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    <p>For the JSON library to be available, you may have to install <code>libjson-ruby</code> from your package manager.</p> <p>To use the 'json' library:</p> <pre><code>require 'json' </code></pre> <p>To convert an object to JSON (these 3 ways are equivalent):</p> <pre><code>JSON.dump object #returns a JSON string JSON.generate object #returns a JSON string object.to_json #returns a JSON string </code></pre> <p>To convert JSON text to an object (these 2 ways are equivalent):</p> <pre><code>JSON.load string #returns an object JSON.parse string #returns an object </code></pre> <p>It will be a bit more difficult for objects from your own classes. For the following class, to_json will produce something like <code>"\"#&lt;A:0xb76e5728&gt;\""</code>.</p> <pre><code>class A def initialize a=[1,2,3], b='hello' @a = a @b = b end end </code></pre> <p>This probably isn't desirable. To effectively serialise your object as JSON, you should create your own to_json method. To go with this, a from_json class method would be useful. You could extend your class like so:</p> <pre><code>class A def to_json {'a' =&gt; @a, 'b' =&gt; @b}.to_json end def self.from_json string data = JSON.load string self.new data['a'], data['b'] end end </code></pre> <p>You could automate this by inheriting from a 'JSONable' class:</p> <pre><code>class JSONable def to_json hash = {} self.instance_variables.each do |var| hash[var] = self.instance_variable_get var end hash.to_json end def from_json! string JSON.load(string).each do |var, val| self.instance_variable_set var, val end end end </code></pre> <p>Then you can use <code>object.to_json</code> to serialise to JSON and <code>object.from_json! string</code> to copy the saved state that was saved as the JSON string to the object.</p>
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    1. PORuby objects and JSON serialization (without Rails)
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    1. COWas looking for a library that didn't require you to write the to_json method on classes. Is there a class you can inherit from that gives you this via reflection? and works on complex objects?
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    2. COI'm looking at the way the YAML code in the stdlib works, but that is little bit much for me to grok at this point.
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    3. CODoes the updated answer help you with this respect?
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