Class: SqlSafetyNet::RackHandler

Inherits:
Object
  • Object
show all
Defined in:
lib/sql_safety_net/rack_handler.rb

Overview

This Rack handler must be added to the middleware stack in order for query analysis to be output. If the configuration option for debug is set to true, it will add response headers indicating information about the queries executed in the course of the request.

Constant Summary collapse

X_SQL_SAFETY_NET_HEADER = 
"X-SqlSafetyNet".freeze
HTML_CONTENT_TYPE_PATTERN = 
/text\/(x?)html/i
XML_CONTENT_TYPE_PATTERN = 
/application\/xml/i

Instance Method Summary collapse

Constructor Details

#initialize(app, logger = Rails.logger) ⇒ RackHandler

Returns a new instance of RackHandler.



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# File 'lib/sql_safety_net/rack_handler.rb', line 13

def initialize(app, logger = Rails.logger)
  @app = app
  @logger = logger
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/sql_safety_net/rack_handler.rb', line 18

def call(env)
  response = nil
  analysis = QueryAnalysis.analyze do
    response = @app.call(env)
  end
  
  if @logger && (analysis.too_many_selects? || analysis.too_many_rows?)
    request = Rack::Request.new(env)
    @logger.warn("Excess database usage: request generated #{analysis.selects} queries and returned #{analysis.rows} rows [#{request.request_method} #{request.url}]")
  end
  
  # Add a response header that contains a summary of the debug info
  if SqlSafetyNet.config.header? || SqlSafetyNet.config.debug?
    headers = response[1]
    headers[X_SQL_SAFETY_NET_HEADER] = "selects=#{analysis.selects}; rows=#{analysis.rows}; elapsed_time=#{(analysis.elapsed_time * 1000).round}; flagged_queries=#{analysis.flagged_queries.size}" if headers
  end
  
  if SqlSafetyNet.config.debug?
    wrapped_response = Rack::Response.new(response[2], response[0], response[1])
    if analysis.flagged? || SqlSafetyNet.config.always_show?
      request = Rack::Request.new(env)
      # Ignore Ajax calls
      unless request.xhr?
        # Only if content type is text/html
        type = wrapped_response.content_type
        if type.nil? || type.to_s.match(HTML_CONTENT_TYPE_PATTERN)
          wrapped_response.write(flagged_sql_html(analysis))
        elsif type.to_s.match(XML_CONTENT_TYPE_PATTERN)
          wrapped_response.write(xml_comment(flagged_sql_text(analysis)))
        end
      end
    end
    response = wrapped_response.finish
  end
  
  response
end

#flagged_sql_html(analysis) ⇒ Object 



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# File 'lib/sql_safety_net/rack_handler.rb', line 56

def flagged_sql_html(analysis)
  flagged_html = ''
  cached_selects = 0
  cached_rows = 0
  cached_elapsed_time = 0.0
  
  if analysis.flagged_queries?
    flagged_html << '<div style="color:#C00;">'
    flagged_html << "<div style=\"font-weight:bold; margin-bottom:10px;\">#{analysis.flagged_queries.size == 1 ? 'This query has' : "These #{analysis.flagged_queries.size} queries have"} flagged query plans:</div>"
    analysis.flagged_queries.each do |query|
      if query[:cached]
        cached_selects += 1
        cached_rows += query[:rows]
        cached_elapsed_time += query[:elapsed_time]
      end
      flagged_html << '<div style="margin-bottom:10px;">'
      flagged_html << "<div style=\"font-weight:bold; margin-bottom: 5px;\">#{query[:rows]} rows returned, #{(query[:elapsed_time] * 1000).round} ms#{ " <span style='color:teal;'>(CACHED)</span>" if query[:cached]}</div>"
      flagged_html << "<div style=\"font-weight:bold; margin-bottom: 5px;\">#{query[:flags].join(', ')}</div>"
      flagged_html << "<div style=\"margin-bottom: 5px;\">#{Rack::Utils.escape_html(query[:sql])}</div>"
      flagged_html << "<div style=\"margin-bottom: 5px;\">Query Plan: #{Rack::Utils.escape_html(query[:query_plan].inspect)}</div>" if query[:query_plan]
      flagged_html << '</div>'
    end
    flagged_html << '</div>'
  end
  
  if analysis.too_many_selects? || analysis.too_many_rows? || SqlSafetyNet.config.always_show?
    flagged_html << "<div style=\"font-weight:bold; margin-bottom:10px;\">#{analysis.non_flagged_queries.size == 1 ? 'This query' : "These #{analysis.non_flagged_queries.size} queries"} did not have flagged query plans:</div>"
    analysis.non_flagged_queries.each do |query|
      if query[:cached]
        cached_selects += 1
        cached_rows += query[:rows]
        cached_elapsed_time += query[:elapsed_time]
      end
      flagged_html << '<div style="margin-bottom:10px;">'
      flagged_html << "<div style=\"font-weight:bold; margin-bottom: 5px;\">#{query[:rows]} rows returned, #{(query[:elapsed_time] * 1000).round} ms#{ " <span style='color:teal;'>(CACHED)</span>" if query[:cached]}</div>"
      flagged_html << "<div style=\"margin-bottom: 5px;\">#{Rack::Utils.escape_html(query[:sql])}</div>"
      flagged_html << '</div>'
    end
  end

  color_scheme = '#060'
  if analysis.flagged_queries?
    color_scheme = '#C00' 
  elsif analysis.flagged?
    color_scheme = '#C60'
  end
  label = (analysis.flagged?) ? 'SQL WARNING' : 'SQL INFO'
  
  cache_html = nil
  if cached_selects > 0
    cache_html = <<-EOS
      <div style="margin-bottom:10px; font-weight:bold;">
        Some of the queries will be cached.
        <div style="color:#C00;">
          Uncached: #{analysis.selects - cached_selects} selects, #{analysis.rows - cached_rows} rows, #{((analysis.elapsed_time - cached_elapsed_time) * 1000).round} ms
        </div> 
        <div style="color:teal;">
          Cached: #{cached_selects} selects, #{cached_rows} rows, #{(cached_elapsed_time * 1000).round} ms
        </div> 
      </div>
    EOS
  end
  
  <<-EOS
    <div id="sql_safety_net_warning" style="font-family:sans-serif; font-size:10px; position:fixed; z-index:999999999; text-align:left; #{SqlSafetyNet.config.position}">
      <div style="background-color:#{color_scheme}; color:#FFF; padding:4px; width:160px; float:right;">
        <a href="javascript:void(document.getElementById('sql_safety_net_warning').style.display = 'none')" style="text-decoration:none; float:right; display:block; font-size:9px;"><span style="color:#FFF; text-decoration:none; font-weight:bold;">&times;</span></a>
        <a href="javascript:void(document.getElementById('sql_safety_net_flagged_queries').style.display = (document.getElementById('sql_safety_net_flagged_queries').style.display == 'block' ? 'none' : 'block'))" style="text-decoration:none;">
          <span style="color:#FFF; text-decoration:none; font-weight:bold;">#{label} &raquo;</span>
        </a>
        <div>#{analysis.selects} selects, #{analysis.rows} rows, #{(analysis.elapsed_time * 1000).round} ms</div>
      </div>
      <div id="sql_safety_net_flagged_queries" style="clear:right; display:none; width:500px; padding:2px; border:1px solid #{color_scheme}; background-color:#FFF; color:#000; overflow:auto; max-height:500px;">
        <div style="margin-bottom:10px; font-weight:bold;">
          There are #{analysis.selects} queries on this page that return #{analysis.rows} rows and took #{(analysis.elapsed_time * 1000).round} ms to execute.
        </div>
        #{cache_html}
        #{flagged_html}
      </div>
    </div>
  EOS
end

#flagged_sql_text(analysis) ⇒ Object 



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# File 'lib/sql_safety_net/rack_handler.rb', line 139

def flagged_sql_text(analysis)
  flagged_text = ''
  cached_selects = 0
  cached_rows = 0
  cached_elapsed_time = 0.0
  
  if analysis.flagged_queries?
    flagged_text << "#{analysis.flagged_queries.size == 1 ? 'This query has' : "These #{analysis.flagged_queries.size} queries have"} flagged query plans:\n\n"
    analysis.flagged_queries.each do |query|
      if query[:cached]
        cached_selects += 1
        cached_rows += query[:rows]
        cached_elapsed_time += query[:elapsed_time]
      end
      flagged_text << "#{query[:rows]} rows returned, #{(query[:elapsed_time] * 1000).round} ms#{ " (CACHED)" if query[:cached]}\n"
      flagged_text << "#{query[:flags].join(', ')}\n\n"
      flagged_text << "#{query[:sql]}\n\n"
      flagged_text << "Query Plan: #{Rack::Utils.escape_html(query[:query_plan].inspect)}\n" if query[:query_plan]
      flagged_text << "\n"
    end
    flagged_text << "\n"
  end
  
  if analysis.too_many_selects? || analysis.too_many_rows? || SqlSafetyNet.config.always_show?
    flagged_text << "#{analysis.non_flagged_queries.size == 1 ? 'This query' : "These #{analysis.non_flagged_queries.size} queries"} did not have flagged query plans:\n\n"
    analysis.non_flagged_queries.each do |query|
      if query[:cached]
        cached_selects += 1
        cached_rows += query[:rows]
        cached_elapsed_time += query[:elapsed_time]
      end
      flagged_text << "#{query[:rows]} rows returned, #{(query[:elapsed_time] * 1000).round} ms#{ " (CACHED)" if query[:cached]}\n\n"
      flagged_text << "#{query[:sql]}\n\n"
      flagged_text << "\n"
    end
  end

  label = (analysis.flagged?) ? 'SQL WARNING' : 'SQL INFO'
  
  cache_text = ""
  if cached_selects > 0
    cache_text << "Some of the queries will be cached.\n\n"
    cache_text << "Uncached: #{analysis.selects - cached_selects} selects, #{analysis.rows - cached_rows} rows, #{((analysis.elapsed_time - cached_elapsed_time) * 1000).round} ms\n"
    cache_text << "Cached: #{cached_selects} selects, #{cached_rows} rows, #{(cached_elapsed_time * 1000).round} ms\n\n"
  end
  
  text = "SqlSafetyNet\n\n"
  text << "There are #{analysis.selects} queries on this page that return #{analysis.rows} rows and took #{(analysis.elapsed_time * 1000).round} ms to execute.\n\n"
  text << cache_text
  text << flagged_text
  text
end

#xml_comment(text) ⇒ Object 



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# File 'lib/sql_safety_net/rack_handler.rb', line 192

def xml_comment(text)
  "<!-- #{text.gsub('-->', '\\-\\->')} -->"
end