From bd34f9f36f93a48ac9abf81da292377a70c2b559 Mon Sep 17 00:00:00 2001
From: wgroeneveld <wouter@brainbaking.com>
Date: Thu, 9 Feb 2023 12:40:56 +0100
Subject: [PATCH] initial commit

---
 .gitignore          |  5 ++++
 README.md           | 14 ++++++++-
 examplerequests.txt | 21 +++++++++++++
 go.mod              |  1 +
 main.go             | 72 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 .gitignore
 create mode 100644 examplerequests.txt
 create mode 100644 go.mod
 create mode 100644 main.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..89591a2
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+
+.idea/
+_rest_stream*
+.DS_Store
+
diff --git a/README.md b/README.md
index f08ce92..2c726cf 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,15 @@
+<<<<<<< HEAD
 # subfmproxy
 
-A Subsonic FM Transmitter Proxy: Stream your music to your retro radios!
\ No newline at end of file
+A Subsonic FM Transmitter Proxy: Stream your music to your retro radios!
+=======
+
+## Inspiration
+
+- https://github.com/dlsniper/fmradio and talk https://www.youtube.com/watch?v=o5MTRQmhvCk 
+  - (with device https://www.adafruit.com/product/1958)
+  - with GoBot to interface with Pi/IC: https://gobot.io/
+- fm transmitter C/C++ projects such as
+  - https://github.com/markondej/fm_transmitter
+  - https://github.com/MundeepL/PiFM
+>>>>>>> 7dbdff8 (initial commit)
diff --git a/examplerequests.txt b/examplerequests.txt
new file mode 100644
index 0000000..a1b3833
--- /dev/null
+++ b/examplerequests.txt
@@ -0,0 +1,21 @@
+http://www.subsonic.org/pages/api.jsp
+
+LOGIN
+
+2023/02/03 14:14:30 req  /rest/ping.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json GET
+
+
+2023/02/03 14:14:30 req  /rest/ping.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json GET
+2023/02/03 14:14:31 req  /rest/getAlbumList2.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&type=recent&size=20 GET
+2023/02/03 14:14:31 req  /rest/getAlbumList2.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&type=frequent&size=20 GET
+2023/02/03 14:14:31 req  /rest/getAlbumList2.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&type=random&size=20 GET
+2023/02/03 14:14:31 req  /rest/getRandomSongs.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&size=50 GET
+
+playing music:
+
+2023/02/03 14:17:16 req  /rest/stream.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&id=59d5e314f94f72d30df1a20c537e158c&maxBitRate=320&format=mp3&estimateContentLength=false GET
+2023/02/03 14:18:07 req  /rest/stream.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&id=1bc38cc2c0cfaa302aecdd379abfe938&maxBitRate=320&format=mp3&estimateContentLength=false GET
+
+doorspoelen naar volgende:
+
+2023/02/03 14:17:47 req  /rest/scrobble.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&id=97394aea4b552463b3c3519777e5d8ca&submission=false GET
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..e34d674
--- /dev/null
+++ b/go.mod
@@ -0,0 +1 @@
+module subfmproxy
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..8bd6947
--- /dev/null
+++ b/main.go
@@ -0,0 +1,72 @@
+package main
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"strings"
+)
+
+type Proxy struct {
+	proxyTarget *url.URL
+}
+
+func NewProxy(target string) *Proxy {
+	proxy := &Proxy{}
+	urlTarget, err := url.Parse(target)
+	if err != nil {
+		log.Fatal("Target not a valid URL!", target)
+	}
+	proxy.proxyTarget = urlTarget
+
+	return proxy
+}
+
+// serves as a reverse proxy to http://www.subsonic.org/pages/api.jsp
+func (pr Proxy) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	log.Println("req ", req.RequestURI, req.Method)
+
+	proxy := httputil.NewSingleHostReverseProxy(pr.proxyTarget)
+
+	// format: 2023/02/03 14:17:16 req  /rest/stream.view?u=jefklak&t=8c90da505334799b3184e9fb0539814d&s=LEcB8n9&v=1.13.0&c=substreamer&f=json&id=59d5e314f94f72d30df1a20c537e158c&maxBitRate=320&format=mp3&estimateContentLength=false GET
+	// returns a binary ID3 file ready to be streamed to the FM receiver system.
+	// Warning, this does NOT work with Navidrome's native system that also has a /rest/stream endpoint (without the .view)
+
+	// TODO wat met "pauzeren"?
+	// zie https://blog.yossarian.net/2022/11/07/Modernizing-my-1980s-sound-system#fnref:model
+	if strings.Contains(req.RequestURI, "/rest/stream.view") {
+		proxy.ModifyResponse = func(resp *http.Response) error {
+			body, err := io.ReadAll(resp.Body)
+			if err != nil {
+				return err
+			}
+			err = resp.Body.Close()
+			if err != nil {
+				return err
+			}
+
+			os.WriteFile(strings.ReplaceAll(req.RequestURI, "/", "_")+".txt", body, 0666)
+
+			// pass on the original body into a new body 'cause the original one has been read out already.
+			resp.Body = io.NopCloser(bytes.NewReader(body))
+			return nil
+		}
+	}
+
+	// allow for SSL redirection if needed
+	req.URL.Host = pr.proxyTarget.Host
+	req.URL.Scheme = pr.proxyTarget.Scheme
+	req.Header.Set("X-Forwarded-Host", req.Header.Get("Host"))
+	req.Host = pr.proxyTarget.Host
+
+	proxy.ServeHTTP(w, req)
+}
+
+func main() {
+	proxy := NewProxy("http://cd.xavier/")
+	http.ListenAndServe(":8080", proxy)
+}