From: Greg Ercolano <erco@(email surpressed)> Subject: [Q+A] Handling of quoting in render commands Date: Wed, 11 May 2011 12:38:36 -0400 |
Msg# 2099 View Complete Thread (2 articles) | All Threads Last Next |
> What's the syntax of quoting for the render command?
> (in other words, the "command" passed to 'rush -submit')
>
> We'd like to invoke commands whose arguments contain spaces.
> We're on windows.
There are a few ways.
IMHO, the most portable is to convert all spaces in arguments
into the ascii DEL character before submit, and then have the
render script convert them back.
So for instance on submit, say we want to run:
perl /path/to/myscript.pl -render "one two" "three four five"
..on the farm. I'd suggest doing it this way:
---- snip
$arg1 = "one two";
$arg2 = "three four five";
# Convert arg's spaces into DEL
$arg1 =~ s/ /\x7f/g;
$arg2 =~ s/ /\x7f/g;
# Build command
$command = "perl /path/to/myscript.pl -render $arg1 $arg2";
open(SUBMIT, "|rush -submit");
print SUBMIT << "EOF";
:
command $command
:
---- snip
On submit, the spaces in the arguments will be the DEL character,
and therefore won't be mistaken as argument delimiters.
Then, when the render script runs on the farm, it first converts
all the DEL's in the arguments back into spaces before using them, eg:
for ( $t=0; $t<=$#ARGV; $t++ ) {
$ARGV[$t] =~ s/\x7f/ /g;
}
This will get the arguments back the way they were, with spaces intact.
There is another way, but it's Microsoft specific, and is something
that Microsoft has not well documented, so I can't tell you much
other than what my empirical tests show.
Under Windows specifically, you can use double quotes (") to protect
strings that contain spaces in the render commands, and the escape
character (\) can be used to protect itself and quotes.
So for example, if you were to submit the following:
title QUOTE_TEST
command "//some/path with spaces/myrender.exe" "one two" "three four"
frames 1-10
cpus +any=5
logdir //some/emptydir
..then it would run on the farm as you'd expect, and with
argv[1] set to "one two",
argv[2] set to "three four"
If you find you need to embed backslashes or quotes,
you can escape them with the backslash character, eg:
command "//some/path/myrender.exe" "This is a quote(\")" "This is a backslash(\\)"
This behavior is handled by the WIN32 call CreateProcess(),
which is documented here (*):
http://msdn.microsoft.com/en-us/library/ms682425%28v=vs.85%29.aspx
As of this writing (May 2011), IMHO the above docs don't go far enough
into enough detail on quoting rules. For instance, what characters does
the backslash escape? Certainly not all, since backslashes can appear
in pathnames and not get confused. Also, UNC paths start with double
backslashes, and in that case \\ doesn't devolve into \, so what's the
rule there?
Anyway, my empirical tests show the above works, which is more or less
consistent with unix shell handling in cases where the character after
the backslash is a quote or another backslash. But obviously there are
differences, since in unix backslash escapes ALL characters that follow it,
whereas in Windows, it doesn't always.
This is why the rush scripts prefer the 'convert everything to DEL'
and to use frontslashes instead of backslashes to avoid running into
weird cross platform parsing differences.
(*) That link may go stale; Microsoft likes to move stuff around.
If it does, just search MSDN for CreateProcess().
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From: Greg Ercolano <erco@(email surpressed)> Subject: Re: [Q+A] Handling of quoting in render commands Date: Wed, 11 May 2011 13:32:19 -0400 |
Msg# 2100 View Complete Thread (2 articles) | All Threads Last Next |
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