of response")
+	listenFlag      = flag.String("listen", ":5678", "address and port to listen")
+	textFlag        = flag.String("text", "", "text to put on the webpage")
+	versionFlag     = flag.Bool("version", false, "display version information")
+	statusFlag      = flag.Int("status-code", 200, "http response code, e.g.: 200")
 
 	// stdoutW and stderrW are for overriding in test.
 	stdoutW = os.Stdout
@@ -57,10 +58,10 @@ func main() {
 
 	// Flag gets printed as a page
 	mux := http.NewServeMux()
-	mux.HandleFunc("/", httpLog(stdoutW, withAppHeaders(*statusFlag, httpEcho(echoText))))
+	mux.HandleFunc("/", httpLog(stdoutW, withAppHeaders(*statusFlag, httpEcho(echoText), *contentTypeFlag)))
 
 	// Health endpoint
-	mux.HandleFunc("/health", withAppHeaders(200, httpHealth()))
+	mux.HandleFunc("/health", withAppHeaders(200, httpHealth(), *contentTypeFlag))
 
 	server := &http.Server{
 		Addr:    *listenFlag,