Changeset 7719

Timestamp:

06/10/10 13:57:33 (2 years ago)

Author:

CrawfordCurrie

Message:

Item2521: restore the ability to generate an unknown length response, by flushing the output with the headers as they have been completed up to that point. This restores the old ability for statistics to generate a progress report as it goes along, rather than compiling the page in memory and emitting it en masse. I've only enabled this on the statistics reporting.

Location:

trunk/core/lib/Foswiki

Files:

• Engine.pm (modified) (8 diffs)
• Response.pm (modified) (15 diffs)
• UI.pm (modified) (2 diffs)
• UI/Statistics.pm (modified) (1 diff)

trunk/core/lib/Foswiki/Engine.pm

@@ -46 +46 @@
 sub run {
     my $this = shift;
-    my $req  = $this->prepare;
+    my $req  = $this->prepare();
     if ( defined $req ) {
         my $res = Foswiki::UI::handleRequest($req);
@@ -88 +88 @@
             $res->print($html);
         }
-        $this->finalizeError($res);
+        $this->finalizeError($res, $req);
         return $e->{status};
     }
@@ -115 +115 @@
             $res->print($text);
         }
-        $this->finalizeError($res);
+        $this->finalizeError($res, $req);
         return 500;    # Internal server error
     };
@@ -268 +268 @@
 sub finalize {
     my ( $this, $res, $req ) = @_;
-    $this->finalizeUploads( $res, $req );
-    $this->finalizeHeaders( $res, $req );
-    $this->finalizeBody($res);
+    if ($res->outputHasStarted()) {
+        $this->flush($res, $req);
+    } else {
+        $this->finalizeUploads( $res, $req );
+        $this->finalizeHeaders( $res, $req );
+        $this->finalizeBody($res);
+    }
 }
 
@@ -289 +293 @@
 =begin TML
 
----++ ObjectMethod finalizeError( $res )
+---++ ObjectMethod finalizeError( $res, $req )
 
 Called if some engine especific error happens.
 
    * =$res= - Foswiki::Response object to get data from
+   * =$req= - Foswiki::Request object to get data from
 
 =cut
 
 sub finalizeError {
-    my ( $this, $res ) = @_;
-    $this->finalizeHeaders($res);
-    $this->finalizeBody($res);
+    my ( $this, $res, $req ) = @_;
+    $this->finalizeHeaders($res, $req);
+    $this->finalizeBody($res, $req);
 }
 
@@ -351 +356 @@
 =begin TML
 
----++ ObjectMethod finalizeBody( $res )
+---++ ObjectMethod finalizeBody( $res, $req )
 
    * =$res= - Foswiki::Response object to get data from
+   * =$req= - Foswiki::Request object to get data from
 
 Should send $res' body to client. This method calls =write()=
@@ -361 +367 @@
 
 sub finalizeBody {
-    my ( $this, $res ) = @_;
+    my ( $this, $res, $req ) = @_;
     my $body = $res->body;
     return unless $body;
@@ -381 +387 @@
 =begin TML
 
+---++ flush($res, $req)
+
+Forces the response headers to be emitted if they haven't already been sent
+(note that this may in some circumstances result in cookies being missed)
+before flushing what is in the body so far.
+
+Before headers are sent, any Content-length is removed, as a call to
+flush is a statement that there's more to follow, but we don't know
+how much at this point.
+
+This function should be used with great care! It requires that the output
+headers are fully complete before it is first called. Once it *has* been
+called, the response object will refuse any modifications that would alter
+the header.
+
+=cut
+
+sub flush {
+    my ($this, $res, $req) = @_;
+
+    unless ($res->outputHasStarted()) {
+        $res->deleteHeader('Content-Length');
+        $this->finalizeUploads( $res, $req );
+        $this->finalizeHeaders( $res, $req );
+        $this->prepareWrite($res);
+        $res->outputHasStarted(1);
+    }
+
+    my $body = $res->body();
+
+    if ( Scalar::Util::blessed($body) || ref( $body ) eq 'GLOB' ) {
+        throw Foswiki::EngineException('Cannot flush non-text response body');
+    }
+
+    $this->write($body);
+    $res->body('');
+}
+
+=begin TML
+
 ---++ ObjectMethod prepareWrite( $res )
 
-Abstract method, must be defined by inherited classes.
+Abstract method, may be defined by inherited classes.
    * =$res= - Foswiki::Response object to get data from
 
-Shold perform any task needed before writing.
+Should perform any task needed before writing.
 That's ok if none needed ;-)
 

trunk/core/lib/Foswiki/Response.pm

@@ -16 +16 @@
 
 package Foswiki::Response;
+
 use strict;
 use warnings;
 use Assert;
-use CGI::Util qw(rearrange expires);
+
+use CGI::Util ();
 
 =begin TML
@@ -28 +30 @@
 
 =cut
-
-# NOTE: CHECK_ORDER is used to indicate when the body assembly has started.
-# By associating an assert with this action we can ensure that headers are
-# fully assembled before the body print starts - an essential precondition
-# for early flushing of output.
-sub CHECK_ORDER {
-    ASSERT( !$_[0]->{startedPrinting} ) if DEBUG;
-}
 
 sub new {
@@ -41 +35 @@
     my $class = ref($proto) || $proto;
     my $this  = {
-        status          => undef,
-        headers         => {},
-        body            => undef,
-        charset         => 'ISO-8859-1',
-        cookies         => [],
-        startedPrinting => 0,
+        status           => undef,
+        headers          => {},
+        body             => undef,
+        charset          => 'ISO-8859-1',
+        cookies          => [],
+        outputHasStarted => 0,
     };
 
@@ -67 +61 @@
     my ( $this, $status ) = @_;
     if ($status) {
-        CHECK_ORDER() if DEBUG;
+        ASSERT(!$this->{outputHasStarted}, 'Too late to change status')
+          if DEBUG;
         $this->{status} = $status =~ /^\d{3}/ ? $status : undef;
     }
@@ -105 +100 @@
     my (@header);
 
-    CHECK_ORDER;
+    ASSERT(!$this->{outputHasStarted}, 'Too late to change headers') if DEBUG;
 
     # Ugly hack to avoid html escape in CGI::Util::rearrange
     local $CGI::Q = { escape => 0 };
     my ( $type, $status, $cookie, $charset, $expires, $attachment, @other ) =
-      rearrange(
+      CGI::Util::rearrange(
         [
             [ 'TYPE',   'CONTENT_TYPE', 'CONTENT-TYPE' ], 'STATUS',
@@ -163 +158 @@
         $this->cookies( \@cookies );
     }
-    $this->{headers}->{Expires} = expires( $expires, 'http' )
+    $this->{headers}->{Expires} = CGI::Util::expires( $expires, 'http' )
       if ( defined $expires );
-    $this->{headers}->{Date} = expires( 0, 'http' )
+    $this->{headers}->{Date} = CGI::Util::expires( 0, 'http' )
       if defined $expires || $cookie;
     $this->{headers}->{'Content-Disposition'} =
@@ -186 +181 @@
     my ( $this, $hdr ) = @_;
     if ($hdr) {
-        CHECK_ORDER;
+        ASSERT(!$this->{outputHasStarted}, 'Too late to change headers')
+          if DEBUG;
         my %headers = ();
         while ( my ( $key, $value ) = each %$hdr ) {
@@ -192 +188 @@
             $headers{$key} = $value;
         }
-        $headers{Expires} = expires( $headers{Expires}, 'http' )
+        $headers{Expires} = CGI::Util::expires( $headers{Expires}, 'http' )
           if defined $headers{Expires};
-        $headers{Date} = expires( 0, 'http' )
+        $headers{Date} = CGI::Util::expires( 0, 'http' )
           if defined $headers{'Set-Cookie'} || defined $headers{Expires};
         if ( defined $headers{'Set-Cookie'} ) {
@@ -253 +249 @@
             }
             elsif ( $hdr eq 'Expires' ) {
-                $value = expires( $value, 'http' );
+                $value = CGI::Util::expires( $value, 'http' );
             }
             elsif ( $hdr eq 'Set-Cookie' ) {
@@ -262 +258 @@
         }
     }
-    $this->{headers}{Date} = expires( 0, 'http' )
+    $this->{headers}{Date} = CGI::Util::expires( 0, 'http' )
       if !exists $this->{headers}{Date}
           && (   defined $this->{headers}{Expires}
@@ -302 +298 @@
     my $this = shift;
 
-    CHECK_ORDER;
+    ASSERT(!$this->{outputHasStarted}, 'Too late to change headers') if DEBUG;
 
     foreach (@_) {
@@ -321 +317 @@
     my ( $this, $hdr, $value ) = @_;
 
-    CHECK_ORDER;
+    ASSERT(!$this->{outputHasStarted}, 'Too late to change headers') if DEBUG;
 
     $hdr =~ s/(?:^|(?<=-))(.)([^-]*)/\u$1\L$2\E/g;
@@ -398 +394 @@
 sub redirect {
     my ( $this, @p ) = @_;
+    ASSERT(!$this->{outputHasStarted}, 'Too late to redirect') if DEBUG;
     my ( $url, $status, $cookies ) =
-      rearrange( [ [qw(LOCATION URL URI)], 'STATUS', [qw(COOKIE COOKIES)], ],
-        @p );
+      CGI::Util::rearrange(
+          [ [qw(LOCATION URL URI)], 'STATUS', [qw(COOKIE COOKIES)], ],
+          @p );
 
     return unless $url;
@@ -415 +413 @@
 ---++ ObjectMethod print(...)
 
-Add content to the end of the body. The print may not be flushed until the
-body is complete.
+Add content to the end of the body.
 
 =cut
@@ -422 +419 @@
 sub print {
     my $this = shift;
-    $this->{startedPrinting} = 1;
     $this->body( ( $this->{body} || '' ) . join( '', @_ ) );
+}
+
+=begin TML
+
+---++ ObjectMethod outputHasStarted([$boolean])
+
+Get/set the output-has-started flag. This is used by the Foswiki::Engine
+to separate header and body output. Once output has started, the headers
+cannot be changed (though the body can be modified)
+
+=cut
+
+sub outputHasStarted {
+    my ($this, $flag ) = @_;
+    $this->{outputHasStarted} = $flag if defined $flag;
+    return $this->{outputHasStarted};
 }
 

trunk/core/lib/Foswiki/UI.pm

@@ -385 +385 @@
             $res->print($html);
         }
-        $Foswiki::engine->finalizeError($res);
+        $Foswiki::engine->finalizeError($res, $session->{request});
         return $e->{status};
     }
@@ -397 +397 @@
         $res ||= new Foswiki::Response();
 
-        $res->header( -type => 'text/plain' );
+        $res->header( -type => 'text/plain' )
+          unless $res->outputHasStarted();
         if (DEBUG) {
 

trunk/core/lib/Foswiki/UI/Statistics.pm

@@ -496 +496 @@
     }
     $session->{response}->print( $msg . "\n" ) if $msg;
+    $Foswiki::engine->flush($session->{response}, $session->{request});
 }