package tiny_httpd

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Byte streams.

Streams are used to represent a series of bytes that can arrive progressively. For example, an uploaded file will be sent as a series of chunks.

These used to live in Tiny_httpd but are now in their own module.

  • since 0.12
type hidden

Type used to make t unbuildable via a record literal. Use make instead.

type t = {
  1. mutable bs : bytes;

    The bytes

  2. mutable off : int;

    Beginning of valid slice in bs

  3. mutable len : int;

    Length of valid slice in bs. If len = 0 after a call to fill, then the stream is finished.

  4. fill_buf : unit -> unit;

    See the current slice of the internal buffer as bytes, i, len, where the slice is bytes[i] .. [bytes[i+len-1]]. Can block to refill the buffer if there is currently no content. If len=0 then there is no more data.

  5. consume : int -> unit;

    Consume n bytes from the buffer. This should only be called with n <= len.

  6. close : unit -> unit;

    Close the stream.

  7. _rest : hidden;

    Use make to build a stream.


A buffered stream, with a view into the current buffer (or refill if empty), and a function to consume n bytes.

The point of this type is that it gives the caller access to its internal buffer (bs, with the slice off,len). This is convenient for things like line reading where one needs to peek ahead.

Some core invariant for this type of stream are:

  • off,len delimits a valid slice in bs (indices: off, off+1, … off+len-1)
  • if fill_buf() was just called, then either len=0 which indicates the end of stream; or len>0 and the slice contains some data.

To actually move forward in the stream, you can call consume n to consume n bytes (where n <= len). If len gets to 0, calling fill_buf() is required, so it can try to obtain a new slice.

To emulate a classic OCaml reader with a read: bytes -> int -> int -> int function, the simplest is:

let read (self:t) buf offset max_len : int =
  let len = min max_len self.len in
  if len > 0 then (
    Bytes.blit buf offset len;
    self.consume len;
val close : t -> unit

Close stream

val empty : t

Stream with 0 bytes inside

val of_input : ?buf_size:int -> Tiny_httpd_io.Input.t -> t

Make a buffered stream from the given channel.

  • since 0.14
val of_chan : ?buf_size:int -> in_channel -> t

Make a buffered stream from the given channel.

val of_chan_close_noerr : ?buf_size:int -> in_channel -> t

Same as of_chan but the close method will never fail.

val of_fd : ?buf_size:int -> Unix.file_descr -> t

Make a buffered stream from the given file descriptor.

val of_fd_close_noerr : ?buf_size:int -> Unix.file_descr -> t

Same as of_fd but the close method will never fail.

val of_bytes : ?i:int -> ?len:int -> bytes -> t

A stream that just returns the slice of bytes starting from i and of length len.

val of_string : string -> t
val iter : (bytes -> int -> int -> unit) -> t -> unit

Iterate on the chunks of the stream

  • since 0.3
val to_chan : out_channel -> t -> unit

Write the stream to the channel.

  • since 0.3
val to_chan' : Tiny_httpd_io.Output.t -> t -> unit

Write to the IO channel.

  • since 0.14
val to_writer : t -> Tiny_httpd_io.Writer.t

Turn this stream into a writer.

  • since 0.14
val make : ?bs:bytes -> ?close:(t -> unit) -> consume:(t -> int -> unit) -> fill:(t -> unit) -> unit -> t

make ~fill () creates a byte stream.

  • parameter fill

    is used to refill the buffer, and is called initially.

  • parameter close

    optional closing.

  • parameter init_size

    size of the buffer.

val with_file : ?buf_size:int -> string -> (t -> 'a) -> 'a

Open a file with given name, and obtain an input stream on its content. When the function returns, the stream (and file) are closed.

val read_line : ?buf:Tiny_httpd_buf.t -> t -> string

Read a line from the stream.

  • parameter buf

    a buffer to (re)use. Its content will be cleared.

val read_all : ?buf:Tiny_httpd_buf.t -> t -> string

Read the whole stream into a string.

  • parameter buf

    a buffer to (re)use. Its content will be cleared.

val limit_size_to : close_rec:bool -> max_size:int -> too_big:(int -> unit) -> t -> t
val read_chunked : ?buf:Tiny_httpd_buf.t -> fail:(string -> exn) -> t -> t

Convert a stream into a stream of byte chunks using the chunked encoding. The size of chunks is not specified.

  • parameter buf

    buffer used for intermediate storage.

  • parameter fail

    used to build an exception if reading fails.

val read_exactly : close_rec:bool -> size:int -> too_short:(int -> unit) -> t -> t

read_exactly ~size bs returns a new stream that reads exactly size bytes from bs, and then closes.

  • parameter close_rec

    if true, closing the resulting stream also closes bs

  • parameter too_short

    is called if bs closes with still n bytes remaining

val output_chunked : ?buf:Tiny_httpd_buf.t -> out_channel -> t -> unit

Write the stream into the channel, using the chunked encoding.

  • parameter buf

    optional buffer for chunking (since 0.14)

val output_chunked' : ?buf:Tiny_httpd_buf.t -> Tiny_httpd_io.Output.t -> t -> unit

Write the stream into the channel, using the chunked encoding.

  • since 0.14

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