21.3. Message Format

Each message is encoded as a URI escaped string. That is, non-alphanumeric characters are encoded as the 3 character sequence %xx, where xx is the hexadecimal value of the character. The message has the format key=value, where key indicates the message type. For example:

    dump=host=h4.private%0aprinter=t1%0aprocess=1613%0a
    update_time=1999-03-23-20:32:17.148%0a\
    value=queue=holdall 0%25250aprinting_aborted=0x0%25250a\
    printing_disabled=0x0%25250aspooling_disabled=\
    0x0%25250a%250a%0a

The following keys are used:

1. dump A status dump of the current contents of a print queue.

Each message has a set of headers and a value. For example, the decoded dump message from the previous section would be:

    host=h4.private
    printer=t1
    process=1613
    update_time=1999-03-23-20:32:17.148
    value=queue=holdall 0%250aprinting_aborted=0x0%250a\
    printing_disabled=0x0%250aspooling_disabled=0x0%250a%0a

Each line consists of a key and a value. The host key indicates the host name, printer is the print queue, process is the process which generated the report or action, update_time is the time at which the report was generated, and value is the value of the report.

The decoded value of the above report is:

    queue='holdall 0%0aprinting_aborted=0x0%0aprinting_disabled=0x0%0a\
    spooling_disabled=0x0%0a

The queue key provides the current value of the queue control file.