README
¶
go-jsonrpc
Low Boilerplate JSON-RPC 2.0 library
Usage examples
Server
// Have a type with some exported methods
type SimpleServerHandler struct {
n int
}
func (h *SimpleServerHandler) AddGet(in int) int {
h.n += in
return h.n
}
func main() {
// create a new server instance
rpcServer := jsonrpc.NewServer()
// create a handler instance and register it
serverHandler := &SimpleServerHandler{}
rpcServer.Register("SimpleServerHandler", serverHandler)
// rpcServer is now http.Handler which will serve jsonrpc calls to SimpleServerHandler.AddGet
// a method with a single int param, and an int response. The server supports both http and websockets.
// serve the api
testServ := httptest.NewServer(rpcServer)
defer testServ.Close()
fmt.Println("URL: ", "ws://"+testServ.Listener.Addr().String())
[..do other app stuff / wait..]
}
Client
func start() error {
// Create a struct where each field is an exported function with signatures matching rpc calls
var client struct {
AddGet func(int) int
}
// Make jsonrp populate func fields in the struct with JSONRPC calls
closer, err := jsonrpc.NewClient(context.Background(), rpcURL, "SimpleServerHandler", &client, nil)
if err != nil {
return err
}
defer closer()
...
n := client.AddGet(10)
// if the server is the one from the example above, n = 10
n := client.AddGet(2)
// if the server is the one from the example above, n = 12
}
Supported function signatures
type _ interface {
// No Params / Return val
Func1()
// With Params
// Note: If param types implement json.[Un]Marshaler, go-jsonrpc will use it
Func2(param1 int, param2 string, param3 struct{A int})
// Returning errors
// * For some connection errors, go-jsonrpc will return jsonrpc.RPCConnectionError{}.
// * RPC-returned errors will be constructed with basic errors.New(__"string message"__)
// * JSON-RPC error codes can be mapped to typed errors with jsonrpc.Errors - https://pkg.go.dev/github.com/jafri/go-jsonrpc#Errors
// * For typed errors to work, server needs to be constructed with the `WithServerErrors`
// option, and the client needs to be constructed with the `WithErrors` option
Func3() error
// Returning a value
// Note: The value must be serializable with encoding/json.
Func4() int
// Returning a value and an error
// Note: if the handler returns an error and a non-zero value, the value will not
// be returned to the client - the client will see a zero value.
Func4() (int, error)
// With context
// * Context isn't passed as JSONRPC param, instead it has a number of different uses
// * When the context is cancelled on the client side, context cancellation should propagate to the server handler
// * In http mode the http request will be aborted
// * In websocket mode the client will send a `xrpc.cancel` with a single param containing ID of the cancelled request
// * If the context contains an opencensus trace span, it will be propagated to the server through a
// `"Meta": {"SpanContext": base64.StdEncoding.EncodeToString(propagation.Binary(span.SpanContext()))}` field in
// the jsonrpc request
//
Func5(ctx context.Context, param1 string) error
// With non-json-serializable (e.g. interface) params
// * There are client and server options which make it possible to register transformers for types
// to make them json-(de)serializable
// * Server side: jsonrpc.WithParamDecoder(new(io.Reader), func(ctx context.Context, b []byte) (reflect.Value, error) { ... }
// * Client side: jsonrpc.WithParamEncoder(new(io.Reader), func(value reflect.Value) (reflect.Value, error) { ... }
// * For io.Reader specifically there's a simple param encoder/decoder implementation in go-jsonrpc/httpio package
// which will pass reader data through separate http streams on a different hanhler.
// * Note: a similar mechanism for return value transformation isn't supported yet
Func6(r io.Reader)
// Returning a channel
// * Only supported in websocket mode
// * If no error is returned, the return value will be an int channelId
// * When the server handler writes values into the channel, the client will receive `xrpc.ch.val` notifications
// with 2 params: [chanID: int, value: any]
// * When the channel is closed the client will receive `xrpc.ch.close` notification with a single param: [chanId: int]
// * The client-side channel will be closed when the websocket connection breaks; Server side will discard writes to
// the channel. Handlers should rely on the context to know when to stop writing to the returned channel.
// NOTE: There is no good backpressure mechanism implemented for channels, returning values faster that the client can
// receive them may cause memory leaks.
Func7(ctx context.Context, param1 int, param2 string) (<-chan int, error)
}
Contribute
PRs are welcome!
License
Dual-licensed under MIT + Apache 2.0
Documentation
¶
Index ¶
- Constants
- func DecodeParams[T any](p RawParams) (T, error)
- func ExtractReverseClient[C any](ctx context.Context) (C, bool)
- func WithClientHandler(ns string, hnd interface{}) func(c *Config)
- func WithClientHandlerAlias(alias, original string) func(c *Config)
- func WithErrors(es Errors) func(c *Config)
- func WithHTTPClient(h *http.Client) func(c *Config)
- func WithNoReconnect() func(c *Config)
- func WithParamEncoder(t interface{}, encoder ParamEncoder) func(c *Config)
- func WithPingInterval(d time.Duration) func(c *Config)
- func WithReconnectBackoff(minDelay, maxDelay time.Duration) func(c *Config)
- func WithTimeout(d time.Duration) func(c *Config)
- type ClientCloser
- type Config
- type ErrClient
- type ErrorCode
- type Errors
- type Option
- type ParamDecoder
- type ParamEncoder
- type RPCConnectionError
- type RPCServer
- type RawParams
- type ServerConfig
- type ServerOption
Constants ¶
View Source
const ( ProxyTagRetry = "retry" ProxyTagNotify = "notify" ProxyTagRPCMethod = "rpc_method" )
View Source
const DEFAULT_MAX_REQUEST_SIZE = 100 << 20 // 100 MiB
Limit request size. Ideally this limit should be specific for each field in the JSON request but as a simple defensive measure we just limit the entire HTTP body. Configured by WithMaxRequestSize.
View Source
const FirstUserCode = 2
Variables ¶
This section is empty.
Functions ¶
func DecodeParams ¶
todo is there a better way to tell 'struct with any number of fields'?
func ExtractReverseClient ¶
ExtractReverseClient will extract reverse client from context. Reverse client for the type will only be present if the server was constructed with a matching WithReverseClient option and the connection was a websocket connection. If there is no reverse client, the call will return a zero value and `false`. Otherwise a reverse client and `true` will be returned.
func WithClientHandler ¶
func WithClientHandlerAlias ¶
WithClientHandlerAlias creates an alias for a client HANDLER method - for handlers created with WithClientHandler
func WithErrors ¶
func WithHTTPClient ¶
func WithNoReconnect ¶
func WithNoReconnect() func(c *Config)
func WithParamEncoder ¶
func WithParamEncoder(t interface{}, encoder ParamEncoder) func(c *Config)
func WithReconnectBackoff ¶
func WithTimeout ¶
Types ¶
type ClientCloser ¶
type ClientCloser func()
ClientCloser is used to close Client from further use
func NewClient ¶
func NewClient(ctx context.Context, addr string, namespace string, handler interface{}, requestHeader http.Header) (ClientCloser, error)
NewClient creates new jsonrpc 2.0 client
handler must be pointer to a struct with function fields Returned value closes the client connection TODO: Example
func NewMergeClient ¶
func NewMergeClient(ctx context.Context, addr string, namespace string, outs []interface{}, requestHeader http.Header, opts ...Option) (ClientCloser, error)
NewMergeClient is like NewClient, but allows to specify multiple structs to be filled in the same namespace, using one connection
type ErrClient ¶
type ErrClient struct {
// contains filtered or unexported fields
}
ErrClient is an error which occurred on the client side the library
type RPCConnectionError ¶
type RPCConnectionError struct {
// contains filtered or unexported fields
}
func (*RPCConnectionError) Error ¶
func (e *RPCConnectionError) Error() string
func (*RPCConnectionError) Unwrap ¶
func (e *RPCConnectionError) Unwrap() error
type RPCServer ¶
type RPCServer struct {
// contains filtered or unexported fields
}
RPCServer provides a jsonrpc 2.0 http server handler
func NewServer ¶
func NewServer(opts ...ServerOption) *RPCServer
NewServer creates new RPCServer instance
func (*RPCServer) AliasMethod ¶
type RawParams ¶
type RawParams json.RawMessage
type ServerConfig ¶
type ServerConfig struct {
// contains filtered or unexported fields
}
type ServerOption ¶
type ServerOption func(c *ServerConfig)
func WithMaxRequestSize ¶
func WithMaxRequestSize(max int64) ServerOption
func WithParamDecoder ¶
func WithParamDecoder(t interface{}, decoder ParamDecoder) ServerOption
func WithReverseClient ¶
func WithReverseClient[RP any](namespace string) ServerOption
WithReverseClient will allow extracting reverse client on **WEBSOCKET** calls. RP is a proxy-struct type, much like the one passed to NewClient.
func WithServerErrors ¶
func WithServerErrors(es Errors) ServerOption
func WithServerPingInterval ¶
func WithServerPingInterval(d time.Duration) ServerOption
Source Files
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