support response urls from slash commands

channels.go

@@ -32,11 +32,7 @@ func (api *Client) channelRequest(ctx context.Context, path string, values url.V
 		return nil, err
 	}
 
-	if err := response.Err(); err != nil {
-		return nil, err
-	}
-
-	return response, nil
+	return response, response.Err()
 }
 
 type channelsConfig struct {
@@ -284,6 +280,7 @@ func (api *Client) GetChannelsContext(ctx context.Context, excludeArchived bool,
 			"token": {api.token},
 		},
 	}
+
 	if excludeArchived {
 		options = append(options, GetChannelsOptionExcludeArchived())
 	}

chat.go

@@ -3,6 +3,7 @@ package slack
 import (
 	"context"
 	"encoding/json"
+	"net/http"
 	"net/url"
 
 	"github.com/nlopes/slack/slackutilsx"
@@ -25,7 +26,7 @@ const (
 
 type chatResponseFull struct {
 	Channel          string `json:"channel"`
-	Timestamp        string `json:"ts"`         //Regualr message timestamp
+	Timestamp        string `json:"ts"`         //Regular message timestamp
 	MessageTimeStamp string `json:"message_ts"` //Ephemeral message timestamp
 	Text             string `json:"text"`
 	SlackResponse
@@ -156,17 +157,18 @@ func (api *Client) SendMessage(channel string, options ...MsgOption) (string, st
 }
 
 // SendMessageContext more flexible method for configuring messages with a custom context.
-func (api *Client) SendMessageContext(ctx context.Context, channelID string, options ...MsgOption) (channel string, timestamp string, text string, err error) {
+func (api *Client) SendMessageContext(ctx context.Context, channelID string, options ...MsgOption) (_channel string, _timestamp string, _text string, err error) {
 	var (
-		config   sendConfig
+		req      *http.Request
+		parser   func(*chatResponseFull) responseParser
 		response chatResponseFull
 	)
 
-	if config, err = applyMsgOptions(api.token, channelID, api.endpoint, options...); err != nil {
+	if req, parser, err = buildSender(api.endpoint, options...).BuildRequest(api.token, channelID); err != nil {
 		return "", "", "", err
 	}
 
-	if err = postForm(ctx, api.httpclient, config.endpoint, config.values, &response, api); err != nil {
+	if err = doPost(ctx, api.httpclient, req, parser(&response), api); err != nil {
 		return "", "", "", err
 	}
 
@@ -200,23 +202,84 @@ func applyMsgOptions(token, channel, apiurl string, options ...MsgOption) (sendC
 	return config, nil
 }
 
+func buildSender(apiurl string, options ...MsgOption) sendConfig {
+	return sendConfig{
+		apiurl:  apiurl,
+		options: options,
+	}
+}
+
 type sendMode string
 
 const (
 	chatUpdate        sendMode = "chat.update"
 	chatPostMessage   sendMode = "chat.postMessage"
 	chatDelete        sendMode = "chat.delete"
 	chatPostEphemeral sendMode = "chat.postEphemeral"
+	chatResponse      sendMode = "chat.responseURL"
 	chatMeMessage     sendMode = "chat.meMessage"
 	chatUnfurl        sendMode = "chat.unfurl"
 )
 
 type sendConfig struct {
-	apiurl   string
+	apiurl       string
+	options      []MsgOption
+	mode         sendMode
+	endpoint     string
+	values       url.Values
+	attachments  []Attachment
+	responseType string
+}
+
+func (t sendConfig) BuildRequest(token, channelID string) (req *http.Request, _ func(*chatResponseFull) responseParser, err error) {
+	if t, err = applyMsgOptions(token, channelID, t.apiurl, t.options...); err != nil {
+		return nil, nil, err
+	}
+
+	switch t.mode {
+	case chatResponse:
+		return responseURLSender{
+			endpoint:     t.endpoint,
+			values:       t.values,
+			attachments:  t.attachments,
+			responseType: t.responseType,
+		}.BuildRequest()
+	default:
+		return formSender{endpoint: t.endpoint, values: t.values}.BuildRequest()
+	}
+}
+
+type formSender struct {
 	endpoint string
 	values   url.Values
 }
 
+func (t formSender) BuildRequest() (*http.Request, func(*chatResponseFull) responseParser, error) {
+	req, err := formReq(t.endpoint, t.values)
+	return req, func(resp *chatResponseFull) responseParser {
+		return newJSONParser(resp)
+	}, err
+}
+
+type responseURLSender struct {
+	endpoint     string
+	values       url.Values
+	attachments  []Attachment
+	responseType string
+}
+
+func (t responseURLSender) BuildRequest() (*http.Request, func(*chatResponseFull) responseParser, error) {
+	req, err := jsonReq(t.endpoint, Msg{
+		Text:         t.values.Get("text"),
+		Timestamp:    t.values.Get("ts"),
+		Attachments:  t.attachments,
+		ResponseType: t.responseType,
+	})
+	return req, func(resp *chatResponseFull) responseParser {
+		return newContentTypeParser(resp)
+	}, err
+}
+
 // MsgOption option provided when sending a message.
 type MsgOption func(*sendConfig) error
 
@@ -279,6 +342,17 @@ func MsgOptionUnfurl(timestamp string, unfurls map[string]Attachment) MsgOption
 	}
 }
 
+// MsgOptionResponseURL supplies a url to use as the endpoint.
+func MsgOptionResponseURL(url string, rt string) MsgOption {
+	return func(config *sendConfig) error {
+		config.mode = chatResponse
+		config.endpoint = url
+		config.responseType = rt
+		config.values.Del("ts")
+		return nil
+	}
+}
+
 // MsgOptionAsUser whether or not to send the message as the user.
 func MsgOptionAsUser(b bool) MsgOption {
 	return func(config *sendConfig) error {
@@ -324,10 +398,17 @@ func MsgOptionAttachments(attachments ...Attachment) MsgOption {
 			return nil
 		}
 
-		attachments, err := json.Marshal(attachments)
+		config.attachments = attachments
+
+		// FIXME: We are setting the attachments on the message twice: above for
+		// the json version, and below for the html version.  The marshalled bytes
+		// we put into config.values below don't work directly in the Msg version.
+
+		attachmentBytes, err := json.Marshal(attachments)
 		if err == nil {
-			config.values.Set("attachments", string(attachments))
+			config.values.Set("attachments", string(attachmentBytes))
 		}
+
 		return err
 	}
 }

conversation.go

@@ -99,6 +99,7 @@ func (api *Client) GetUsersInConversationContext(ctx context.Context, params *Ge
 		ResponseMetaData responseMetaData `json:"response_metadata"`
 		SlackResponse
 	}{}
+
 	err := api.postMethod(ctx, "conversations.members", values, &response)
 	if err != nil {
 		return nil, "", err
@@ -160,6 +161,7 @@ func (api *Client) ArchiveConversationContext(ctx context.Context, channelID str
 		"token":   {api.token},
 		"channel": {channelID},
 	}
+
 	response := SlackResponse{}
 	err := api.postMethod(ctx, "conversations.archive", values, &response)
 	if err != nil {
@@ -229,6 +231,7 @@ func (api *Client) SetPurposeOfConversationContext(ctx context.Context, channelI
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
+
 	err := api.postMethod(ctx, "conversations.setPurpose", values, &response)
 	if err != nil {
 		return nil, err
@@ -253,6 +256,7 @@ func (api *Client) RenameConversationContext(ctx context.Context, channelID, cha
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
+
 	err := api.postMethod(ctx, "conversations.rename", values, &response)
 	if err != nil {
 		return nil, err
@@ -277,6 +281,7 @@ func (api *Client) InviteUsersToConversationContext(ctx context.Context, channel
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
+
 	err := api.postMethod(ctx, "conversations.invite", values, &response)
 	if err != nil {
 		return nil, err
@@ -297,6 +302,7 @@ func (api *Client) KickUserFromConversationContext(ctx context.Context, channelI
 		"channel": {channelID},
 		"user":    {user},
 	}
+
 	response := SlackResponse{}
 	err := api.postMethod(ctx, "conversations.kick", values, &response)
 	if err != nil {
@@ -479,6 +485,7 @@ func (api *Client) GetConversationsContext(ctx context.Context, params *GetConve
 		ResponseMetaData responseMetaData `json:"response_metadata"`
 		SlackResponse
 	}{}
+
 	err = api.postMethod(ctx, "conversations.list", values, &response)
 	if err != nil {
 		return nil, "", err
@@ -516,6 +523,7 @@ func (api *Client) OpenConversationContext(ctx context.Context, params *OpenConv
 		AlreadyOpen bool     `json:"already_open"`
 		SlackResponse
 	}{}
+
 	err := api.postMethod(ctx, "conversations.open", values, &response)
 	if err != nil {
 		return nil, false, false, err
@@ -540,6 +548,7 @@ func (api *Client) JoinConversationContext(ctx context.Context, channelID string
 		} `json:"response_metadata"`
 		SlackResponse
 	}{}
+
 	err := api.postMethod(ctx, "conversations.join", values, &response)
 	if err != nil {
 		return nil, "", nil, err

files.go

@@ -321,6 +321,7 @@ func (api *Client) UploadFileContext(ctx context.Context, params FileUploadParam
 		}
 		err = postWithMultipartResponse(ctx, api.httpclient, api.endpoint+"files.upload", params.Filename, "file", values, params.Reader, response, api)
 	}
+
 	if err != nil {
 		return nil, err
 	}

files_test.go

@@ -177,7 +177,8 @@ func TestUploadFile(t *testing.T) {
 
 	reader := bytes.NewBufferString("test reader")
 	params = FileUploadParameters{
-		Filename: "test.txt", Reader: reader,
+		Filename: "test.txt",
+		Reader:   reader,
 		Channels: []string{"CXXXXXXXX"}}
 	if _, err := api.UploadFile(params); err != nil {
 		t.Errorf("Unexpected error: %s", err)

messages.go

@@ -98,6 +98,13 @@ type Msg struct {
 	Blocks Blocks `json:"blocks,omitempty"`
 }
 
+const (
+	// ResponseTypeInChannel in channel response for slash commands.
+	ResponseTypeInChannel = "in_channel"
+	// ResponseTypeEphemeral ephemeral respone for slash commands.
+	ResponseTypeEphemeral = "ephemeral"
+)
+
 // Icon is used for bot messages
 type Icon struct {
 	IconURL   string `json:"icon_url,omitempty"`