/
rpc.go
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/
rpc.go
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// Package rpc is a go-micro rpc handler.
package rpc
import (
"encoding/json"
"io"
"net/http"
"net/textproto"
"strconv"
"strings"
"github.com/asim/go-micro/v3/api"
"github.com/asim/go-micro/v3/api/handler"
"github.com/asim/go-micro/v3/api/internal/proto"
"github.com/asim/go-micro/v3/client"
"github.com/asim/go-micro/v3/codec"
"github.com/asim/go-micro/v3/codec/jsonrpc"
"github.com/asim/go-micro/v3/codec/protorpc"
"github.com/asim/go-micro/v3/errors"
"github.com/asim/go-micro/v3/logger"
"github.com/asim/go-micro/v3/metadata"
"github.com/asim/go-micro/v3/registry"
"github.com/asim/go-micro/v3/selector"
"github.com/asim/go-micro/v3/util/ctx"
"github.com/asim/go-micro/v3/util/qson"
jsonpatch "github.com/evanphx/json-patch/v5"
"github.com/oxtoacart/bpool"
)
const (
Handler = "rpc"
)
var (
// supported json codecs
jsonCodecs = []string{
"application/grpc+json",
"application/json",
"application/json-rpc",
}
// support proto codecs
protoCodecs = []string{
"application/grpc",
"application/grpc+proto",
"application/proto",
"application/protobuf",
"application/proto-rpc",
"application/octet-stream",
}
bufferPool = bpool.NewSizedBufferPool(1024, 8)
)
type rpcHandler struct {
opts handler.Options
s *api.Service
}
type buffer struct {
io.ReadCloser
}
func (b *buffer) Write(_ []byte) (int, error) {
return 0, nil
}
// strategy is a hack for selection
func strategy(services []*registry.Service) selector.Strategy {
return func(_ []*registry.Service) selector.Next {
// ignore input to this function, use services above
return selector.Random(services)
}
}
func (h *rpcHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
bsize := handler.DefaultMaxRecvSize
if h.opts.MaxRecvSize > 0 {
bsize = h.opts.MaxRecvSize
}
r.Body = http.MaxBytesReader(w, r.Body, bsize)
defer r.Body.Close()
var service *api.Service
if h.s != nil {
// we were given the service
service = h.s
} else if h.opts.Router != nil {
// try get service from router
s, err := h.opts.Router.Route(r)
if err != nil {
writeError(w, r, errors.InternalServerError("go.micro.api", err.Error()))
return
}
service = s
} else {
// we have no way of routing the request
writeError(w, r, errors.InternalServerError("go.micro.api", "no route found"))
return
}
ct := r.Header.Get("Content-Type")
// Strip charset from Content-Type (like `application/json; charset=UTF-8`)
if idx := strings.IndexRune(ct, ';'); idx >= 0 {
ct = ct[:idx]
}
// micro client
c := h.opts.Client
// create context
cx := ctx.FromRequest(r)
// get context from http handler wrappers
md, ok := metadata.FromContext(r.Context())
if !ok {
md = make(metadata.Metadata)
}
// fill contex with http headers
md["Host"] = r.Host
md["Method"] = r.Method
// get canonical headers
for k := range r.Header {
// may be need to get all values for key like r.Header.Values() provide in go 1.14
md[textproto.CanonicalMIMEHeaderKey(k)] = r.Header.Get(k)
}
// merge context with overwrite
cx = metadata.MergeContext(cx, md, true)
// set merged context to request
*r = *r.Clone(cx)
// if stream we currently only support json
if isStream(r, service) {
// drop older context as it can have timeouts and create new
// md, _ := metadata.FromContext(cx)
//serveWebsocket(context.TODO(), w, r, service, c)
serveWebsocket(cx, w, r, service, c)
return
}
// create strategy
so := selector.WithStrategy(strategy(service.Services))
// walk the standard call path
// get payload
br, err := requestPayload(r)
if err != nil {
writeError(w, r, err)
return
}
var rsp []byte
switch {
// proto codecs
case hasCodec(ct, protoCodecs):
request := &proto.Message{}
// if the extracted payload isn't empty lets use it
if len(br) > 0 {
request = proto.NewMessage(br)
}
// create request/response
response := &proto.Message{}
req := c.NewRequest(
service.Name,
service.Endpoint.Name,
request,
client.WithContentType(ct),
)
// make the call
if err := c.Call(cx, req, response, client.WithSelectOption(so)); err != nil {
writeError(w, r, err)
return
}
// marshall response
rsp, err = response.Marshal()
if err != nil {
writeError(w, r, err)
return
}
default:
// if json codec is not present set to json
if !hasCodec(ct, jsonCodecs) {
ct = "application/json"
}
// default to trying json
var request json.RawMessage
// if the extracted payload isn't empty lets use it
if len(br) > 0 {
request = json.RawMessage(br)
}
// create request/response
var response json.RawMessage
req := c.NewRequest(
service.Name,
service.Endpoint.Name,
&request,
client.WithContentType(ct),
)
// make the call
if err := c.Call(cx, req, &response, client.WithSelectOption(so)); err != nil {
writeError(w, r, err)
return
}
// marshall response
rsp, err = response.MarshalJSON()
if err != nil {
writeError(w, r, err)
return
}
}
// write the response
writeResponse(w, r, rsp)
}
func (rh *rpcHandler) String() string {
return "rpc"
}
func hasCodec(ct string, codecs []string) bool {
for _, codec := range codecs {
if ct == codec {
return true
}
}
return false
}
// requestPayload takes a *http.Request.
// If the request is a GET the query string parameters are extracted and marshaled to JSON and the raw bytes are returned.
// If the request method is a POST the request body is read and returned
func requestPayload(r *http.Request) ([]byte, error) {
var err error
// we have to decode json-rpc and proto-rpc because we suck
// well actually because there's no proxy codec right now
ct := r.Header.Get("Content-Type")
switch {
case strings.Contains(ct, "application/json-rpc"):
msg := codec.Message{
Type: codec.Request,
Header: make(map[string]string),
}
c := jsonrpc.NewCodec(&buffer{r.Body})
if err = c.ReadHeader(&msg, codec.Request); err != nil {
return nil, err
}
var raw json.RawMessage
if err = c.ReadBody(&raw); err != nil {
return nil, err
}
return ([]byte)(raw), nil
case strings.Contains(ct, "application/proto-rpc"), strings.Contains(ct, "application/octet-stream"):
msg := codec.Message{
Type: codec.Request,
Header: make(map[string]string),
}
c := protorpc.NewCodec(&buffer{r.Body})
if err = c.ReadHeader(&msg, codec.Request); err != nil {
return nil, err
}
var raw proto.Message
if err = c.ReadBody(&raw); err != nil {
return nil, err
}
return raw.Marshal()
case strings.Contains(ct, "application/www-x-form-urlencoded"):
r.ParseForm()
// generate a new set of values from the form
vals := make(map[string]string)
for k, v := range r.Form {
vals[k] = strings.Join(v, ",")
}
// marshal
return json.Marshal(vals)
// TODO: application/grpc
}
// otherwise as per usual
ctx := r.Context()
// dont user meadata.FromContext as it mangles names
md, ok := metadata.FromContext(ctx)
if !ok {
md = make(map[string]string)
}
// allocate maximum
matches := make(map[string]interface{}, len(md))
bodydst := ""
// get fields from url path
for k, v := range md {
k = strings.ToLower(k)
// filter own keys
if strings.HasPrefix(k, "x-api-field-") {
matches[strings.TrimPrefix(k, "x-api-field-")] = v
delete(md, k)
} else if k == "x-api-body" {
bodydst = v
delete(md, k)
}
}
// map of all fields
req := make(map[string]interface{}, len(md))
// get fields from url values
if len(r.URL.RawQuery) > 0 {
umd := make(map[string]interface{})
err = qson.Unmarshal(&umd, r.URL.RawQuery)
if err != nil {
return nil, err
}
for k, v := range umd {
matches[k] = v
}
}
// restore context without fields
*r = *r.Clone(metadata.NewContext(ctx, md))
for k, v := range matches {
ps := strings.Split(k, ".")
if len(ps) == 1 {
req[k] = v
continue
}
em := make(map[string]interface{})
em[ps[len(ps)-1]] = v
for i := len(ps) - 2; i > 0; i-- {
nm := make(map[string]interface{})
nm[ps[i]] = em
em = nm
}
if vm, ok := req[ps[0]]; ok {
// nested map
nm := vm.(map[string]interface{})
for vk, vv := range em {
nm[vk] = vv
}
req[ps[0]] = nm
} else {
req[ps[0]] = em
}
}
pathbuf := []byte("{}")
if len(req) > 0 {
pathbuf, err = json.Marshal(req)
if err != nil {
return nil, err
}
}
urlbuf := []byte("{}")
out, err := jsonpatch.MergeMergePatches(urlbuf, pathbuf)
if err != nil {
return nil, err
}
switch r.Method {
case "GET":
// empty response
if strings.Contains(ct, "application/json") && string(out) == "{}" {
return out, nil
} else if string(out) == "{}" && !strings.Contains(ct, "application/json") {
return []byte{}, nil
}
return out, nil
case "PATCH", "POST", "PUT", "DELETE":
bodybuf := []byte("{}")
buf := bufferPool.Get()
defer bufferPool.Put(buf)
if _, err := buf.ReadFrom(r.Body); err != nil {
return nil, err
}
if b := buf.Bytes(); len(b) > 0 {
bodybuf = b
}
if bodydst == "" || bodydst == "*" {
if out, err = jsonpatch.MergeMergePatches(out, bodybuf); err == nil {
return out, nil
}
}
var jsonbody map[string]interface{}
if json.Valid(bodybuf) {
if err = json.Unmarshal(bodybuf, &jsonbody); err != nil {
return nil, err
}
}
dstmap := make(map[string]interface{})
ps := strings.Split(bodydst, ".")
if len(ps) == 1 {
if jsonbody != nil {
dstmap[ps[0]] = jsonbody
} else {
// old unexpected behaviour
dstmap[ps[0]] = bodybuf
}
} else {
em := make(map[string]interface{})
if jsonbody != nil {
em[ps[len(ps)-1]] = jsonbody
} else {
// old unexpected behaviour
em[ps[len(ps)-1]] = bodybuf
}
for i := len(ps) - 2; i > 0; i-- {
nm := make(map[string]interface{})
nm[ps[i]] = em
em = nm
}
dstmap[ps[0]] = em
}
bodyout, err := json.Marshal(dstmap)
if err != nil {
return nil, err
}
if out, err = jsonpatch.MergeMergePatches(out, bodyout); err == nil {
return out, nil
}
//fallback to previous unknown behaviour
return bodybuf, nil
}
return []byte{}, nil
}
func writeError(w http.ResponseWriter, r *http.Request, err error) {
ce := errors.Parse(err.Error())
switch ce.Code {
case 0:
// assuming it's totally screwed
ce.Code = 500
ce.Id = "go.micro.api"
ce.Status = http.StatusText(500)
ce.Detail = "error during request: " + ce.Detail
w.WriteHeader(500)
default:
w.WriteHeader(int(ce.Code))
}
// response content type
w.Header().Set("Content-Type", "application/json")
// Set trailers
if strings.Contains(r.Header.Get("Content-Type"), "application/grpc") {
w.Header().Set("Trailer", "grpc-status")
w.Header().Set("Trailer", "grpc-message")
w.Header().Set("grpc-status", "13")
w.Header().Set("grpc-message", ce.Detail)
}
_, werr := w.Write([]byte(ce.Error()))
if werr != nil {
if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
logger.Error(werr)
}
}
}
func writeResponse(w http.ResponseWriter, r *http.Request, rsp []byte) {
w.Header().Set("Content-Type", r.Header.Get("Content-Type"))
w.Header().Set("Content-Length", strconv.Itoa(len(rsp)))
// Set trailers
if strings.Contains(r.Header.Get("Content-Type"), "application/grpc") {
w.Header().Set("Trailer", "grpc-status")
w.Header().Set("Trailer", "grpc-message")
w.Header().Set("grpc-status", "0")
w.Header().Set("grpc-message", "")
}
// write 204 status if rsp is nil
if len(rsp) == 0 {
w.WriteHeader(http.StatusNoContent)
}
// write response
_, err := w.Write(rsp)
if err != nil {
if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
logger.Error(err)
}
}
}
func NewHandler(opts ...handler.Option) handler.Handler {
options := handler.NewOptions(opts...)
return &rpcHandler{
opts: options,
}
}
func WithService(s *api.Service, opts ...handler.Option) handler.Handler {
options := handler.NewOptions(opts...)
return &rpcHandler{
opts: options,
s: s,
}
}