Make oj optional: support pure-Ruby JSON fallback#39
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- Create pure-Ruby JsonWriter that implements Oj::StringWriter API via string concatenation, enabling the library to work without the oj gem - Make oj a soft dependency: loads oj if available, falls back to json gem - Add JSON::Fragment support in JsonValue for pre-encoded JSON embedding - Create benchmark harness comparing oj vs Ruby's built-in JSON gem: - benchmarks/runner.rb: standalone runner with --backend=oj|json flag - benchmarks/run_comparison.rb: orchestrator spawning isolated processes - benchmarks/generate_charts.rb: HTML chart generator with Chart.js - Store benchmark results and comparison charts in benchmarks/results/ - Update oj to 3.16.16, json gem to 2.19.2 Key findings (Ruby 3.3.6, no YJIT): - Hash path + JSON.generate matches or beats Oj for all scenarios - Pure-Ruby JsonWriter is ~1.7x slower than Oj::StringWriter - The json gem has closed the gap significantly with oj https://claude.ai/code/session_018LrqGa8M4Cnvt8cZ2489Vn
Remove the hard dependency on oj from the gemspec. The library now works with either oj (for maximum performance via Oj::StringWriter) or Ruby's built-in JSON gem (via the pure-Ruby JsonWriter fallback). Users who want the oj backend can add `gem 'oj'` to their Gemfile. https://claude.ai/code/session_018LrqGa8M4Cnvt8cZ2489Vn
Remove OjSerializers::JsonWriter, Oj::StringWriter integration, and all write_ APIs (write_one, write_many, write_to_json). Remove default_format since the format is always :hash. Simplify define_serialization_shortcuts, cached method, and code generation to only use the hash path. - Delete lib/oj_serializers/json_writer.rb and setup.rb - Remove code_to_write_to_json, code_to_write_attribute, code_to_write_association - Remove one_as_json, many_as_json, new_json_writer - Simplify json_string_encoder to use JSON.generate - Remove defined?(Oj) checks from json_value.rb - Remove write_one/write_many from compat.rb - Update all benchmarks to use JSON.generate instead of Oj.dump - Delete gemfiles/Gemfile-json-only and spec/support/non_blank_json_writer.rb https://claude.ai/code/session_018LrqGa8M4Cnvt8cZ2489Vn
Rename directories, files, modules, and class references throughout: - lib/oj_serializers/ → lib/json_serializers/ - OjSerializers → JsonSerializers - Oj::Serializer → JsonSerializer (with backward-compat alias) - Update README to emphasize hash-based architecture and memory efficiency - Update MIGRATION_GUIDE.md and CHANGELOG.md references https://claude.ai/code/session_018LrqGa8M4Cnvt8cZ2489Vn
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Summary
This change makes the
ojgem optional for oj_serializers by implementing a pure-Ruby fallback when oj is not available. The library now gracefully degrades to using Ruby's built-in JSON gem instead of requiring oj as a hard dependency.Key Changes
Made oj optional in gemspec: Changed
ojfrom a required dependency to an optional one, allowing the library to work without it installed.Implemented JsonWriter fallback: Added
OjSerializers::JsonWriter, a pure-Ruby replacement forOj::StringWriterthat builds JSON via string concatenation. It implements the same API used by generated serialization code, enabling seamless fallback when oj is unavailable.Updated library initialization: Modified
lib/oj_serializers.rbto conditionally require oj and its setup, falling back to loading JsonWriter when oj is not available.Enhanced Serializer#new_json_writer: Updated to detect whether
Oj::StringWriteris available and use either the oj implementation or the pure-Ruby JsonWriter accordingly.Fixed JsonValue compatibility: Updated
JsonValue#as_jsonto return aJSON::Fragmentwhen oj is not loaded, ensuring pre-encoded JSON strings are properly embedded byJSON.generate.Fixed json_string_encoder: Corrected the fallback to use
JSON.generateinstead ofOj.dumpwhen oj is unavailable.Benchmark Infrastructure
Added comprehensive benchmarking tools to measure performance differences:
benchmarks/runner.rb: Standalone benchmark runner that tests both backends (oj and json) with optional YJIT support, measuring iterations per second across three scenarios (one object, 100 albums, 1000 albums).
benchmarks/run_comparison.rb: Orchestrator that spawns separate Ruby processes for each configuration to ensure clean state, then generates comparison charts.
benchmarks/generate_charts.rb: Generates interactive HTML charts and markdown summaries from benchmark results using Chart.js.
gemfiles/Gemfile-json-only: Dedicated Gemfile for json-only benchmarking that excludes oj to ensure clean backend isolation.
Sample benchmark results: Included baseline results showing oj's performance advantage in streaming scenarios (as_json) while as_hash approaches parity.
Notable Implementation Details
https://claude.ai/code/session_018LrqGa8M4Cnvt8cZ2489Vn