Help, *.CHM, etc

[Tom]

A question for gui application programmers. . .
I 've got some GUI programs, written in Python/wxPython, and I've got
a help button and a help menu item. Also, I've got a compiled file
made with the microsoft HTML workshop utility, lets call it
c:\path\help.ch m. My question is how do you launch it from the GUI?
What logic do I put behind the "help" button, in other words.

I thought it would be

os.spawnv(os.P_ DETACH, "c:\\path\\help .chm", [])

but I get an error:

OSError: [Errno 8] Exec format error

so I guess help.chm isn't executable itself, but is associated with
some unknown executable. I tried explorer.exe- at the dos cmd line it
basically works to type

explorer.exe c:\path\help.ch m

although there is a nag screen that would be nice to do without.

so you'd think

os.spawnv(os.P_ DETACH, 'explorer.exe', ["c:\\path\\help .chm"])

would be equivalent but it fails. I have to believe someone out there
in python community likes to include help.chm with their applications,
nad there is a right way to do this.

On another note, are there pure python based help viewers that people
use instead? The reason I ask is that would be more portable then the
*.chm files are. If there is such a beast I can't find it.

[Josiah Carlson]

Re: Help, *.CHM, etc

> A question for gui application programmers. . .[color=blue]
> I 've got some GUI programs, written in Python/wxPython, and I've got
> a help button and a help menu item. Also, I've got a compiled file
> made with the microsoft HTML workshop utility, lets call it
> c:\path\help.ch m. My question is how do you launch it from the GUI?
> What logic do I put behind the "help" button, in other words.
>
> I thought it would be
>
> os.spawnv(os.P_ DETACH, "c:\\path\\help .chm", [])[/color]

needs to be:

os.spawnv(os.P_ DETACH, "c:\\path\\help .chm", ["c:\\path\\help .chm"])
[color=blue]
> so I guess help.chm isn't executable itself, but is associated with
> some unknown executable. I tried explorer.exe- at the dos cmd line it
> basically works to type[/color]
[color=blue]
> os.spawnv(os.P_ DETACH, 'explorer.exe', ["c:\\path\\help .chm"])[/color]

os.spawnv(os.P_ DETACH, 'explorer.exe', ['explorer.exe', "c:\\path\\help .chm"])
[color=blue]
> would be equivalent but it fails. I have to believe someone out there
> in python community likes to include help.chm with their applications,
> nad there is a right way to do this.
>
> On another note, are there pure python based help viewers that people
> use instead? The reason I ask is that would be more portable then the
> *.chm files are. If there is such a beast I can't find it.[/color]

Personally, I would suggest:
os.startfile("c :\\path\\help.c hm")

It is documented to do exactly what you want it to do, open up the help
file with the microsoft help file viewer.

- Josiah

[Josiah Carlson]

Re: Help, *.CHM, etc

> Personally, I would suggest:[color=blue]
> os.startfile("c :\\path\\help.c hm")
>
> It is documented to do exactly what you want it to do, open up the help
> file with the microsoft help file viewer.[/color]

That is, if .chm files are associated with the microsoft help file
viewer.

Technically os.system("c:\\ path\\help.chm" ) and
os.system("star t c:\\path\\help. chm") also work, though are less
intuitive.

- Josiah

[Michael Geary]

Re: Help, *.CHM, etc

Josiah Carlson wrote:[color=blue][color=green]
> > Personally, I would suggest:
> > os.startfile("c :\\path\\help.c hm")
> >
> > It is documented to do exactly what you want it to do,
> > open up the help file with the microsoft help file viewer.[/color]
>
> That is, if .chm files are associated with the microsoft
> help file viewer.
>
> Technically os.system("c:\\ path\\help.chm" ) and
> os.system("star t c:\\path\\help. chm") also work, though
> are less intuitive.[/color]

No, os.system is the wrong way to do it. That function launches a new
command shell, which in turn runs the program you want. Because of that, if
you're not already running in a console window, it will open a new console
window.

You had it right with os.startfile. That calls the ShellExecute function in
Windows, which is the way you would do it in a native Windows application
written in C.

-Mike

[Josiah Carlson]

Re: Help, *.CHM, etc

> > Technically os.system("c:\\ path\\help.chm" ) and[color=blue][color=green]
> > os.system("star t c:\\path\\help. chm") also work, though
> > are less intuitive.[/color]
>
> No, os.system is the wrong way to do it. That function launches a new
> command shell, which in turn runs the program you want. Because of that, if
> you're not already running in a console window, it will open a new console
> window.
>
> You had it right with os.startfile. That calls the ShellExecute function in
> Windows, which is the way you would do it in a native Windows application
> written in C.[/color]

Mike,

When the command completes, the window dissappears. This is the case
when running from a script within pythonw or even inside of a py2exe
frozen module. While it may not be the 100% correct way of doing things
(and you have to properly escape spaces in the file name, which then
results in having to give a window title, etc.), it does result in a
final outcome that is the same - the help file is open, your program
continues execution.

Certainly he will be using os.startfile(), but knowing that you can use
windows shell commands with os.system can be useful.

- Josiah

[Michael Geary]

Re: Help, *.CHM, etc

> > > Technically os.system("c:\\ path\\help.chm" ) and[color=blue][color=green][color=darkred]
> > > os.system("star t c:\\path\\help. chm") also work,
> > > though are less intuitive.[/color][/color][/color]
[color=blue][color=green]
> > No, os.system is the wrong way to do it. That function
> > launches a new command shell, which in turn runs
> > the program you want. Because of that, if you're not
> > already running in a console window, it will open a
> > new console window.
> >
> > You had it right with os.startfile. That calls the
> > ShellExecute function in Windows, which is the way
> > you would do it in a native Windows application
> > written in C.[/color][/color]
[color=blue]
> When the command completes, the window dissappears.
> This is the case when running from a script within
> pythonw or even inside of a py2exe frozen module. While
> it may not be the 100% correct way of doing things (and
> you have to properly escape spaces in the file name, which
> then results in having to give a window title, etc.), it does
> result in a final outcome that is the same - the help file is
> open, your program continues execution.
>
> Certainly he will be using os.startfile(), but knowing that
> you can use windows shell commands with os.system
> can be useful.[/color]

Hi Josiah,

Yes, it is definitely useful to know that you can use os.system to run
Windows shell commands. That's what os.system is meant for. But you really
wouldn't want to use it to run a GUI app such as the HTML Help viewer.

If your application's Help menu opens a spurious console window along with
the help viewer, your users will wonder what the heck is going on. :-) It
also takes more memory and other resources, but that's less significant than
the user experience.

So do it the right way, with os.startfile. Or if you want more control over
the exact parameters to the underlying ShellExecute function, you can use
win32api.ShellE xecute (if you know that the win32api module will be
available on the target systems).

-Mike

[Markus Wankus]

Re: Help, *.CHM, etc

If you are interested, here is a snippet of how I did it a long time ago
in a galaxy far, far away. It avoids spawning multiple instances of the
same .chm.

#
----------------------------------------------------------------------------
# The Help..Contents menu command
def OnMnuHelpConten ts(self, event):
"""This method opens the Help file (if it isn't open already)."""
# Display the help file - nothing fancy - just run it
# ToDo - if already running bring to top (I can't see a way to do
# this, currently)
global helpfile_active

helpfilename = os.path.join(r' path_to_your_he lpfile',
r'yourhelpfile. chm')
if not helpfile_active :
helpprocid = wxNewId()
self.helpfile_p rocess = wxProcess(self, helpprocid)
EVT_END_PROCESS (self, helpprocid, self.OnHelpWind owTerminate)
helpfile_active = wxExecute('hh.e xe %s' % helpfilename, False,
self.helpfile_p rocess)
#
----------------------------------------------------------------------------
def OnHelpWindowTer minate(self, event):
"""This event function is fired when the help window is closed."""
global helpfile_active

if helpfile_active :
self.helpfile_p rocess.Detach()
self.helpfile_p rocess.Destroy( )
helpfile_active = 0
#
----------------------------------------------------------------------------

Couldn't tell you if os.startfile is better or not...but I imagine
wxExecute is calling the Windows ShellExecute under the covers anyway. Of
course, this also fails if they do not have hh.exe installed but this is
only on stock Win95 or older NT machines with IE < 5.0. I imagine you
could spruce it up with more error checking.

You may also want to get rid of the global and use a real attribute...thi s
is from my beginner days. ;o)

Markus.

On 20 Jan 2004 18:03:36 -0800, Tom <its1louder@yah oo.com> wrote:
[color=blue]
> A question for gui application programmers. . .
> I 've got some GUI programs, written in Python/wxPython, and I've got
> a help button and a help menu item. Also, I've got a compiled file
> made with the microsoft HTML workshop utility, lets call it
> c:\path\help.ch m. My question is how do you launch it from the GUI?
> What logic do I put behind the "help" button, in other words.
>
> I thought it would be
>
> os.spawnv(os.P_ DETACH, "c:\\path\\help .chm", [])
>
> but I get an error:
>
> OSError: [Errno 8] Exec format error
>
> so I guess help.chm isn't executable itself, but is associated with
> some unknown executable. I tried explorer.exe- at the dos cmd line it
> basically works to type
>
> explorer.exe c:\path\help.ch m
>
> although there is a nag screen that would be nice to do without.
>
> so you'd think
>
> os.spawnv(os.P_ DETACH, 'explorer.exe', ["c:\\path\\help .chm"])
>
> would be equivalent but it fails. I have to believe someone out there
> in python community likes to include help.chm with their applications,
> nad there is a right way to do this.
>
> On another note, are there pure python based help viewers that people
> use instead? The reason I ask is that would be more portable then the
> *.chm files are. If there is such a beast I can't find it.[/color]

[Tom]

Re: Help, *.CHM, etc

Hah, thanks for the prompt help. I've been using the _programming on
win32_ (Hammond) book as a reference and now I see that right under
spawnve in Appendix A p. 523 (which I was using as my os module
reference) is the bit about system(command) . From C that should have
been obvious.

Trying it, os.system() didn't really work but os.startfile() works
exactly as I'd like it. fixing my os.system() call is probably is
easy but irrellevant.

As for the other question, a portable html browser that looks & feels
like the chm help browser. I realized that Boa Constructor Project
has such a component, since I've used Boa help in windows and unix. I
wonder if anyone has written a cross-platform CHM decoder and browser
that has the help browser look & feel. I can't find one, but it seems
that python would be a great language to make such a thing. Maybe
I'll take a crack if it hasn't been done. I like monolithic,
compressed help vs. a big directory full of html.

[Jarek Zgoda]

Re: Help, *.CHM, etc

Michael Geary <Mike@DeleteThi s.Geary.com> pisze:
[color=blue]
> You had it right with os.startfile. That calls the ShellExecute function in
> Windows, which is the way you would do it in a native Windows application
> written in C.[/color]

Only if you don't pretend to be "Real-Hardcore-Win32-Hackah". We use
CreateProcessEx .

--
Jarek Zgoda
Unregistered Linux User #-1
http://www.zgoda.biz/ JID:zgoda-a-chrome.pl http://zgoda.jogger.pl/

[JanC]

Re: Help, *.CHM, etc

its1louder@yaho o.com (Tom) schreef:
[color=blue]
> As for the other question, a portable html browser that looks & feels
> like the chm help browser. I realized that Boa Constructor Project
> has such a component, since I've used Boa help in windows and unix. I
> wonder if anyone has written a cross-platform CHM decoder and browser
> that has the help browser look & feel. I can't find one, but it seems
> that python would be a great language to make such a thing. Maybe
> I'll take a crack if it hasn't been done. I like monolithic,
> compressed help vs. a big directory full of html.[/color]

helpviewer.py in site-packages/wxPython/tools is part of wxPython, not Boa:

"""
helpviewer.py -- Displays HTML Help in a wxHtmlHelpContr oller window.

Usage:
helpviewer [--cache=path] helpfile [helpfile(s)...]

Where helpfile is the path to either a .hhp file or a .zip file
which contians a .hhp file. The .hhp files are the same as those
used by Microsoft's HTML Help Workshop for creating CHM files.
"""


Also try xCHM for a cross-platform .CHM viewer:
<http://xchm.sourceforg e.net/>

--
JanC

"Be strict when sending and tolerant when receiving."
RFC 1958 - Architectural Principles of the Internet - section 3.9