datalinklint:
Validates DataLink documents
datalinklint runs a series of tests on a VOTable
that is supposed to conform to the {links}-response format
defined in the IVOA
DataLink
specification, and reports the results.
This is not likely to be of use to normal users,
it is intended for people developing or operating DataLink-compliant
services to assess correctness, perhaps with a view to improving
compliance.
To run it, you point it at the URL or filename of a VOTable of interest,
and it runs various tests on it and reports them to standard output.
Only the input table itself, and if the input location uses HTTP the
HTTP headers, are tested, this validator does not inspect any other
resources.
As well as validation checks, some reporting of the table's content
(such as a summary of the link defined by each row and a listing of
the defined service descriptors) is provided as INFO-level output
for convenience. This can be suppressed if preferred by use of
the report parameter.
This operates in much the same way as
the taplint command,
and the output has a similar format, though unlike
taplint this command does not divide the testing up
into stages.
Each report line is of the form:
T-MMMMxN aaaaa...where the parts have the following meanings:
T: Report type,
one of E(rror), W(arning), I(nfo), S(ummary), F(ailure).
See the documentation of the report parameter for
further description of what these mean.
The report parameter can be used to suppress some of these;
only E indicates actual service compliance errors, but
including the others may make it easier to see what's going on.
MMMM: Message label, which is always the same for
messages generated by the same test, is usually different for
messages generated by different tests, and may be somewhat mnemonic.
x: Continuation indicator,
either "-" or "+".
In most cases it is "-", indicating the first line of
a message, but multi-line messages (rare) use "-" for the first
line and "+" for any continuation lines.
N: Sequence number, which is 1 for the first time
message T-MMMM is reported, and increases by one
for each subsequent appearance.
After a certain maximum (determined by the maxrepeat
parameter) additional reports with the same code are no longer output
individually, but a summary of the number of reports so discarded
is written at the end of the section with the character "x"
instead of the sequence number.
This behaviour prevents the output being swamped by
multiple reports of the same issue.
If the maxrepeat parameter is increased above 9, more than
one digit will be used here (so e.g. for maxrepeat=999, the format would
be NNN not N).
aaaaa...: Message text, a free text description of
what is being reported.
If you don't like that format, others may be selected using the
format parameter, which currently also supports JSON.
For more flexible interaction with the output you can invoke
datalinklint programmatically
and supply your own
OutputReporter
instance.
As with any validator, this command does not guarantee to pick up everything wrong with the indicated VOTable, but it tries as hard as it can to check against the rules set out in the DataLink specification and other related documents as appropriate. A non-exhaustive list of the items checked is:
votlint
access_url,
service_def, error_message
error_message column valuescontent_type column valuessemantics column valuescontent_qualifier column values if presentlink_auth column values if presentHTTP connections made by this validator are flagged in the
User-Agent field with the token
"(IVOA-test)".