Copyright (c) 2009-2023 Benoรฎt Chesneau.
Version: 1.5.0
Couchbeam is a simple erlang library for Barrel or Apache CouchDB. Couchbeam provides you a full featured and easy client to access and manage multiple nodes.
- Complete support of the BarrelDB and Apache CouchDB API
- Stream view results to your app
- Stream changes feeds
- reduced memory usage
- fetch and send attachments in a streaming fashion
- by default use the JSX module to encode/decode JSON
- support Jiffy a JSON encoder/decoder in C.
couchbeam
: Thecouchbeam
module is the main interface for interaction with this application. It includes functions for managing connections to Apache CouchDB or RCOUCH servers and databases and for performing document creations, updates, deletes, views...couchbeam_doc
Module to manipulate Documents structures. You can set values, updates keys, ...couchbeam_attachments
: Module to manipulate attachments. You can add, remove attachments in a Document structure (inline attachments).couchbeam_view
: Module to manage view results.couchbeam_changes
: Module to manage changes feeds. Follow continuously the changes in a db or get all changes at once.
The goal of Couchbeam is to ease the access to the Apache CouchDB and RCOUCH HTTP API in erlang.
Read the NEWS file to get last changelog.
Download the sources from our Github repository
To build the application simply run 'make'. This should build .beam, .app files and documentation.
To run tests run 'make test'. To generate doc, run 'make doc'.
Or add it to your rebar config
erlang
{deps, [
....
{couchbeam, ".*", {git, "git://github.com/benoitc/couchbeam.git", {branch, "master"}}}
]}.
Note to compile with jiffy you need to define in the erlang options the
variable WITH_JIFFY
.
if you use rebar, add to your rebar.config
:
erlang
{erl_opts, [{d, 'WITH_JIFFY'}]}.
or use the rebar
command with the -D
options:
sh
rebar compile -DWITH_JIFFY
Couchbeam is an OTP application. You have to start it first before using any of the functions. The couchbeam application will start the default socket pool for you.
To start in the console run:
sh
$ erl -pa ebin
1> couchbeam:start().
ok
It will start hackney and all of the application it depends on:
erlang
application:start(crypto),
application:start(asn1),
application:start(public_key),
application:start(ssl),
application:start(hackney),
application:start(couchbeam).
Or add couchbeam to the applications property of your .app in a release
To create a connection to a server machine:
erlang
Url = "http://localhost:5984",
Options = [],
S = couchbeam:server_connection(Url, Options).
Test the connection with couchbeam:server_info/1
:
erlang
{ok, _Version} = couchbeam:server_info(S).
All document operations are done in databases. To open a database simply do:
erlang
Options = [],
{ok, Db} = couchbeam:open_db(Server, "testdb", Options).
To create a new one:
erlang
Options = [],
{ok, Db} = couchbeam:create_db(Server, "testdb", Options).
You can also use the shorcut couchbeam:open_or_create_db/3
. that
will create a database if it does not exist.
Make a new document:
erlang
Doc = {[
{<<"_id">>, <<"test">>},
{<<"content">>, <<"some text">>}
]}.
And save it to the database:
erlang
{ok, Doc1} = couchbeam:save_doc(Db, Doc).
The couchbeam:save_doc/2
return a new document with updated
revision and if you do not specify the _id, a unique document id.
To change an document property use functions from couchbeam_doc
.
To retrieve a document do:
erlang
{ok, Doc2} = couchbeam:open_doc(Db, "test").
If you want a specific revision:
erlang
Rev = couchbeam_doc:get_rev(Doc1),
Options = [{rev, Rev}],
{ok, Doc3} = couchbeam:open_doc(Db, "test", Options).
Here we get the revision from the document we previously stored. Any options from the Apache CouchDB and RCOUCH API can be used.
To get all documents you have first to create an object that will keep all informations.
erlang
Options = [include_docs],
{ok, AllDocs} = couchbeam_view:all(Db, Options).
Ex of results:
erlang
{ok,[{[{<<"id">>,<<"7a0ce91d0d0c5e5b51e904d1ee3266a3">>},
{<<"key">>,<<"7a0ce91d0d0c5e5b51e904d1ee3266a3">>},
{<<"value">>,
{[{<<"rev">>,<<"15-15c0b3c4efa74f9a80d28ac040f18bdb">>}]}},
{<<"doc">>,
{[{<<"_id">>,<<"7a0ce91d0d0c5e5b51e904d1ee3266a3">>},
{<<"_rev">>,<<"15-15c0b3c4efa74f9a80d28ac040f18"...>>}]}}]},
]}.
All functions to manipulate these results are in the couchbeam_view
module.
Views are workin like all_docs. You have to create a View object before doing anything.
erlang
Options = [],
DesignName = "designname",
ViewName = "viewname",
{ok, ViewResults} = couchbeam_view:fetch(Db, {DesignName, ViewName}, Options).
Like the all_docs
function, use the functions
from couchbeam_view
module to manipulate results. You can pass
any querying options from the view API.
Design doc are created like any documents:
erlang
DesignDoc = {[
{<<"_id">>, <<"_design/couchbeam">>},
{<<"language">>,<<"javascript">>},
{<<"views">>,
{[{<<"test">>,
{[{<<"map">>,
<<"function (doc) {\n if (doc.type == \"test\") {\n emit(doc._id, doc);\n}\n}">>
}]}
},{<<"test2">>,
{[{<<"map">>,
<<"function (doc) {\n if (doc.type == \"test2\") {\n emit(doc._id, null);\n}\n}">>
}]}
}]}
}
]},
{ok, DesignDoc1} = couchbeam:save_doc(Db, DesignDoc).
You can also use couchapp to manage them more easily.
While you can get results using couchbeam_views:fetch/2
, you can also retrieve
all rows in a streaming fashion:
erlang
ViewFun = fun(Ref, F) ->
receive
{Ref, done} ->
io:format("done", []),
done;
{Ref, {row, Row}} ->
io:format("got ~p~n", [Row]),
F(Ref, F);
{error, Ref, Error} ->
io:format("error: ~p~n", [Error])
end
end,
{ok, StreamRef} = couchbeam_view:stream(Db, 'all_docs'),
ViewFun(StreamRef, ViewFun),
{ok, StreamRef2} = couchbeam_view:stream(Db, 'all_docs', [include_docs]),
ViewFun(StreamRef2, ViewFun).
You can of course do the same with a view:
erlang
DesignNam = "designname",
ViewName = "viewname",
{ok, StreamRef3} = couchbeam_view:stream(Db, {DesignNam, ViewName}, [include_docs]),
ViewFun(StreamRef3, ViewFun).
You can add attachments to any documents. Attachments could be anything.
To send an attachment:
erlang
DocID = "test",
AttName = "test.txt",
Att = "some content I want to attach",
Options = []
{ok, _Result} = couchbeam:put_attachment(Db, DocId, AttName, Att, Options).
All attachments are streamed to servers. Att
could be also be an iolist
or functions, see couchbeam:put_attachment/5
for more information.
To fetch an attachment:
erlang
{ok Att1} = couchbeam:fetch_attachment(Db, DocId, AttName).
You can use couchbeam:stream_fetch_attachment/6
for the stream
fetch.
To delete an attachment:
erlang
{ok, Doc4} = couchbeam:open_doc(Db, DocID),
ok = couchbeam:delete_attachment(Db, Doc4, AttName).
Apache CouchDB and RCOUCH provide a means to get a list of changes made to documents in
the database. With couchbeam you can get changes using couchbeam_changes:follow_once/2
.
This function returns all changes immediately. But you can also retrieve
all changes rows using longpolling :
erlang
Options = [],
{ok, LastSeq, Rows} = couchbeam_changes:follow_once(Db, Options).
Options can be any Changes query parameters. See the change API for more informations.
You can also get continuous:
erlang
ChangesFun = fun(StreamRef, F) ->
receive
{StreamRef, {done, LastSeq}} ->
io:format("stopped, last seq is ~p~n", [LastSeq]),
ok;
{StreamRef, {change, Change}} ->
io:format("change row ~p ~n", [Change]),
F(StreamRef, F);
{StreamRef, Error}->
io:format("error ? ~p ~n,", [Error])
end
end,
Options = [continuous, heartbeat],
{ok, StreamRef} = couchbeam_changes:follow(Db, Options),
ChangesFun(StreamRef, ChangesFun).
Note: a
gen_changes
behaviour exists in couchbeam that you can use to create your own specific gen_server receiving changes. Have a look in the example for more info.
You can authenticate to the database or Apache CouchDB or RCOUCH server by filling
options to the Option list in couchbeam:server_connection/4
for the
server or in couchbeam:create_db/3
, couchbeam:open_db/3
,
couchbeam:wopen_or_create_db/3
functions.
To set basic_auth on a server:
erlang
UserName = "guest",
Password = "test",
Url = "http://localhost:5984",
Options = [{basic_auth, {UserName, Password}}],
S1 = couchbeam:server_connection(Url, Options).
Couchbeam support SSL, OAuth, Basic Authentication, and Proxy. You can
also set a cookie. For more informations about the options have a look
in the couchbeam:server_connection/2
documentation.
For issues, comments or feedback please create an issue.