How can I get three catalogs be published on the same site but independently? I mean, a user can enter the site and choose on what catalog to search…
“out-of-the-box” each NP site is based on publishing a single Portfolio catalogue. Assuming two sites published as site names XXX and YYY, there are separately accessed via URLs:
Do bear in mind that NP cookies (certainly in built-in template sets) have domain scope cookies (so readable via /res/ and /netpub/ virtual folders) with the result that if XXX and YYY use the same-named cookie and a user visits both sites, data from the two sites will overwrite each other.
To make it so that different sites are accessed via different domains is a web server configuration issue done outside NP.
The ‘alias’ method used with sites (look at a site’s alias.properties file) allows a single site to interact with multiple catalogues. The search mechanism allows cross-catalogue results, i.e. a page of results drawn from more than one catalogue (assuming aliases have been set up correctly). Neither of the latter aspects of are documented to a significant degree, though you’ll find a few notes about the alias structure here. To use this method you’ll need to publish a site and then edit the published sites files (so factor in those changes in the context of re-publishing such a site). IIRC, from v1-, I think the Bravado set is set up so it will cope with multi-catlaogue data sources are used.
Rather than have the association of multiple sites/catalogues within the NP site, you can write a normal HTML website on the server and have different parts of the latter target different existing discrete NP sites.
A catalogue may supply more than one NP site.
All such sites don’t need to be the same scope - e.g. one might be the whole catalogue, whilst others might be for different galleries (tip for the latter smart galleries are good).
Different sites of the same catalogue may simply be a different template set showing the same data; different templates can offer different user experience.
The alias.properties system allows one NP site to access data more than one catalogue (indeed more than one Portfolio Server) but must be configured manually after publishing a normal single catalogue site.
To make different NP sites on the same NP server available via different domains, i.e. different web URLs, configure the web server accordingly to make each domain point to appropriate content.
NP security is limited to a password-only single password for all users per-site. By default, sites have no password.
If greater security is needed either, use web pages elsewhere to set a login cookie and track that in NP templates (not highly secure but often good enough), ‘shell’ the NP code in ASP/PHP to ensure login session data is maintained, or set up the web server so NP URLs are only accessible via a secured portal. The latter is a network/webserver configuration issue.