Adds an example of header/footers.

Also, header and footer content is now escaped. So that the user doesn't
have to worry about that.

Change-Id: Ib35b2eca6755d9b2d9974be25887734873d6e64a

2 files changed, 27 insertions, 11 deletions

diff --git a/examples/example.rb b/examples/example.rb
index 87678a2e..1e93f4f8 100755
--- a/examples/example.rb
+++ b/examples/example.rb
@@ -35,6 +35,7 @@ examples = []
 #examples << :repeated_header
 #examples << :defined_name
 #examples << :printing
+#examples << :header_footer
 #examples << :comments
 #examples << :panes
 examples << :conditional_formatting
@@ -149,7 +150,7 @@ if examples.include? :surrounding_border
   # LEARN IT! LIVE IT! LOVE IT!
   defaults =  { :style => :thick, :color => "000000" }
   borders = Hash.new do |hash, key|
-    hash[key] = wb.styles.add_style :border => defaults.merge( { :edges => key.to_s.split('_').map(&:to_sym) } ) 
+    hash[key] = wb.styles.add_style :border => defaults.merge( { :edges => key.to_s.split('_').map(&:to_sym) } )
   end
   top_row =  [0, borders[:top_left], borders[:top], borders[:top], borders[:top_right]]
   middle_row = [0, borders[:left], nil, nil, borders[:right]]
@@ -167,11 +168,11 @@ if examples.include? :surrounding_border
   end
 end
 
-#```ruby 
+#```ruby
 # Hacking border styles
 if examples.include? :deep_custom_borders
   wb.styles do |s|
-    top_bottom =  s.add_style :border => { :style => :thick, :color =>"FFFF0000", :edges => [:top, :bottom] }  
+    top_bottom =  s.add_style :border => { :style => :thick, :color =>"FFFF0000", :edges => [:top, :bottom] }
     border = s.borders[s.cellXfs[top_bottom].borderId]
     # edit existing border parts
     border.prs.each do |part|
@@ -511,7 +512,7 @@ if examples.include? :repeated_header
   wb.add_worksheet(:name => "repeated header") do |sheet|
     sheet.add_row %w(These Column Header Will Render On Every Printed Sheet)
     200.times { sheet.add_row %w(1 2 3 4 5 6 7 8) }
-    wb.add_defined_name("'repeated header'!$1:$1", :local_sheet_id => sheet.index, :name => '_xlnm.Print_Titles') 
+    wb.add_defined_name("'repeated header'!$1:$1", :local_sheet_id => sheet.index, :name => '_xlnm.Print_Titles')
   end
 end
 
@@ -546,7 +547,17 @@ if examples.include? :printing
 end
 #```
 
-## Add Comments to your spreadsheet 
+## Add headers and footers to a worksheet
+#``` ruby
+if examples.include? :header_footer
+  header_footer = {:different_first => false, :odd_header => '&L&F : &A&R&D &T', :odd_footer => '&C&Pof&N'}
+  wb.add_worksheet(:name => "header footer", :header_footer => header_footer) do |sheet|
+    sheet.add_row ["this sheet has a header and a footer"]
+  end
+end
+#```
+
+## Add Comments to your spreadsheet
 #``` ruby
 if examples.include? :comments
   wb.add_worksheet(:name => 'comments') do |sheet|
diff --git a/lib/axlsx/workbook/worksheet/header_footer.rb b/lib/axlsx/workbook/worksheet/header_footer.rb
index 58e89d9e..20d7b0eb 100644
--- a/lib/axlsx/workbook/worksheet/header_footer.rb
+++ b/lib/axlsx/workbook/worksheet/header_footer.rb
@@ -1,6 +1,11 @@
 module Axlsx
   # Header/Footer options for printing a worksheet. All settings are optional.
   #
+  # Headers and footers are generated using a string which is a combination
+  # of plain text and control characters. A fairly comprehensive list of control
+  # characters can be found here:
+  # https://github.com/randym/axlsx/blob/master/notes_on_header_footer.md
+  #     
   # @note The recommended way of managing header/footers is via Worksheet#header_footer
   # @see Worksheet#initialize
   class HeaderFooter
@@ -41,14 +46,14 @@ module Axlsx
       serialized_attributes str
       str << ">"
 
-      str << "<oddHeader>#{odd_header}</oddHeader>" unless odd_header.nil?
-      str << "<oddFooter>#{odd_footer}</oddFooter>" unless odd_footer.nil?
+      str << "<oddHeader>#{::CGI.escapeHTML(odd_header)}</oddHeader>" unless odd_header.nil?
+      str << "<oddFooter>#{::CGI.escapeHTML(odd_footer)}</oddFooter>" unless odd_footer.nil?
 
-      str << "<evenHeader>#{even_header}</evenHeader>" unless even_header.nil?
-      str << "<evenFooter>#{even_footer}</evenFooter>" unless even_footer.nil?
+      str << "<evenHeader>#{::CGI.escapeHTML(even_header)}</evenHeader>" unless even_header.nil?
+      str << "<evenFooter>#{::CGI.escapeHTML(even_footer)}</evenFooter>" unless even_footer.nil?
 
-      str << "<firstHeader>#{first_header}</firstHeader>" unless first_header.nil?
-      str << "<firstFooter>#{first_footer}</firstFooter>" unless first_footer.nil?
+      str << "<firstHeader>#{::CGI.escapeHTML(first_header)}</firstHeader>" unless first_header.nil?
+      str << "<firstFooter>#{::CGI.escapeHTML(first_footer)}</firstFooter>" unless first_footer.nil?
 
       str << "</headerFooter>"
     end