PLT-4403 Add server-based channel autocomplete, search and paging (#4585)

* Add more channel paging API

* Add channel paging support to client

* Add DB channel search functions

* Add API for searching more channels

* Add more channel search functionality to client

* Add API for autocompleting channels

* Add channel autocomplete functionality to the client

* Move to be deprecated APIs to their own file

* Final clean-up

* Fixes related to feedback

* Localization changes

* Add unit as suffix to timeout constants

model/client.go

@@ -1164,6 +1164,7 @@ func (c *Client) GetChannel(id, etag string) (*Result, *AppError) {
 	}
 }
 
+// SCHEDULED FOR DEPRECATION IN 3.7 - use GetMoreChannelsPage instead
 func (c *Client) GetMoreChannels(etag string) (*Result, *AppError) {
 	if r, err := c.DoApiGet(c.GetTeamRoute()+"/channels/more", "", etag); err != nil {
 		return nil, err
@@ -1174,6 +1175,43 @@ func (c *Client) GetMoreChannels(etag string) (*Result, *AppError) {
 	}
 }
 
+// GetMoreChannelsPage will return a page of open channels the user is not in based on
+// the provided offset and limit. Must be authenticated.
+func (c *Client) GetMoreChannelsPage(offset int, limit int) (*Result, *AppError) {
+	if r, err := c.DoApiGet(fmt.Sprintf(c.GetTeamRoute()+"/channels/more/%v/%v", offset, limit), "", ""); err != nil {
+		return nil, err
+	} else {
+		defer closeBody(r)
+		return &Result{r.Header.Get(HEADER_REQUEST_ID),
+			r.Header.Get(HEADER_ETAG_SERVER), ChannelListFromJson(r.Body)}, nil
+	}
+}
+
+// SearchMoreChannels will return a list of open channels the user is not in, that matches
+// the search criteria provided. Must be authenticated.
+func (c *Client) SearchMoreChannels(channelSearch ChannelSearch) (*Result, *AppError) {
+	if r, err := c.DoApiPost(c.GetTeamRoute()+"/channels/more/search", channelSearch.ToJson()); err != nil {
+		return nil, err
+	} else {
+		defer closeBody(r)
+		return &Result{r.Header.Get(HEADER_REQUEST_ID),
+			r.Header.Get(HEADER_ETAG_SERVER), ChannelListFromJson(r.Body)}, nil
+	}
+}
+
+// AutocompleteChannels will return a list of open channels that match the provided
+// string. Must be authenticated.
+func (c *Client) AutocompleteChannels(term string) (*Result, *AppError) {
+	url := fmt.Sprintf("%s/channels/autocomplete?term=%s", c.GetTeamRoute(), url.QueryEscape(term))
+	if r, err := c.DoApiGet(url, "", ""); err != nil {
+		return nil, err
+	} else {
+		defer closeBody(r)
+		return &Result{r.Header.Get(HEADER_REQUEST_ID),
+			r.Header.Get(HEADER_ETAG_SERVER), ChannelListFromJson(r.Body)}, nil
+	}
+}
+
 func (c *Client) GetChannelCounts(etag string) (*Result, *AppError) {
 	if r, err := c.DoApiGet(c.GetTeamRoute()+"/channels/counts", "", etag); err != nil {
 		return nil, err