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class IO::Delimited
inherits IO

An IO that wraps another IO, and only reads up to the beginning of a specified delimiter.

This is useful for exposing part of an underlying stream to a client.

io = IO::Memory.new "abc||123"
delimited = IO::Delimited.new(io, read_delimiter: "||")

delimited.gets_to_end # => "abc"
delimited.gets_to_end # => ""
io.gets_to_end        # => "123"

Class methods

.new(io : IO, read_delimiter : String, sync_close : Bool = false)

Creates a new IO::Delimited which wraps io, and can read until the byte sequence read_delimiter (interpreted as UTF-8) is found. If sync_close is set, calling #close calls #close on the underlying IO.

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.new(io : IO, read_delimiter : Bytes, sync_close : Bool = false)

Creates a new IO::Delimited which wraps io, and can read until the byte sequence read_delimiter is found. If sync_close is set, calling #close calls #close on the underlying IO.

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Methods

#close

Closes this IO.

IO defines this is a no-op method, but including types may override.

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#closed? : Bool

Returns true if this IO is closed.

IO defines returns false, but including types may override.

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#read(slice : Bytes)

Reads at most slice.size bytes from this IO into slice. Returns the number of bytes read, which is 0 if and only if there is no more data to read (so checking for 0 is the way to detect end of file).

io = IO::Memory.new "hello"
slice = Bytes.new(4)
io.read(slice) # => 4
slice          # => Bytes[104, 101, 108, 108]
io.read(slice) # => 1
slice          # => Bytes[111, 101, 108, 108]
io.read(slice) # => 0
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#read_delimiter : Slice(UInt8)

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#sync_close=(sync_close)

If #sync_close? is true, closing this IO will close the underlying IO.

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#sync_close? : Bool

If #sync_close? is true, closing this IO will close the underlying IO.

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#write(slice : Bytes) : Nil

Writes the contents of slice into this IO.

io = IO::Memory.new
slice = Bytes.new(4) { |i| ('a'.ord + i).to_u8 }
io.write(slice)
io.to_s # => "abcd"
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