[pclasses-devel] http serializer now works via s11nconvert/s11nbrowser :)

[stephan b. <st...@s1...>]

s11n now supports 9 (count 'em: 9) data transport layers, including 
http. This new format is a bit unusual in that it proxies arbitrary 
formats, and doesn't really provide a data format itself. For writing 
it defaults to using 'funtxt', but for loading it supports any format 
supported by s11nlite.

Plugging in P's http-based serializer required no s11n-level changes, as 
we can dynamically load the serializer via the name 'phttp' and treat 
it like any other Serializer:

Witness:

A s11n data file:

~> cat in.s11n
(s11n::parens)
data_node=(list
        data_node=(lex_t (v 42))
        data_node=(lex_t (v -42.420000))
        data_node=(lex_t (v fourty two))
        data_node=(lex_t (v x))
)


Import it from the file and re-save it over the web:

~> s11nconvert -f in.s11n -s phttp -o 
'http://s11n/ps11n.php?node_name=sumdumlist'
// -f == input file
// -s == output serializer
// -o == output file

Now it's in the db:

~> mysql -e 'select id,name from ps11n' ps11n
+----+------------+
| id | name       |
+----+------------+
| 15 | bar        |
| 28 | bob        |
| 29 | boo        |
| 19 | egal       |
|  1 | foo        |
| 26 | fred       |
| 33 | mylist     |
HERE ----> | 34 | sumdumlist |
| 24 | thelist    |
| 32 | wow        |
| 23 | yourlist   |
+----+------------+


Now load it, saving it to stdout in another format:

~> s11nconvert -f 'http://s11n/ps11n.php?node_name=sumdumlist' -S phttp 
-s funxml
// -f == input file
// -S == *force* input serializer phttp
//       (it cannot yet be dynamically dispatched this way)
// -s == output serializer

The output:

<!DOCTYPE SerialTree>
<data_node class="list">
        <data_node class="lex_t">
                <v>42</v>
        </data_node>
        <data_node class="lex_t">
                <v>-42.420000</v>
        </data_node>
        <data_node class="lex_t">
                <v>fourty two</v>
        </data_node>
        <data_node class="lex_t">
                <v>x</v>
        </data_node>
</data_node>

Cool, eh? It also plugs in to the s11nbrowser interface:
	http://s11n.net/s11nbrowser/
see the last 2 screenshots.


Caveats:

a) because i'm using http GET, saving is probably limited to relatively 
small, not-extremely-complex objects. i'll figure out how to resolve 
this later on. Loading should work for arbitrarily large data, as long 
as it can all fit in a std::string buffer.

b) if you pass a non-well-formed URL it may cause a segfault in P::URL, 
catch() notwithstanding:
	s11nconvert -f in.s11n -s phttp -o not_a_http_url
	Aborted

c) Never call s11nlite::serializer_class("phttp"). That will set 
s11nlite's default output format to phttp, and will hose things.  
s11nlite tries to save it's config post-main() and probably can't if 
phttp is it's default output format.

d) If using s11nbrowser, make sure to accidentally do (c) by accident 
(it's easy to do).

e) When saving/loading to/from a stream, e.g., save(obj,cout) it writes 
using its proxy format, and does no http operations.



-- 
----- st...@s1...   http://s11n.net
"...pleasure is a grace and is not obedient to the commands
of the will." -- Alan W. Watts