You can use Office Online Server with Seafile. How to install OOS you can read it here.

https://docs.microsoft.com/en-us/officeonlineserver/deploy-office-online-server

Config File for Seafile

vim /opt/seafile/conf/seahub_settings.py


# Enable Office Online Server
ENABLE_OFFICE_WEB_APP = True

# Url of Office Online Server's discovery page
# The discovery page tells Seafile how to interact with Office Online Server when view file online
# You should change `http://example.office-web-app.com` to your actual Office Online Server server address
OFFICE_WEB_APP_BASE_URL = 'http://192.168.2.131/hosting/discovery'

# Expiration of WOPI access token
# WOPI access token is a string used by Seafile to determine the file's
# identity and permissions when use Office Online Server view it online
# And for security reason, this token should expire after a set time period
WOPI_ACCESS_TOKEN_EXPIRATION = 30 * 60

# List of file formats that you want to view through Office Online Server
# You can change this value according to your preferences
# And of course you should make sure your Office Online Server supports to preview
# the files with the specified extensions
OFFICE_WEB_APP_FILE_EXTENSION = ('ods', 'xls', 'xlsb', 'xlsm', 'xlsx',
    'ppsx', 'ppt','pptm', 'pptx', 'doc', 'docm', 'docx')

# Enable edit files through Office Online Server
ENABLE_OFFICE_WEB_APP_EDIT = True

# types of files should be editable through Office Online Server
# Note, Office Online Server 2016 is needed for editing docx
OFFICE_WEB_APP_EDIT_FILE_EXTENSION = ('xlsx', 'pptx', 'docx')

restart seahub service

found here
https://blog.csdn.net/weixin_43136674/article/details/103484972