stdin, stdout, redmon

[Bernard Desnoues]

Hi,

I've got a problem with the use of Redmon (redirection port monitor). I
intend to develop a virtual printer so that I can modify data sent to
the printer.
Redmon send the data flow to the standard input and lauchs the Python
program which send modified data to the standard output (Windows XP and
Python 2.5 context).
I can manipulate the standard output.

"import sys
sys.stdout.write(data)"

it works.
But how to manipulate standard input so that I can store data in a
string or in an object file ? There's no "read" method.

"a = sys.stdin.read()" doesn't work.
"f = open(sys.stdin)" doesn't work.

I don't find anything in the documentation. How to do that ?
Thanks in advance.

Bernard Desnoues
Librarian
Bibliothèque de géographie - Sorbonne

 

[Rolf van de Krol]

According to various tutorials this should work.

<code>
|import sys
data = sys.stdin.readlines()
print "Counted", len(data), "lines."|
</code>

Please use google before asking such questions. This was found with only
one search for the terms 'python read stdin'

Rolf

 

[Bernard Desnoues]

Rolf van de Krol a écrit :

According to various tutorials this should work.

<code>
|import sys
data = sys.stdin.readlines()
print "Counted", len(data), "lines."|
</code>

Please use google before asking such questions. This was found with only
one search for the terms 'python read stdin'

Rolf

Hello Rolf,

I know this code because I have search a solution !
Your google code doesn't work ! No attribute "readlines".

Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
data = sys.stdin.readlines()
AttributeError: readlines

 

[Rolf van de Krol]

I don't know what you did with your Python installation, but for me this
works perfectly.

test3.py contains:
<code>
import sys

print sys.stdin.readlines()
</code>

test.txt contains:
<code>
Testline1
Testline2
</code>

Output of 'python test3.py < test.txt' is:
<code>
['Testline1\n', 'Testline2']
</code>

Just plain simple and just works.

Rolf

 

[Bernard Desnoues]

Hello,

I checked under linux and it works :
text.txt :
"first line of the text file
second line of the text file"

test.py :
"import sys
a = sys.stdin.readlines()
x = ''.join(a)
x = x.upper()
sys.stdout.write(x)"

>cat text.txt | python test.py

But I reinstalled Python 2.5 under Windows XP and it doesn't work
anyway. Can you confirm that your script works with Win XP and Python 2.5 ?

Regards

Rolf van de Krol a écrit :

I don't know what you did with your Python installation, but for me this
works perfectly.

test3.py contains:
<code>
import sys

print sys.stdin.readlines()
</code>

test.txt contains:
<code>
Testline1
Testline2
</code>

Output of 'python test3.py < test.txt' is:
<code>
['Testline1\n', 'Testline2']
</code>

Just plain simple and just works.

Rolf

Rolf van de Krol a écrit :


Hello Rolf,

I know this code because I have search a solution !
Your google code doesn't work ! No attribute "readlines".


Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
data = sys.stdin.readlines()
AttributeError: readlines

 

[Tim Golden]

Hello,

I checked under linux and it works :
text.txt :
"first line of the text file
second line of the text file"

test.py :
"import sys
a = sys.stdin.readlines()
x = ''.join(a)
x = x.upper()
sys.stdout.write(x)"


But I reinstalled Python 2.5 under Windows XP and it doesn't work
anyway. Can you confirm that your script works with Win XP and Python 2.5 ?

How are you invoking the script under WinXP? If you're
using the standard file associations then stdin/stdout
won't work correctly. However, they produce a specific
error message:

<dump>
C:\temp>type test3.py
import sys

print sys.stdin.readlines ()
C:\temp>
C:\temp>type test3.py | test3.py
Traceback (most recent call last):
File "C:\temp\test3.py", line 3, in <module>
print sys.stdin.readlines ()
IOError: [Errno 9] Bad file descriptor

C:\temp>type test3.py | python test3.py
['import sys\n', '\n', 'print sys.stdin.readlines ()']

</dump>

TJG

 

[John Machin]

Hello,

I checked under linux and it works :
text.txt :
"first line of the text file
second line of the text file"

test.py :
"import sys
a = sys.stdin.readlines()
x = ''.join(a)
x = x.upper()
sys.stdout.write(x)"

cat text.txt | python test.py

But I reinstalled Python 2.5 under Windows XP and it doesn't work
anyway. Can you confirm that your script works with Win XP and Python 2.5 ?

Regards

Rolf van de Krol a écrit :

I don't know what you did with your Python installation, but for me this
works perfectly.

test3.py contains:
<code>
import sys

print sys.stdin.readlines()
</code>

test.txt contains:
<code>
Testline1
Testline2
</code>

Output of 'python test3.py < test.txt' is:
<code>
['Testline1\n', 'Testline2']
</code>

Just plain simple and just works.

Excuse me, gentlemen, may I be your referee *before* you resort to
pistols at dawn?

===== IDLE =====
IDLE 1.2.1
Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
sys.stdin.readlines
AttributeError: readlines
===== Command Prompt =====
C:\junk>python
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
HTH,
John

 

[Rolf van de Krol]

Well, that's at least weird. I did test my code with Python 2.5 on Win
XP, using the command prompt. But testing it with IDLE gives exactly the
same error Bernard has. So apparently STDIN can't be accessed with IDLE.

Rolf

Excuse me, gentlemen, may I be your referee *before* you resort to
pistols at dawn?

===== IDLE =====
IDLE 1.2.1

Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
sys.stdin.readlines
AttributeError: readlines


===== Command Prompt =====
C:\junk>python
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
<built-in method readlines of file object at 0x00B1F020>


HTH,
John

 

[Konstantin Shaposhnikov]

Hi,

This is Windows bug that is described here: http://support.microsoft.com/default.aspx?kbid=321788

This article also contains solution: you need to add registry value:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies
\Explorer
InheritConsoleHandles = 1 (REG_DWORD type)

Do not forget to launch new console (cmd.exe) after editing registry.

Alternatively you can use following command

cat file | python script.py

instead of

cat file | python script.py

Regards,
Konstantin

Well, that's at least weird. I did test my code with Python 2.5 on Win
XP, using the command prompt. But testing it with IDLE gives exactly the
same error Bernard has. So apparently STDIN can't be accessed with IDLE.

Rolf

Excuse me, gentlemen, may I be your referee *before* you resort to
pistols at dawn?

===== IDLE =====
IDLE 1.2.1

Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
sys.stdin.readlines
AttributeError: readlines

===== Command Prompt =====
C:\junk>python
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.

import sys
sys.stdin.readlines

<built-in method readlines of file object at 0x00B1F020>

HTH,
John

 

[Konstantin Shaposhnikov]

Sorry, I meant:

Alternatively you can use following command

cat file | python script.py

instead of

cat file | script.py

Hi,

This is Windows bug that is described here:http://support.microsoft.com/default.aspx?kbid=321788

This article also contains solution: you need to add registry value:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies
\Explorer
InheritConsoleHandles = 1 (REG_DWORD type)

Do not forget to launch new console (cmd.exe) after editing registry.

Alternatively you can use following command

cat file | python script.py

instead of

cat file | python script.py

Regards,
Konstantin

Well, that's at least weird. I did test my code with Python 2.5 on Win
XP, using the command prompt. But testing it with IDLE gives exactly the
same error Bernard has. So apparently STDIN can't be accessed with IDLE.

Rolf

John Machin wrote:

Excuse me, gentlemen, may I be your referee *before* you resort to
pistols at dawn?
===== IDLE =====
IDLE 1.2.1
import sys
sys.stdin.readlines
Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
sys.stdin.readlines
AttributeError: readlines
===== Command Prompt =====
C:\junk>python
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
import sys
sys.stdin.readlines
<built-in method readlines of file object at 0x00B1F020>
HTH,
John

 

[Thynnus]

Hi,

This is Windows bug that is described here: http://support.microsoft.com/default.aspx?kbid=321788

This article also contains solution: you need to add registry value:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies
\Explorer
InheritConsoleHandles = 1 (REG_DWORD type)

Do not forget to launch new console (cmd.exe) after editing registry.

Alternatively you can use following command

cat file | python script.py

instead of

cat file | python script.py

Regards,
Konstantin

Nice one, Konstantin!

I can confirm that adding the registry key solves the problem on XPsp2:

-----After adding InheritConsoleHandles DWORD 1 key-----
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

D:\temp>type test3.py | test3.py
['import sys\n', '\n', 'print sys.stdin.readlines ()\n']

D:\temp>

The KB article is quite poorly written. Even though it seems to state that
issue was 'solved for win2k with sp4, for XP with sp1', and gives no indication
that the key is needed after the sp's are applied *even though* it is in fact
necessary to the solution.

Questions:
-Any side effects to look out for?
-If the change is relatively benign, should it be part of the install?
-Is this worth a documentation patch? If yes to where, and I'll give it a
shot.

-Thynnus

 

[Thynnus]

Hi,

I've got a problem with the use of Redmon (redirection port monitor). I
intend to develop a virtual printer so that I can modify data sent to
the printer.

FWIW: there is a nice update the RedMon (v1.7) called RedMon EE (v1.81)
available at http://www.is-foehr.com/ that I have used and like a lot.

From the developers website:
Fixed issues and features [with respect to the orininal RedMon]
* On Windows Terminal Server or Windows XP with fast user switching, the
"Prompt for filename" dialog will appear on the current session.
* "SaveAs" now shows XP style dialogs if running under XP
* Support for PDF Security added - experimental -.
* Support for setting the task priority - experimental -
* Use of file-shares as output
* Environment variables are passed to the AfterWorks Process now.
* Environment variables are replaced in the program arguments. No
workaround is needed.
* RedMon EE comes with an RPC communication feature which could transfer
output-files back to the client starting the print job on a print server.
Error messages will be send to the client.
* Redmon EE may start a process after the print job has finished (After
works process).
e.g. starting a presentation program to show the pdf generated by
GhostScript.
* additional debug messages may be written for error analysis.
No special debug version is needed.
* user interface has been rewritten. May be it's more friendly.
Added some basic system information which may help if running in failures.
* new feature: running on a print server.
* cleanup of documentnames "Microsoft -"
* define templates for output-file names with full environment variable
substitution
e.g. %homedrive%\%homedir%\%redmon-user%-%date%-%time%-%n.pdf
* RedMon EE does not support for NT 3.5 and Windows 95/98 !

-Thynnus