Hui 辉 Build Status Hex pm

Hui 辉 (“shine” in Chinese) is a Solr client and library for Elixir.

Usage

Hui enables Solr querying and other forms of interaction (forthcoming) in Elixir or Phoenix applications. Typical Solr data can be contained within a core (index) held on a single server or a data collection in distributed server architecture (cloud).

Example

  Hui.q("scott") # keywords search
  Hui.q(q: "loch", rows: 5) # arbitrary keyword list
  Hui.q(%Hui.Q{q: "loch", rows: 5, start: 20}) # structured query
  Hui.q(%Hui.Q{q: "author:I*", rows: 5}, %Hui.F{field: ["cat", "author_str"], mincount: 1})

  Hui.search(:library, %Hui.Q{q: "loch", fq: ["type:illustration", "format:image/jpeg"]})

  # more elaborated search
  x = %Hui.Q{q: "*", rows: 5}
  range1 = %Hui.F.Range{range: "price", start: 0, end: 100, gap: 10, per_field: true}
  range2 = %Hui.F.Range{range: "popularity", start: 0, end: 5, gap: 1, per_field: true}
  y = %Hui.F{field: ["cat", "author_str"], mincount: 1, range: [range1, range2]}
  Hui.search(:library, x, y)
  # this spawns a request with the following query string

  # q=%2A&rows=5&facet=true&facet.field=cat&facet.field=author_str&facet.mincount=1&
  # f.price.facet.range.end=100&f.price.facet.range.gap=10&facet.range=price&
  # f.price.facet.range.start=0&f.popularity.facet.range.end=5&
  # f.popularity.facet.range.gap=1&
  # facet.range=popularity&f.popularity.facet.range.start=0

The q examples queries a default endpoint - see Configuration below. A query could be a string, a Keyword list or built-in query Structs providing a structured way for invoking the comprehensive and powerful features of Solr.

Queries may also be issued to other endpoints and request handlers:

  # URL binary string
  Hui.search("http://localhost:8983/solr/collection", %Hui.Q{q: "loch"})

  # URL key referring to an endpoint in configuration - see "Configuration"
  url = :library
  Hui.search(url, q: "edinburgh", rows: 10)

  # URL in a struct
  url = %Hui.URL{url: "http://localhost:8983/solr/collection", handler: "suggest"}
  Hui.search(url, suggest: true, "suggest.dictionary": "mySuggester", "suggest.q": "el")
  # this -> http://http://localhost:8983/solr/collection/suggest?suggest=true&suggest.dictionary=mySuggester&suggest.q=el

See the API reference and Solr reference guide for more details on available search parameters.

HTTP headers and options

HTTP headers and options can be specified via the Hui.URL.t/0 struct.

  # setting up a header and a 10s receiving connection timeout
  url = %Hui.URL{url: "..", headers: [{"accept", "application/json"}], options: [recv_timeout: 10000]}
  Hui.search(url, q: "solr rocks")

Headers and options for a specific endpoint may also be configured - see “Configuration”.

Software library

Hui modules and data structures can be used for building Solr application in Elixir and Phoenix.

The following struct modules provide an idiomatic and structured way for creating and encoding Solr parameters:

  • Standard and common query: Hui.Q
  • Faceting: Hui.F, Hui.F.Range, Hui.F.Interval
  • structs for other request handlers are forthcoming

For example, instead of prefixing and repeating fq=filter, facet.field=fieldname, facet.range.gap=10, multiple filter and facet fields can be specified using fq: ["field1", "field2"], field: ["field1", "field2"], gap: 10 Elixir codes.

“Per-field” faceting for multiple ranges and intervals can be specified in a succinct and unified way, e.g. gap instead of the long-winded f.[fieldname].facet.range.gap (per field) or facet.range.gap (single field range). Per-field use case for a facet can easily be set (or unset) with the per_field key - see below.

  x = %Hui.Q{q: "loch", fq: ["type:image/jpeg", "year:2001"], fl: "id,title", rows: 20}
  x |> Hui.URL.encode_query
  # -> "fl=id%2Ctitle&fq=type%3Aimage%2Fjpeg&fq=year%3A2001&q=loch&rows=20"

  x = %Hui.F{field: ["type", "year", "subject"], query: "edited:true"}
  x |> Hui.URL.encode_query
  # -> "facet=true&facet.field=type&facet.field=year&facet.field=subject&facet.query=edited%3Atrue"
  # there's no need to set "facet: true" as it is implied and a default setting in the struct

  # a unified way to specify per-field or singe-field range
  x = %Hui.F.Range{range: "age", gap: 10, start: 0, end: 100}
  x |> Hui.URL.encode_query
  # -> "facet.range.end=100&facet.range.gap=10&facet.range=age&facet.range.start=0"

  x = %{x | per_field: true} # toggle per field faceting
  x |> Hui.URL.encode_query
  # -> "f.age.facet.range.end=100&f.age.facet.range.gap=10&facet.range=age&f.age.facet.range.start=0"

The structs also provide binding to and introspection of the available fields.

  iex> %Hui.F{field: ["type", "year"], query: "year:[2000 TO NOW]"}
  %Hui.F{
    contains: nil,
    "contains.ignoreCase": nil,
    "enum.cache.minDf": nil,
    excludeTerms: nil,
    exists: nil,
    facet: true,
    field: ["type", "year"],
    interval: nil,
    limit: nil,
    matches: nil,
    method: nil,
    mincount: nil,
    missing: nil,
    offset: nil,
    "overrequest.count": nil,
    "overrequest.ratio": nil,
    pivot: [],
    "pivot.mincount": nil,
    prefix: nil,
    query: "year:[2000 TO NOW]",
    range: nil,
    sort: nil,
    threads: nil
  }

Parsing Solr results

Hui returns Solr results as HTTPoison.Response struct containing the Solr response.

  {:ok,
   %HTTPoison.Response{
    body: "...[Solr reponse]..",
    headers: [
      {"Content-Type", "application/json;charset=utf-8"},
      {"Content-Length", "4005"}
    ],
    request_url: "http://localhost:8983/solr/gettingstarted/select?q=%2A",
    status_code: 200
   }
  }

JSON response is automatically parsed and decoded as Map. It is accessible via the body key.

  {status, resp} = Hui.q(solr_params)

  # getting a list of Solr documents (Map)
  solr_docs = resp.body["response"]["docs"]
  total_hits = resp.body["response"]["numFound"]

Note: other response formats such as XML, are currently being returned in raw text.

Other low-level HTTP client features

Under the hood, Hui uses HTTPoison - an HTTP client to interact with Solr. The existing low-level functions of HTTPoison e.g. get/1, get/3 remain available in the Hui.Search module.

Installation

Hui is available in Hex, the package can be installed by adding hui to your list of dependencies in mix.exs:

  def deps do
    [
      {:hui, "~> 0.5.3"}
    ]
  end

Then run $ mix deps.get.

Documentation can be found at https://hexdocs.pm/hui.

Configuration

A default Solr endpoint may be specified in the application configuration as below:

  config :hui, :default,
    url: "http://localhost:8983/solr/gettingstarted",
    handler: "select", # optional
    headers: [{"accept", "application/json"}], # optional
    options: [recv_timeout: 10000] # optional

HTTP headers and options may also be configured.

See Hui.URL.default_url!/0.

Solr provides various request handlers for many purposes (search, autosuggest, spellcheck, indexing etc.). The handlers are configured in different custom or normative names in Solr configuration, e.g. “select” for search queries.

Additional endpoints and request handlers can be configured in Hui using arbitrary config keys (e.g. :suggester):

  config :hui, :suggester,
    url: "http://localhost:8983/solr/collection",
    handler: "suggest"

Use the config key in functions such as Hui.search/2, Hui.search/3 to send queries to the endpoint or retrieve URL settings from configuration e.g. Hui.URL.configured_url/1.

License

Hui is released under Apache 2 License. Check the LICENSE file for more information.