From 75cfb666e8faa09b13a07df848adc5073db74253 Mon Sep 17 00:00:00 2001
From: Stephen von Takach <steve@place.technology>
Date: Sat, 29 Jul 2023 14:32:22 +1000
Subject: [PATCH] feat: breakout CoAP header

allows for improved payload processing as we can check if the data is possibly good before processing or buffering
---
 shard.lock                 |  4 ++--
 shard.yml                  |  2 +-
 src/coap/client.cr         |  6 +++---
 src/coap/client/request.cr |  8 ++++----
 src/coap/message.cr        | 10 ++++++++--
 5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/shard.lock b/shard.lock
index 8af909e..7dc5e4f 100644
--- a/shard.lock
+++ b/shard.lock
@@ -2,11 +2,11 @@ version: 2.0
 shards:
   ameba:
     git: https://github.com/veelenga/ameba.git
-    version: 0.14.2
+    version: 1.5.0
 
   bindata:
     git: https://github.com/spider-gazelle/bindata.git
-    version: 1.8.3
+    version: 1.11.1
 
   dtls:
     git: https://github.com/spider-gazelle/crystal-dtls.git
diff --git a/shard.yml b/shard.yml
index 559241a..6740002 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,5 +1,5 @@
 name: coap
-version: 1.1.0
+version: 1.2.0
 crystal: ">= 0.36.1"
 
 dependencies:
diff --git a/src/coap/client.cr b/src/coap/client.cr
index dd09364..04e06ca 100644
--- a/src/coap/client.cr
+++ b/src/coap/client.cr
@@ -25,10 +25,10 @@ class CoAP::Client
   end
 
   def self.new(uri : URI, tls : TLSContext = nil)
-    scheme = uri.scheme.not_nil!.downcase
+    scheme = uri.scheme.as(String).downcase
     port = uri.port || URI.default_port(scheme) || raise("unable to infer CoAP port for #{uri}")
     raise "TLS required for coaps" if tls == false && scheme == "coaps"
-    self.new(uri.host.not_nil!, port, tls)
+    self.new(uri.host.as(String), port, tls)
   end
 
   @mutex = Mutex.new(:reentrant)
@@ -131,7 +131,7 @@ class CoAP::Client
   end
 
   def exec!(request : CoAP::Request) : CoAP::ResponseHandler
-    exec(request).not_nil!
+    exec(request).as(CoAP::ResponseHandler)
   end
 
   # message_id => token id
diff --git a/src/coap/client/request.cr b/src/coap/client/request.cr
index e819d9e..8590645 100644
--- a/src/coap/client/request.cr
+++ b/src/coap/client/request.cr
@@ -23,14 +23,14 @@ class CoAP::Request < HTTP::Request
     message.code_detail = CoAP::MethodCode.parse(self.method.upcase).to_u8
 
     options = self.path.split('/').compact_map { |segment| CoAP::Option.new.string(segment).type(CoAP::Options::Uri_Path) if segment.presence }
-    options << CoAP::Option.new.string(self.query.not_nil!).type(CoAP::Options::Uri_Query) if self.query.presence
+    options << CoAP::Option.new.string(self.query.as(String)).type(CoAP::Options::Uri_Query) if self.query.presence
 
     if origin = self.headers.delete("Origin")
       uri = URI.parse origin
-      default_port = URI.default_port(uri.scheme.not_nil!.downcase)
+      default_port = URI.default_port(uri.scheme.as(String).downcase)
       port = uri.port || default_port || raise("unable to infer CoAP port for #{origin}")
 
-      options << CoAP::Option.new.string(uri.host.not_nil!).type(CoAP::Options::Uri_Host)
+      options << CoAP::Option.new.string(uri.host.as(String)).type(CoAP::Options::Uri_Host)
       options << CoAP::Option.new.uri_port(port).type(CoAP::Options::Uri_Port) unless port == default_port
     else
       raise "no 'Origin' header provided"
@@ -79,7 +79,7 @@ class CoAP::Request < HTTP::Request
       # Extract the payload
       buffer = IO::Memory.new
       buf = Bytes.new(64)
-      while ((bytes = data.read(buf)) > 0)
+      while (bytes = data.read(buf)) > 0
         buffer.write(buf[0, bytes])
       end
       message.payload_data = buffer.to_slice
diff --git a/src/coap/message.cr b/src/coap/message.cr
index 48f8d02..0607a3c 100644
--- a/src/coap/message.cr
+++ b/src/coap/message.cr
@@ -5,8 +5,7 @@ require "./option"
 # coap://  default port 5683
 # coaps:// default port 5684
 
-# https://tools.ietf.org/html/rfc7252#section-3
-class CoAP::Message < BinData
+class CoAP::Header < BinData
   endian big
 
   enum Type
@@ -25,7 +24,14 @@ class CoAP::Message < BinData
     enum_bits 2, type : Type = Type::Confirmable
 
     bits 4, :token_length, value: ->{ token.size.to_u8 }
+  end
+end
 
+# https://tools.ietf.org/html/rfc7252#section-3
+class CoAP::Message < CoAP::Header
+  endian big
+
+  bit_field do
     # https://tools.ietf.org/html/rfc7252#section-12.1
     enum_bits 3, code_class : CodeClass = CodeClass::Method