multi: add instructions and example server

Author: guggero

Makefile

@@ -93,3 +93,6 @@ rpc-check: rpc
 
 rpc-stubs:
 	cd cmd/wasm-client; ./gen_stubs.sh
+
+example-server:
+	go run example-server.go example/ 8080

README.md

@@ -1,2 +1,30 @@
 # terminal-connect
 Placeholder repository for everything that is needed for Terminal Connect.
+
+## Run the example WASM application
+
+### Prerequisites
+
+1. Install and run `aperture` from the
+   [`mailbox` branch of the internal repo](https://github.com/lightninglabs/aperture-mailbox/tree/mailbox).
+   We assume `aperture` is running with TLS on `localhost:11110`.
+
+### Run lnd
+
+1. Compile and run `lnd` from the [`mailbox` branch of the internal repo](https://github.com/lightninglabs/lnd-mailbox/tree/mailbox).
+2. Run `lnd connectmailbox localhost:11110 --dev_server`, copy the password for
+   later use. You'll need to run this command again to generate a new password
+   for each new connection attempt. At the moment re-using the same password
+   across multiple runs of the WASM client doesn't work cleanly.
+
+### Compile and run the example
+
+1. In this repo, run `make wasm` to compile the example client to WASM.
+2. Run `make example-server` to start the example HTTP server.
+3. Open [https://localhost:11110](https://localhost:11110) and make sure you
+   add an exception for `aperture`'s TLS certificate! This might not work in
+   Chrome. This step is crucial, without it the connection from the example app
+   to `aperture` will fail.
+3. Visit [http://localhost:8080](http://localhost:8080) to see the example
+   client in action. It is recommended to open the browser console (F12) to see
+   the console logs.

example-server.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"strings"
+)
+
+func main() {
+	if len(os.Args) != 3 {
+		log.Fatal("Not enough arguments provided. Please provide the " +
+			"file serving directory and the port.")
+	}
+	dir := os.Args[1]
+	port := os.Args[2]
+	fs := http.FileServer(http.Dir(dir))
+	log.Print("Serving " + dir + " on http://localhost:" + port)
+	err := http.ListenAndServe(":"+port, http.HandlerFunc(
+		func(resp http.ResponseWriter, req *http.Request) {
+			log.Println(req.URL)
+			resp.Header().Add("Cache-Control", "no-cache")
+			if strings.HasSuffix(req.URL.Path, ".wasm") {
+				resp.Header().Set("content-type", "application/wasm")
+			}
+			resp.Header().Set("Access-Control-Allow-Origin", "*")
+			fs.ServeHTTP(resp, req)
+		},
+	))
+	if err != nil {
+		log.Fatalf("Error running server: %v", err)
+	}
+}