From e4fde3d278b4ee83caa4eff5be1ae78e38718607 Mon Sep 17 00:00:00 2001
From: Brandon Robins <brandon@onebnottwo.com>
Date: Sat, 28 Oct 2017 12:02:44 -0500
Subject: [PATCH] Update WebDavRequests controller

Adds the various WebDavRequest and preconditional methods
---
 .../rails/web_dav_requests_controller.rb      | 140 ++++++++++++++++++
 1 file changed, 140 insertions(+)

diff --git a/lib/calligraphy/rails/web_dav_requests_controller.rb b/lib/calligraphy/rails/web_dav_requests_controller.rb
index 656f805..822af45 100644
--- a/lib/calligraphy/rails/web_dav_requests_controller.rb
+++ b/lib/calligraphy/rails/web_dav_requests_controller.rb
@@ -38,6 +38,146 @@ module Calligraphy::Rails
       @resource = @resource_class.new resource: resource_id, req: request
     end
 
+    def headers
+      request.headers
+    end
+
+    def check_preconditions
+      return true unless headers['If'].present?
+
+      evaluate_if_header
+    end
+
+    def evaluate_if_header
+      conditions_met = false
+
+      condition_lists = get_if_conditions
+      condition_lists.each do |list|
+        conditions = parse_preconditions list
+
+        conditions_met = evaluate_preconditions conditions
+        break if conditions_met
+      end
+
+      conditions_met
+    end
+
+    def get_if_conditions
+      lists = if headers['If'][0] == '<'
+        headers['If'].split Calligraphy::TAGGED_LIST_REGEX
+      else
+        headers['If'].split Calligraphy::UNTAGGAGED_LIST_REGEX
+      end
+
+      lists
+    end
+
+    def parse_preconditions(list)
+      conditions = { dav_no_lock: nil, etag: nil, lock_token: nil, resource: nil }
+
+      conditions[:dav_no_lock] = if list =~ Calligraphy::DAV_NO_LOCK_REGEX
+        list =~ Calligraphy::DAV_NOT_NO_LOCK_REGEX ? nil : true
+      end
+
+      if list =~ Calligraphy::RESOURCE_REGEX
+        conditions[:resource] = list.scan(Calligraphy::RESOURCE_REGEX).flatten[0]
+      end
+
+      if list =~ Calligraphy::LOCK_TOKEN_REGEX
+        conditions[:lock_token] = list.scan(Calligraphy::LOCK_TOKEN_REGEX).flatten[0]
+      end
+
+      if list =~ Calligraphy::ETAG_IF_REGEX
+        conditions[:etag] = list.scan(Calligraphy::ETAG_IF_REGEX).flatten[0]
+      end
+
+      conditions
+    end
+
+    def evaluate_preconditions(conditions)
+      conditions_met = true
+      target = if conditions[:resource]
+        @resource_class.new(
+          resource: conditions[:resource],
+          mount: @resource.mount_point
+        )
+      else
+        @resource
+      end
+
+      if conditions[:lock_token]
+        if target.locked?
+          conditions_met = false unless target.lock_tokens&.include? conditions[:lock_token]
+        else
+          conditions_met = false if target.locked_to_user? headers
+        end
+      end
+
+      if conditions[:etag]
+        validators = [@resource.etag, ""]
+        conditions_met = false unless validate_etag validators, conditions[:etag]
+      end
+
+      conditions_met = false if conditions[:dav_no_lock]
+      conditions_met
+    end
+
+    def validate_etag(etag_validators, validate_against)
+      cache_key = ActiveSupport::Cache.expand_cache_key etag_validators
+      "W/\"#{Digest::MD5.hexdigest(cache_key)}\"" == validate_against
+    end
+
+    def web_dav_request
+      { headers: headers, request: request, resource: @resource, response: response }
+    end
+
+    def options
+      response.headers['DAV'] = '1, 2, 3'
+      :ok
+    end
+
+    def get(head: false)
+      fresh_when(@resource, etag: @resource.etag) if @resource.readable?
+      
+      Calligraphy::Get.new(web_dav_request).request(head: head)
+    end
+
+    def put
+      Calligraphy::Put.new(web_dav_request).request
+    end
+
+    def delete
+      Calligraphy::Delete.new(web_dav_request).request
+    end
+
+    def copy
+      Calligraphy::Copy.new(web_dav_request).request
+    end
+
+    def move
+      Calligraphy::Move.new(web_dav_request).request
+    end
+
+    def mkcol
+      Calligraphy::Mkcol.new(web_dav_request).request
+    end
+
+    def propfind
+      Calligraphy::Propfind.new(web_dav_request).request
+    end
+
+    def proppatch
+      Calligraphy::Proppatch.new(web_dav_request).request
+    end
+
+    def lock
+      Calligraphy::Lock.new(web_dav_request).request
+    end
+
+    def unlock
+      Calligraphy::Unlock.new(web_dav_request).request
+    end
+
     def send_response(status:, body: nil)
       if body.nil?
         head status