I left a response on the post (https://stackoverflow.com/a/56247939/127977), but I’ll x-post it here:
I think the answer is no (as of
v0.4.20). The process IPFS goes through when retrieving a block is:
- Do the following at the same time:
- Notify all current peers that you want the block (e.g.
- Ask the network to find providers of the block you want (e.g.
- If a peer has the block, it will send it over and you will disregard any providers that are found.
- If no peer has the block and a provider is found, then the provider is added as a peer and is notified that you want the block (e.g.
QmXjFR1...), at which point the peer starts sending the block over.
In theory, if you run the IPFS node you could maybe do things to determine what peer a block is coming from. But the gateway doesn’t offer that information through its interface AFAIK.
Anyway, I don’t see anything in the response headers. Here’s an example from hitting the gateway API:
λ curl -v https://gateway.ipfs.io/api/v0/cat/QmT78zSuBmuS4z925WZfrqQ1qHaJ56DQaTfyMUF7F8ff5o
* Trying 2602:fea2:2::1...
* TCP_NODELAY set
* Connected to gateway.ipfs.io (2602:fea2:2::1) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
* CAfile: /etc/ssl/cert.pem
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Client hello (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS change cipher, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use h2
* Server certificate:
* subject: CN=ipfs.io
* start date: May 7 21:37:01 2019 GMT
* expire date: Aug 5 21:37:01 2019 GMT
* subjectAltName: host "gateway.ipfs.io" matched cert's "*.ipfs.io"
* issuer: C=US; O=Let's Encrypt; CN=Let's Encrypt Authority X3
* SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x7ff002806600)
> GET /api/v0/cat/QmT78zSuBmuS4z925WZfrqQ1qHaJ56DQaTfyMUF7F8ff5o HTTP/2
> Host: gateway.ipfs.io
> User-Agent: curl/7.54.0
> Accept: */*
* Connection state changed (MAX_CONCURRENT_STREAMS updated)!
< HTTP/2 200
< server: nginx
< date: Wed, 22 May 2019 04:32:43 GMT
< content-type: text/plain
< vary: Accept-Encoding
< trailer: X-Stream-Error
< vary: Origin
< x-content-length: 12
< x-stream-output: 1
< access-control-allow-origin: *
< access-control-allow-methods: GET, POST, OPTIONS
< access-control-allow-headers: X-Requested-With, Range, Content-Range, X-Chunked-Output, X-Stream-Output
< access-control-expose-headers: Content-Range, X-Chunked-Output, X-Stream-Output
< x-ipfs-pop: gateway-bank2-sjc1
< strict-transport-security: max-age=31536000; includeSubDomains; preload
* Connection #0 to host gateway.ipfs.io left intact