Fix iCal support for special characters (newline, comma, semicolon, backslash)

Jared Turner · Jared Turner · commit 041f65b61e93 · 2020-06-22T11:53:34.000+01:00
diff --git a/Gemfile.lock b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    add_to_calendar (0.2.2)
+    add_to_calendar (0.2.3)
       tzinfo (>= 1.1, < 3)
       tzinfo-data (~> 1.2020)
 
diff --git a/README.md b/README.md
@@ -104,11 +104,12 @@ cal = AddToCalendar::URLs.new(event_attributes)
 
 - Offset values eg. "2020-05-13 15:31:00 **+05:00**" are ignored. It is only important that you have the correct date and time numbers set. The timezone is set directly using its own attribute `timezone`.
 - You must set a timezone so that when users add the event to their calendar it shows at their correct local time. 
-  - Eg. London event @ `2020-05-13 13:30:00` will save in a New Yorkers calendar as local time `2020-05-13 17:30:00`
+  - Eg. London event @ `2020-05-13 13:30:00` will save in a New Yorker's calendar as local time `2020-05-13 17:30:00`
 
 ### Browser support
 
-- IE11 and lower will not work for `ical_url`, `apple_url` and `outlook_url` (IE does not properly support [data-uri links](https://caniuse.com/#feat=datauri). See [#16](https://github.com/jaredlt/add_to_calendar/issues/16)). 
+- IE11 and lower will not work for `ical_url`, `apple_url` and `outlook_url` (IE does not properly support [data-uri links](https://caniuse.com/#feat=datauri). See [#16](https://github.com/jaredlt/add_to_calendar/issues/16)).
+- IE11 will also not work with `Yahoo`, but this is because Yahoo only offers a simplified interface for IE11 which does not work with the add event URL.
 
 ### More details
 
diff --git a/lib/add_to_calendar.rb b/lib/add_to_calendar.rb
@@ -95,8 +95,8 @@ def outlook_com_url
     end
 
     def ical_url
-      # Downloads a *.ics file provided as a data:text href
-      # Eg. data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0AVERSION:2.0%0ABEGIN:VEVENT%0ADTSTART=20200610T123000Z%0ADTEND=20200610T133000Z%0ASUMMARY=Holly%27s%208th%20Birthday%21%0AURL=https%3A%2F%2Fwww.example.com%2Fevent-details%0ADESCRIPTION=Come%20join%20us%20for%20lots%20of%20fun%20%26%20cake%21\n\nhttps%3A%2F%2Fwww.example.com%2Fevent-details%0ALOCATION=Flat%204%2C%20The%20Edge%2C%2038%20Smith-Dorrien%20St%2C%20London%2C%20N1%207GU%0AUID=-https%3A%2F%2Fwww.example.com%2Fevent-details%0AEND:VEVENT%0AEND:VCALENDAR
+      # Downloads a *.ics file provided as a data-uri
+      # Eg. "data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0AVERSION:2.0%0ABEGIN:VEVENT%0ADTSTART:20200512T123000Z%0ADTEND:20200512T160000Z%0ASUMMARY:Holly%27s%208th%20Birthday%21%0AURL:https%3A%2F%2Fwww.example.com%2Fevent-details%0ADESCRIPTION:Come%20join%20us%20for%20lots%20of%20fun%20%26%20cake%21\\n\\nhttps%3A%2F%2Fwww.example.com%2Fevent-details%0ALOCATION:Flat%204%5C%2C%20The%20Edge%5C%2C%2038%20Smith-Dorrien%20St%5C%2C%20London%5C%2C%20N1%207GU%0AUID:-https%3A%2F%2Fwww.example.com%2Fevent-details%0AEND:VEVENT%0AEND:VCALENDAR"
       calendar_url = "data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0AVERSION:2.0%0ABEGIN:VEVENT"
       params = {}
       params[:DTSTART] = utc_datetime(start_datetime)
@@ -105,19 +105,19 @@ def ical_url
       else
         params[:DTEND] = utc_datetime(start_datetime + 60*60) # 1 hour later
       end
-      params[:SUMMARY] = url_encode(title)
+      params[:SUMMARY] = url_encode_ical(title)
       params[:URL] = url_encode(url) if url
-      params[:DESCRIPTION] = url_encode_ical_description(description) if description
+      params[:DESCRIPTION] = url_encode_ical(description) if description
       if add_url_to_description && url
         if params[:DESCRIPTION]
           params[:DESCRIPTION] << "\\n\\n#{url_encode(url)}"
         else
           params[:DESCRIPTION] = url_encode(url)
         end
       end
-      params[:LOCATION] = url_encode(location) if location
+      params[:LOCATION] = url_encode_ical(location) if location
       params[:UID] = "-#{url_encode(url)}" if url
-      params[:UID] = "-#{utc_datetime(start_datetime)}-#{url_encode(title)}" unless params[:UID] # set uid based on starttime and title only if url is unavailable
+      params[:UID] = "-#{utc_datetime(start_datetime)}-#{url_encode_ical(title)}" unless params[:UID] # set uid based on starttime and title only if url is unavailable
       
       new_line = "%0A"
       params.each do |key, value|
@@ -239,12 +239,17 @@ def newlines_to_html_br(string)
         string.gsub(/(?:\n\r?|\r\n?)/, '<br>')
       end
 
-      def url_encode_ical_description(description)
-        description.split("\n").map { |e| 
-          if e == "\n"
-            "\\n"
+      def url_encode_ical(string)
+        # per https://tools.ietf.org/html/rfc5545#section-3.3.11
+        string.gsub!("\\", "\\\\\\") # \ >> \\     --yes, really: https://stackoverflow.com/questions/6209480/how-to-replace-backslash-with-double-backslash
+        string.gsub!(",", "\\,")
+        string.gsub!(";", "\\;")
+        string.gsub!("\r\n", "\n") # so can handle all newlines the same
+        string.split("\n").map { |e|
+          if e.empty?
+            e
           else
-            url_encode(e) if e != "\n" 
+            url_encode(e)
           end
         }.join("\\n")
       end
diff --git a/lib/add_to_calendar/version.rb b/lib/add_to_calendar/version.rb
@@ -1,3 +1,3 @@
 module AddToCalendar
-  VERSION = "0.2.2"
+  VERSION = "0.2.3"
 end
diff --git a/test/add_to_calendar_test.rb b/test/add_to_calendar_test.rb
@@ -169,24 +169,74 @@ def test_newlines_convert_to_html_br
   def test_ical_description_url_encoded_with_newlines
     # final *.ics file must include `\n`
     # which means the string output must be `\\n` (not url encoded)
+    # this is to ensure it works when included in data-uris
     # this method should:
     # url encode all characters except newlines \n
     # update all newlines \n to \\n
-    cal = AddToCalendar::URLs.new(
-      start_datetime: Time.new(@next_month_year,@next_month_month,@next_month_day,13,30,00,0), 
-      end_datetime: Time.new(@next_month_year,@next_month_month,@next_month_day,17,00,00,0), 
-      title: @title, 
-      timezone: @timezone
-    )
-    string_without_newlines = cal.send(:url_encode_ical_description, "string without newlines")
+    event_attributes = {
+      start_datetime: Time.new(2020,12,12,9,00,00,0), # required
+      end_datetime: Time.new(2020,12,12,17,00,00,0),
+      title: "Ruby Conference", # required
+      timezone: 'America/New_York', # required
+      location: "20 W 34th St, New York, NY 10001", 
+      url: "https://www.ruby-lang.org/en/",
+      description: "Join us to learn\n\nall about Ruby.",
+      add_url_to_description: true # defaults to true
+    }
+    cal = AddToCalendar::URLs.new(event_attributes)
+
+    string_without_newlines = cal.send(:url_encode_ical, "string without newlines")
     assert string_without_newlines == "string%20without%20newlines"
 
-    string_with_newline = cal.send(:url_encode_ical_description, "string with\nnewline")
+    string_with_newline = cal.send(:url_encode_ical, "string with\nnewline")
     assert string_with_newline == "string%20with\\nnewline"
 
-    string_with_newlines = cal.send(:url_encode_ical_description, "string\nwith\n\nnewlines")
+    string_with_newlines = cal.send(:url_encode_ical, "string\nwith\n\nnewlines")
     assert string_with_newlines == "string\\nwith\\n\\nnewlines"
 
   end
 
+  def test_ical_escapes_special_characters
+    # per https://tools.ietf.org/html/rfc5545#section-3.3.11
+    # special characters are: BACKSLASH, COMMA, SEMICOLON, NEWLINE
+    event_attributes = {
+      start_datetime: Time.new(2020,12,12,9,00,00,0), # required
+      end_datetime: Time.new(2020,12,12,17,00,00,0),
+      title: "Ruby Conference; Rails Conference", # required
+      timezone: 'America/New_York', # required
+      location: "20 W 34th St, New York, NY 10001", 
+      url: "https://www.ruby-lang.org/en/",
+      description: "Join us to learn all about Ruby \\ Rails.",
+      add_url_to_description: true # defaults to true
+    }
+    cal = AddToCalendar::URLs.new(event_attributes)
+
+    backslash = cal.send(:url_encode_ical, "Ruby\\Rails")
+    assert backslash == "Ruby%5C%5CRails" # url_encoded `\\`` where %5C == \
+
+    comma = cal.send(:url_encode_ical, "Ruby,Rails")
+    assert comma == "Ruby%5C%2CRails" # url_encoded `\,` where %2C == ,
+
+    semicolon = cal.send(:url_encode_ical, "Ruby;Rails")
+    assert semicolon == "Ruby%5C%3BRails" # url_encoded `\;` where %3B == ;
+  end
+
+  def test_rn_newline_should_be_detected_converted_and_escaped
+    # \r\n should be converted to \n so that we can also escape them to \\n
+    event_attributes = {
+      start_datetime: Time.new(2020,12,12,9,00,00,0), # required
+      end_datetime: Time.new(2020,12,12,17,00,00,0),
+      title: "Ruby Conference; Rails Conference", # required
+      timezone: 'America/New_York', # required
+      location: "20 W 34th St, New York, NY 10001", 
+      url: "https://www.ruby-lang.org/en/",
+      description: "Join us to learn all about Ruby \\ Rails.",
+      add_url_to_description: true # defaults to true
+    }
+    cal = AddToCalendar::URLs.new(event_attributes)
+
+    rn_newline = cal.send(:url_encode_ical, "rn\r\nnewline")
+    assert rn_newline == "rn\\nnewline"
+  end
+
 end
diff --git a/test/urls/ical_url_test.rb b/test/urls/ical_url_test.rb
@@ -27,14 +27,14 @@ def setup
 
   def test_with_only_required_attributes
     cal = AddToCalendar::URLs.new(start_datetime: Time.new(@next_month_year,@next_month_month,@next_month_day,13,30,00,0), title: @title, timezone: @timezone)
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
     assert cal.ical_url == @url_with_defaults_required + uid + @url_end
   end
   
   def test_without_end_datetime
     # should set end as start + 1 hour
     cal = AddToCalendar::URLs.new(start_datetime: Time.new(@next_month_year,@next_month_month,@next_month_day,13,30,00,0), title: @title, timezone: @timezone)
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
     assert cal.ical_url == "data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0AVERSION:2.0%0ABEGIN:VEVENT" +
                            "%0ADTSTART:#{@next_month_year}#{@next_month_month}#{@next_month_day}T123000Z" + 
                            "%0ADTEND:#{@next_month_year}#{@next_month_month}#{@next_month_day}T133000Z" + 
@@ -50,7 +50,7 @@ def test_with_end_datetime
       title: @title, 
       timezone: @timezone
     )
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
     assert cal.ical_url == "data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0AVERSION:2.0%0ABEGIN:VEVENT" +
                            "%0ADTSTART:#{@next_month_year}#{@next_month_month}#{@next_month_day}T123000Z" + 
                            "%0ADTEND:#{@next_month_year}#{@next_month_month}#{@next_month_day}T160000Z" + 
@@ -66,7 +66,7 @@ def test_with_end_datetime_after_midnight
       title: @title, 
       timezone: @timezone
     )
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
     assert cal.ical_url == "data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0AVERSION:2.0%0ABEGIN:VEVENT" +
                            "%0ADTSTART:#{@next_month_year}#{@next_month_month}#{@next_month_day}T123000Z" + 
                            "%0ADTEND:#{@next_month_year}#{@next_month_month}#{@next_month_day.to_i+1}T160000Z" + 
@@ -77,8 +77,8 @@ def test_with_end_datetime_after_midnight
   
   def test_with_location
     cal = AddToCalendar::URLs.new(start_datetime: Time.new(@next_month_year,@next_month_month,@next_month_day,13,30,00,0), title: @title, timezone: @timezone, location: @location)
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
-    assert cal.ical_url == @url_with_defaults_required + "%0ALOCATION:Flat%204%2C%20The%20Edge%2C%2038%20Smith-Dorrien%20St%2C%20London%2C%20N1%207GU" + uid + @url_end
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
+    assert cal.ical_url == @url_with_defaults_required + "%0ALOCATION:Flat%204%5C%2C%20The%20Edge%5C%2C%2038%20Smith-Dorrien%20St%5C%2C%20London%5C%2C%20N1%207GU" + uid + @url_end
   end
   
   def test_with_url_without_description
@@ -97,7 +97,7 @@ def test_description_with_newlines
     # final *.ics file must include `\n`
     # which means the string output must be `\\n`
     cal = AddToCalendar::URLs.new(start_datetime: Time.new(@next_month_year,@next_month_month,@next_month_day,13,30,00,0), title: @title, timezone: @timezone, description: "Come join us for lots of fun & cake!\n\nBring a towel!")
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
     assert cal.ical_url == @url_with_defaults_required + "%0ADESCRIPTION:Come%20join%20us%20for%20lots%20of%20fun%20%26%20cake%21\\n\\nBring%20a%20towel%21" + uid + @url_end
   end
   
@@ -108,7 +108,7 @@ def test_add_url_to_description_false_without_url
       timezone: @timezone,
       add_url_to_description: false,
     )
-    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{url_encode(cal.title)}"
+    uid = "%0AUID:-#{cal.send(:utc_datetime, cal.start_datetime)}-#{cal.send(:url_encode_ical, cal.title)}"
     assert cal.ical_url == @url_with_defaults_required + uid + @url_end
   end
   
@@ -141,7 +141,7 @@ def test_with_all_attributes
                            "%0ASUMMARY:Holly%27s%208th%20Birthday%21" + 
                            "%0AURL:https%3A%2F%2Fwww.example.com%2Fevent-details" + 
                            "%0ADESCRIPTION:Come%20join%20us%20for%20lots%20of%20fun%20%26%20cake%21\\n\\nhttps%3A%2F%2Fwww.example.com%2Fevent-details" + 
-                           "%0ALOCATION:Flat%204%2C%20The%20Edge%2C%2038%20Smith-Dorrien%20St%2C%20London%2C%20N1%207GU" + 
+                           "%0ALOCATION:Flat%204%5C%2C%20The%20Edge%5C%2C%2038%20Smith-Dorrien%20St%5C%2C%20London%5C%2C%20N1%207GU" + 
                            uid + 
                            @url_end
   end
