* rpc: improve codec abstraction
rpc.ServerCodec is an opaque interface. There was only one way to get a
codec using existing APIs: rpc.NewJSONCodec. This change exports
newCodec (as NewFuncCodec) and NewJSONCodec (as NewCodec). It also makes
all codec methods non-public to avoid showing internals in godoc.
While here, remove codec options in tests because they are not
supported anymore.
* p2p/simulations: use github.com/gorilla/websocket
This package was the last remaining user of golang.org/x/net/websocket.
Migrating to the new library wasn't straightforward because it is no
longer possible to treat WebSocket connections as a net.Conn.
* vendor: delete golang.org/x/net/websocket
* rpc: fix godoc comments and run gofmt
New APIs added:
client.RegisterName(namespace, service) // makes service available to server
client.Notify(ctx, method, args...) // sends a notification
ClientFromContext(ctx) // to get a client in handler method
This is essentially a rewrite of the server-side code. JSON-RPC
processing code is now the same on both server and client side. Many
minor issues were fixed in the process and there is a new test suite for
JSON-RPC spec compliance (and non-compliance in some cases).
List of behavior changes:
- Method handlers are now called with a per-request context instead of a
per-connection context. The context is canceled right after the method
returns.
- Subscription error channels are always closed when the connection
ends. There is no need to also wait on the Notifier's Closed channel
to detect whether the subscription has ended.
- Client now omits "params" instead of sending "params": null when there
are no arguments to a call. The previous behavior was not compliant
with the spec. The server still accepts "params": null.
- Floating point numbers are allowed as "id". The spec doesn't allow
them, but we handle request "id" as json.RawMessage and guarantee that
the same number will be sent back.
- Logging is improved significantly. There is now a message at DEBUG
level for each RPC call served.
There is no need to depend on the old context package now that the
minimum Go version is 1.7. The move to "context" eliminates our weird
vendoring setup. Some vendored code still uses golang.org/x/net/context
and it is now vendored in the normal way.
This change triggered new vet checks around context.WithTimeout which
didn't fire with golang.org/x/net/context.
