Binary Data in XML : Turning back the clock

david at david at
Wed Sep 30 18:37:41 BST 1998

Jonathan  A. Borden writes:

 > The problem with base64 encoding of binary data in and of itself is that it
 > says NOTHING about the format of the data, so despite the fact that it can
 > be included within an XML document from a syntactical point of view, if
 > people are complaining about 'ugly binary data' this does not solve the
 > problem. Not that MIME has this problem completely fixed, but at least there
 > is a Content-Type header which says at least something about the format of
 > the data. MIME (and hence the cid: URI) has a standard mechanism for typing
 > binary data.
 > The Web has exploded in use not because of HTML itself, rather this in
 > conjunction with HTTP's MIME variant -- to be realistic what would the Web
 > be like without pictures i.e. gif and jpeg). If base64 is used within XML, a
 > similar typing mechanism is also required.

Quite right.  Right now, XML 1.0 has notations for this purpose, as
Eliot keeps reminding us; it would also be possible to invent a
standard attribute like 'xml:content', for use whether or not an
element's content was Base64-encoded:

 <data xml:content="application/pdf" xml:packed="Base64">...</data>

All the best,


David Megginson                 david at

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