httpwire

nimony/lib/std/http/httpwire.nim

• const WriteFull: int64

  Did not fit. Nothing past i was written; grow dest and retry.

• proc writeByte(dest: var openArray; i: int64; c: char): int64
• proc writeBytes(dest: var openArray; i: int64; s: openArray): int64
• proc writeCrLf(dest: var openArray; i: int64): int64
• proc digitCount(x: int64): int64

  Digits in the decimal form of a non-negative x. Multiplications, not divisions: headLen asks this for every integer header of every head just to size a buffer, and writeInt then does the one division pass that actually produces the digits.

• proc writeInt(dest: var openArray; i: int64; x: int64): int64

  Decimal, formatted in place. Negative values are not written: nothing in an HTTP head is signed, and a -1 reaching the wire would be a bug downstream rather than a value.

  Written back-to-front from the last digit, so the single div loop lands the digits straight in dest — no temporary to reverse out of.

• proc reasonPhrase(status: int64): string

  The conventional phrase. Clients ignore it and HTTP/1.1 allows it to be empty, but middleboxes are happier when it is there. Unlisted codes get their class's phrase rather than nothing.

• proc writeChunkHeader(dest: var openArray; i: int64; size: int64): int64

  SIZE CRLF. The data follows, then its own CRLF — see writeChunkEnd. No extensions are ever written: nothing reads them, and every byte in this line is a byte another parser has to agree with us about.

• proc writeChunkEnd(dest: var openArray; i: int64): int64

  The CRLF that closes a chunk's data.

• proc writeLastChunk(dest: var openArray; i: int64): int64

  0 CRLF CRLF — the zero-length chunk and an empty trailer section. Written together because a body that stops after the zero chunk is a body the peer is still waiting on.

• proc writeChunk(dest: var openArray; i: int64; data: openArray): int64

  SIZE CRLF data CRLF — a whole chunk, staged in one place so the caller can send it in one write. A chunk split across writes is a chunk a peer can be left half-way through.

• proc chunkOverhead(size: int64): int64

  Bytes writeChunkHeader + writeChunkEnd add around size bytes of data, so a caller can size a buffer without writing twice: one hex digit and the two CRLFs, plus a digit for every further nibble.

• proc writeRequestHead(dest: var openArray; i: int64; m: HttpMsg): int64

  METHOD SP target SP version CRLF, the headers, and the blank line.

• proc writeResponseHead(dest: var openArray; i: int64; m: HttpMsg): int64

  version SP status SP reason CRLF, the headers, and the blank line.

• proc writeHead(dest: var openArray; i: int64; m: HttpMsg): int64

  Whichever kind m is.

• proc headLen(m: HttpMsg): int64

  Exactly how many bytes writeHead will produce. One extra walk of a tree that is already in cache, and it means the common path sizes its buffer once instead of writing, failing and retrying.