From cc3286f6690a7ba6d095ae8247bb6cf25d09547c Mon Sep 17 00:00:00 2001
From: Karl Baker <karl.baker@digital.cabinet-office.gov.uk>
Date: Wed, 24 Oct 2018 09:57:35 +0100
Subject: [PATCH] Add ability to batch search Rummager

This commit enables the new batch search endpoint to be called on Rummager, where each of the individual queries to be batched is encoded in a readable string as part of the query string.

Co-authored-by: Oscar Wyatt <oscar.wyatt@digital.cabinet-office.gov.uk>
---
 CHANGELOG.md            |  4 ++++
 lib/gds_api/rummager.rb | 14 ++++++++++++++
 test/rummager_test.rb   | 15 +++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f0e68b9d..81fe8249 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 54.1.0
+
+* Add ability to batch search Rummager
+
 # 54.0.0
 
 * Expect `GdsApi::TestHelpers::Organisations` to be using the public API instead of Whitehall.
diff --git a/lib/gds_api/rummager.rb b/lib/gds_api/rummager.rb
index 2aee0cd8..61cb3be1 100644
--- a/lib/gds_api/rummager.rb
+++ b/lib/gds_api/rummager.rb
@@ -70,6 +70,20 @@ def search(args, additional_headers = {})
       get_json(request_url, additional_headers)
     end
 
+    # Perform a batch search.
+    #
+    # @param searches [Array] An array valid search queries. Maximum of 6. See Rummager documentation for options.
+    #
+    # # @see https://github.com/alphagov/rummager/blob/master/doc/search-api.md
+    def batch_search(searches, additional_headers = {})
+      url_friendly_searches = searches.each_with_index.map do |search, index|
+        { index => search }
+      end
+      searches_query = { search: url_friendly_searches }
+      request_url = "#{base_url}/batch_search?.json?search=#{Rack::Utils.build_nested_query(searches_query)}"
+      get_json(request_url, additional_headers)
+    end
+
     # Perform a search, returning the results as an enumerator.
     #
     # The enumerator abstracts away rummager's pagination and fetches new pages when
diff --git a/test/rummager_test.rb b/test/rummager_test.rb
index a68c1bb1..9af37648 100644
--- a/test/rummager_test.rb
+++ b/test/rummager_test.rb
@@ -5,6 +5,7 @@
   before(:each) do
     stub_request(:get, /example.com\/advanced_search/).to_return(body: "[]")
     stub_request(:get, /example.com\/search/).to_return(body: "[]")
+    stub_request(:get, /example.com\/batch_search/).to_return(body: "[]")
   end
 
   # tests for #advanced_search
@@ -138,6 +139,20 @@
     assert_requested :get, /.*/, headers: { "authorization" => "token" }
   end
 
+  it "#batch_search should issue a single request containing all queries" do
+    GdsApi::Rummager.new("http://example.com").batch_search([{ q: 'self assessment' }, { q: 'tax return' }])
+
+    assert_requested :get, /\[\]\[0\]\[q\]=self assessment/
+    assert_requested :get, /\[\]\[1\]\[q\]=tax return/
+  end
+
+  it "#batch_search should return the search deserialized from json" do
+    batch_search_results = [{ "title" => "document-title" }, { "title" => "document-title-2" }]
+    stub_request(:get, /example.com\/batch_search/).to_return(body: batch_search_results.to_json)
+    results = GdsApi::Rummager.new("http://example.com").batch_search([{ q: 'self assessment' }, { q: 'tax return' }])
+    assert_equal batch_search_results, results.to_hash
+  end
+
   # tests for search_enum
   it "#search_enum returns two pages - last page is half full" do
     stub_request(:get, /example.com\/search/)