Add support to node 12.x and Gazebo 11

[FelipeGdM]

Hello everyone,

From v8 version 6.0 (shipped w/ node 10) to v8 7.0 (shipped w/ node 12), there was a major change in API methods that prevented the project to run with node 12. Unfortunately, these changes break compatibility with node 8.x and 10.x as well, maybe it is interesting to release a major version of gzweb.

This PR addresses this problem and changes the calls to v8 API following the new syntax. No logic or functional changes were made.

Another change is the update to Gazebo version 11. It was necessary to pass the flag -std=c++17 in order tho compile the dependency sdf format version 9.0

Thank you everyone! =)

Useful references:

v8/node deprecated APIs and how to handle them bcoin-org/bcrypto#7
APIs removed in V8 7.0 and native addons nodejs/node#23122
[v10.x] deps: increase V8 deprecation levels nodejs/node#23159
Properly handle the requirement of C++17 at the CMake exported target level gazebosim/sdformat#251

Closes #204
Closes #203
Closes #174

[iche033]

thanks for the pull request!

This works for me when building with node v12 + gazebo9. My only question is if we could ifdef the changes based on node version so users can still choose v10 if that works for them?

[FelipeGdM]

Hi @iche033!

I have done some research in order to find the best way to achieve multi-version support (I am not an expert on writing node C++ addons 😝 ) and the cleanest way to do that seems to use the native abstractions for nodejs. From the project's README

Thanks to the crazy changes in V8 (and some in Node core), keeping native addons compiling happily across versions, particularly 0.10 to 0.12 to 4.0, is a minor nightmare. The goal of this project is to store all logic necessary to develop native Node.js addons without having to inspect NODE_MODULE_VERSION and get yourself into a macro-tangle.

A small refactor across the file will be necessary, but the code will be easier to maintain along node updates.

What do you think @iche033 ?

If you send a thumbs up, I may update the PR with these refactor, otherwise I may add ifdef statements to guard the problematic parts

[newcanopies]

@FelipeGdM @iche033

Thanks very much to both.
I applied:

d58203c
6d926df
9b49579
e907a39

however, building v12.20.0 against Gazebo11/Foxy/Focal does not work. Any clues?

`

npm start
[email protected] start /home/user/gzweb
if [ $npm_config_port ]; then port=$npm_config_port; fi; cd gzbridge && ./server.js $port

internal/modules/cjs/loader.js:818
throw err;
^

Error: Cannot find module './build/Debug/gzbridge'
Require stack:

• /home/user/gzweb/gzbridge/server.js
  at Function.Module._resolveFilename (internal/modules/cjs/loader.js:815:15)
  at Function.Module._load (internal/modules/cjs/loader.js:667:27)
  at Module.require (internal/modules/cjs/loader.js:887:19)
  at require (internal/modules/cjs/helpers.js:74:18)
  at Object. (/home/user/gzweb/gzbridge/server.js:9:18)
  at Module._compile (internal/modules/cjs/loader.js:999:30)
  at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
  at Module.load (internal/modules/cjs/loader.js:863:32)
  at Function.Module._load (internal/modules/cjs/loader.js:708:14)
  at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:60:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ '/home/user/gzweb/gzbridge/server.js' ]
  }
  npm ERR! code ELIFECYCLE
  npm ERR! errno 1
  npm ERR! [email protected] start: if [ $npm_config_port ]; then port=$npm_config_port; fi; cd gzbridge && ./server.js $port
  npm ERR! Exit status 1
  npm ERR!
  npm ERR! Failed at the [email protected] start script.
  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR! /home/user/.npm/_logs/2021-01-31T10_14_17_397Z-debug.log
`

[FelipeGdM]

@newcanopies, it seems that the error is happening when you build the project, may you you post the output of npm run deploy?

I would be happy to help, but I would ask you to post this within an issue (like #204), as troubleshooting is not the main purpose of a pull request

[iche033]

cleanest way to do that seems to use the native abstractions for nodejs.

thanks for looking into this. This also led me down to some light reading on the different abstractions for nodejs. So there is NAN, and there is also N-API and its C++ wrapper node-addon-api. My understanding is that NAN is more mature and supports older verions of nodejs but more projects are starting to transition to using N-API (or its C++ wrapper). The downside of using N-API is that it's only available in nodejs version 8 (introduced as experimental) and above.

I'm fine with either of these options. I'm not sure how much effort it'll take but if you're up for the task, I'm happy to review the changes and get it into gzweb!

[FelipeGdM]

Since both options solve our problem, compatibility with older versions of node is a desirable feature and the work needed to migrate to nan is considerably simpler than migrating to N-API (due to the high similarity between nan and plain v8 calls), I decided to migrate to nan

As stated in this StackOverflow answer

use nan if you want something mature and very backwards-compatible

This article from MongoDB developers illustrates the work needed to migrate from nan/v8 to N-API

That said, the code structure remains the same, but several method calls were replaced by its nan counterpart.

I was able to run with node v8.17.0, v10.23.2, v12.20.1 and v14.15.4

[iche033]

Sounds good to me. Let's go with nan

I tested with node v8, 10, and 12 with gazebo9 on Bionic and they all work fine!

[rubenanapu]

Awesome. I was struggling to have a custom gzweb compiled for Gazebo 11 until I found this PR.