--- loncom/xml/lontexconvert.pm	2008/12/04 19:53:53	1.93
+++ loncom/xml/lontexconvert.pm	2011/02/10 20:07:00	1.98.2.1
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.93 2008/12/04 19:53:53 riegler Exp $
+# $Id: lontexconvert.pm,v 1.98.2.1 2011/02/10 20:07:00 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -47,8 +47,8 @@ use Apache::lonlocal;
 use Apache::lonnet;
 use lib '/home/httpd/lib/perl/';
 use LONCAPA;
-use LWP::UserAgent;
- 
+use URI::Escape;
+use IO::Socket::INET;
 
 # ====================================================================== Header
 
@@ -243,31 +243,51 @@ sub init_math_support {
 }
 
 sub mimetex_valign {
-    my ($texstring)=@_;
-    my $ua = LWP::UserAgent->new; #from the perldoc of LWP::UserAgent
-    $ua->timeout(10); 
-    $ua->env_proxy;
-    #header without imagedata saved to response:
-    my $response = $ua->head('http://localhost.localdomain/cgi-bin/mimetex.cgi?'.$texstring);
-    if ($response->is_success) {
-        #get the valign-value:
-        return($response->headers->{'vertical-align'});}
-    else {
-        return(0); #if (error) than continue without valign
+    my ($esc_texstring)=@_;
+    my $valign = 0;
+    my $lonhost = $Apache::lonnet::perlvar{'lonHostID'};
+    my $hostname = &Apache::lonnet::hostname($lonhost);
+    my $path = '/cgi-bin/mimetex.cgi?'.$esc_texstring;
+    my $socket;
+    &Apache::lonxml::start_alarm();
+    my $socket = IO::Socket::INET->new(PeerAddr => $hostname,
+                                       PeerPort => 'http(80)',
+                                       Proto    => 'tcp');
+    if ($socket) {
+        my $headreq = "HEAD $path HTTP/1.0\r\n\r\n";
+        print $socket $headreq;
+        while (<$socket>) {
+            if (/Vertical\-Align\:\s*?([\-\d]+)/) {
+                $valign = $1;
+            }
+        }
+        $socket->close();
     }
+    &Apache::lonxml::end_alarm();
+    return $valign;
 }
 
 sub mimetex_converted {
     my $texstring=shift;
+
+# Alt-Argument for screen readers
+    my $alt_string=$$texstring;
+    $alt_string=~s/\"/\'\'/g;
+
+# Is this displaystyle?
+
     my $displaystyle=&displaystyle($texstring);
 
+# Remove math environment delimiters
+
     &clean_out_math_mode($texstring);
 
     if ($displaystyle) {
 	$$texstring='\\displaystyle \\Large '.$$texstring;
     }
-
-   my $result='<img src="/cgi-bin/mimetex.cgi?'.&escape($$texstring).'" style="vertical-align:'.&mimetex_valign($$texstring).'px" alt="$'.$$texstring.'$" />';
+    my $esc_texstring = &uri_escape($$texstring);
+    my $valign = &mimetex_valign($esc_texstring);
+    my $result='<img src="/cgi-bin/mimetex.cgi?'.$esc_texstring.'" style="vertical-align:'.$valign.'px" alt="'.$alt_string.'" />';
     if ($displaystyle) {
 	$result='<center>'.$result.'</center>';
     }
@@ -283,6 +303,8 @@ sub converted {
 	return &jsMath_converted($string);
     } elsif ($mode =~ /mimetex/i) {
 	return &mimetex_converted($string);
+    } elsif ($mode =~ /raw/i) {
+        return $$string;
     }
     return &tth_converted($string);
 }
@@ -479,6 +501,39 @@ Header
 
 =item init_math_support()
 
+=item mimetex_valign()
+
+ Makes a HEAD call to /cgi-bin/mimetex.cgi via IO:: to retrieve the
+ vertical alignment, before the subsequent call to mimetex_converted()
+ which generates the <img> tag and the corresponding image.
+
+ Input: 1.  $esc_texstring (escaped TeX to be rendered by mimetex).
+ Output: 1. $valign - number of pixels: positive or negative integer
+            which will be included in <img> tag for mimetex image to
+            support vertical alignment of image within a line of text.
+
+ If a server is running SSL, and Apache rewrite rules are in place
+ to rewrite requests for http to https, modification will most likely
+ be needed for pass through for HEAD requests for /cgi-bin/mimetex.cgi.
+
+ Example rewrite rules which rewrite all http traffic to https,
+ except HEAD requests for /cgi-bin/mimetex.cgi are:
+
+ <IfModule mod_rewrite.c>
+     RewriteEngine On
+     RewriteLogLevel 0
+
+     RewriteCond %{HTTPS} off
+     RewriteCond %{HTTP:Host} (.*)
+     RewriteCond %{REQUEST_METHOD} !HEAD
+     RewriteRule ^/(.*) https://%1/$1 [R=301,L]
+
+     RewriteCond %{HTTPS} off
+     RewriteCond %{HTTP:Host} (.*)
+     RewriteCond %{REQUEST_METHOD} HEAD
+     RewriteCond %{REQUEST_URI} !^/cgi-bin/mimetex.cgi
+     RewriteRule ^/(.*) https://%1/$1 [R=301,L]
+ </IfModule>
 
 =item mimetex_converted()