Activity - fileAccessActivity

Activity Type: File

Description

Access the contents of a file.

Examples

<fileAccessActivity name="readBytesActivity">
  <file>some/file.ext</file>
  <bytes offset="3" length="9"/>
  <output name="fileBytesAccessOutput" base64encode="false"/>
</fileAccessActivity>

<fileAccessActivity name="readLinesActivity">
  <file>some/file.ext</file>
  <lines offset="2" length="5"/>
  <output name="fileLinesAccessOutput" base64encode="true"/>
</fileAccessActivity>

Specification

Element fileAccessActivity:

• Attribute name - unique name for the activity within the scope of a request.
• Element file (required) - contains the path to the file to access. This path should be relative to the top-level directory exposed by the associated OGSA-DAI service and must not attempt to traverse up the directory hierarchy higher than this directory.
• One of the following two elements (required):
  • Element bytes - access the contents of a file on a byte-by-byte basis.
    • Attribute offset - index of first byte to access.
    • Attribute length - number of bytes to access.
  • Element lines - access the contents of a file on a line-by-line basis.
    • Attribute offset - index of first line to access.
    • Attribute length - number of lines to access.
• output (required) - output stream.
  • Attribute name - name of the activity's output stream.
  • Attribute base64encode - flag indicating whether the output will be base64 encoded (true) or not (false).

Input and Output Types

• Output: output:
  • java.lang.String (could be base64 encoded)
  • byte[]

Warning to Service Deployers

This activity can be used by clients to potentially access any directory on your server below that exposed by the associated OGSA-DAI service.

Data Resource Accessor

This activity requires a data resource accessor that implements the following interface: uk.org.ogsadai.dataresource.FileAccessProvider

XML Schema

OGSA-DAI/schema/ogsadai/xsd/activities/file_access.xsd

Class

uk.org.ogsadai.activity.files.FileAccessActivity

Client Toolkit Class

None at present.