class Rack::SteadyETag
Based on Rack::Etag github.com/rack/rack/blob/master/lib/rack/etag.rb
Automatically sets the ETag header on all String bodies.
The ETag header is skipped if ETag or Last-Modified headers are sent or if a sendfile body (body.responds_to :to_path) is given (since such cases should be handled by apache/nginx).
Constants
- DEFAULT_CACHE_CONTROL
- IGNORE_PATTERNS
Public Class Methods
new(app, no_digest_cache_control: nil, digest_cache_control: DEFAULT_CACHE_CONTROL, ignore_patterns: IGNORE_PATTERNS.dup)
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# File lib/rack/steady_etag.rb, line 27 def initialize(app, no_digest_cache_control: nil, digest_cache_control: DEFAULT_CACHE_CONTROL, ignore_patterns: IGNORE_PATTERNS.dup) @app = app @digest_cache_control = digest_cache_control @no_digest_cache_control = no_digest_cache_control @ignore_patterns = ignore_patterns end
Public Instance Methods
call(env)
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# File lib/rack/steady_etag.rb, line 34 def call(env) status, headers, body = @app.call(env) headers = Utils::HeaderHash[headers] session = env[RACK_SESSION] if etag_status?(status) && etag_body?(body) && !skip_caching?(headers) original_body = body digest, new_body = digest_body(body, headers, session) body = Rack::BodyProxy.new(new_body) do original_body.close if original_body.respond_to?(:close) end headers[ETAG] = %(W/"#{digest}") if digest end [status, headers, body] end
Private Instance Methods
cache_control_private?(headers)
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# File lib/rack/steady_etag.rb, line 73 def cache_control_private?(headers) headers[CACHE_CONTROL] && headers[CACHE_CONTROL] =~ /\bprivate\b/ end
digest_body(body, headers, session)
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# File lib/rack/steady_etag.rb, line 77 def digest_body(body, headers, session) parts = [] digest = nil body.each do |part| parts << part if part.present? set_cache_control_with_digest(headers) if cache_control_private?(headers) part = strip_ignore_patterns(part) end unless digest digest = Digest::SHA256.new if session && (session_id = session['session_id']) digest << session_id.to_s end end digest << part end end if digest digest = digest.hexdigest.byteslice(0,32) else set_cache_control_without_digest(headers) end [digest, parts] end
etag_body?(body)
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# File lib/rack/steady_etag.rb, line 65 def etag_body?(body) !body.respond_to?(:to_path) end
etag_status?(status)
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# File lib/rack/steady_etag.rb, line 61 def etag_status?(status) status == 200 || status == 201 end
set_cache_control_with_digest(headers)
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# File lib/rack/steady_etag.rb, line 53 def set_cache_control_with_digest(headers) headers[CACHE_CONTROL] ||= @digest_cache_control if @digest_cache_control end
set_cache_control_without_digest(headers)
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# File lib/rack/steady_etag.rb, line 57 def set_cache_control_without_digest(headers) headers[CACHE_CONTROL] ||= @no_digest_cache_control if @no_digest_cache_control end
skip_caching?(headers)
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# File lib/rack/steady_etag.rb, line 69 def skip_caching?(headers) headers.key?(ETAG) || headers.key?('Last-Modified') end
strip_ignore_patterns(html)
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# File lib/rack/steady_etag.rb, line 112 def strip_ignore_patterns(html) @ignore_patterns.each do |ignore_pattern| if ignore_pattern.respond_to?(:call) html = ignore_pattern.call(html) else html = html.gsub(ignore_pattern, '') end end html end