Fix streaming via /ipfs/<cid> and /content/<cid>

[vicky-g]

Description

There was an error Cannot set headers after they are sent to the client with moving the headers right after creating the stream because on the end event, we call res.end(). This prevents us from adding headers cus the response is closed.

So, this fix is to add the the cache-control header + content-disposition header before creating the stream, and on err, remove the cache-control

Tests

• hit ipfs/cid route with cid that responds with 200
• hit ipfs/cid route with cid that responds with 404
• hit ipfs/cid route with cid that responds with 200, and the file is empty (original scenario for source of bug)

Monitoring - How will this change be monitored? Are there sufficient logs / alerts?

See [getCID] decision tree logs, or see requestUrl: /ipfs/<cid> in logs

[SidSethi]

instead of "Logs surrounding /ipfs/, which was how we found this issue to begin with 😬" in Monitoring section, would be really helpful if you could provide specific log substring and/or loggly link to make it easy for others to monitor

[vicky-g]

instead of "Logs surrounding /ipfs/, which was how we found this issue to begin with 😬" in Monitoring section, would be really helpful if you could provide specific log substring and/or loggly link to make it easy for others to monitor

updated