initial commit

client/client.sh

@@ -0,0 +1,59 @@
+#!/bin/sh
+
+REMOTE='http://localhost:8080'
+INTERVAL=1
+
+requirecmd()
+{
+	which "$1" 2>1 > /dev/null
+	if [ "$?" -ne 0 ]; then
+		echo "Missing command: $1"
+		exit 1
+	fi
+}
+
+requirecmd curl
+requirecmd fbv
+requirecmd shasum
+
+calchash()
+{
+	shasum --algorithm 1 "$1" 2>/dev/null | cut -d ' ' -f 1
+}
+
+PICFILE="pic"
+PICHASH=$(calchash "$PICFILE")
+PROGPID=$$
+
+# Loop responsible for requesting to the server
+# and updating the picture if necessary
+requestloop()
+{
+	while :; do
+		URL="$REMOTE/$PICHASH"
+		curl --silent "$URL" > refresh
+
+		# Empty response means the file hasn't changed
+		if [ $(file refresh | cut -d ' ' -f 2) = "empty" ]; then
+			rm refresh
+
+		# If the response is non-empty, we received an image file.
+		# We move that file to $PICFILE, then display it
+		else
+			mv refresh "$PICFILE"
+			PICHASH=$(calchash "$PICFILE")
+			pkill --parent "$PROGPID" fbv
+		fi
+		sleep "$INTERVAL"
+	done
+}
+
+requestloop &
+
+while :; do
+	if [ -f "$PICFILE" ]; then
+		fbv --noclear --noinfo "$PICFILE"
+	else
+		sleep 2;
+	fi
+done

server/server.js

@@ -0,0 +1,29 @@
+var fs = require("fs");
+var http = require("http");
+var crypto = require("crypto");
+
+function Pic(path) {
+	var content = fs.readFileSync(path);
+	var hash = crypto.createHash("sha1").update(content).digest("hex");
+
+	var self = {
+		path: path,
+		hash: hash,
+		content: content
+	}
+
+	return self;
+}
+
+var currentPic = Pic("/home/martin/background.jpg");
+
+http.createServer((req, res) => {
+	var hash = req.url.substring(1); // Remove the first / to get only hash
+	console.log("got hash "+hash+", existing hash is "+currentPic.hash);
+
+	if (hash === currentPic.hash) {
+		res.end();
+	} else {
+		res.end(currentPic.content);
+	}
+}).listen(8080);