# Autocompletex
Autocompletex is a low-latency plug-and-play autocomplete tool using Redis sorted set. Written in pure Elixir, it focuses on rapid prototyping using your existing stack: simply start a redis instance, and start_link a GenServer.
Currently, it provides these implementation:
* Google-like query prediction based on popularity. E.G. ne -> netflix, new york times
* Lexicographic. Sorted in alphabetical order (faster)
There are two ways to run it:
* Use it as a standalone microservice with HTTP connection.
* GenServer
## Installation
Add the `:autocompletex` to your `mix.ecs` file:
```elixir
def deps do
[{:autocompletex, "~> 0.1.0"}]
end
```
Then add it to `applications`:
```elixir
defp application() do
[applications: [:logger, :redix]]
end
```
Then, run mix deps.get in your shell to fetch the new dependency.
## Usage
### Overview
Currently, two types of autocompletion is support:
* Lexicographic
* Predictive
If you want to suggest another scheme, please post an issue.
There are 3 ways to run it.
1. Standalone HTTP service
2. Using a GenServer
3. Supervision tree
### Manual
To start a GenServer manually:
```elixir
# For Lexicographic:
{:ok, conn} = Redix.start_link
db = "testdb"
{:ok, worker} = Autocompletex.Lexicographic.start_link(conn, db, Autocompletex)
# For Predictive:
{:ok, conn} = Redix.start_link
{:ok, worker} = start_link(conn, :ac)
```
Alternatively, you can use it in a supervision tree.
Add this to `config.exs`:
```elixir
config :autocompletex,
redis_host: "localhost",
redis_port: 6379,
redis_string: nil,
http_server: true,
http_port: 3000,
debug: false, # runs :observer.start if true
type: :lexicographic #:predictive
```
Then call
```elixir
Autocompletex.Lexicographic.upsert(Autocompletex.Lexicographic, ["test", "example"])
```
If `http_server` is set to `true`, two http endpoints will be accessible at the designated `http_port`(default: 3000).
```
upsert -> /add?term=Elixir
complete -> /complete?term=te
```
## API
There are two functions: `upsert` and `complete`.
`upsert/2` means insert or update. For Lexicographic, if a query is already inserted, it will do nothing. For Predictive, it will increment the score of the query.
`complete/3` returns a list of matched results. It takes 3 parameters: `pid`, `prefix`, `rangelen`. rangelen is the number of results to be returned. Defaults to 50.
```elixir
:ok = Autocompletex.Lexicographic.upsert(worker, ["test", "example"])
{:ok, val} == complete(worker, "te") # assert val == ["test"]
```
## Misc
If you have a list of user-generated search queries, you can use a mix task to index and provision the redis instance.
Simply do:
`mix autocompletex.import --filename [path/to/file] [--predictive]`
## Docs
To be updated. In the meantime, I'm happy to answer questions in issues.
