Inline/pasted images in Teams arrive with a contentUrl on
smba.trafficmanager.net (/v3/attachments/...). Unlike file uploads
(pre-authenticated SharePoint downloadUrls), these connector URLs
require the bot's own bearer token; fetching them anonymously fails
with 401 Unauthorized and the image is silently dropped.
- add _get_botframework_token(): client-credentials token for
https://api.botframework.com/.default, cached until ~5 min before
expiry
- _fetch_attachment_bytes(): attach the token when the attachment
host is *.trafficmanager.net / *.botframework.com; SharePoint and
other URLs remain auth-free as before
- route image/* attachments with Bot Framework contentUrls through
the authenticated fetch instead of cache_image_from_url (which
sends no Authorization header)
SSRF guards unchanged. Verified on a live Teams personal-scope bot:
pasted images previously logged '[teams] Failed to cache image
attachment: 401 Unauthorized' and now cache and deliver correctly.
Jacob S.
0eff6bc200