Advanced

RESTCONF HTTP Request Access

This is useful for custom authorization or general need to access the HTTP request information

Steps:

1.) Register a request restconf.RequestFilter with RESTCONF restconf.Server instance

2.) Filter returns a context.Context that contains any custom data that you might extract from the HTTP request like HTTP header information, URL parameters or certificate information.

3.) Values from that context.Context will be made available to all your node.Node implementations

Example Code:

s := restconf.NewServer(d)
s.Filters = append(s.Filters, filter)

func filter(ctx context.Context, w http.ResponseWriter, r *http.Request) (context.Context, error) {
    return context.WithValue(ctx, "mykey", "my-value"), nil
}

func myNode() node.Node {
    return nodeutil.Basic{
        OnAction: func(r node.ActionRequest) (node.Node, error) {
            myval := r.Selection.Context.Value("mykey")
        }
    }
}

Transitioning to stricter RESTCONF RFC compliance

There are a number of breaking changes in FreeCONF yang and restconf libraries needed to be made to be in compliance with RFC. This is of course important so FreeCONF can be used with other libraries. In order to not break existing codebases, there are two data structures that you can use to restore previous operations until you have time to port your code over to the stricter compliance. Eventually this legacy mode will be removed.

restconf.Compliance = restconf.Simplistic
yang.Compliance = yang.Simplistic

Returning 401, 409 and 400 class errors

When coding your node.Node implementation, if you return an error from any function, your http clients will receive a 500 error, but if you want to return an error with a different HTTP status code, you can use or wrap one of the predefined errors

import (
  "github.com/freeconf/yang/fc"
)

  ...
  // Option #1 - straight 401 error
  return fc.UnauthorizedError 

  // Option #2 - enhanced but still an 401 error
  return fmt.Errorf("Bad ACL %w", fc.UnauthorizedError)