Add POST and DELETE /license endpoints for v4 (#6665)

* Add POST and DELETE /license endpoints for v4

* Fix comment text

model/client4.go

@@ -1835,7 +1835,7 @@ func (c *Client4) InvalidateCaches() (bool, *Response) {
 	}
 }
 
-// UpdateConfig will update the server configuration
+// UpdateConfig will update the server configuration.
 func (c *Client4) UpdateConfig(config *Config) (*Config, *Response) {
 	if r, err := c.DoApiPut(c.GetConfigRoute(), config.ToJson()); err != nil {
 		return nil, &Response{StatusCode: r.StatusCode, Error: err}
@@ -1845,6 +1845,50 @@ func (c *Client4) UpdateConfig(config *Config) (*Config, *Response) {
 	}
 }
 
+// UploadLicenseFile will add a license file to the system.
+func (c *Client4) UploadLicenseFile(data []byte) (bool, *Response) {
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+
+	if part, err := writer.CreateFormFile("license", "test-license.mattermost-license"); err != nil {
+		return false, &Response{Error: NewAppError("UploadLicenseFile", "model.client.set_profile_user.no_file.app_error", nil, err.Error(), http.StatusBadRequest)}
+	} else if _, err = io.Copy(part, bytes.NewBuffer(data)); err != nil {
+		return false, &Response{Error: NewAppError("UploadLicenseFile", "model.client.set_profile_user.no_file.app_error", nil, err.Error(), http.StatusBadRequest)}
+	}
+
+	if err := writer.Close(); err != nil {
+		return false, &Response{Error: NewAppError("UploadLicenseFile", "model.client.set_profile_user.writer.app_error", nil, err.Error(), http.StatusBadRequest)}
+	}
+
+	rq, _ := http.NewRequest("POST", c.ApiUrl+c.GetLicenseRoute(), bytes.NewReader(body.Bytes()))
+	rq.Header.Set("Content-Type", writer.FormDataContentType())
+	rq.Close = true
+
+	if len(c.AuthToken) > 0 {
+		rq.Header.Set(HEADER_AUTH, c.AuthType+" "+c.AuthToken)
+	}
+
+	if rp, err := c.HttpClient.Do(rq); err != nil {
+		return false, &Response{StatusCode: http.StatusForbidden, Error: NewAppError(c.GetLicenseRoute(), "model.client.connecting.app_error", nil, err.Error(), http.StatusForbidden)}
+	} else if rp.StatusCode >= 300 {
+		return false, &Response{StatusCode: rp.StatusCode, Error: AppErrorFromJson(rp.Body)}
+	} else {
+		defer closeBody(rp)
+		return CheckStatusOK(rp), BuildResponse(rp)
+	}
+}
+
+// RemoveLicenseFile will remove the server license it exists. Note that this will
+// disable all enterprise features.
+func (c *Client4) RemoveLicenseFile() (bool, *Response) {
+	if r, err := c.DoApiDelete(c.GetLicenseRoute()); err != nil {
+		return false, &Response{StatusCode: r.StatusCode, Error: err}
+	} else {
+		defer closeBody(r)
+		return CheckStatusOK(r), BuildResponse(r)
+	}
+}
+
 // Webhooks Section
 
 // CreateIncomingWebhook creates an incoming webhook for a channel.