An open discussion list for topics related to the eduGAIN interfederation service.

[Stefan Winter <stefan.winter AT restena.lu>]

Hi,

base64 expresses three binary bytes as four printable characters. There is thus an approximate relation that a base64 string is 4/3 (four thirds) of the binary source. The additional few bytes at the beginning of the URI become less and less significant the bigger the file is.

So you can easily say to customers "the file needs to be below 40 KB" and at the same time have code that checks for a base64 string size of say 60KCharacters (this is enough to include both 40 KB and 40 KiB and all the overheads of the URI, plus a few bytes of grace).

Greetings,

Stefan Winter

Am 17.03.20 um 07:46 schrieb Guy Halse:

      Hi

On 2020/03/16 20:26, Ian Young wrote:

It's also slightly harder to say (and to code) "A data: URL that is more than X bytes when stripped of its prefix up to and including the 'base64,', then converted from Base64 to binary" than it is to say "Any URL that is more than X bytes." But it's obviously not very much harder (except for someone coding this up in XSLT, but I don't know how many people other than myself are that masochistic).

      I can see why people would want to use the encoded form, because
      that's what is likely processed in aggregates and so as Ian
      rightly points out it's easier to just consider the whole data:
      url.
      
      The reason we use the unencoded form is it is easier to explain to
      the technical staff at various providers. It refers to an actual
      file size they can see on disk, and is something they can readily
      ask their graphic designers to produce. "I need a logo that is x
      by y, but it must be smaller than 40KB."
      
      IMHO keeping it simpler at that end is more important than the
      once-off cost of dealing with the code complexity :-)
      
      - Guy

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Guy Halse
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