heruvym/tools/tools.go
2022-02-27 18:27:44 +03:00

149 lines
2.8 KiB
Go

package tools
import (
"context"
"encoding/json"
"fmt"
"net/http"
"reflect"
"time"
)
type DataEmitter func(ctx context.Context) chan interface{}
const ContextURLKey = "url"
func SseWrapper(emitter DataEmitter) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
defer func() {
if v := recover(); v != nil {
fmt.Println("sse her err", v)
}
} ()
// Отправляем header event-stream
w.Header().Set("Content-Type", "text/event-stream")
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Connection", "keep-alive")
flusher, ok := w.(http.Flusher)
if !ok {
http.Error(
w,
"flushing is not allowed",
http.StatusFailedDependency,
)
return
}
ctx := context.WithValue(
r.Context(),
ContextURLKey,
r.URL.Query().Get("ticket"),
)
dE := emitter(ctx)
if dE == nil {
http.Error(w, "no token",http.StatusUnauthorized )
return
}
defer close(dE)
for {
select {
case <-r.Context().Done():
return
case <-time.After(time.Second * 10):
SSEPing(w)
case m := <-dE:
if m == nil {
continue
}
if err, ok := m.(error); ok {
if _, err := w.Write(
[]byte(
fmt.Sprintf(
"data: %s\n\n",
err.Error(),
),
),
); err != nil {
panic(err)
}
flusher.Flush()
return
}
line, err := json.Marshal(m)
if err != nil {
panic(err)
}
if _, err := w.Write(
[]byte(
fmt.Sprintf(
"data: %s\n\n",
string(line),
),
),
); err != nil {
panic(err)
}
flusher.Flush()
}
}
}
}
// Sends SSE ping
func SSEPing(w http.ResponseWriter) {
if _, err := w.Write([]byte(":ping\n\n")); err != nil {
panic(err)
}
if flusher, ok := w.(http.Flusher); ok {
flusher.Flush()
} else {
panic("streaming unsupported")
}
}
func HandlerWrapper(f interface{}) http.HandlerFunc {
fRV := reflect.ValueOf(f)
fRT := fRV.Type()
var argRT reflect.Type
var argTypeRV reflect.Value
var argExist bool
if fRT.NumIn() > 1 {
argExist = true
argRT = fRT.In(1)
argTypeRV = reflect.New(argRT)
}
return func(w http.ResponseWriter, q *http.Request) {
q.Header.Set("Content-Type", "application/json")
var fResultRV []reflect.Value
if argExist {
arg := argTypeRV.Interface()
if err := json.NewDecoder(q.Body).Decode(&arg); err != nil {
http.Error(w, "invalid request data", http.StatusBadRequest)
} else {
fResultRV = fRV.Call([]reflect.Value{reflect.ValueOf(q.Context()), reflect.ValueOf(arg).Elem()})
}
fmt.Println("GET STRANGE", arg)
} else {
fResultRV = fRV.Call([]reflect.Value{reflect.ValueOf(q.Context())})
}
w.WriteHeader(fResultRV[1].Interface().(int))
if err := json.NewEncoder(w).Encode(fResultRV[0].Interface()); err != nil {
panic(err)
}
}
}