Variable Substitution in URLs

The url keyword value is used to build a URL to send to a catalog server or execute as a local command. The syntax for HTTP based catalog servers is as follows:

 
url: http://host:port/cgi-bin/server?arg1&arg2&...argn

If : port is missing, it defaults to 80. If the URL refers to a local command, the syntax is like this:

 
url: /pathname/command arg1 arg2 ... argn

Substitutions are performed on the URL as follows, based on the query arguments set in the application:

Variable	Description
%ra, %dec	World coordinates of center point (for catalogs supporting World Coordinates).
%x, %y	Image pixel coordinates of center point (for pixel based catalogs).
%w, %h	Width and height in arcmin (if used with %ra, %dec) or image pixels (for %x, %y).
%r1, %r2	Min and max radius (for circular query) in arcmin (for %ra, %dec) or pixels (%x, %y). The order is unimportant.
%r	Use when server only accepts single radius value.
%m1, %m2	Min and max magnitude (order unimportant, see also %cond for an alternative)
%m	Use when server only accepts single magnitude.
%n	Max number of rows to return.
%cols	List of columns to return. Default (empty) means return all columns. The column names, if any were specified, are inserted in the format: col1,col2,...coln .
%id	ID field of item to return, for search by unique object id.
%mime-type	Value for HTTP mime-type field to insert in HTTP get command.
%sort	Inserts a list of sort columns in the format: col1,col2,...,coln . An empty list means none or default sorting.
%sortorder	Inserts the string: `increasing` or `decreasing` to indicate the sort order.
%cond	Inserts a search condition string, if any was specified in the query, in the format colName1=minVal,maxVal&colName2=minVal,maxVal,\ colName3=value,... The catalog server should return only rows where the given columns have values in the given ranges, or, in the case of a single value (colName=value) , where the value in the value in given column equals the given value. The values may be empty, if the user did not specify any values, in which case the server should use a default value or ignore the value.