Add non-blocking channel

README.md

@@ -17,29 +17,46 @@ dependencies:
 ## Usage
 
 ```crystal
-require "json"
 require "cocoon"
 require "http/client"
 
 alias Response = HTTP::Client::Response
 cocoon = Cocoon::Wrapper(Response).new
 
-channel = cocoon.wrap do
-  headers = HTTP::Headers{ "Accept" => "application/vnd.github.v3+json" }
-  HTTP::Client.get "https://api.github.com/networks/crystal-lang/crystal/events", headers: headers
-end
-
-if resp = channel.receive
-  if resp.is_a?(Response)
-    if resp.success?
-      pp Array(Hash(String, JSON::Any)).from_json(resp.body)
+loop do
+  result = cocoon.wrap do
+    if Random.rand > 0.5
+      HTTP::Client.get("https://github.com")
     else
-      Log.warn{ HTTP::Status.new(resp.status_code).description }
+      raise "Connection is lost"
     end
-  elsif resp.is_a?(Exception)
-    Log.warn exception: resp, &.emit("Hi dear! I missed you.")
   end
+
+  # something in the &block raised Exception
+  if result.is_a?(Exception)
+    puts result.message
+  end
+
+  # &block is done
+  if result.is_a?(Response)
+    puts "X-GitHub-Request-Id: #{result.headers["X-GitHub-Request-Id"]}"
+  end
+
+  # &block has no result or task is not ended yet
+  if result.is_a?(Nil)
+    puts "Nothing..."
+  end
+
+  sleep 1
 end
+
+# => Nothing...
+# => X-GitHub-Request-Id: EF51:10C35:3A33E0D:3BCCF8A:603C72E7
+# => Connection is lost
+# => X-GitHub-Request-Id: EF52:0AF5:44114C4:45B5044:603C72E9
+# => X-GitHub-Request-Id: EF53:E298:B55ADC:B9B0DF:603C72EA
+# => Connection is lost
+# => Connection is lost
 ```
 
 ## Contributing

sample/base.cr

@@ -0,0 +1,32 @@
+require "cocoon"
+require "http/client"
+
+alias Response = HTTP::Client::Response
+cocoon = Cocoon::Wrapper(Response).new
+
+loop do
+  result = cocoon.wrap do
+    if Random.rand > 0.5
+      HTTP::Client.get("https://github.com")
+    else
+      raise "Connection is lost"
+    end
+  end
+
+  # something in the &block raised Exception
+  if result.is_a?(Exception)
+    puts result.message
+  end
+
+  # &block is done
+  if result.is_a?(Response)
+    puts "X-GitHub-Request-Id: #{result.headers["X-GitHub-Request-Id"]}"
+  end
+
+  # &block has no result or task is not ended yet
+  if result.is_a?(Nil)
+    puts "Nothing..."
+  end
+
+  sleep 1
+end

shard.yml

@@ -1,5 +1,5 @@
 name: cocoon
-version: 0.1.3
+version: 0.2.3
 
 authors:
   - Sergey Fedorov <creadone@gmail.com>

spec/cocoon_spec.cr

@@ -5,7 +5,7 @@ describe Cocoon do
     cocoon = Cocoon::Wrapper(Int32).new
 
     it "should return sum of integers" do
-      if result = cocoon.wrap{ 1 + 3 }.receive
+      if result = cocoon.wrap { 1 + 3 }
         result.should eq(4)
       end
     end

src/cocoon.cr

@@ -3,28 +3,30 @@ module Cocoon
 
   class Wrapper(T)
     def initialize(
-      @result = Channel(T | Exception).new,
-      @output = Channel(T | Exception).new
+      @result = Channel(T | Exception | Nil).new,
+      @output = Channel(T | Exception | Nil).new
     )
     end
 
     def wrap(&block : -> T) forall T
       spawn(name: "executor") do
-        if data = block.call
-          @result.send data
-        end
-        rescue ex
-          @result.send ex
+        data = block.call
+        @result.send data
+      rescue ex
+        @result.send ex
       end
 
       Fiber.yield
 
       spawn(name: "receiver") do
-        if data = @result.receive
+        select
+        when data = @result.receive
           @output.send data
+        else
+          @output.send nil
         end
       end
-      @output
+      @output.receive
     end
   end
 end