Use postcodes io gem

Gemfile

@@ -37,6 +37,7 @@ gem "devise", github: "ghiculescu/devise", branch: "error-code-422"
 # UK postcode parsing and validation
 gem "uk_postcode"
 # Use Ruby objects to build reusable markup. A React inspired evolution of the presenter pattern
+gem "postcodes_io"
 gem "view_component"
 
 group :development, :test do

Gemfile.lock

@@ -171,6 +171,7 @@ GEM
       dotenv (= 2.7.6)
       railties (>= 3.2)
     erubi (1.10.0)
+    excon (0.89.0)
     factory_bot (6.2.0)
       activesupport (>= 5.0.0)
     factory_bot_rails (6.2.0)
@@ -255,6 +256,8 @@ GEM
     parser (3.0.3.1)
       ast (~> 2.4.1)
     pg (1.2.3)
+    postcodes_io (0.4.0)
+      excon (~> 0.39)
     pry (0.13.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
@@ -432,6 +435,7 @@ DEPENDENCIES
   listen (~> 3.3)
   overcommit (>= 0.37.0)
   pg (~> 1.1)
+  postcodes_io
   pry-byebug
   puma (~> 5.0)
   rack-mini-profiler (~> 2.0)

app/models/case_log.rb

@@ -1,6 +1,7 @@
 require "uri"
 require "net/http"
 require "json"
+require "postcodes_io"
 
 class CaseLogValidator < ActiveModel::Validator
   # Validations methods need to be called 'validate_' to run on model save
@@ -163,6 +164,8 @@ class CaseLog < ApplicationRecord
 
 private
 
+  PIO = Postcodes::IO.new
+
   def update_status!
     self.status = if all_fields_completed? && errors.empty?
                     "completed"
@@ -202,13 +205,12 @@ private
   end
 
   def get_la(postcode)
-    uri = URI("https://api.os.uk/search/places/v1/postcode?key=#{ENV['OS_PLACES_API_KEY']}&postcode=#{postcode}&dataset=LPI")
-    res = Net::HTTP.get_response(uri)
-    response_body = JSON.parse(res.body)
-    if res.is_a?(Net::HTTPSuccess) && (response_body["header"]["totalresults"]).to_i.positive?
+    postcode_lookup = PIO.lookup(postcode)
+    unless postcode_lookup.info.nil?
       self.is_la_inferred = true
-      response_body["results"][0]["LPI"]["ADMINISTRATIVE_AREA"].downcase.capitalize
+      return postcode_lookup.admin_district
     end
+    self.la = nil
     self.is_la_inferred = false
   end
 

spec/features/form/page_routing_spec.rb

@@ -63,8 +63,8 @@ RSpec.describe "Form Page Routing" do
     end
 
     it "does not show question if the answer could be inferred" do
-      stub_request(:get, /api.os.uk/)
-        .to_return(status: 200, body: "{\"header\": {\"totalresults\": \"1\"}, \"results\": [{\"LPI\": {\"ADMINISTRATIVE_AREA\": \"MANCHESTER\"}}]}", headers: {})
+      stub_request(:get, /api.postcodes.io/)
+        .to_return(status: 200, body: "{\"status\":200,\"result\":{\"admin_district\":\"Manchester\"}}", headers: {})
 
       visit("/case-logs/#{id}/property-postcode")
       fill_in("case-log-property-postcode-field", with: "P0 5ST")

spec/models/case_log_spec.rb

@@ -1023,8 +1023,8 @@ RSpec.describe Form, type: :model do
     
     context "addresses" do
       before do
-        stub_request(:get, /api.os.uk/)
-          .to_return(status: 200, body: "{\"header\": {\"totalresults\": \"1\"}, \"results\": [{\"LPI\": {\"ADMINISTRATIVE_AREA\": \"MANCHESTER\"}}]}", headers: {})
+        stub_request(:get, /api.postcodes.io/)
+          .to_return(status: 200, body: "{\"status\":200,\"result\":{\"admin_district\":\"Manchester\"}}", headers: {})
       end
 
       let!(:address_case_log) do

spec/request_helper.rb

@@ -3,7 +3,7 @@ require "webmock/rspec"
 module RequestHelper
   def self.stub_http_requests
     WebMock.disable_net_connect!(allow_localhost: true)
-    WebMock.stub_request(:get, /api.os.uk/)
-      .to_return(status: 200, body: "{\"header\": {\"totalresults\": \"0\"}}", headers: {})
+    WebMock.stub_request(:get, /api.postcodes.io/)
+      .to_return(status: 200, body: "{\"status\":404,\"error\":\"Postcode not found\"}", headers: {})
   end
 end