On 13.11.2019 19:37, Damyan Ivanov wrote:
-=| André Warnier (tomcat/perl), 13.11.2019 19:12:10 +0100 |=-
while (my $sz = $f->read(my $buffer, BUFF_LEN)) {
..
and then I need to pass this data to another module for processing
(Template::Toolkit).
To make a long story short, Template::Toolkit misinterprets the data I'm
sending to it, because this data /is/ actually UTF-8, but apparently not
marked so internally by the $f->read(). So TT2 re-encodes it, leading to
double UTF-8 encoding.
My question is : can I - and how -, set the filehandle that corresponds to
the $f->read(), to a UTF-8 layer ?
I have tried
line 155: binmode($f,'encoding:(UTF-8)');
and that triggers an error :
Not a GLOB reference at (my filter) line 155.\n
)
Or do I need to read the data 'as is', and separately do an
$decoded_buffer = decode('UTF-8', $buffer);
There's a middle ground - partial decoding. See Encode(1)/FB_QUIET:
If CHECK is set to "Encode::FB_QUIET", encoding and decoding
immediately return the portion of the data that has been processed so
far when an error occurs. The data argument is overwritten with
everything after that point; that is, the unprocessed portion of the
data. This is handy when you have to call "decode" repeatedly in the
case where your source data may contain partial multi-byte character
sequences, (that is, you are reading with a fixed-width buffer). Here's
some sample code to do exactly that:
my($buffer, $string) = ("", "");
while (read($fh, $buffer, 256, length($buffer))) {
$string .= decode($encoding, $buffer, Encode::FB_QUIET);
# $buffer now contains the unprocessed partial character
}
Looks exactly like your case.
Thanks for the response and the tip.
My idea of adding a UTF-8 layer to the filehandle through which Apache2::Filter reads the
incoming data was probably wrong anyway : it cannot do that, because it gets this data
originally in chunks, as "bucket brigades" from Apache httpd. And there is no guarantee
that such a bucket brigade would always end in "complete" UTF-8 character sequences.
At the very least, this would probably complicate the code underlying
$f->read() quite a bit.
It is clearer to handle that in the filter itself.
The Encode::FB_QUIET flag above, with the incremental buffer read, is really
smart.
Unfortunately, the Apache2::Filter read() method does not allow as many arguments, and all
one has is something like this :
my $accumulated_content = "";
while (my $sz = $f->read(my $buffer, BUFF_LEN)) {
$accumulated_content .= $buffer;
}
Luckily, in this case, I have to accumulate the complete response content anyway, before I
can decide to call Template::Toolkit on it or not. So I can do a single decode() on
$accumulated_content. Not the most efficient memory-wise, but good enough in this case.
