simplify signature check, update docs

Author: umputun

README.md

@@ -1,8 +1,8 @@
 # jrpc - rpc with json [![Build](https://github.com/go-pkgz/jrpc/actions/workflows/ci.yml/badge.svg)](https://github.com/go-pkgz/jrpc/actions/workflows/ci.yml) [![Go Report Card](https://goreportcard.com/badge/github.com/go-pkgz/jrpc)](https://goreportcard.com/report/github.com/go-pkgz/jrpc) [![Coverage Status](https://coveralls.io/repos/github/go-pkgz/jrpc/badge.svg?branch=master)](https://coveralls.io/github/go-pkgz/jrpc?branch=master) [![godoc](https://godoc.org/github.com/go-pkgz/jrpc?status.svg)](https://godoc.org/github.com/go-pkgz/jrpc)
 
 jrpc library provides client and server for RPC-like communication over HTTP with json encoded messages.
-The protocol is a somewhat simplified version of json-rpc with a single POST call sending Request json 
-(method name and the list of parameters) moreover, receiving json Response with result data and an error string.
+The protocol is a somewhat simplified version of json-rpc with a single POST call sending `Request` json 
+(method name and the list of parameters) moreover, receiving json `Response` with result data and an error string.
 
 ## Usage
 
@@ -28,29 +28,27 @@ plugin.Run(9090)
 
 The constructor `NewServer` accept two parameters:
 * `API` - a base url for rpc calls
-* `Options` - allows configure server parameters such is timeouts, logger, limits, middlewares and etc.  
-
-##### options
-`jrpc.NewServer` call accepts functional options:
-* `jrpc.Auth` - set credentials basic auth to server, accepts `username` and `password`
-* `jrpc.WithTimeout` - sets global timeouts for server requests, such as read, write and idle. Call accept `Timeouts` struct.
-* `jrpc.WithLimits` - define limit for server call, accepts limit value in `float64` type
-* `jrpc.WithThrottler` - sets throttler middleware with specify limit value
-* `jrpc.WithMiddlewares` - sets custom middlewares list to server, accepts list of handler with idiomatic type `func(http.Handler) http.Handler`
-* `jrpc.WithtSignature` - sets server signature, accept appName, author and version. Disable by default. 
-* `jrpc.WithLogger` - define custom logger (e.g. [lgr](https://github.com/go-pkgz/lgr))
+* `Options` - optional parameters such is timeouts, logger, limits, middlewares and etc.
+  * `Auth` - set credentials basic auth to server, accepts `username` and `password`
+  * `WithTimeout` - sets global timeouts for server requests, such as read, write and idle. Call accept `Timeouts` struct.
+  * `WithLimits` - define limit for server call, accepts limit value in `float64` type
+  * `WithThrottler` - sets throttler middleware with specify limit value
+  * `WithtSignature` - sets server signature, accept appName, author and version. Disable by default. 
+  * `WithLogger` - define custom logger (e.g. [lgr](https://github.com/go-pkgz/lgr))
+  * `WithMiddlewares` - sets custom middlewares list to server, accepts list of handler with idiomatic type `func(http.Handler) http.Handler`
 
 Example with options:
 ```go
 plugin := NewServer("/command",
+	    Auth("user", "password"),
 		WithTimeout(Timeouts{ReadHeaderTimeout: 5 * time.Second, WriteTimeout: 5 * time.Second, IdleTimeout: 10 * time.Second}),
 		WithThrottler(120),
-		WithLimits(100), 
-		WithMiddlewares(middleware.Heartbeat('/ping'), middleware.Profiler, middleware. StripSlashes),
+		WithLimits(100),
+        WithtSignature("the best plugin ever", "author", "1.0.0"),
+		WithMiddlewares(middleware.Heartbeat('/ping'), middleware.Profiler, middleware.StripSlashes),
 )
 ``` 
-**NOTICE:**
-Such middlewares as `RealIP`,`Recoverer`,`Ping`,`NoCache` and `basicAuth` define by default.
+
 ### Application (client)
 
 ```go

options.go

@@ -54,7 +54,7 @@ func WithMiddlewares(middlewares ...func(http.Handler) http.Handler) Option {
 // WithSignature sets signature data for server response headers
 func WithSignature(appName, author, version string) Option {
 	return func(s *Server) {
-		s.signature = &signaturePayload{
+		s.signature = signaturePayload{
 			appName: appName,
 			author:  author,
 			version: version,

server.go

@@ -26,8 +26,7 @@ type Server struct {
 	authPasswd        string      // basic auth password, should match Client.AuthPasswd, optional
 	customMiddlewares middlewares // list of custom middlewares, should match array of http.Handler func, optional
 
-	// use as pointer for checks all fields at one time
-	signature *signaturePayload // add server signature to server response headers appName, author, version), disable by default
+	signature signaturePayload // add server signature to server response headers appName, author, version), disable by default
 
 	timeouts Timeouts // values and timeouts for the server
 	limits   limits   // values and limits for the server
@@ -106,7 +105,7 @@ func (s *Server) Run(port int) error {
 
 	router.Use(middleware.RealIP, rest.Ping, rest.Recoverer(s.logger))
 
-	if s.signature != nil {
+	if s.signature.version != "" || s.signature.author != "" || s.signature.appName != "" {
 		router.Use(rest.AppInfo(s.signature.appName, s.signature.author, s.signature.version))
 	}
 

server_test.go

@@ -313,7 +313,7 @@ func TestServer_WithSignature(t *testing.T) {
 	}
 
 	s = NewServer("/v1/cmd", WithSignature("testApp", "testAuthor", "0.1.0"), WithMiddlewares(checkSignatureMiddlewareFn))
-	assert.Equal(t, &signaturePayload{"testApp", "testAuthor", "0.1.0"}, s.signature)
+	assert.Equal(t, signaturePayload{"testApp", "testAuthor", "0.1.0"}, s.signature)
 
 	s.Add("fn1", func(id uint64, params json.RawMessage) Response {
 		return Response{}