Waitman Gobble, San Jose California
Hello, I am experimenting with the "Database as a Program" methodology described by [http://wiki.tcl.tk/78%|%D. Richard Hipp%|%] in the article [http://www.tcl.tk/community/tcl2004/Papers/D.RichardHipp/drh.html%|%SQLite and Tcl%|%]
At the moment my application consists of a short and simple main.tcl which decides which code segment to load from an sqlite3 database, executes the code and outputs the result.
I'm using the [http://tcl.apache.org/websh/%|%websh wrapper%|%] via [http://tcl.apache.org/websh/quickref/apache_module_specific_commands.html%|%mod_websh%|%]
Here is some sample code:
The app will process a request URI like http://example.com/main.ws3/hello
Strategy: Create a directory on the machine to create all the snippet Tcl files, then package into SQLite database
package.tcl (package all tcl scripts in current directory into SQLite database)
===
load /usr/local/lib/sqlite3/libtclsqlite3.so Sqlite3
sqlite3 db task.db
db eval {CREATE TABLE hd(path TEXT,src TEXT)}
set files [glob *.tcl]
foreach x $files {
set fp [open $x r]
set src [read $fp]
close $fp
set path /$x
db eval {INSERT INTO hd VALUES ($path,$src)}
}
db close
===
hello.tcl (hello world example)
===
set content "Hello, World"
===
main.ws3 (process request in URI and load corresponding tcl code)
===
set fp [open "layout.html" r]
set layout [read $fp]
close $fp
set path [web::request PATH_INFO].tcl
load /usr/local/lib/sqlite3/libtclsqlite3.so Sqlite3
sqlite3 db task.db
set process [db onecolumn {SELECT src FROM hd WHERE path=$path}]
eval $process
db close
set html [regsub "" $layout $content]
web::put $html
===
layout.html (a template)
===
boo
===
Sample output (note, in development ;-)
#1 display CGI env info
http://creamy.mobi/test-series/testdt/main.ws3/testcmd
testcmd.tcl
===
set request [web::request -names]
set combine [join $request ", "]
set path [web::request PATH_INFO]
set content "Request Info
${combine}
${path}
"
===
#2 load and display static HTML file. The static page is specified in the query string (parameter pg).
For test purposes adds the page request at the top.
NOTE: You have to modify glob line in package.tcl, above, to also package html files in the current directory.
http://creamy.mobi/test-series/testdt/main.ws3/static?pg=contact
static.tcl (load html)
===
web::dispatch -postdata "" -cmd ""
set page /[web::param pg].html
set content "$page
"
append content [db onecolumn {SELECT src FROM hd WHERE path=$page}]
===
contact.html
===
Contact
Contact us page
(650) 396-7580
===
Notes using websh/mod_websh
1. using mod_websh cwd is set to "/" (and not the directory in which the script is running)
2. when using mod_websh pkg download from site, also in freebsd /usr/ports/www/websh/ does not appear to log errors. download from svn and build seems to fix this problem (?)
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