XML Schema

Name

xs:base64Binary — Binary content coded as “base64”.

Derived from:

xs:anySimpleType

Primary:

xs:base64Binary

Known subtypes:

none

Facets:

xs:enumeration, xs:length, xs:maxLength, xs:minLength, xs:pattern, xs:whiteSpace

<xs:simpleType name="base64Binary" id="base64Binary">
  <xs:restriction base="xs:anySimpleType">
    <xs:whiteSpace value="collapse" fixed="true"/>
  </xs:restriction>
</xs:simpleType>

Description

The value space of xs:base64Binary is the set of arbitrary binary contents. Its lexical space is the same set after base64 coding. This coding is described in Section 6.8 of RFC 2045.

Restrictions

RFC 2045 has been defined to transfer binary contents over text-based mail systems. It imposes a line break at least every 76 characters to avoid the inclusion of arbitrary line breaks by the mail systems. Sending base64 content without line breaks is nevertheless a common usage for applications such as SOAP and the W3C XML Schema Working Group. After a request from other W3C Working Groups, the W3C XML Schema Working Group decided to remove the obligation to include these line breaks from the constraints on the lexical space. (This decision was made after the publication of the W3C XML Schema Recommendation and should be included in a release of the errata.)

Example

<xs:element name="picture">
  <xs:complexType>
    <xs:simpleContent>
      <xs:extension base="xs:base64Binary">
        <xs:attribute name="type" type="graphicalFormat"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
</xs:element>