N-API NodeSummit-2017
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N-API is a new stable C/C++ API for building native modules in Node.js that provides ABI compatibility across Node.js versions and platforms without requiring recompilation. It allows modules to be compiled once and run on multiple Node.js versions and platforms. Several major modules have already been ported to N-API including Node-Sass, Canvas, SQLite, LevelDown, and Nanomsg. The presenters encourage more native module maintainers to consider porting to help improve compatibility and reduce maintenance costs.
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N-API NodeSummit-2017
- 1. N-API: Next Generation Node API for native modules Arunesh Chandra, Microsoft Michael Dawson, IBM
- 2. Arunesh Chandra, Microsoft Senior Program Manager @ Microsoft Developer Tools and Services for Node.js Time-Travel Debugging Node.js Community Node-ChakraCore, N-API WG Contact me: Arunesh.Chandra@Microsoft.com Twitter: @AruneshC Github: @aruneshchandra
- 3. Michael Dawson, IBM Senior Software Developer @ IBM IBM Node.js community lead/IBM Runtime Technologies Node.js collaborator, CTC and TSC member Active in LTS, build, benchmarking, api and post-mortem working groups Contact me: michael_dawson@ca.ibm.com Twitter: @mhdawson1 Github: @mhdawson Linkedin: https://www.linkedin.com/in/michael-dawson-6051282
- 4. Contributors
- 5. What is N-API ? N-API is a stable Node API layer for native modules, that provides ABI compatibility guarantees across different Node versions & flavors. N-API enables native modules to just work across different versions and flavors of Node.js without recompilations! Available as Experimental in Node.js 8
- 6. Why do I care about N-API ? Reduces maintenance cost for Native module maintainers Reduces friction from upgrading to newer Node.js versions in production deployments
- 7. What are people saying about it …
- 8. Is it the new NaN ? • N-API has more complete isolation from V8 • Compile once/run multiple versions and flavors of Node • Both C and C++ usage supported • N-API expected to replace NaN usage
- 9. Ported Modules • Node-Sass • Canvas • SQLlite • LevelDown • Nanomsg • IoTivity
- 10. N-API Coverage Data based on Top 30 depended on native modules 195 Total V8 APIs used in 30 modules 140/195 N-API equivalent exists 83/195 Exercised by 5 ported modules v8:Isolate APIs no N-API equivalence planned
- 11. N-API Demo ---------------------------------------------------------------------------------------------------- github: https://github.com/boingoing/napi_demo YouTube: https://www.youtube.com/watch?v=nmXhJ88nZsk
- 12. API Shape napi_status napi_create_array(napi_env env, napi_value* result); napi_status napi_get_last_error_info(napi_env e, const napi_extended_error_info** result); napi_status napi_is_exception_pending(napi_env e, bool* result); napi_status napi_get_and_clear_last_exception(napi_env e, napi_value* result); napi_status napi_throw(napi_env e, napi_value error); • Collection of C APIs available natively in Node.js 8.0 • API Docs - https://nodejs.org/dist/latest-v8.x/docs/api/n-api.html • ../src/node_api.h
- 13. Examples – C- API #include <node_api.h> napi_value RunCallback(napi_env env, const napi_callback_info info) { ... } #define DECLARE_NAPI_METHOD(name, func) { name, 0, func, 0, 0, 0, napi_default, 0 } void Init(napi_env env, napi_value exports, napi_value module, void* priv) { napi_status status; napi_property_descriptor desc = DECLARE_NAPI_METHOD("exports", RunCallback); status = napi_define_properties(env, module, 1, &desc); assert(status == napi_ok); } NAPI_MODULE(addon, Init) https://github.com/nodejs/abi-stable-node-addon-examples 3_callbacks
- 14. Examples – C- API #include <node_api.h> napi_value RunCallback(napi_env env, const napi_callback_info info) { napi_status status; size_t argc = 1; napi_value args[1]; status = napi_get_cb_info(env, info, &argc, args, NULL, NULL); napi_value cb = args[0]; napi_value argv[1]; status = napi_create_string_utf8(env, "hello world", -1, argv); napi_value global; status = napi_get_global(env, &global); napi_value result; status = napi_call_function(env, global, cb, 1, argv, &result); return nullptr; } optional 'this' optional 'data pointer' optional length NODE_BUILD=/home/mhdawson/newpull/io.js export PATH=$NODE_BUILD:$NODE_BUILD/../abi-stable-node-addon- examples/node_modules/node-gyp/bin/:$PATH export NPM=$NODE_BUILD/deps/npm/bin/npm-cli.js alias npm=$NPM alias node-gyp=node-gyp.js export npm_config_nodedir=$NODE_BUILD export NODE_OPTIONS=--napi-modules
- 15. Example – C++ Wrapper Module https://github.com/nodejs/node-addon-api https://www.npmjs.com/package/node-addon-api https://nodejs.github.io/node-addon-api/namespace_napi.html
- 16. Example – C++ Wrapper Example NaN node-addon-api void Init(v8::Local<v8::Object> exports, v8::Local<v8::Object> module) { Nan::SetMethod(module, "exports", RunCallback); } void RunCallback(const Napi::CallbackInfo& info) { Napi::Function cb = info[0].As<Napi::Function>(); cb.MakeCallback(info.Env().Global(), { Napi::String::New(info.Env(), "hello world") }); } https://github.com/nodejs/node-addon-api/blob/master/tools/conversion.js #include <nan.h> void RunCallback(const Nan::FunctionCallbackInfo<v8::Value>& info) { v8::Local<v8::Function> cb = info[0].As<v8::Function>(); const unsigned argc = 1; v8::Local<v8::Value> argv[argc] = { Nan::New("hello world").ToLocalChecked() }; Nan::MakeCallback(Nan::GetCurrentContext()->Global(), cb, argc, argv); } NODE_MODULE(addon, Init) #include <napi.h> void Init(Napi::Env env, Napi::Object exports, Napi::Object module) { module.DefineProperty(Napi::PropertyDescriptor::Function("exports", RunCallback)); } NODE_API_MODULE(addon, Init)
- 17. Backward Compatibility • Available in 8.x • Plan to backport to 6.x • For 4.x • Copy of API built into node-addon-api module • Do NOT get build once/run any version • Can maintain module with single code base
- 18. Tools for getting started • From scratch • https://github.com/digitalinfinity/generator-napi-module (C++ Wrapper) • Migrating from NaN • https://github.com/nodejs/node-addon-api/blob/master/tools/conversion.js
- 19. How you can help • Port a module • Try out one of the ported modules • Help improve the documentation • Improve test coverage • Join the N-API Working Group
- 20. Calling all native module maintainers • Feedback is key to success • Earlier the Better • Helps overall community • API additions prioritized by need • We are reaching out • Need leading modules to help out • We understand it will take time • Guidance for publishing n-api versions • https://nodejs.org/en/docs/guides/publishing-napi-modules/ https://github.com/nodejs/abi-stable-node/milestone/5
- 21. Copyright and Trademarks © IBM Corporation and Microsoft Corporation, 2017. All Rights Reserved IBM, the IBM logo, ibm.com are trademarks or registered trademarks of International Business Machines Corp., registered in many jurisdictions worldwide. Other product and service names might be trademarks of IBM or other companies. A current list of IBM trademarks is available on the Web at “Copyright and trademark information” at www.ibm.com/legal/copytrade.shtml Microsoft is a trademark of Microsoft Corporation in the United States, other countries, or both. Node.js is an official trademark of Joyent. IBM SDK for Node.js is not formally related to or endorsed by the official Joyent Node.js open source or commercial project. Java, JavaScript and all Java-based trademarks and logos are trademarks or registered trademarks of Oracle and/or its affiliates. npm is a trademark of npm, Inc.