| <!-- | |
| Copyright (C) Daniel Stenberg, <[email protected]>, et al. | |
| SPDX-License-Identifier: curl | |
| --> | |
| # Alt-Svc | |
| curl features support for the Alt-Svc: HTTP header. | |
| ## Enable Alt-Svc in build | |
| `./configure --enable-alt-svc` | |
| (enabled by default since 7.73.0) | |
| ## Standard | |
| [RFC 7838](https://datatracker.ietf.org/doc/html/rfc7838) | |
| # Alt-Svc cache file format | |
| This is a text based file with one line per entry and each line consists of nine | |
| space separated fields. | |
| ## Example | |
| h2 quic.tech 8443 h3-22 quic.tech 8443 "20190808 06:18:37" 0 0 | |
| ## Fields | |
| 1. The ALPN id for the source origin | |
| 2. The hostname for the source origin | |
| 3. The port number for the source origin | |
| 4. The ALPN id for the destination host | |
| 5. The hostname for the destination host | |
| 6. The port number for the destination host | |
| 7. The expiration date and time of this entry within double quotes. The date format is "YYYYMMDD HH:MM:SS" and the time zone is GMT. | |
| 8. Boolean (1 or 0) if "persist" was set for this entry | |
| 9. Integer priority value (not currently used) | |
| If the hostname is an IPv6 numerical address, it is stored with brackets such | |
| as `[::1]`. | |