91 lines
3.7 KiB
Crystal
91 lines
3.7 KiB
Crystal
module Kemal
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# :nodoc:
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class FilterHandler
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include HTTP::Handler
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INSTANCE = new
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# This middleware is lazily instantiated and added to the handlers as soon as a call to `after_X` or `before_X` is made.
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def initialize
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@tree = Radix::Tree(Array(FilterBlock)).new
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Kemal.config.add_filter_handler(self)
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end
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# The call order of the filters is `before_all -> before_x -> X -> after_x -> after_all`.
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def call(context : HTTP::Server::Context)
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return call_next(context) unless context.route_found?
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call_block_for_path_type("ALL", context.request.path, :before, context)
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call_block_for_path_type(context.request.method, context.request.path, :before, context)
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if Kemal.config.error_handlers.has_key?(context.response.status_code)
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raise Kemal::Exceptions::CustomException.new(context)
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end
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call_next(context)
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call_block_for_path_type(context.request.method, context.request.path, :after, context)
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call_block_for_path_type("ALL", context.request.path, :after, context)
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context
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end
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# :nodoc: This shouldn't be called directly, it's not private because
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# I need to call it for testing purpose since I can't call the macros in the spec.
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# It adds the block for the corresponding verb/path/type combination to the tree.
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def _add_route_filter(verb : String, path, type, &block : HTTP::Server::Context -> _)
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lookup = lookup_filters_for_path_type(verb, path, type)
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if lookup.found? && lookup.payload.is_a?(Array(FilterBlock))
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lookup.payload << FilterBlock.new(&block)
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else
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@tree.add radix_path(verb, path, type), [FilterBlock.new(&block)]
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end
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end
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# This can be called directly but it's simpler to just use the macros,
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# it will check if another filter is not already defined for this
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# verb/path/type and proceed to call `add_route_filter`
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def before(verb : String, path : String = "*", &block : HTTP::Server::Context -> _)
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_add_route_filter verb, path, :before, &block
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end
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# This can be called directly but it's simpler to just use the macros,
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# it will check if another filter is not already defined for this
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# verb/path/type and proceed to call `add_route_filter`
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def after(verb : String, path : String = "*", &block : HTTP::Server::Context -> _)
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_add_route_filter verb, path, :after, &block
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end
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# This will fetch the block for the verb/path/type from the tree and call it.
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private def call_block_for_path_type(verb : String?, path : String, type, context : HTTP::Server::Context)
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lookup = lookup_filters_for_path_type(verb, path, type)
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if lookup.found? && lookup.payload.is_a? Array(FilterBlock)
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blocks = lookup.payload
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blocks.each &.call(context)
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end
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end
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# This checks is filter is already defined for the verb/path/type combination
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private def filter_for_path_type_defined?(verb : String, path : String, type)
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lookup = @tree.find radix_path(verb, path, type)
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lookup.found? && lookup.payload.is_a? FilterBlock
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end
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# This returns a lookup for verb/path/type
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private def lookup_filters_for_path_type(verb : String?, path : String, type)
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@tree.find radix_path(verb, path, type)
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end
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private def radix_path(verb : String?, path : String, type : Symbol)
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"/#{type}/#{verb}/#{path}"
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end
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# :nodoc:
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class FilterBlock
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property block : HTTP::Server::Context -> String
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def initialize(&block : HTTP::Server::Context -> _)
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@block = ->(context : HTTP::Server::Context) { block.call(context).to_s }
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end
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def call(context : HTTP::Server::Context)
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@block.call(context)
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end
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end
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end
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end
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