rpc: test cors, and respect option on rest endpoints

internal/services/jsonrpc/methods.go

@@ -140,6 +140,13 @@ func (s *Server) handleMethod(ctx context.Context, method jsonrpc.Method, params
 
 	argsPtr, handler := maker(ctx, s)
 
+	// Treat omitted params as null, which may or may not be acceptable
+	// depending on the handler's parameters type. Otherwise json.Unmarshal
+	// always errors with "unexpected end of JSON input".
+	if params == nil {
+		params = []byte(`null`)
+	}
+
 	err := json.Unmarshal(params, argsPtr)
 	if err != nil {
 		return nil, jsonrpc.NewError(jsonrpc.ErrorInvalidParams, err.Error(), nil)

internal/services/jsonrpc/server.go

@@ -305,21 +305,27 @@ func NewServer(addr string, log log.Logger, opts ...Opt) (*Server, error) {
 		w.Header().Set("content-type", "application/json; charset=utf-8")
 		http.ServeContent(w, r, "openrpc.json", time.Time{}, bytes.NewReader(s.spec))
 	})
-	specHandler = corsHandler(specHandler)
+	if cfg.enableCORS {
+		specHandler = corsHandler(specHandler)
+	}
 	specHandler = recoverer(specHandler, log)
 	mux.Handle(pathSpecV1, specHandler)
 
 	// aggregate health endpoint handler
 	var healthHandler http.Handler
 	healthHandler = http.HandlerFunc(s.healthMethodHandler)
-	healthHandler = corsHandler(healthHandler)
+	if cfg.enableCORS {
+		healthHandler = corsHandler(healthHandler)
+	}
 	healthHandler = recoverer(healthHandler, log)
 	mux.Handle(pathHealthV1, healthHandler)
 
 	// service specific health endpoint handler with wild card for service
 	var userHealthHandler http.Handler
 	userHealthHandler = http.HandlerFunc(s.handleSvcHealth)
-	userHealthHandler = corsHandler(userHealthHandler)
+	if cfg.enableCORS {
+		userHealthHandler = corsHandler(userHealthHandler)
+	}
 	userHealthHandler = recoverer(userHealthHandler, log)
 	mux.Handle(pathSvcHealthV1, userHealthHandler)
 

internal/services/jsonrpc/server_test.go

@@ -1,9 +1,13 @@
 package rpcserver
 
 import (
+	"context"
 	"encoding/json"
+	"io"
 	"net/http"
 	"net/http/httptest"
+	"slices"
+	"strings"
 	"testing"
 	"time"
 
@@ -69,3 +73,148 @@ func Test_timeout(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, resp.Error.Code, jsonrpc.ErrorTimeout)
 }
+
+func Test_options(t *testing.T) {
+	logger := log.NewStdOut(log.WarnLevel)
+
+	const testOrigin = "whoever"
+
+	wantCorsHeaders := http.Header{
+		"Access-Control-Allow-Credentials": {"true"},
+		"Access-Control-Allow-Headers":     {strings.Join([]string{"Accept", "Content-Type", "Content-Length", "Accept-Encoding", "Authorization", "ResponseType", "Range"}, ", ")},
+		"Access-Control-Allow-Methods":     {strings.Join([]string{http.MethodGet, http.MethodPost, http.MethodOptions}, ", ")},
+		"Access-Control-Allow-Origin":      {testOrigin},
+	}
+
+	for _, tt := range []struct {
+		name         string
+		path         string
+		withcors     bool
+		reqMeth      string
+		expectStatus int
+		reqBody      io.Reader
+	}{
+		// JSON-RPC endpoint
+		{
+			name:         "no cors, options req",
+			path:         pathRPCV1,
+			withcors:     false,
+			reqMeth:      http.MethodOptions,
+			expectStatus: http.StatusMethodNotAllowed,
+		},
+		{
+			name:         "with cors, options req",
+			path:         pathRPCV1,
+			withcors:     true,
+			reqMeth:      http.MethodOptions,
+			expectStatus: http.StatusOK,
+		},
+		{
+			name:         "no cors, get req",
+			path:         pathRPCV1,
+			withcors:     false,
+			reqMeth:      http.MethodGet,
+			expectStatus: http.StatusMethodNotAllowed,
+		},
+		{
+			name:         "with cors, post empty req",
+			path:         pathRPCV1,
+			withcors:     true,
+			reqMeth:      http.MethodPost,
+			expectStatus: http.StatusBadRequest, // not a jsonrpc req => 400 status code
+			reqBody:      nil,
+		},
+		{
+			name:         "with cors, post json req no method",
+			path:         pathRPCV1,
+			withcors:     true,
+			reqMeth:      http.MethodPost,
+			expectStatus: http.StatusNotFound, // method not found => 404 status code
+			reqBody:      strings.NewReader(`{"jsonrpc":"2.0","id":2,"method":"rpc.nope"}`),
+		},
+		{
+			name:         "with cors, post json req valid method",
+			path:         pathRPCV1,
+			withcors:     true,
+			reqMeth:      http.MethodPost,
+			expectStatus: http.StatusOK, // method not found => 404 status code
+			reqBody:      strings.NewReader(`{"jsonrpc":"2.0","id":2,"method":"rpc.dummy","params":null}`),
+		},
+		{
+			name:         "with cors, post json req valid method (no params)",
+			path:         pathRPCV1,
+			withcors:     true,
+			reqMeth:      http.MethodPost,
+			expectStatus: http.StatusOK, // method not found => 404 status code
+			reqBody:      strings.NewReader(`{"jsonrpc":"2.0","id":2,"method":"rpc.dummy"}`),
+		},
+		// REST endpoints
+		{
+			name:         "no cors, rest options req",
+			path:         pathSpecV1,
+			withcors:     false,
+			reqMeth:      http.MethodOptions,
+			expectStatus: http.StatusMethodNotAllowed,
+		},
+		{
+			name:         "with cors, rest options req",
+			path:         pathSpecV1,
+			withcors:     true,
+			reqMeth:      http.MethodOptions,
+			expectStatus: http.StatusOK,
+		},
+		{
+			name:         "with cors, rest get req",
+			path:         pathSpecV1,
+			withcors:     true,
+			reqMeth:      http.MethodGet,
+			expectStatus: http.StatusOK,
+		},
+		{
+			name:         "with cors, rest health options req",
+			path:         pathHealthV1,
+			withcors:     true,
+			reqMeth:      http.MethodOptions,
+			expectStatus: http.StatusOK,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			opts := []Opt{}
+			if tt.withcors {
+				opts = append(opts, WithCORS())
+			}
+			srv, err := NewServer("127.0.0.1:", logger, opts...)
+			require.NoError(t, err)
+
+			srv.RegisterMethodHandler(
+				"rpc.dummy",
+				MakeMethodHandler(func(context.Context, *any) (*json.RawMessage, *jsonrpc.Error) {
+					respjson := []byte(`"hi"`)
+					return (*json.RawMessage)(&respjson), nil
+				}),
+			)
+
+			r := httptest.NewRequest(tt.reqMeth, tt.path, tt.reqBody)
+			r.Header.Set("origin", testOrigin)
+			w := httptest.NewRecorder()
+			srv.srv.Handler.ServeHTTP(w, r)
+
+			assert.Equal(t, tt.expectStatus, w.Code)
+
+			if tt.withcors && tt.expectStatus == http.StatusOK {
+				// expect the cors headers fields
+				rhdr := w.Result().Header
+				for hk, hvs := range wantCorsHeaders {
+					vs, have := rhdr[hk]
+					if !have {
+						t.Fatalf("missing cors header %v", hk)
+					}
+					if !slices.Equal(vs, hvs) {
+						t.Errorf("different cors headers: got %v, want %v", vs, hvs)
+					}
+				}
+
+			}
+		})
+	}
+}

internal/version/version.go

@@ -15,7 +15,7 @@ import (
 //   - 0.6.0+release
 //   - 0.6.1
 //   - 0.6.2-alpha0+go1.21.nocgo
-const kwilVersion = "0.9.0-pre"
+const kwilVersion = "0.9.2-pre" // remove "-pre" for the tagged commit
 
 // KwildVersion may be set at compile time by:
 //