Merge pull request #12 from yjean/feat/chat-streaming-callback

feat(chat): handle block to received streamed data

Author: andreibondarev

README.md

@@ -29,35 +29,51 @@ If bundler is not being used to manage dependencies, install the gem by executin
 ## Usage
 
 ### Instantiating API client
+
 ```ruby
 require "cohere"
 
 client = Cohere::Client.new(
   ENV['COHERE_API_KEY']
 )
 ```
+
 ### Generate
+
 ```ruby
 client.generate(
     prompt: "Once upon a time in a magical land called"
 )
 ```
 
 ### Chat
+
 ```ruby
 client.chat(
     message: "Hey! How are you?"
 )
 ```
 
+`chat` supports a streaming option. You can pass a block to the `chat` method and it will yield a new chunk as soon as it is received.
+
+```ruby
+client.chat(message: "Hey! How are you?", stream: true) do |chunk, overall_received_bytes|
+  puts "Received #{overall_received_bytes} bytes: #{chunk.force_encoding(Encoding::UTF_8)}"
+end
+```
+
+`force_encoding` is preferred to avoid JSON parsing issue when Cohere returns emoticon.
+
 ### Embed
+
 ```ruby
 client.embed(
     texts: ["hello!"]
 )
 ```
 
 ### Classify
+
 ```ruby
 examples = [
     { text: "Dermatologists don't like her!", label: "Spam" },
@@ -84,27 +100,31 @@ client.classify(
 ```
 
 ### Tokenize
+
 ```ruby
 client.tokenize(
     text: "hello world!"
 )
 ```
 
 ### Detokenize
+
 ```ruby
 client.detokenize(
     tokens: [33555, 1114 , 34]
 )
 ```
 
 ### Detect language
+
 ```ruby
 client.detect_language(
     texts: ["Здравствуй, Мир"]
 )
 ```
 
 ### Summarize
+
 ```ruby
 client.summarize(
     text: "..."

lib/cohere/client.rb

@@ -29,12 +29,16 @@ def chat(
       k: nil,
       p: nil,
       frequency_penalty: nil,
-      presence_penalty: nil
+      presence_penalty: nil,
+      &block
     )
       response = connection.post("chat") do |req|
         req.body = {message: message}
         req.body[:model] = model if model
-        req.body[:stream] = stream if stream
+        if stream || block
+          req.body[:stream] = true
+          req.options.on_data = block if block
+        end
         req.body[:preamble_override] = preamble_override if preamble_override
         req.body[:chat_history] = chat_history if chat_history
         req.body[:conversation_id] = conversation_id if conversation_id