ABC-90 Add POST /emoji/search and GET /emoji/autocomplete API endpoints (#8125)

* Add POST /emoji/search and GET /emoji/autocomplete API endpoints

* Add constant to be clearer

model/client4.go

@@ -3070,6 +3070,27 @@ func (c *Client4) GetEmojiImage(emojiId string) ([]byte, *Response) {
 	}
 }
 
+// SearchEmoji returns a list of emoji matching some search criteria.
+func (c *Client4) SearchEmoji(search *EmojiSearch) ([]*Emoji, *Response) {
+	if r, err := c.DoApiPost(c.GetEmojisRoute()+"/search", search.ToJson()); err != nil {
+		return nil, BuildErrorResponse(r, err)
+	} else {
+		defer closeBody(r)
+		return EmojiListFromJson(r.Body), BuildResponse(r)
+	}
+}
+
+// AutocompleteEmoji returns a list of emoji starting with or matching name.
+func (c *Client4) AutocompleteEmoji(name string, etag string) ([]*Emoji, *Response) {
+	query := fmt.Sprintf("?name=%v", name)
+	if r, err := c.DoApiGet(c.GetEmojisRoute()+"/autocomplete"+query, ""); err != nil {
+		return nil, BuildErrorResponse(r, err)
+	} else {
+		defer closeBody(r)
+		return EmojiListFromJson(r.Body), BuildResponse(r)
+	}
+}
+
 // Reaction Section
 
 // SaveReaction saves an emoji reaction for a post. Returns the saved reaction if successful, otherwise an error will be returned.

model/emoji_search.go

@@ -0,0 +1,34 @@
+// Copyright (c) 2018-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type EmojiSearch struct {
+	Term       string `json:"term"`
+	PrefixOnly bool   `json:"prefix_only"`
+}
+
+func (es *EmojiSearch) ToJson() string {
+	b, err := json.Marshal(es)
+	if err != nil {
+		return ""
+	} else {
+		return string(b)
+	}
+}
+
+func EmojiSearchFromJson(data io.Reader) *EmojiSearch {
+	decoder := json.NewDecoder(data)
+	var es EmojiSearch
+	err := decoder.Decode(&es)
+	if err == nil {
+		return &es
+	} else {
+		return nil
+	}
+}

model/emoji_search_test.go

@@ -0,0 +1,19 @@
+// Copyright (c) 2018-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestEmojiSearchJson(t *testing.T) {
+	emojiSearch := EmojiSearch{Term: NewId()}
+	json := emojiSearch.ToJson()
+	remojiSearch := EmojiSearchFromJson(strings.NewReader(json))
+
+	if emojiSearch.Term != remojiSearch.Term {
+		t.Fatal("Terms do not match")
+	}
+}