download deps before build

Makefile

@@ -2,7 +2,7 @@
 host=10.11.99.1
 
 printer.arm:
-	go get
+	go get ./...
 	env GOOS=linux GOARCH=arm GOARM=5 go build -o printer.arm
 
 printer.x86:

README.md

@@ -42,6 +42,12 @@ See [Add a network printer by its IP address](https://support.apple.com/guide/ma
 
 No authentication, so keep WiFi off while not in use.
 
+## How it works
+
+Virtually all network printers accept raw Postscript/PDF data on TCP port 9100 via the Appsocket/HP Jetdirect protocol.  Sometimes this data is preceded by a few plaintext lines telling the printer information such as the print job name and print settings.
+
+This script simply listens on TCP 9100 and waits for a PDF header, then begins saving data to a pdf file (while also creating the accompanying .metadata file).  The output filename is extracted from the print job name line, if it exists.
+
 ## Testing on host
 
     $ make printer.x86

main.go

@@ -128,6 +128,7 @@ func handleRequest(conn net.Conn) {
 			title = strings.Split(line, "\"")[1]
 			debug("Setting title to", title)
 		}
+		// PDF section started
 		if strings.HasPrefix(line, "%PDF-") {
 			debug("PDF begin")
 			_, err := f.WriteString(line)