THREDDS Reference: TDS Catalog Service

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The TDS provides various services for THREDDS catalogs. Catalogs served by the TDS can be subset and/or viewed as HTML. Remote catalogs, if allowed, can be validated, displayed as HTML, or subset.

Supported Parameters

Not all of the following parameters are supported in all situations.

• catalog - Specifies a remote target catalog.
• cmd - Specifies the action to perform. Possible values are:
• "show" - Provide an HTML view of the target catalog [the default unless a dataset parameter is given].
• "subset" - Subset the target catalog [the default only when a dataset parameter is given].
• "validate" - Validate the target catalog and return validation messages.
• dataset - Specifies the ID of the dataset in the target catalog to be used in subsetting the catalog.
• debug - Indicates that verbose validation messages are desired ("true" or "false" [default]).

Supported URL Endpoints

URL Endpoint: "/thredds/catalog.xml" or "/thredds/catalog.html"

When no "catalog" parameter is given, perform the requested service on the root TDS catalog. If a "catalog" parameter is given, the value must be the URL of a remote THREDDS catalog. The requested service is then performed on the catalog at the given URL.

The following requests are supported:

• No parameters - Return the XML view (when the URL ends with ".xml") or the HTML view (when the URL ends with ".html") of the root TDS catalog.
• "?dataset=<dsID>" - Return a subset of the root TDS catalog (XML or HTML depending on the file extension).
• "?dataset=<dsID>&cmd=subset" - Same as above.
• "?catalog=<catURL>" - Return the HTML view (only if the ".html" form of the URL endpoint is used) of the target catalog.
• "?catalog=<catURL>&cmd=validate" - Parse and validate the target catalog and return validation messages.
• "?catalog=<catURL>&cmd=validate&debug=true" - Same as above with verbose messages.
• "?catalog=<catURL>&dataset=<dsID>" - Return  a subset of the target catalog (XML or HTML view depending on the URL endpoint file extension).
• "?catalog=<catURL>&dataset=<dsID>&cmd=subset" - Same as above.

Where "<dsId>" must be the dataset ID of a dataset in the target catalog and "<catURL>" must be the URL of a remote THREDDS catalog.

URL Endpoint: "/thredds/catalogServices"

The "catalog" parameter is required. An HTML view is only given if the value of the "cmd" parameter is "show".

The supported requests are:

• "?catalog=<catURL>" - Return the HTML view of the target catalog.
• "?catalog=<catURL>&cmd=validate" - Parse and validate the target catalog and return validation messages.
• "?catalog=<catURL>&cmd=validate&debug=true" - Same as above with verbose messages.
• "?catalog=<catURL>&dataset=<dsID>" - Return  a subset of the target catalog as XML.
• "?catalog=<catURL>&dataset=<dsID>&cmd=subset" - Same as above.
• "?catalog=<catURL>&dataset=<dsID>&cmd=show" - Return a subset of the target catalog as HTML.

URL Endpoint: "/thredds/**/*.xml" or "/thredds/**/*.html"

Support catalog services for all local TDS served catalogs (except for the root catalog which is discussed above). The "catalog" parameter is not supported. The target catalog is givened by the URL path. Whether the XML view or the HTML view are returned depends on the file extension (".xml" or ".html").

The supported requests are:

• No parameters - Return the XML view or the HTML view of the target catalog.
• "?dataset=<dsID>" - Return a subset of the target catalog in XML or HTML.
• "?dataset=<dsID>&cmd=subset" - Same as above.

Note: This includes configuration catalogs (e.g., "/thredds/idd/models.xml") as well as dynamically generated catalogs (e.g., "/thredds/catalog/model/NCEP/NAM/catalog.xml").

Configuration

Local catalogs always support subsetting (with the "dataset" and "cmd=subset" parameters) and HTML view (with the ".html" extension).

Remote catalogs are only allowed if the following is added to the content/thredds/threddsConfig.xml file:

<CatalogServices>
    <allowRemote>true</allowRemote>
</CatalogServices>