Extract file handling out (as a plugin?) to enable casbin to be used on React Native

Hey,

firstly thanks for this awesome library!

I noticed that the frontend casbin library uses this under-the-hood, so I’m using this library on both microservice and Frontend.

However, I’d love to be able to use this library on React Native - which would work, but because the model loading from file uses the fs library, I can’t.

How likely/possible would it be to extract out model loading from a file/file handling to be a plugin/adapter to remove the need for fs? (I load the model and policy dynamically from the microservice).

Thanks!

[nodece]

@hsluoyz I agreed with @Sefriol and @harveyappleton idea.

The following is my integration steps:

• create fs-adapter/model plugins in node-casbin project, we doesn’t need to export this in index.ts, node-casbin only uses string/memory adapter/model for cross-platform compatible.
  • fs-adapter
  • fs-model
  • memory-adapter
  • memory-model
• remove ip package from node-casbin, this package uses os module, we can rewrite this package: #266
• globMatch depends on the micromatch package, micromatch uses util provided by Node.js , so we need to consider to use minimatch instead of micromatch: #264

[Sefriol]

node-casbin includes os and fs module from Node. I tried to fix fs module by load fs and react-native-fs dynamically, but still failed, so I suggest to use the rn-nodeify to fix this error.

rn-nodeify looks really scary. I would rather keep fs as is than use it.

If covert the node-casbin to plain javascript, it looks good, but I’ll worry about losing some user, because node-casbin only accepts string model or policy, the user must to install plugin to load the file model or policy.

Same could be said for not doing the change: users won’t use Casbin since it does not work on their platform. Adapters are already in use and I do not see file adapter any more special than any other adapter.

In my opinion, since string / in memory adapter is usable between all platforms, it should be the default one and file adapter should be a plugin like the rest of them.

So pretty much two options:

1. File-adapter will be deprecated in node-casbin and add it shall be a plugin. Plugin is added into devDependancies for the tests.
2. We dynimically install/load a library based on the platform.