Redix

v0.6.1

Redix v0.6.1 Redix.Protocol

This module provides functions to work with the Redis binary protocol.

Summary

Types

on_parse(value)
redis_value()

Functions

pack(items)

Packs a list of Elixir terms to a Redis (RESP) array

parse(data)

Parses a RESP-encoded value from the given data

parse_multi(data, nelems)

Parses n RESP-encoded values from the given data

Types

on_parse(value) 
on_parse(value) ::
  {:ok, value, binary} |
  {:continuation, (binary -> on_parse(value))}
redis_value() 
redis_value ::
  binary |
  integer |
  nil |
  Redix.Error.t |
  [redis_value]

Functions

pack(items) 
pack([binary]) :: iodata

Packs a list of Elixir terms to a Redis (RESP) array.

This function returns an iodata (instead of a binary) because the packed result is usually sent to Redis through :gen_tcp.send/2 or similar. It can be converted to a binary with IO.iodata_to_binary/1.

All elements of elems are converted to strings with to_string/1, hence this function supports encoding everything that implements String.Chars.

Examples 

iex> iodata = Redix.Protocol.pack(["SET", "mykey", 1])
iex> IO.iodata_to_binary(iodata)
"*3\r\n$3\r\nSET\r\n$5\r\nmykey\r\n$1\r\n1\r\n"
parse(data) 
parse(binary) :: on_parse(<a href="#t:redis_value/0">redis_value</a>)

Parses a RESP-encoded value from the given data.

Returns {:ok, value, rest} if a value is parsed successfully, or a continuation in the form {:continuation, fun} if the data is incomplete.

Examples 

iex> Redix.Protocol.parse("+OK\r\ncruft")
{:ok, "OK", "cruft"}

iex> Redix.Protocol.parse("-ERR wrong type\r\n")
{:ok, %Redix.Error{message: "ERR wrong type"}, ""}

iex> {:continuation, fun} = Redix.Protocol.parse("+OK")
iex> fun.("\r\n")
{:ok, "OK", ""}
parse_multi(data, nelems) 
parse_multi(binary, non_neg_integer) :: on_parse([<a href="#t:redis_value/0">redis_value</a>])

Parses n RESP-encoded values from the given data.

Each element is parsed as described in parse/1. If an element can’t be fully parsed or there are less than n elements encoded in data, then a continuation in the form of {:continuation, fun} is returned. Otherwise, {:ok, values, rest} is returned. If there’s an error in decoding, a Redix.Protocol.ParseError exception is raised.

Examples 

iex> Redix.Protocol.parse_multi("+OK\r\n+COOL\r\n", 2)
{:ok, ["OK", "COOL"], ""}

iex> {:continuation, fun} = Redix.Protocol.parse_multi("+OK\r\n", 2)
iex> fun.("+OK\r\n")
{:ok, ["OK", "OK"], ""}