Update ct.gov connector and parser for ct.gov API v2

Refactor to use v2 API and update URLs that referenced "classic" site for study pages.

Connector changes:
1. Recurse over its pages of results -- no longer an option to return more than 100 studies at once when searching with location etc. criteria.
2. Show status messages for both current "page" and overall.
3. Fix #clear, which had not been updated to delete TrialSubgroups when those were added (hence was failing to delete Trials with a reference error).

Parser changes:
1. Major changes to switch from XML/xpath to the new JSON format for API responses.
2. Don't re-fetch data for each study individually, data for studies loads in each "page" in the connector and that data for each study is included in the parser object initialization (each parser instance represents handling of data for a single study).
3. Change location matching from exact to substring (via regex). This fixes an issue where e.g. a location of "University of Minnesota/Cancer Center" would not match if the location in the site settings is "University of Minnesota". This was causing data for studies to be incorrectly omitted.
4. New contacts algorithm, V2 API no longer has "contact" and "backup contact".
5. Misc. updates for API changes to case in enumerated values, naming and nesting, etc.

Spec changes:
Added many tests and updated existing ones for ct.gov parser.

Rake task changes:
Update for new private connector API.

README changes:
Include update notes.

README.md

@@ -10,9 +10,11 @@ Contact the StudyFinder team at [email protected] if you:
 - Have any questions about StudyFinder, or
 - Want to learn more about updates or enhancements of the tool.
 
-## Upgrade notes for 2.1
+## Upgrade notes for 2.2
+The built-in clinicaltrials.gov connector has been transitioned fully to the clinicaltrials.gov V2 API. This includes two breaking changes in the private API for the ctgov connector. 
 
-The main page carousel/video feature was an accessibility and usability issue, and has been replaced with a three-wide panel of "featured studies". These can be configured in the admin panel, where the carousel configuration formerly was.
+1. In `Connectors::Ctgov#load(start_date,end_date)` the start and end dates must now be in ISO format YYYY-MM-DD (the old format was MM/DD/YYYY). Any custom tasks that directly call this method should be updated.
+2. `Connectors::Ctgov#load(start_date,end_date)` now calls `Connectors::Ctgov#process` itself to recurse through the V2 API's paged results. Formerly, `load` and `process` had to be called separately in that order. Remove any direct calls to `process` in order to avoid a redundant re-processing of the last "page" of data from the API. 
 
 ## Development
 

app/views/studies/_clinicaltrialsgov_button.html.erb

@@ -1,5 +1,5 @@
 <% if Trial.is_nct_number?(study.nct_id) %>
-  <a class="btn btn-school btn-more-info" href="https://www.clinicaltrials.gov/ct2/show/study/<%= study.nct_id%>" onclick="track('send', 'event', 'ctgov', 'click', {'nct_id':'<%= study.nct_id %>'});" target="_blank">
+  <a class="btn btn-school btn-more-info" href="https://www.clinicaltrials.gov/study/<%= study.nct_id%>" onclick="track('send', 'event', 'ctgov', 'click', {'nct_id':'<%= study.nct_id %>'});" target="_blank">
     <i class="fa-solid fa-info-circle"></i>
     See this study on ClinicalTrials.gov
   </a>

lib/connectors/ctgov.rb

@@ -5,77 +5,98 @@ class Ctgov
 
     def initialize
       @system_info = SystemInfo.current
-      @parser_id = Parser.find_by({ klass: 'Parsers::Ctgov'}).id
 
       if @system_info.nil?
         raise "There is no system info associated. Please run the seeds file, or add the info in the system administration section."
       end
-    end
-
-    def load(start_date=nil, end_date=nil)
-      start_load_time = Time.now
 
-      url = "https://clinicaltrials.gov/ct2/results/download_studies?locn=#{ERB::Util.url_encode(@system_info.search_term)}"
+      @parser_id = Parser.find_by({ klass: 'Parsers::Ctgov'}).id
+      @location = @system_info.search_term
+      @page_token = nil
+      @payload = nil
+      @start_date = 'MIN'
+      @end_date = 'MAX'
+      @start_load_time = nil
+      @total_count = nil
+      @count = 0
+    end
 
-      if !start_date.nil? and !end_date.nil?
-        puts "Loading clinicaltrials.gov results for #{@system_info.search_term} ... from #{start_date} to #{end_date}"
-        url = url + "&lup_s=#{ERB::Util.url_encode(start_date)}&lup_e=#{ERB::Util.url_encode(end_date)}"
-      else
-        puts "Loading all clinicaltrials.gov results for #{@system_info.search_term} ..."
+    def study_filters
+      q = {
+          'query.locn' => "AREA[LocationFacility]#{@location} AND AREA[LocationStatus]RECRUITING",
+          'query.term' => "AREA[LastUpdatePostDate]RANGE[#{@start_date},#{@end_date}]",
+          countTotal: true,
+          pageSize: 100,
+          format: "json"
+        }
+      # API only wants a pageToken arg at all if we are actually asking for one.
+      if !@page_token.blank?
+        q[:pageToken] = @page_token
       end
 
-      puts "Search URL: #{url}"
-      # @zipfile = Tempfile.new('file')
-      # @zipfile.binmode
+      return q
+    end
 
-      dirname = "#{Rails.root}/tmp/"
-      unless File.directory?(dirname)
-        FileUtils.mkdir_p(dirname)
-      end
+    def studies_page
+      response = HTTParty.get(
+        "https://clinicaltrials.gov/api/v2/studies",
+        query: self.study_filters
+      )
+      @payload = JSON.parse(response.body || "{}")
+      @total_count ||= @payload.dig('totalCount')
+      puts "Retrieved page (#{@page_token})"
+    end
 
-      FileUtils.rm_rf("#{dirname}search_result.zip")
-      File.open("#{dirname}search_result.zip", "w+") do |f|
-        f.write(HTTParty.get(url).body)
-      end
-      # @zipfile.write(HTTParty.get(url).body)
-      # @zipfile.close
+    def load(start_date="MIN", end_date="MAX")
+      puts "Adding/Updating trials in the database.  If it is a full reload it's going to be awhile...  Maybe get some coffee? :)"
+      @start_date = start_date
+      @end_date = end_date
+      @start_load_time ||= Time.now
 
-      puts "Extracting trials from zip file"
-      extract()
-      end_load_time = Time.now
+      self.studies_page
 
-      puts "Time elapsed #{(end_load_time - start_load_time)} seconds"
-    end
+      # Process the studies we just received, and ...
+      self.process
+      # ... recurse if there's another page. 
 
-    def extract
-      start_load_time = Time.now
-      extract_zip()
-      end_load_time = Time.now
+      if @payload.dig("nextPageToken")
+        @page_token = @payload.dig("nextPageToken")
+      else
+        @page_token = nil
+      end
 
-      puts "Zip time elapsed: #{(end_load_time - start_load_time)}"
-      return true
+      if @page_token.blank? 
+        puts "clinicaltrials.gov load COMPLETE."
+      else
+        puts "Now we'll load page #{@payload.dig("nextPageToken")}}"
+        @payload = nil
+        self.load(@start_date,@end_date)
+      end
     end
 
     def process
-      start_load_time = Time.now
-      count = 0
-      puts "Adding/Updating trials in the database.  If it is a full reload it's going to be awhile...  Maybe get some coffee? :)"
-
-      Dir.glob("#{Rails.root}/tmp/trials/*.xml") do |file|
-        p = Parsers::Ctgov.new( file.gsub("#{Rails.root}/tmp/trials/", "").gsub(".xml", ""), @parser_id)
-        p.load(file)
+      page_start_load_time = Time.now
+      page_count = 0
+      puts "Processing page (#{@page_token})"
+
+      @payload.dig('studies').each do |study|
+        @id = study.dig('protocolSection', 'identificationModule', 'nctId')
+        p = Parsers::Ctgov.new(@id, @parser_id, study)
+        puts "Processing: #{@id} (#{@count + 1} of #{@total_count})"
         p.process
-        count = count + 1
+        page_count = page_count + 1
+        @count = @count + 1
       end
-      end_load_time = Time.now
+      page_end_load_time = Time.now
 
-      puts "Logging update to updaters table. Processed #{count} records."
+      puts "Logging update to updaters table."
       Updater.create({
         parser_id: @parser_id,
-        num_updated: count
+        num_updated: page_count
       })
 
-      puts "Process time elapsed: #{(end_load_time - start_load_time)} seconds"
+      puts "Page time elapsed: #{(page_end_load_time - page_start_load_time)} seconds for #{page_count} records."
+      puts "Total process elapsed: #{(page_end_load_time - @start_load_time)} seconds for #{@count} records."
       return true
     end
 
@@ -86,8 +107,9 @@ def clear
       TrialLocation.delete_all
       TrialKeyword.delete_all
       Location.delete_all
-      Trial.delete_all
+      TrialSubgroup.delete_all
       TrialCondition.delete_all
+      Trial.delete_all
     end
 
     def site_nct_ids
@@ -103,7 +125,6 @@ def cleanup_stray_trials
     end
 
     def nct_ids_for_location(location, page_token = nil)
-      csc = 'M Health Fairview Clinics and Surgery Center'
       ids = []
       q = {
           'query.locn' => "SEARCH[Location](AREA[LocationFacility]#{location} AND AREA[LocationStatus]RECRUITING)",