Merge pull request #84 from RyoJerryYu/feat-add-new-gatewayx

feat: add new gatewayx marshaler

pkg/gatewayx/constants.go

@@ -0,0 +1,7 @@
+package gatewayx
+
+const (
+	MIMETextEventStream = "text/event-stream"
+	MIMETextPlain       = "text/plain"
+	MIMEApplicationJSON = "application/json"
+)

pkg/gatewayx/event_stream_marshaler.go → pkg/gatewayx/marshaler_event_stream.go

@@ -7,12 +7,16 @@ import (
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 )
 
+// EventStreamMarshaler is a marshaler that returns each stream message as:
+// data: {"result": {...result}}
+// This will impliment the MDN EventStream for gRPC-Gateway server stream methods.
+// spec: https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events
 type EventStreamMarshaler struct {
 	runtime.Marshaler
 }
 
 func (m *EventStreamMarshaler) ContentType(_ interface{}) string {
-	return "text/event-stream"
+	return MIMETextEventStream
 }
 
 func (m *EventStreamMarshaler) Marshal(v interface{}) ([]byte, error) {
@@ -39,12 +43,17 @@ func (m EventStreamMarshaler) NewEncoder(w io.Writer) runtime.Encoder {
 	})
 }
 
+// UnwrapEventStreamMarshaler is a marshaler that unwraps the result or error field from the response
+// it will return the result as:
+// data: {...result}
+// instead of:
+// data: {"result": {...result}}
 type UnwrapEventStreamMarshaler struct {
 	runtime.Marshaler
 }
 
 func (m *UnwrapEventStreamMarshaler) ContentType(_ interface{}) string {
-	return "text/event-stream"
+	return MIMETextEventStream
 }
 
 func (m *UnwrapEventStreamMarshaler) Marshal(v interface{}) ([]byte, error) {

pkg/gatewayx/marshaler_plain_text.go

@@ -0,0 +1,38 @@
+package gatewayx
+
+import (
+	"io"
+
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+)
+
+type PlainTextMarshaler struct {
+	runtime.Marshaler
+}
+
+func (m *PlainTextMarshaler) ContentType(_ interface{}) string {
+	return MIMETextPlain
+}
+
+func (m *PlainTextMarshaler) Marshal(v interface{}) ([]byte, error) {
+	switch v := v.(type) {
+	case string:
+		return []byte(v), nil
+	case []byte:
+		return v, nil
+	}
+	// if number, bool, or other types, use the default marshaller,
+	// JSON marshal would work well for them.
+	return m.Marshaler.Marshal(v)
+}
+
+func (m PlainTextMarshaler) NewEncoder(w io.Writer) runtime.Encoder {
+	return runtime.EncoderFunc(func(v interface{}) error {
+		data, err := m.Marshal(v)
+		if err != nil {
+			return err
+		}
+		_, err = w.Write(data)
+		return err
+	})
+}

pkg/gatewayx/middleware.go

@@ -0,0 +1,54 @@
+package gatewayx
+
+import "net/http"
+
+/**
+Sometime Only use the gRPC-Gateway is not enough.
+You may need to add some middleware to the gateway to handle some special cases.
+*/
+
+type pathMatcher func(string) bool
+
+func PathEqual(path string) pathMatcher {
+	return func(p string) bool {
+		return p == path
+	}
+}
+
+func PathPrefix(prefix string) pathMatcher {
+	return func(p string) bool {
+		return len(p) >= len(prefix) && p[:len(prefix)] == prefix
+	}
+}
+
+// OverwriteAccept returns a middleware that overwrites the Accept header of the request
+// It's useful when you cannot force the client to send the correct Accept header
+func OverwriteAccept(accept string, matchers ...pathMatcher) func(handler http.Handler) http.Handler {
+	return func(handler http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			for _, matcher := range matchers {
+				if matcher(r.URL.Path) {
+					r.Header.Set("Accept", accept)
+					break
+				}
+			}
+			handler.ServeHTTP(w, r)
+		})
+	}
+}
+
+// OverwriteContentType returns a middleware that overwrites the Content-Type header of the http request
+// It's useful when you cannot force the client to send the correct Content-Type header
+func OverwriteContentType(contentType string, matchers ...pathMatcher) func(handler http.Handler) http.Handler {
+	return func(handler http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			for _, matcher := range matchers {
+				if matcher(r.URL.Path) {
+					r.Header.Set("Content-Type", contentType)
+					break
+				}
+			}
+			handler.ServeHTTP(w, r)
+		})
+	}
+}