Add two examples: input2ipc and fromipc (serialization of IPC messages).

crystal/makefile

@@ -9,8 +9,8 @@ CRYSTAL_BUILD_OPTIONS += $(CRYSTAL_STATIC_BUILD)
 
 LIBIPC_RUNDIR ?= /tmp/libipc-run
 
-all: build
-build: build-pongd build-pong
+all: run
+build: build-pongd build-pong build-input2ipc build-fromipc
 run: run-pongd
 
 include ../mk/makefile.utils
@@ -27,3 +27,11 @@ build-pong:
 
 run-pong:
 	$(LD_LIBRARY_PATH) ./bin/pong
+
+-include makefile.user
+
+build-input2ipc:
+	$(CRYSTAL_LIBRARY_PATH) shards build input2ipc $(CRYSTAL_BUILD_OPTIONS)
+
+build-fromipc:
+	$(CRYSTAL_LIBRARY_PATH) shards build fromipc $(CRYSTAL_BUILD_OPTIONS)

crystal/shard.yml

@@ -13,11 +13,20 @@ targets:
   pongd:
     main: src/pongd.cr
 
+  # Those two examples show what it is required to serialize and deserialize
+  # an IPC message, which only is to add (and remove) the message length in
+  # the first 4 bytes of the message.
+  # They can be used to handle messages from a simple shell script.
+  fromipc:
+    main: src/fromipc.cr
+  input2ipc:
+    main: src/input2ipc.cr
+
 dependencies:
   ipc:
     git: https://git.baguette.netlib.re/Baguette/ipc.cr
     branch: master
 
-crystal: 1.7.1
+crystal: 1.8.2
 
 license: ISC

crystal/src/fromipc.cr

@@ -0,0 +1,4 @@
+# Read an IPC network packet and remove the first 4 bytes.
+buffer = Bytes.new 1_000_000
+len = STDIN.read buffer
+STDOUT.write buffer[4.. len -1]

crystal/src/input2ipc.cr

@@ -0,0 +1,5 @@
+# Input to IPC network packets.
+buffer = Bytes.new 1_000_000
+len = STDIN.read buffer
+STDOUT.write_bytes len, IO::ByteFormat::BigEndian
+STDOUT.write buffer[0.. len -1]