/
server.go
281 lines (234 loc) · 6.88 KB
/
server.go
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package goajax
import (
"sync"
"reflect"
"log"
"utf8"
"os"
"unicode"
"http"
"json"
"strings"
"strconv"
)
type service struct {
name string // name of service
rcvr reflect.Value // receiver of methods for the service
typ reflect.Type // type of the receiver
method map[string]*methodType // registered methods
}
type methodType struct {
sync.Mutex // protects counters
method reflect.Method
argTypes []reflect.Type
returnType reflect.Type
numCalls uint
}
type Server struct {
sync.Mutex // protects the serviceMap
serviceMap map[string]*service
}
type jsonRequest struct {
Id *json.RawMessage "id"
Method string "method"
Params *json.RawMessage "params"
}
type jsonResponse struct {
Id *json.RawMessage "id"
Result interface{} "result"
Error interface{} "error"
}
func NewServer() *Server {
s := new(Server)
s.serviceMap = make(map[string]*service)
return s
}
// Precompute the reflect type for os.Error. Can't use os.Error directly
// because Typeof takes an empty interface value. This is annoying.
var unusedError *os.Error
var typeOfOsError = reflect.TypeOf(unusedError).Elem()
func (server *Server) register(rcvr interface{}, name string, useName bool) os.Error {
server.Lock()
defer server.Unlock()
s := new(service)
s.typ = reflect.TypeOf(rcvr)
s.rcvr = reflect.ValueOf(rcvr)
sname := reflect.Indirect(s.rcvr).Type().Name()
if useName {
sname = name
}
if sname == "" {
log.Fatalln("rpc: no service name for type", s.typ.String())
}
if s.typ.PkgPath() != "" && !isExported(sname) && !useName {
s := "rpc Register: type " + sname + " is not exported"
log.Print(s)
return os.ErrorString(s)
}
if _, present := server.serviceMap[sname]; present {
return os.ErrorString("rpc: service already defined: " + sname)
}
s.name = sname
s.method = make(map[string]*methodType)
// Install the methods
MethodLoop:
for m := 0; m < s.typ.NumMethod(); m++ {
method := s.typ.Method(m)
mtype := method.Type
mname := method.Name
if mtype.PkgPath() != "" || !isExported(mname) {
continue
}
args := []reflect.Type{}
for i := 1; i < mtype.NumIn(); i++ {
argType := mtype.In(i)
if argPointerType := argType; argPointerType.Kind() == reflect.Ptr {
if argPointerType.Elem().PkgPath() != "" && !isExported(argPointerType.Elem().Name()) {
log.Println(mname, "argument type not exported:", argPointerType.Elem().Name())
continue MethodLoop
}
}
args = append(args, argType)
}
if mtype.NumOut() != 2 {
log.Println("method", mname, "has wrong number of outs:", mtype.NumOut())
continue
}
returnType := mtype.Out(0)
if returnPointerType := returnType; returnPointerType.Kind() == reflect.Ptr {
if returnPointerType.Elem().PkgPath() != "" && !isExported(returnPointerType.Elem().Name()) {
log.Println(mname, "return type not exported:", returnPointerType.Elem().Name())
continue
}
}
if errorType := mtype.Out(1); errorType != typeOfOsError {
log.Println("method", mname, "returns", errorType.String(), "not os.Error")
continue
}
s.method[mname] = &methodType{method: method, argTypes: args, returnType: returnType}
}
if len(s.method) == 0 {
s := "rpc Register: type " + sname + " has no exported methods of suitable type"
log.Print(s)
return os.ErrorString(s)
}
server.serviceMap[s.name] = s
return nil
}
func (server *Server) Register(rcvr interface{}) os.Error {
return server.register(rcvr, "", false)
}
func (server *Server) RegisterName(name string, rcvr interface{}) os.Error {
return server.register(rcvr, name, true)
}
func _new(t reflect.Type) reflect.Value {
v := reflect.Zero(t)
v.Set(reflect.Zero(t.Elem()).Addr())
return v
}
// Is this an exported - upper case - name?
func isExported(name string) bool {
rune, _ := utf8.DecodeRuneInString(name)
return unicode.IsUpper(rune)
}
func (server *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
dec := json.NewDecoder(r.Body)
req := new(jsonRequest)
err := dec.Decode(req)
if err != nil {
s := "Invalid JSON-RPC."
sendError(w, s)
return
}
serviceMethod := strings.Split(req.Method, ".", -1)
server.Lock()
service, ok := server.serviceMap[serviceMethod[0]]
server.Unlock()
if !ok {
s := "Service not found."
sendError(w, s)
return
}
mtype, ok := service.method[serviceMethod[1]]
if !ok {
s := "Method not found."
sendError(w, s)
return
}
args, err := getParams(req, mtype.argTypes)
if err != nil {
sendError(w, err.String())
return
}
args = append([]reflect.Value{service.rcvr}, args...)
mtype.Lock()
mtype.numCalls++
mtype.Unlock()
function := mtype.method.Func
returnValues := function.Call(args)
// The return value for the method is an os.Error.
errInter := returnValues[1].Interface()
errmsg := ""
if errInter != nil {
errmsg = errInter.(os.Error).String()
}
resp := new(jsonResponse)
if errmsg != "" {
resp.Error = errmsg
} else {
resp.Result = returnValues[0].Interface()
}
resp.Id = req.Id
w.Header().Set("Content-Type", "application/json; charset=utf-8")
enc := json.NewEncoder(w)
enc.Encode(resp)
}
func sendError(w http.ResponseWriter, s string) {
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.Write([]byte("{\"jsonrpc\": \"2.0\", \"id\":null, \"error\":\"" + s + "\"}"))
}
func getParams(req *jsonRequest, argTypes []reflect.Type) ([]reflect.Value, os.Error) {
params := make([]*json.RawMessage, 0)
err := json.Unmarshal(*req.Params, ¶ms)
if err != nil {
return nil, err
}
if len(params) != len(argTypes) {
return nil, os.ErrorString("Incorrect number of parameters.")
}
args := make([]reflect.Value, 0, len(argTypes))
for i, argType := range argTypes {
argPointerType := argType
if argPointerType.Kind() == reflect.Ptr {
argPointer := reflect.New(argType)
err := json.Unmarshal(*params[i], argPointer.Interface())
if err != nil {
return nil, os.ErrorString("Type mismatch parameter " + strconv.Itoa(i+1) + ".")
}
args = append(args, reflect.Indirect(argPointer))
} else {
var arg reflect.Value
var v interface{}
err := json.Unmarshal(*params[i], &v)
if err != nil {
return nil, os.ErrorString("Type mismatch parameter " + strconv.Itoa(i+1) + ".")
}
value := reflect.ValueOf(v)
if value.Type() == argType {
arg = reflect.ValueOf(v)
} else if value.Type().Kind() == reflect.Float32 || value.Type().Kind() == reflect.Float64 {
if argType.Kind() == reflect.Int || argType.Kind() == reflect.Int8 ||
argType.Kind() == reflect.Int16 || argType.Kind() == reflect.Int32 ||
argType.Kind() == reflect.Int64 {
arg = reflect.ValueOf(int(v.(float64)))
} else {
return nil, os.ErrorString("Type mismatch parameter " + strconv.Itoa(i+1) + ".")
}
} else {
return nil, os.ErrorString("Type mismatch parameter " + strconv.Itoa(i+1) + ".")
}
args = append(args, reflect.Value(arg))
}
}
return args, nil
}