crystal-rethinkdb
Crystal RethinkDB
This is a RethinkDB Driver for the Crystal Language.
Installation
Add this to your application's shard.yml
:
dependencies:
rethinkdb:
github: kingsleyh/crystal-rethinkdb
Usage
This library is meant to be compatible with RethinkDB's Ruby API. Thus, all official documentation should be valid here. If you find something that behaves differently, please open an issue.
require "rethinkdb"
include RethinkDB::Shortcuts
# Let’s connect and create a table:
conn = r.connect(host: "localhost")
r.db("test").table_create("tv_shows").run(conn)
# Now, let’s insert some JSON documents into the table:
r.table("tv_shows").insert([
{name: "Star Trek TNG", episodes: 178},
{name: "Battlestar Galactica", episodes: 75}
]).run(conn)
# We’ve just inserted two rows into the tv_shows table. Let’s verify the number of rows inserted:
pp r.table("tv_shows").count().run(conn)
# Finally, let’s do a slightly more sophisticated query. Let’s find all shows with more than 100 episodes.
p r.table("tv_shows").filter {|show| show["episodes"] > 100 }.run(conn).to_a
# As a result, we of course get the best science fiction show in existence.
Connecting as a user
If you made a user called bob
with password secret
in the rethinkdb system table users
e.g.:
r.db('rethinkdb').table('users').insert({id: 'bob', password: 'secret'})
require "rethinkdb"
include RethinkDB::Shortcuts
conn = r.connect(host: "localhost", db: "my_database", user: "bob", password: "secret")
Read more about users and permissions here: https://rethinkdb.com/docs/permissions-and-accounts/
Useful Queries
Here are some more complex queries - mostly as a reminder to myself on how to do various more complicated things:
Something to note is that depending on the query you write you could get back one of these 3 things:
RethinkDB::QueryResult
RethinkDB:Cursor
RethinkDB::Array(RethinkDB::QueryResult)
Inserting
r.table("users").insert({
name: name, email: email, password: password,
activeChannel: {} of String => String,
channels: [] of String, groups: [] of String,
isOnline: false
}
).run(@connection)
r.table("messages").insert({channelId: channelId, userId: userId, content: content, date: r.now.to_iso8601}).run(@connection)
Finding All
r.table("users").map{|u|
{id: u["id"], name: u["name"], isOnline: u["isOnline"]}
}.run(@connection) }
r.table("users").filter{|u| r.expr(u["groups"]).contains(groupId) }.map{|u|
{id: u["id"], name: u["name"], isOnline: u["isOnline"]}
}.run(@connection)
r.table("groups").map{|g|
{id: g["id"], name: g["name"], landingChannel: r.table("channels").filter({isLanding: true, groupId: g["id"]})[0]["id"]}
}.run(@connection)
r.table("users").filter({id: userId}).map{|user|
{
channels: r.table("channels").filter{|ch| ch["groupId"] == groupId}.coerce_to("array"),
activeChannel: r.branch(user["activeChannel"].has_fields("channelId"),
{groupId: user["activeChannel"]["groupId"], channelId: user["activeChannel"]["channelId"], name: r.table("channels").get(user["activeChannel"]["channelId"])["name"]},
{groupId: "", channelId: "", name: ""}),
groupId: r.table("groups").get(groupId)["id"],
name: r.table("groups").get(groupId)["name"]
}
}.run(@connection)
Finding One
r.table("users").get(userId).run(@connection)
r.table("users").filter({id: userId}).map{|user|
{
channels: r.table("channels").filter{|ch| r.expr(user["channels"]).contains(ch["id"])}.filter{|ch| ch["groupId"] == groupId}.coerce_to("array"),
groups: r.table("groups").filter{|g| r.expr(user["groups"]).contains(g["id"])}.map{|g| {id: g["id"], name: g["name"], landingChannel: r.table("channels").filter({isLanding: true, groupId: g["id"]})[0]["id"]}}.coerce_to("array"),
messages: r.table("messages").filter{|m| m["channelId"] == channelId }.map{|m| {messageId: m["id"], userId: m["userId"], name: r.table("users").get(m["userId"])["name"], content: m["content"], date: m["date"]} }.coerce_to("array"),
channel: r.table("channels").get(channelId),
group: r.table("groups").get(groupId),
userIsOnline: user["isOnline"]
}
}.run(@connection).to_a.first
Updates
r.table("users").get(userId).update({isOnline: isOnline}).run(@connection)
r.table("users").get(userId).update{|u|
{channels: u.get_field("channels").set_insert(channelId),
groups: u.get_field("groups").set_insert(groupId),
activeChannel: {groupId: groupId, channelId: channelId}
}
}.run(@connection) }
r.table("users").get(userId).update{|u| {groups: u.get_field("groups").set_insert(groupId)}}.run(@connection)
Creating a database
def recreate_database
puts "dropping database: #{@env.database.name}"
begin
r.db_drop(@env.database.name).run( @connection)
rescue ex
puts ex.message
end
puts "creating database: #{@env.database.name}"
r.db_create(@env.database.name).run(@connection)
# add tables
puts "adding tables: users, groups, channels, messages"
r.db(@env.database.name).table_create("users").run(@connection)
r.db(@env.database.name).table_create("groups").run(@connection)
r.db(@env.database.name).table_create("channels").run(@connection)
r.db(@env.database.name).table_create("messages").run(@connection)
puts "done"
end
Contributing
- Fork it (https://github.com/kingsleyh/crystal-rethinkdb/fork)
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create a new Pull Request
Contributors
- kingsleyh Kingsley Hendrickse - creator, maintainer
- caspiano Caspian Baska - contributor, maintainer
- fenicks Christian Kakesa - contributor
Thanks
- Guilherme Bernal for his hard work on which this project is based.