can't flush buffers?
I posted something like this a week ago, but typos in my message kept
anyone from understanding the issue.
I am trying to return each row to the client as it comes from the
database, instead of waiting for all the rows to be returned before
displaying them.
I have set $|=1 and added $r-flush; after every print statement ( I
realize this is redundant ) but to no avail.
This is the relevant code:
while ($sth-fetch) {
$r-print ("TR",
map("TD$_/TD",@cols),
"/TR");
$r-rflush;
}
Here is the complete package:
package Sql::Client;
use Apache::Request;
use strict;
use warnings;
use Apache::Constants qw(:common);
my $r; #request
my $apr; #Apache::Request
my $host; #hostname of remote user
my $sql;#sql to execute
$|=1;
sub getarray ($) {
my $dbh; # Database handle
my $sth;# Statement handle
my $p_sql; # sql statement passed as parameter
my @cols; #column array to bind results
my $titles; # array ref to column headers
$p_sql = shift;
# Connect
$dbh = DBI-connect (
"DBI:mysql:links_db::localhost",
"nobody",
"somebody",
{
PrintError = 1,# warn() on errors
RaiseError = 0, # don't die on error
AutoCommit = 1,# commit executes
immediately
}
);
# prepare statment
$sth = $dbh-prepare($p_sql);
$sth-execute;
$titles = $sth-{NAME_uc};
#--
# for minimal memory use, do it this way
@cols[0..$#$titles] = ();
$sth-bind_columns(\(@cols));
$r-print( "TABLE BORDER");
$r-print ("TR",
map("TD$_/TD",@$titles),
"/TR");
while ($sth-fetch) {
$r-print ("TR",
map("TD$_/TD",@cols),
"/TR");
$r-rflush;
}
$r-print ("/TABLE");
return;
}
sub handler {
$r = shift;
$apr = Apache::Request-new($r);
$sql = $apr-param('sql') || 'SELECT';
$sql='SELECT' if $apr-param('reset');
$r-content_type( 'text/html' );
$r-send_http_header;
return OK if $r-header_only;
$host = $r-get_remote_host;
$r-print(HTMLEND);
HTML
HEAD
LINK REL="stylesheet" TYPE="text/css"
HREF="/styles/lightstyle.css"
TITLEHello $host/TITLE
BODY
H1Sql Client/H1
FORM METHOD="POST"
PEnter your Select Statement:
BR
TEXTAREA NAME="sql" ROWS=8 COLS=60 WRAP$sql/TEXTAREA
BR
INPUT TYPE="SUBMIT" VALUE="Submit"
INPUT TYPE="SUBMIT" NAME="reset" VALUE="Reset"
/FORM
HTMLEND
$r-rflush;
getarray($sql) unless $sql =~ /^SELECT$/;
$r-print(HTMLEND);
/BODY
/HTML
HTMLEND
return OK;
}
1;
can't flush buffer?
As a test of my new mod_perl abilities I wrote a trivial SQL client.
It works, but if the query returns many rows then it takes a while.
As a first step I thought I would call $r-rflush; with every row
printed but
this does not work. I also tried $|=0; with no effect.
Here is the full module, 100 lines. The rows are printed in getarray
($$)
Any ideas would be appreciated
~quagly
package Sql::Client;
use Apache::Request;
use strict;
use warnings;
use Apache::Constants qw(:common);
my $r; #request
my $apr; #Apache::Request
my $host; #hostname of remote user
my $sql;#sql to execute
sub getarray ($$) {
my $dbh; # Database handle
my $sth;# Statement handle
my $p_sql; # sql statement passed as parameter
my @cols; #column array to bind results
my $titles; # array ref to column headers
my $r; # maybe if I pass the request it will
work
$p_sql = shift;
$r = shift;
# Connect
$dbh = DBI-connect (
"DBI:mysql:links_db::localhost",
"nobody",
"somebody",
{
PrintError = 1,# warn() on errors
RaiseError = 0, # don't die on error
AutoCommit = 1,# commit executes
immediately
}
);
# prepare statment
$sth = $dbh-prepare($p_sql);
$sth-execute;
$titles = $sth-{NAME_uc};
#--
# for minimal memory use, do it this way
@cols[0..$#$titles] = ();
$sth-bind_columns(\(@cols));
print "TABLE BORDER";
print "TR",
map("TD$_/TD",@$titles),
"/TR";
while ($sth-fetch) {
print "TR",
map("TD$_/TD",@cols),
$r-rflush;
}
print "/TABLE";
return;
}
sub handler {
$r = shift;
$apr = Apache::Request-new($r);
$sql = $apr-param('sql') || 'SELECT';
$sql='SELECT' if $apr-param('reset');
$r-content_type( 'text/html' );
$r-send_http_header;
return OK if $r-header_only;
$host = $r-get_remote_host;
$r-print(HTMLEND);
HTML
HEAD
LINK REL="stylesheet" TYPE="text/css"
HREF="/styles/lightstyle.css"
TITLEHello $host/TITLE
BODY
H1Sql Client/H1
FORM METHOD="POST"
PEnter your Select Statement:
BR
TEXTAREA NAME="sql" ROWS=8 COLS=60 WRAP$sql/TEXTAREA
BR
INPUT TYPE="SUBMIT" VALUE="Submit"
INPUT TYPE="SUBMIT" NAME="reset" VALUE="Reset"
/FORM
HTMLEND
getarray($sql,$r) unless $sql =~ /^SELECT$/;
$r-print(HTMLEND);
/BODY
/HTML
HTMLEND
return OK;
}
1;
~
"/TR";
Re: can't flush buffer?
Yes, I have read all of that. That is what I am following. It just doesn't work. ~quagly
Re: can't flush buffer?
oops, typos in my message. In fact, I have done just as you suggest, but it doesn't work. Thanks, ~quagly
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