For use with the Microsoft Bot Builder SDK v4, particularly when developing a bot for Microsoft Teams. Users will often @mention the bot or other users within a Team, which pollutes incoming messages with possibly undesired <at> tags. This package helps strip these <at> tags from the message.

For example, if the user typed

@Teams Bot Schedule a meeting with @John Smith

then your bot would receive the string

<at>Teams Bot</at> Schedule a meeting with <at>John Smith</at>

and this package could produce the string

Schedule a meeting with John Smith

Your bot can use() this middleware as usual:

const stripMentions = new StripMentions();
adapter.use(stripMentions);

The stripped text is placed in context.request.text. You can retrieve the unstripped text using the getOriginalText() method. (Note that this may not be the truly original text, particularly if you're using other middleware that modifies context.request.text before this one.)

adapter.processRequest(req, res, context => {
    if (context.request.type === ActivityTypes.Message) {
        const originalText = stripMentions.getOriginalText(context);
        console.log(`Original text: ${originalText}`);
        console.log(`Stripped text: ${context.request.text}`);
    }
});

You can configure how the tags are stripped for your bot vs. for other users via the StripMentions constructor. See Configuration for details.

// These are the default values for the middleware
new StripMentions({
    botBehavior: 'whole',
    userBehavior: 'tags'
})

Alternatively, you can call the strip logic yourself without using middleware:

adapter.processRequest(req, res, context => {
    if (context.request.type === ActivityTypes.Message) {
        const mentions = context.request.entities.filter(e => e.type === 'mention');
        const strippedText = stripMentions(context.request.text, mentions, 'tags');
    }
});

You can configure how the tags are stripped using the last parameter to stripMentions(). See Configuration for details.

The valid behaviors are

• whole: The tags and contained text are removed
• tags: Only the tags are removed
• none: Nothing is removed

For example, for this example utterance from before:

@Teams Bot Schedule a meeting with @John Smith

the middleware could produce the following: