[MM-9938] Add support for multiple responses from a slash command (#9836)

* slash command response now supports multiple posts

* change wording of Posts to ExtraResponses

app/command.go

@@ -277,6 +277,18 @@ func (a *App) ExecuteCommand(args *model.CommandArgs) (*model.CommandResponse, *
 }
 
 func (a *App) HandleCommandResponse(command *model.Command, args *model.CommandArgs, response *model.CommandResponse, builtIn bool) (*model.CommandResponse, *model.AppError) {
+	a.HandleCommandResponsePost(command, args, response, builtIn)
+
+	if response.ExtraResponses != nil {
+		for _, resp := range response.ExtraResponses {
+			a.HandleCommandResponsePost(command, args, resp, builtIn)
+		}
+	}
+
+	return response, nil
+}
+
+func (a *App) HandleCommandResponsePost(command *model.Command, args *model.CommandArgs, response *model.CommandResponse, builtIn bool) (*model.CommandResponse, *model.AppError) {
 	post := &model.Post{}
 	post.ChannelId = args.ChannelId
 	post.RootId = args.RootId

model/command_response.go

@@ -18,14 +18,15 @@ const (
 )
 
 type CommandResponse struct {
-	ResponseType string             `json:"response_type"`
-	Text         string             `json:"text"`
-	Username     string             `json:"username"`
-	IconURL      string             `json:"icon_url"`
-	Type         string             `json:"type"`
-	Props        StringInterface    `json:"props"`
-	GotoLocation string             `json:"goto_location"`
-	Attachments  []*SlackAttachment `json:"attachments"`
+	ResponseType   string             `json:"response_type"`
+	Text           string             `json:"text"`
+	Username       string             `json:"username"`
+	IconURL        string             `json:"icon_url"`
+	Type           string             `json:"type"`
+	Props          StringInterface    `json:"props"`
+	GotoLocation   string             `json:"goto_location"`
+	Attachments    []*SlackAttachment `json:"attachments"`
+	ExtraResponses []*CommandResponse `json:"extra_responses"`
 }
 
 func (o *CommandResponse) ToJson() string {
@@ -63,5 +64,11 @@ func CommandResponseFromJson(data io.Reader) (*CommandResponse, error) {
 
 	o.Attachments = StringifySlackFieldValue(o.Attachments)
 
+	if o.ExtraResponses != nil {
+		for _, resp := range o.ExtraResponses {
+			resp.Attachments = StringifySlackFieldValue(resp.Attachments)
+		}
+	}
+
 	return &o, nil
 }

model/command_response_test.go

@@ -131,6 +131,71 @@ func TestCommandResponseFromJson(t *testing.T) {
 			},
 			false,
 		},
+		{
+			"multiple responses returned",
+			`
+			{
+				"text": "message 1",
+				"extra_responses": [
+					{"text": "message 2"}
+				]
+			}
+			`,
+			&CommandResponse{
+				Text: "message 1",
+				ExtraResponses: []*CommandResponse{
+					&CommandResponse{
+						Text: "message 2",
+					},
+				},
+			},
+			false,
+		},
+		{
+			"multiple responses returned, with attachments",
+			`
+			{
+				"text": "message 1",
+				"attachments":[{"fields":[{"title":"foo","value":"bar","short":true}]}],
+				"extra_responses": [
+					{
+						"text": "message 2",
+						"attachments":[{"fields":[{"title":"foo 2","value":"bar 2","short":false}]}]
+					}
+				]
+			}`,
+			&CommandResponse{
+				Text: "message 1",
+				Attachments: []*SlackAttachment{
+					{
+						Fields: []*SlackAttachmentField{
+							{
+								Title: "foo",
+								Value: "bar",
+								Short: true,
+							},
+						},
+					},
+				},
+				ExtraResponses: []*CommandResponse{
+					&CommandResponse{
+						Text: "message 2",
+						Attachments: []*SlackAttachment{
+							{
+								Fields: []*SlackAttachmentField{
+									{
+										Title: "foo 2",
+										Value: "bar 2",
+										Short: false,
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			false,
+		},
 	}
 
 	for _, testCase := range testCases {