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json parsing in ruby

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Sometime we want to convert json response to  Hash or array , so that we can easily use it. Ruby provide, json parsing as its core feature. The detail documentation is available here. Let us assume that our json response is stored in sample_json file at  /db/data/sample_json of your project root. Some sample data is available here.  Add one of the sample data to this file, I used the first one. Now, we will parse it on the console

$rails c #move to the console

1.9.3p194 :005 >json_file =“db”, “data”, “sample_json”)) # It will open the json file

1.9.3p194 :006 > json_data = # file value is read and stored in json data, this is basically our response, which you will get from some API cals, some methods etc.

1.9.3p194 :007 > a=JSON.parse(json_data) # your response wil be as below

=> {“glossary”=>{“title”=>”example glossary”, “GlossDiv”=>{“title”=>”S”, “GlossList”=>{“GlossEntry”=>{“ID”=>”SGML”, “SortAs”=>”SGML”, “GlossTerm”=>”Standard Generalized Markup Language”, “Acronym”=>”SGML”, “Abbrev”=>”ISO 8879:1986”, “GlossDef”=>{“para”=>”A meta-markup language”, “GlossSeeAlso”=>[“GML”, “XML”]}, “GlossSee”=>”markup”}}}}}

You can also pass, different option to the parser as below

1.9.3p194 :023 > b=JSON.parse(json_d, :max_nesting => false,:allow_nan => true, :symbolize_names => true)
=> {:glossary=>{:title=>”example glossary”, :GlossDiv=>{:title=>”S”, :GlossList=>{:GlossEntry=>{:ID=>”SGML”, :SortAs=>”SGML”, :GlossTerm=>”Standard Generalized Markup Language”, :Acronym=>”SGML”, :Abbrev=>”ISO 8879:1986″, :GlossDef=>{:para=>”A meta-markup language”, :GlossSeeAlso=>[“GML”, “XML”]}, :GlossSee=>”markup”}}}}}

The complete list of option for parse method is as below

parse(source, opts = {}) #Parse the JSON document source into a Ruby data structure 
and return it.

opts can have the following keys:

max_nesting: #The maximum depth of nesting allowed in the parsed data structures. 
Disable depth checking with :max_nesting => false. It defaults to 19.

allow_nan: #If set to true, allow NaN, Infinity and -Infinity in defiance of RFC 4627
to be parsed by the Parser. This option defaults to false.

symbolize_names: #If set to true, returns symbols for the names (keys) in a JSON object.
Otherwise strings are returned.Strings are the default.

create_additions: #If set to false, the Parser doesn't create additions even if a matching class 
and ::create_id was found.This option defaults to true.

object_class: #Defaults to Hash

array_class: #Defaults to Array

Author: arunyadav4u

over 7 years experience in web development with Ruby on Rails.Involved in all stage of development lifecycle : requirement gathering, planing, coding, deployment & Knowledge transfer. I can adept to any situation, mixup very easily with people & can be a great friend.

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