Revert "FIX: Recover from Bedrock returning invalid base64 payloads during streaming (#352)" (#353)

This reverts commit ef7d4cc509.

lib/completions/endpoints/aws_bedrock.rb

@@ -71,7 +71,7 @@ module DiscourseAi
             .string
             .then { JSON.parse(_1) }
             .dig("bytes")
-            .then { Base64.decode64(_1.to_s) }
+            .then { Base64.decode64(_1) }
         rescue JSON::ParserError,
                Aws::EventStream::Errors::MessageChecksumError,
                Aws::EventStream::Errors::PreludeChecksumError => e

spec/lib/completions/endpoints/aws_bedrock_spec.rb

@@ -78,10 +78,12 @@ RSpec.describe DiscourseAi::Completions::Endpoints::AwsBedrock do
   def stream_line(delta, finish_reason: nil)
     encoder = Aws::EventStream::Encoder.new
 
-    bytes =
-      if delta.nil?
-        nil
-      else
+    message =
+      Aws::EventStream::Message.new(
+        payload:
+          StringIO.new(
+            {
+              bytes:
                 Base64.encode64(
                   {
                     completion: delta,
@@ -92,10 +94,10 @@ RSpec.describe DiscourseAi::Completions::Endpoints::AwsBedrock do
                     model: "claude-2",
                     exception: nil,
                   }.to_json,
+                ),
+            }.to_json,
+          ),
       )
-      end
-
-    message = Aws::EventStream::Message.new(payload: StringIO.new({ bytes: bytes }.to_json))
 
     encoder.encode(message)
   end
@@ -120,17 +122,4 @@ RSpec.describe DiscourseAi::Completions::Endpoints::AwsBedrock do
   end
 
   it_behaves_like "an endpoint that can communicate with a completion service"
-
-  it "skips empty deltas" do
-    completion_deltas = [nil, "Mount", "ain", " ", "Tree ", "Frog"]
-    stub_streamed_response(prompt, completion_deltas)
-    completion_response = +""
-
-    model.perform_completion!(prompt, Fabricate(:user)) do |partial, cancel|
-      completion_response << partial
-      cancel.call if completion_response.split(" ").length == 2
-    end
-
-    expect(completion_response).to eq(completion_deltas[0...-1].join)
-  end
 end