start-proxy.rb as app entry point, reads YAML file for config

config.ru

@@ -1,5 +1,5 @@
 require 'rack'
 require_relative './fhir-proxy.rb'
 
-# rackup config.ru -p 9292 -o 0.0.0.0
+# FHIR_PROXY_BACKEND="https://r4.smarthealthit.org" rackup config.ru -p 9292 -o 0.0.0.0
 run FHIRProxy.new

fhir-proxy.rb

@@ -3,13 +3,13 @@
 require_relative 'fhir-transaction-db.rb'
 
 class FHIRProxy < Rack::Proxy
-  attr_accessor :config_mode #global var
-  def initialize(app = nil, opts = {})
+  attr_accessor :config_mode # global var
+  def initialize(myopts = {}, app = nil, opts = {})
     super(app, opts)
     @streaming = false
     File.open('log.txt', 'w') { |f| f.write "#{Time.now} - User logged in\n" }
-    set_backend_or_die
-    @fhir_db = FHIRTransactionDB.new('fhir-transactions.db')
+    parse_myopts(myopts)
+    @fhir_db = FHIRTransactionDB.new(@db_name)
   end
 
   def call(env)
@@ -20,7 +20,6 @@ def call(env)
     # Client -> Proxy (Save req here) -> Server
     # Client <- (Save res here) Proxy <- Server
     new_env = rewrite_env(env)
-    # -> new class validation (env)
     req_id = record_request(new_env)
     res_triple = rewrite_response(perform_request(new_env))
     res_id = record_response(res_triple, req_id)
@@ -51,7 +50,7 @@ def rewrite_env(env)
       elsif  dst && URI(dst).is_a?(URI::HTTP) && dst.to_s.include?('https:')
         @backend = URI(dst)
         @use_ssl= true
-        #env["HTTP_X_FORWARDED_PROTO"] = 'https'
+        # env["HTTP_X_FORWARDED_PROTO"] = 'https'
         msg_out(msg)
       end
     end
@@ -108,16 +107,18 @@ def msg_out(msg, stdout = true, file = true)
     File.write('log.txt', "#{msg} \n", mode: 'a') if file
   end
 
-  def set_backend_or_die
-    dst = ENV['FHIR_PROXY_BACKEND']
-    if dst && URI(dst).is_a?(URI::HTTP)
-      @backend = URI(dst)
-      msg_out("@backend set to: #{dst}")
+  def parse_myopts(myopts)
+    @db_name = myopts[:db] || 'fhir-transactions.db'
+    backend_str = ENV['FHIR_PROXY_BACKEND'] if ENV['FHIR_PROXY_BACKEND']
+    backend_str = myopts[:backend] if myopts[:backend]
+    if backend_str && URI(backend_str).is_a?(URI::HTTP)
+      @backend = URI(backend_str)
+      msg_out("@backend set to: #{@backend}")
     else
       msg = <<~HELP_DOC
-        FHIR_PROXY_BACKEND environment variable not set or bad URI.
-        Please specify proxy destination.
-        Example: FHIR_PROXY_BACKEND="https://r4.fhir-server-dest.com" rackup config.ru -p 9292 -o 0.0.0.0
+        Proxy 'backend' config option not set or bad URI.
+        Please specify proxy destination via proxy.yml file or environment variable FHIR_PROXY_BACKEND
+        Example: "https://r4.smarthealthit.org"
       HELP_DOC
       msg_out(msg)
       exit(1)

proxy.yml

@@ -0,0 +1,5 @@
+---
+:Host: 0.0.0.0
+:Port: 9292
+:backend: https://r4.smarthealthit.org
+:db: fhir-transactions.db

start-proxy.rb

@@ -0,0 +1,28 @@
+require 'rack'
+require 'yaml'
+require_relative './fhir-proxy.rb'
+
+# Options for Rack are listed here
+# https://github.com/rack/rack/blob/master/lib/rack/server.rb
+#
+begin
+  proxy_options = YAML.load_file('proxy.yml')
+rescue Errno::ENOENT
+  puts "Could not find file 'proxy.yml'"
+  puts 'Creating one with default values'
+  proxy_options = {
+      Host: '0.0.0.0',
+      Port: 9292,
+      backend: 'https://r4.smarthealthit.org',
+      db: 'fhir-transactions.db'
+  }
+  File.write('proxy.yml', proxy_options.to_yaml)
+end
+Rack::Server.start(
+  app: FHIRProxy.new(
+      'backend': proxy_options[:backend],
+      'db': proxy_options[:db]
+  ),
+  Host: proxy_options[:Host],
+  Port: proxy_options[:Port]
+)