0x02 - Fetch 🧪

Do an HTTPS request to specified URL.

SSE is expected to be implemented as an abstraction over this API (rather than be provided as its own portal).

Connection

Host device channel is opened upon readiness (allocated only if successful). The channel allocation should happen immediately upon return of ar(), and must follow in the order of the ready list.

Readiness

Becomes ready once either

• The resource host can't be reached (network error), capacity set to 0.
• The resource host hung up, capacity set to 0.
• The resource host has sent back a chunk of the resource (a new device channel has been opened)
  1. Buffer is not big enough, buffer overwritten up to capacity bytes, and capacity modified how many more bytes are required
  2. Buffer is big enough, buffer overwritten, capacity unchanged.

Command: Fetch

Fields

• url: Text - URL to do an HTTPS request to (does not include https:// protocol)
• headers: Text - Extra headers to send (separated by \n)
• body: opt[List[byte]] - Optional payload/content body to send
• method: int - 0: GET, 1: HEAD, 2: POST, 3: PUT, 4: DELETE.
• capacity: ptr[int] - (In/Out) Pointer to capacity of buffer.
• buffer: ptr[List[byte]] - (In/Out) Pointer to buffer for receiving parts of the HTTP response.

Traps

0. If url does not start with one of
   • Domain name lowercase (ranged a~z or 0~9, - and . allowed after first character, but not consecutively, and not last character before termination character - one of :/?)
   • IPv4 Address - 4 integers ranged 0:255 each separated by .)
   • Ipv6 Address - [, then 8 lowercase hexaxecimal numbers from 1 to 4 digits separated by :, and ]. A grouping of consecutive zero numbers can be replaced with ::, rather than requiring all 8 numbers.
1. If url after domain/IP doesn't either start with one of :/? or end
2. If url sections :/? are out of order
3. If url port after : is not in range 0~65535
4. If url path after / is not a~z, A~Z, -, _, %, ., ~, +, or /
5. If url query after ? is not a~z, A~Z, 0~9, -, _ ., ~, +, =, ;, or &
6. If headers begins with \n or ends with \n
7. If headers line does not match Title-Kebab-Case: expected-type (no \r allowed)
8. If headers line contains an invalid (Like Not-A-Header), redudant (Like Content-Length), or insecure (Also like Content-Length) header
9. If input capacity is less than buffer.size
10. If address at (input) buffer.addr + body.capacity has no page
11. If address at body.addr + body.size has no page
12. If address at url.addr + url.size has no page
13. If address at headers.addr + headers.size has no page
14. If address at body + 3 has no page
15. If address at capacity + 3 has no page
16. If address at buffer + 3 has no page