CBERL

NIF based Erlang bindings for couchbase based on libcouchbase.

Please submit bugs and patches if you find any.

Tested on OSX, Debian Squeeze and Amazon Linux.

Quick Setup/Start

First you must have libcouchbase installed.

On OSX install homebrew if you haven't already then run:

brew update && brew install libcouchbase

On Amazon linux:

sudo wget -O/etc/yum.repos.d/couchbase.repo http://packages.couchbase.com/rpm/couchbase-centos62-x86_64.repo
sudo yum check-update
sudo yum install --enablerepo=epel libcouchbase2 libcouchbase-devel

For installing libcouchbase on other systems visit http://www.couchbase.com/develop/c/current.

Then:

git clone git@github.com:wcummings/cberl.git
cd cberl
# assuming you have rebar in your path
rebar get-deps compile

Or just include it as a dependency in your rebar config.

Example

Make sure you have couchbase running on localhost or use cberl:new(Host) instead.

% create a connection pool  of 5 connections named cberl_default
% you can provide more argument like host, username, password, 
% bucket and transcoder - look at https://github.com/wcummings/cberl/blob/master/src/cberl.erl for more detail 
cberl:start_link(cberl_default, 5).
{ok, <0.33.0>}
% Poolname, Key, Expire - 0 for infinity, Value
cberl:set(cberl_default, <<"fkey">>, 0, <<"cberl">>).
{ok,CAS}
cberl:get(cberl_default, <<"fkey">>).
{<<"fkey">>, ReturnedCasValue, <<"cberl">>}

For more information on all the functions -> ./rebar doc (most of documentation is out of date right now)

Views

cberl has support for querying views via the view/4 functions:

cberl:view(cberl_default, "all", "all", []).
{ok,{1,
    [[{<<"id">>,<<"test">>},
    {<<"key">>,<<"test">>},
    {<<"value">>,null}]]}}

Shorthand for foldl, foldr and foreach are also provided.

N1QL

cberl has support for N1QL queries via the n1ql/4 and n1ql/5 functions:

Dog = {[{<<"type">>,<<"dog">>},
  {<<"name">>,<<"tom">>},
  {<<"age">>,5},
  {<<"color">>,<<"white">>}]}.
cberl:set(cberl_default, <<"tom">>, 0, Dog).
cberl:n1ql(cberl_default, <<"SELECT * FROM default WHERE type=$1 and age=$2 and color=$3">>, [<<"\"dog\"">>, <<"5">>, <<"\"white\"">>], false).
{ok,{[{<<"requestID">>,
       <<"a00b80e8-aea8-4a23-a0a9-5aba26d2b48f">>},
      {<<"signature">>,{[{<<"*">>,<<"*">>}]}},
      {<<"results">>,[]},
      {<<"status">>,<<"success">>},
      {<<"metrics">>,
       {[{<<"elapsedTime">>,<<"21.644116ms">>},
         {<<"executionTime">>,<<"21.60625ms">>},
         {<<"resultCount">>,1},
         {<<"resultSize">>,171}]}}]},
    [{[{<<"default">>,
        {[{<<"age">>,5},
          {<<"color">>,<<"white">>},
          {<<"name">>,<<"tom">>},
          {<<"type">>,<<"dog">>}]}}]}]}

Custom Transcoders

You can have your custom transcoders, your transcoder must export 3 functions:

encode_value/2:

Takes in an encoder|encoder list and the original value and turns it into a binary.

decode_value/2:

Takes in a flag (from couchbase) and the value (as binary) and turns it into the actual value.

flag/1:

Turns an encoder_name (or list of them) into an integer. This value is sent to CB during set operations and this is what you get in decode value. You must return a value for 'standard' encoder if you are not planning to specify an encoder for every set operation.

Check out cberl_transcoder.erl it is pretty straightforward.