问题
I had gone through the documentation of slack on how to develop slack app. When i installed google drive slack app i saw that the google drive options(create new file, etc) can be accessed when clicking the '+' button on the left side of send message input. How is this achieved?
回答1:
Unfortunately, this feature is not available to all 3rd party developers.
In general there is a difference between the features available to all developers and to companies that have develop apps in close cooperation with the Slack team, like Google, Twitter and others.
You can see all features available to all 3rd party developers in the official Slack documentation, e.g. here.
However, Slack is constantly adding new features to its platform and might add this feature down the road. If you want to see what new features are currently planned checkout the Slack Platform Roadmap.
There is one interesting feature from Google Drive though, that is available to all devs. And that is the link detection. When you link a google drive document, it will be automatically detected as such and you will be presented with options what to do next in Slack. That you can also do with your own Slack apps with the Slack app unfurling feature.
来源：https://stackoverflow.com/questions/48425499/how-to-integrate-with-slack-similar-to-how-google-drive-did