From 1cae4152f949f5a99609d568d4f540b8887443eb Mon Sep 17 00:00:00 2001
From: Chaitanya Bankanhal <bchaitanya15@gmail.com>
Date: Mon, 27 Jul 2020 23:31:35 +0530
Subject: [PATCH] rc: add NeedsResponse for rc calls

---
 fs/rc/params.go            | 19 ++++++++++++++++++-
 fs/rc/rcserver/rcserver.go |  4 ++++
 fs/rc/registry.go          | 13 +++++++------
 3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/fs/rc/params.go b/fs/rc/params.go
index ae7f932e5..e74e81b44 100644
--- a/fs/rc/params.go
+++ b/fs/rc/params.go
@@ -91,7 +91,7 @@ func (p Params) Get(key string) (interface{}, error) {
 	return value, nil
 }
 
-// GetHTTPRequest gets a http.Request parameter associated with the request with the key "HttpRequest"
+// GetHTTPRequest gets a http.Request parameter associated with the request with the key "_request"
 //
 // If the parameter isn't found then error will be of type
 // ErrParamNotFound and the returned value will be nil.
@@ -108,6 +108,23 @@ func (p Params) GetHTTPRequest() (*http.Request, error) {
 	return request, nil
 }
 
+// GetHTTPResponseWriter gets a http.ResponseWriter parameter associated with the request with the key "_response"
+//
+// If the parameter isn't found then error will be of type
+// ErrParamNotFound and the returned value will be nil.
+func (p Params) GetHTTPResponseWriter() (*http.ResponseWriter, error) {
+	key := "_response"
+	value, err := p.Get(key)
+	if err != nil {
+		return nil, err
+	}
+	request, ok := value.(*http.ResponseWriter)
+	if !ok {
+		return nil, ErrParamInvalid{errors.Errorf("expecting http.ResponseWriter value for key %q (was %T)", key, value)}
+	}
+	return request, nil
+}
+
 // GetString gets a string parameter from the input
 //
 // If the parameter isn't found then error will be of type
diff --git a/fs/rc/rcserver/rcserver.go b/fs/rc/rcserver/rcserver.go
index 7f324c21b..f6509baa6 100644
--- a/fs/rc/rcserver/rcserver.go
+++ b/fs/rc/rcserver/rcserver.go
@@ -265,6 +265,10 @@ func (s *Server) handlePost(w http.ResponseWriter, r *http.Request, path string)
 		in["_request"] = r
 	}
 
+	if call.NeedsResponse {
+		in["_response"] = &w
+	}
+
 	// Check to see if it is async or not
 	isAsync, err := in.GetBool("_async")
 	if rc.NotErrParamNotFound(err) {
diff --git a/fs/rc/registry.go b/fs/rc/registry.go
index f2f5a1fb8..4cc80541a 100644
--- a/fs/rc/registry.go
+++ b/fs/rc/registry.go
@@ -17,12 +17,13 @@ type Func func(ctx context.Context, in Params) (out Params, err error)
 // Call defines info about a remote control function and is used in
 // the Add function to create new entry points.
 type Call struct {
-	Path         string // path to activate this RC
-	Fn           Func   `json:"-"` // function to call
-	Title        string // help for the function
-	AuthRequired bool   // if set then this call requires authorisation to be set
-	Help         string // multi-line markdown formatted help
-	NeedsRequest bool   // if set then this call will be passed the original request object as _request
+	Path          string // path to activate this RC
+	Fn            Func   `json:"-"` // function to call
+	Title         string // help for the function
+	AuthRequired  bool   // if set then this call requires authorisation to be set
+	Help          string // multi-line markdown formatted help
+	NeedsRequest  bool   // if set then this call will be passed the original request object as _request
+	NeedsResponse bool   // if set then this call will be passed the original response object as _response
 }
 
 // Registry holds the list of all the registered remote control functions