configured_url/1 for retrieving additional endpoints / handlers from …

…config

README.md

@@ -17,11 +17,11 @@ which typically distributed across many servers.
   Hui.search(q: "loch", rows: 5, fq: ["type:illustration", "format:image/jpeg"])
 ```
 
-The above examples query a pre-configured default Solr endpoint - see `Configuration` below.
-The query may involves search words (string) or a [keywords list](https://elixir-lang.org/getting-started/keywords-and-maps.html#keyword-lists) 
+The above queries the default Solr endpoint - see `Configuration` below.
+A query may involves search words (string) or a [keywords list](https://elixir-lang.org/getting-started/keywords-and-maps.html#keyword-lists)
 of Solr parameters, invoking the comprehensive and powerful features of Solr.
 
-For any endpoint and request handlers defined in binary or struct format:
+Queries may also be issued to other endpoints and request handlers, defined in binary or struct format:
 
 ```
   Hui.search("http://localhost:8983/solr/collection", q: "loch")
@@ -89,25 +89,29 @@ be found at [https://hexdocs.pm/hui](https://hexdocs.pm/hui).
 
 ## Configuration
 
-If your application only provides services to a single Solr core or collection. 
-A default URL may be specified in the application configuration as below:
+A default Solr endpoint may be specified in the application configuration as below:
 
-  ```
-    config hui, default_url,
-      url: "http://localhost:8983/solr/gettingstarted",
-      handler: "select" # optional
-  ```
+```
+  config :hui, :default_url,
+    url: "http://localhost:8983/solr/gettingstarted",
+    handler: "select" # optional
+```
 
-- `url`: Typical Solr endpoint including the core or collection name. This could also be a load balancer
-endpoint fronting several upstream servers
-- `handler`: name of a handler that processes requests (per endpoint).
+See `Hui.URL.default_url!/0`.
 
-Solr provides [a variety of request
+Solr provides [various request
 handlers](http://lucene.apache.org/solr/guide/7_4/overview-of-searching-in-solr.html#overview-of-searching-in-solr)
 for many purposes (search, autosuggest, spellcheck, indexing etc.). The handlers are configured
 in different custom or normative names in
 [Solr configuration](http://lucene.apache.org/solr/guide/7_4/requesthandlers-and-searchcomponents-in-solrconfig.html#requesthandlers-and-searchcomponents-in-solrconfig),
 e.g. "select" for search queries.
 
-Hui sends queries to the default URL if it exists (when none is supplied programmtically).
+Multiple endpoints with different Solr request handlers can be configured in Hui with an arbitrary config key (e.g. `:suggester`):
+
+```
+  config :hui, :suggester,
+    url: "http://localhost:8983/solr/collection",
+    handler: "suggest"
+```
 
+Use the config key in `Hui.search/2` to send queries to the endpoint or retrieve from configuration e.g. `Hui.URL.config_url(:suggester)`.

config/config.exs

@@ -3,5 +3,12 @@ use Mix.Config
 # A default Solr endpoint may be configured via the 'default_url' property
 #
 config :hui, :default_url, # default endpoint
-  url: "http://localhost:8983/solr/gettingstarted",
+  url: "http://localhost:8983/solr/gettingstarted", # core or collection endpoint
   handler: "select" # optional
+
+# Additional Solr endpoints may be configured using any config key, e.g. :suggester.
+# Use Hui.URL.config_url(:suggester) function to retrieve the corresponding URL struct
+#
+config :hui, :suggester,
+  url: "http://localhost:8983/solr/collection",
+  handler: "suggest"

lib/hui/url.ex

@@ -11,35 +11,58 @@ defmodule Hui.URL do
   @type t :: %__MODULE__{url: nil | binary, handler: nil | binary}
 
   @doc """
-  Returns any configured Solr url as `t:Hui.URL.t/0` struct.
+  Returns a configured default Solr endpoint as `t:Hui.URL.t/0` struct.
 
-  ```
       iex> Hui.URL.default_url!
       %Hui.URL{handler: "select", url: "http://localhost:8983/solr/gettingstarted"}
-  ```
 
-  A default URL may be specified in the application configuration as below:
+  The default endpoint can be specified in application configuration as below:
 
   ```
-    config hui, default_url,
+    config :hui, :default_url,
       url: "http://localhost:8983/solr/gettingstarted",
       handler: "select" # optional
   ```
 
-  - `url`: Typical Solr endpoint including the core or collection name. This could also be a load balancer
-  endpoint fronting several upstream servers
-  - `handler`: name of a handler that processes requests (per endpoint).
-
+  - `url`: typical endpoint including the core or collection name. This may also be a load balancer
+  endpoint fronting several Solr upstreams.
+  - `handler`: name of a request handler that processes requests.
 
   """
   @spec default_url! :: t | nil
   def default_url! do
-    {x, y} = {Application.get_env(:hui, :default_url)[:url], Application.get_env(:hui, :default_url)[:handler]}
+    {status, default_url} = config_url(:default_url)
+    case status do
+      :ok -> default_url
+      :error -> nil
+    end
+  end
+
+  @doc """
+  Retrieve url configuration as `t:Hui.URL.t/0` struct.
+
+  ## Example
+
+      iex> Hui.URL.config_url(:suggester)
+      {:ok, %Hui.URL{handler: "suggest", url: "http://localhost:8983/solr/collection"}}
+
+  The above retrieves the following endpoint configuration e.g. from `config.exs`:
+
+  ```
+    config :hui, :suggester,
+      url: "http://localhost:8983/solr/collection",
+      handler: "suggest"
+  ```
+
+  """
+  @spec config_url(atom) :: {:ok, t} | {:error, binary} | nil
+  def config_url(config_key) do
+    {x, y} = {Application.get_env(:hui, config_key)[:url], Application.get_env(:hui, config_key)[:handler]}
     case {x,y} do
-      {nil, nil} -> nil
-      {nil, _} -> nil
-      {_, nil} -> %Hui.URL{url: x}
-      {_, _} -> %Hui.URL{url: x, handler: y}
+      {nil, nil} -> {:error, "URL not found in configuration"}
+      {nil, _} -> {:error, "URL not found in configuration"}
+      {_, nil} -> {:ok, %Hui.URL{url: x}}
+      {_, _} -> {:ok, %Hui.URL{url: x, handler: y}}
     end
   end
 
@@ -70,7 +93,7 @@ defmodule Hui.URL do
   def encode_query(enumerable) when is_list(enumerable), do: Enum.map_join(enumerable, "&", &encode/1)
   def encode_query(_), do: ""
 
-  @doc "Returns the string representation of the given `t:Hui.URL.t/0` struct."
+  @doc "Returns the string representation (URL path) of the given `t:Hui.URL.t/0` struct."
   @spec to_string(t) :: binary
   def to_string(%__MODULE__{url: url, handler: handler}), do: "#{url}/#{handler}"
 

test/hui_test.exs

@@ -2,16 +2,26 @@ defmodule HuiTest do
   use ExUnit.Case, async: true
   doctest Hui.URL
 
-  # Using the config :hui, :default_url example
-  test "default_url! should return a %Hui.URL stuct" do
-    assert %Hui.URL{url: "http://localhost:8983/solr/gettingstarted", handler: "select"} = Hui.URL.default_url!
-  end
+  describe "Hui.URL" do
+
+    # Using the config :hui, :default_url example in config.exs
+    test "default_url! should return %Hui.URL stuct" do
+      assert %Hui.URL{url: "http://localhost:8983/solr/gettingstarted", handler: "select"} = Hui.URL.default_url!
+    end
+
+    # Using the config :hui, :suggester example in config.exs
+    test "url function should return %Hui.URL stuct for a given config" do
+      assert {:ok, %Hui.URL{url: "http://localhost:8983/solr/collection", handler: "suggest"}} = Hui.URL.config_url(:suggester)
+      assert {:error, "URL not found in configuration"} = Hui.URL.config_url(:random_url_not_in_config)
+    end
+
+    test "to_string should return a URL" do
+      x = %Hui.URL{url: "http://localhost:8983/solr/newspapers", handler: "suggest"}
+      y = %Hui.URL{url: "http://localhost:8983/solr/newspapers"}
+      assert "http://localhost:8983/solr/newspapers/suggest" = x |> Hui.URL.to_string
+      assert "http://localhost:8983/solr/newspapers/select" = y |> Hui.URL.to_string
+    end
 
-  test "Hui.URL.to_string should return a URL" do
-    x = %Hui.URL{url: "http://localhost:8983/solr/newspapers", handler: "suggest"}
-    y = %Hui.URL{url: "http://localhost:8983/solr/newspapers"}
-    assert "http://localhost:8983/solr/newspapers/suggest" = x |> Hui.URL.to_string
-    assert "http://localhost:8983/solr/newspapers/select" = y |> Hui.URL.to_string
   end
 
 end