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---+ GAIA Site Layout

%TOC%

It is assumed that a user =gaia= will exist and that the GAIA software will be stored in the =~gaia= home directory. Listed below are the directories used, with comments about important files contained in them. The URL through which they are accessed is given in square brackets.

---++ ~/public_html [/]

The base directory for all web accesses (ie Apache's =DocumentRoot= directory).


---++ ~/public_html/dtd [/dtd]
Data type definition files for XML.

---++ ~/public_html/js [/js]
!JavaScript libraries and functions. Access with =.js= extension. For ones generated by PHP omit the =.php= extension.
   $ =config.php.js=: GAIA and mirror configuration information, written out as a !JavaScript object.

---++ ~/public_html/img [/img]
General purpose images, flags to indicate mirror locations, etc.

%ICON{tip}% Cannot call the directory =icons= since most Apache installations use the URL =/icons= for Apache's own use (eg. when generating directory listings).

---++ ~/public_html/inc [ _not accessible_ ]
PHP include files. Accessible to PHP but not accessible via HTTP.

---++ ~/public_html/rest [/rest_html, /rest_json, /rest_mat, /rest_xml]

REST web services directory.

   $ =next_mirror.php=: Script to handle the case when an image cannot be loaded. Requires type (=thumbnail= | =keogram=), channel_id and date. Output is an XML document containing the new URL, and mirror_id. mirror_id=0 represent the fallbck URL. mirror_id=-1 represents the missing image location.

---+++ Possible structure for REST web services

Below is a possible scheme. It assumes the 'intermediate' XML documents output data with =xlink= attributes.

<verbatim>
/rest/project
/rest/project/themis
/rest/project/norstar
/rest/project/norstar/gill
/rest/project/norstar/gill/557.7 nm

/rest/site
/rest/site/gill
/rest/site/gill/canopus
/rest/site/gill/norstar
/rest/site/gill/norstar/557.7 nm

/rest/mirror
/rest/mirror/1   or   /rest/mirror/uk.gaia-vxo.org:8080
</verbatim>
%ICON{bubble}% Yuck - spaces in URL are bad - need abbreviated name for data channel, or something without spaces. Alternatively we map spaces to underscore and disallow underscores in the name (better, not great). Otherwise we use non-obvious numbers.

%ICON{bubble}% If we allow different methods to find data (which seems reasonable) we can then end up with different paths to the same data, which isn't RESTful. Should a =redirect= header be issued, so that a request for =/rest/site/gill/norstar/557.7 nm= is redirected to =/rest/project/norstar/gill/557.7 nm=? It might then mean the client would not need to fetch new data for that request. Is that more RESTful?

%ICON{bubble}% How do we implement geographic searches? That is much harder to describe, so perhaps query parameters are not unreasonable? (=/rest/geolocate?latitude=69&longitude=23&distance=300km= ?)





---++ &lt;summary_plot_dir&gt; [/summary_plots ?]
Directory where summary plots are stored. Need not be inside the =gaia= user directory; location configurable for each mirror via =server_config.php=. For tarred images use Apache's =ErrorDocument= directive to call a PHP script which returns a =301 Moved Permanently= status to redirect the browser to the cached area (but only after untarring the images).

%ICON{warning}% =summary_plots= is too long, it will be appearing in every data image! We need a shorter name.

%ICON{tip}% When untarring may wish to consider using Apache's =mod_asis= module, and attach HTTP headers to the images so that they can be sent 'as is', which may give performance benefits.

---++ &lt;image_cache&gt; [/tmp ?]
Directory where untarred and colourised images should be stored. It is possible browsers may return here for images after they have been deleted. In this case use essentially the same =ErrorDocument= as for =/summary_plots=, but maybe the return status should be =302 Moved Temporarily=?

%ICON{warning}% Keep separate from &lt;summary_plot_dir&gt; otherwise there is a risk =tmpwatch= will delete wanted images.
Topic revision: r5 - 2007-02-02 - 23:13:43 - SteveMarple
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