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Descending into a complex (json) object
this example from a Well House Consultants training course
Source code: tj3.rb Module: R113
#!/usr/bin/env ruby
# Descending into a complex (json) object require 'json' require 'open-uri' source = URI.parse("http://www.wellho.net/services/_.json") fh = source.open stuff = fh.read # Convert the string into something more useable (a Hash or an Array) things = JSON.parse(stuff) # and clever stuff to print it out # Two alternative classes to return our data insets / keys # (selected by the user from the command line in sample code below) class InsetStack def initialize(name = "") @inset = "" end def push(adder = " ") @inset += " " return self end def pop() @inset = @inset[0..-3] end def show(k) return @inset + k.to_s end end class TreeStack def initialize(name = "") @inset = Array.new @name = name end def push(adder = "xx") @inset.push(adder) return self end def pop() @inset.pop end def show(k) rv = @name (@inset+[k]).each do |el| if el.is_a?(String) rv += "['#{el}']" else rv += "[#{el}]" end end return rv end end # This is a pair of recursive methods which will descend into the object. # They're really a reimplementation of "pp" but you can do far more that print if you want ;-) def displayHash(what,offset=InsetStack.new) what.each do |k,v| current = what[k] if current.is_a?(Hash) puts "#{offset.show k} :" displayHash(current,offset.push(k)) elsif current.is_a?(Array) puts "#{offset.show k} :" displayArray(current,offset.push(k)) else puts "#{offset.show k} = '#{v}'" end end offset.pop end def displayArray(what,offset=InsetStack.new) k = 0 what.each do |v| current = what[k] if current.is_a?(Hash) puts "#{offset.show k} :" displayHash(current,offset.push(k)) elsif current.is_a?(Array) puts "#{offset.show k} :" displayArray(current,offset.push(k)) else puts "#{offset.show} k} = '#{v}'" end k += 1 end offset.pop end # Main code again - decide how we want to output, using command line option if ARGV[0] == "-c" using = InsetStack.new else using = TreeStack.new(ARGV[0] || "xv") end if things.is_a?(Hash) then displayHash(things,using) else displayArray(things,using) end __END__ Sample outputs WomanWithCat:kingston grahamellis$ ./tj3.rb | head xv['timedat'] = '1433225042' xv['lookfor'] = '' xv['acc'] : xv['acc'][0] : xv['acc'][0]['when'] = '0' xv['acc'][0]['where'] = '86.148.79.xx' xv['acc'][0]['which'] = '/pix/my1_36.jpg' xv['acc'][1] : xv['acc'][1]['when'] = '1' xv['acc'][1]['where'] = '66.249.64.xx' WomanWithCat:kingston grahamellis$ ./tj3.rb bob | head bob['timedat'] = '1433225056' bob['lookfor'] = '' bob['acc'] : bob['acc'][0] : bob['acc'][0]['when'] = '1' bob['acc'][0]['where'] = '66.249.64.xx' bob['acc'][0]['which'] = '/forum/The-Tcl-programming-language/Extracting-bit-fields-from-binary.html' bob['acc'][1] : bob['acc'][1]['when'] = '3' bob['acc'][1]['where'] = '86.148.79.xx' WomanWithCat:kingston grahamellis$ ./tj3.rb -c | head timedat = '1433225074' lookfor = '' acc : 0 : when = '0' where = '66.249.64.xx' which = '/mouth/2239_Cornerstone-Cafe-Melksham.html' 1 : when = '3' where = '157.55.39.xx' WomanWithCat:kingston grahamellis$ Learn about this subject
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