Sphinx Client API

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This document gives an overview of what is Sphinx itself and how to use it from your Ruby on Rails application. For more information about Sphinx and its API documentation visit sphinxsearch.com.

Sphinx

Sphinx is a standalone full-text search engine, meant to provide fast, size-efficient and relevant fulltext search functions to other applications. Sphinx was specially designed to integrate well with SQL databases and scripting languages. Currently built-in data sources support fetching data either via direct connection to MySQL, or from an XML pipe.

Simplest way to communicate with Sphinx is to use searchd — a daemon to search through full text indexes from external software.

Installation

Add the "sphinx" gem to your Gemfile.

gem 'sphinx'

And run bundle install command.

Documentation

Complete Sphinx plugin documentation could be found on GitHub Pages.

Also you can find documentation on rdoc.info.

You can build the documentation locally by running:

rake yard

Complete Sphinx API documentation could be found on Sphinx Search Engine site. This plugin is fully compatible with original PHP API implementation.

Ruby naming conventions

Sphinx Client API supports Ruby naming conventions, so every API method name is in underscored, lowercase form:

SetServer    -> set_server
RunQueries   -> run_queries
SetMatchMode -> set_match_mode

Every method is aliased to a corresponding one from standard Sphinx API, so you can use both SetServer and set_server with no differrence.

There are three exceptions to this naming rule:

GetLastError   -> last_error
GetLastWarning -> last_warning
IsConnectError -> connect_error?

Of course, all of them are aliased to the original method names.

Using multiple Sphinx servers

Since we actively use this plugin in our Scribd development workflow, there are several methods have been added to accommodate our needs. You can find documentation on Ruby-specific methods in documentation.

First of all, we added support of multiple Sphinx servers to balance load between them. Also it means that in case of any problems with one of servers, library will try to fetch the results from another one. Every consequence request will be executed on the next server in list (round-robin technique).

sphinx.set_servers([
  { :host => 'browse01.local', :port => 3312 },
  { :host => 'browse02.local', :port => 3312 },
  { :host => 'browse03.local', :port => 3312 }
])

By default library will try to fetch results from a single server, and fail if it does not respond. To setup number of retries being performed, you can use second (additional) parameter of the set_connect_timeout and set_request_timeout methods:

sphinx.set_connect_timeout(1, 3)
sphinx.set_request_timeout(1, 3)

There is a big difference between these two methods. First will affect only on requests experiencing problems with connection (socket error, pipe error, etc), second will be used when request is broken somehow (temporary searchd error, incomplete reply, etc). The workflow looks like this:

  1. Increase retries number. If is less or equal to configured value, try to connect to the next server. Otherwise, raise an error.
  2. In case of connection problem go to 1.
  3. Increase request retries number. If it less or equal to configured value, try to perform request. Otherwise, raise an error.
  4. In case of connection problem go to 1.
  5. In case of request problem, go to 3.
  6. Parse and return response.

Withdrawals:

  1. Request could be performed connect_retries * request_retries times. E.g., it could be tried request_retries times on each of connect_retries servers (when you have 1 server configured, but connect_retries is 5, library will try to connect to this server 5 times).
  2. Request could be tried to execute on each server 1..request_retries times. In case of connection problem, request will be moved to another server immediately.

Usually you will set connect_retries equal to servers number, so you will be sure each failing request will be performed on all servers. This means that if one of servers is live, but others are dead, you request will be finally executed successfully.

Sphinx constants

Most Sphinx API methods expecting for special constants will be passed. For example:

sphinx.set_match_mode(Sphinx::SPH_MATCH_ANY)

Please note that these constants defined in a Sphinx module. You can use symbols or strings instead of these awful constants:

sphinx.set_match_mode(:any)
sphinx.set_match_mode('any')

Setting query filters

Every set_ method returns Sphinx::Client object itself. It means that you can chain filtering methods:

results = Sphinx::Client.new.
            set_match_mode(:any).
            set_ranking_mode(:bm25).
            set_id_range(10, 1000).
            query('test')

There is a handful ability to set query parameters directly in query call. If block does not accept any parameters, it will be eval'ed inside Sphinx::Client instance:

results = Sphinx::Client.new.query('test') do
  match_mode :any
  ranking_mode :bm25
  id_range 10, 1000
end

As you can see, in this case you can omit the set_ prefix for this methods. If block accepts a parameter, sphinx instance will be passed into the block. In this case you should you full method names including the set_ prefix:

results = Sphinx::Client.new.query('test') do |sphinx|
  sphinx.set_match_mode :any
  sphinx.set_ranking_mode :bm25
  sphinx.set_id_range 10, 1000
end

Example

This simple example illustrates base connection establishing, search results retrieving, and excerpts building. Please note how does it perform database select using ActiveRecord to save the order of records established by Sphinx.

sphinx = Sphinx::Client.new
result = sphinx.query('test')
ids = result['matches'].map { |match| match['id'] }
posts = Post.all :conditions => { :id => ids },
                 :order => "FIELD(id,#{ids.join(',')})"

docs = posts.map(&:body)
excerpts = sphinx.build_excerpts(docs, 'index', 'test')

Logging

You can ask Sphinx client API to log it's activity to some log. In order to do that you can pass a logger object into the Sphinx::Client constructor:

require 'logger'
Sphinx::Client.new(Logger.new(STDOUT)).query('test')

Logger object should respond to methods :debug, :info, and :warn, and accept blocks (this is what standard Ruby Logger class does). Here is what you will see in your log:

  • DEBUG -- query, add_query, run_queries method calls with configured filters.
  • INFO -- initialization with Sphinx version, servers change, attempts to re-connect, and all attempts to do an API call with server where request being performed.
  • WARN -- various connection and socket errors.

Support

You can find source code for this library on GitHub.

To suggest a feature or report a bug use GitHub Issues

Credits

Special thanks to Alexey Kovyrin

Special thanks to Mike Perham for his awesome memcache-client gem, where latest Sphinx gem got new sockets handling from.

License

This library is distributed under the terms of the Ruby license. You can freely distribute/modify this library.