HTTP Etag survey

Julian Reschke asked on HTTP Working Group mailing list if the character backslash "\" was used frequently inside Etags values.

How the HTTP ETags are used in the wild? So I downloaded the Top Alexa sites list and created a very quick dirty shell script to check on the first 500. This is not a reliable survey, but just to give a quick overview. The results are still surprising.

39 sites have an "etag" including (note the spelling mistake)

• 36 using

  ETag:
  

• 3 using

  Etag:
  

On these 39 sites,

• 5 using

  ETag: W/"chars"
  

• 3 not using double quotes at all

• 1 being

  ETag: GgZz"ba1e66504638a1a318ce1edb1c843c8a"
  

\ none using the char backslash "\" \