61 lines
2.3 KiB
Ruby
61 lines
2.3 KiB
Ruby
# Copyright (C) 2012-2021 Zammad Foundation, http://zammad-foundation.org/
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# The name AssetsSet combines the Assets term in Zammad with the Set class from the Ruby StdLib.
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# Zammad Assets serve the purpose to limit requests to the REST API. For a requested object all
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# related and relevant objects are collected recursively and then send to the client in one go.
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# A Ruby Set implements a collection of unordered values with no duplicates.
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#
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# This class implements a collection of Zammad Assets with no duplicates.
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# This is done by having two structures:
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#
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# 1st: The actual Assets Hash (e.g. `assets[model_name][object_id] = object_attributes`)
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# 2nd: A lookup table for keeping track which elements were added to the actual Assets Hash
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#
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# The actual Assets Hash should be flushed after sending it to the client. This will keep the
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# lookup table untouched. The next time a object that was already send to the client
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# should be added to the actual Assets Hash the lookup table will recognize the object
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# and will prevent the addition to the actual Assets Hash.
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# This way Assets will be send only once to the client for the lifetime of a AssetsSet instance.
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class AssetsSet < SimpleDelegator
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# This method overwrites the SimpleDelegator initializer
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# to be able to have the actual Assets Hash as an optional argument.
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def initialize(assets = {})
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super(assets)
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end
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# This method initializes the the global lookup table.
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# Each (accessed) Model gets it's own sub structure in it.
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def lookup_table
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@lookup_table ||= {}
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end
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# This method flushes the actual Assets Hash.
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def flush
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__setobj__({})
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end
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# This method intercepts `assets[model_name]` calls by registering a AssetsSet::Proxy.
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# Instead of creating an entry in the actual Assets Hash a AssetsSet::Proxy.
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# See AssetsSet::Proxy for further information.
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# Existing proxies will be reused.
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def [](model)
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__getobj__[model] ||= proxy(model)
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end
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# This method is used to convert the AssetsSet into a regular Hash which then can be send to the client.
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# It cleans up empty Model sub structures in the internal structure.
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def to_h
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super.delete_if { |_model, assets| assets.blank? }.transform_values!(&:to_h)
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end
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private
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def proxy(model)
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lookup_table[model] ||= {}
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::AssetsSet::Proxy.new.tap do |proxy|
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proxy.lookup_table = lookup_table[model]
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end
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end
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end
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