Scraping Output from a console application

[Christopher Lutz]

Basically my goal in an code experiment that I am messing around with would
to be to extract the output of a text application running in a dos window
using the windows API. I already have something working using the DOS > redirection
operator, but I think the most "elegant" solution would be to use the windows
API and not have to create an intermediate file to capture the output.

After going through the various white papers, code snippets, and L.J. Johnson's
vb console application (VBPJ March 1998), I can dynamically create a console
window, write text out to it and receive user key input (using the AllocConsole(),
WriteConsole(), etc... APIs ). However I can not figure out how to "scrape"
static text outputed by a dos application in this console window.

If anyone knows of an API, or has done this and give me a quick hint. (I'm
not looking for a complete solution, I just need a quick hint to point me
in the right direction so I can puzzle it out myself and learn something
in the process)

Thanks in advance for any Input....

Chris Lutz

[L.J. Johnson]

Christopher,

> After going through the various white papers, code snippets, and L.J.
Johnson's
> vb console application (VBPJ March 1998), I can dynamically create a
console
> window, write text out to it and receive user key input (using the
AllocConsole(),
> WriteConsole(), etc... APIs ). However I can not figure out how to
"scrape"
> static text outputed by a dos application in this console window.


> If anyone knows of an API, or has done this and give me a quick hint. (I'm
> not looking for a complete solution, I just need a quick hint to point me
> in the right direction so I can puzzle it out myself and learn something
> in the process)

I haven't done this, but according to MS documentation, you would need to
use the CreateFile API to get a handle of the console's active screen buffer
(it can have many buffers, but the active screen buffer is the one you see
on the screen). The screen buffer has its own 2-dimmed array of character
info records, and each record is stored in a CHAR_INFO structure (which
consists of two items -- see below). So, you should be able to iterate thru
the records and reconstruct the screen, particularly if you use the
GetConsoleScreenBufferInfo call to figure out the "size" of the console (#
lines, #columns, etc).

Char
Specifies either the Unicode (wide-character) or ANSI character of a screen
buffer character cell, depending on whether the Unicode or ANSI version of
the function is used.
Attributes
Specifies the foreground (text) and background colors in which a screen
buffer character cell is drawn. This member can be zero, or it can be any
combination of the following values:
BACKGROUND_BLUE
FOREGROUND_BLUE
BACKGROUND_GREEN
FOREGROUND_GREEN
BACKGROUND_RED
FOREGROUND_RED
BACKGROUND_INTENSITY
FOREGROUND_INTENSITY

--
L.J. Johnson, Slightly Tilted Software
Microsoft MVP (Visual Basic)
LJJohnsn@Flash.Net or LJJohnson@mvps.org
<http://www.flash.net/~ljjohnsn>
Ask The NT Pro at <http://www.inquiry.com>

[Mattias Sjögren]

Christopher,

>If anyone knows of an API, or has done this and give me a quick hint. (I'm
>not looking for a complete solution, I just need a quick hint to point me
>in the right direction so I can puzzle it out myself and learn something
>in the process)

I have a sample of how to redirect the output from a console app into
a VB string at my site. If it's too much of a "complete solution" for
you, you could start looking at the CreatePipe API, and the
STARTUPINFO structure used in a call to CreateProcess.


Mattias

____________________________________________
Mattias Sjögren - mattiass @ hem.passagen.se
http://hem.spray.se/mattias.sjogren/
Docendo discimus

[L.J. Johnson]

Mattias,

> I have a sample of how to redirect the output from a console app into
> a VB string at my site.

Cool.

--
L.J. Johnson, Slightly Tilted Software
Microsoft MVP (Visual Basic)
LJJohnsn@Flash.Net or LJJohnson@mvps.org
<http://www.flash.net/~ljjohnsn>
Ask The NT Pro at <http://www.inquiry.com>

[Christopher Lutz]

"L.J. Johnson" <ljjohnsn@flash.net> wrote:
>Mattias,
>
>> I have a sample of how to redirect the output from a console app into
>> a VB string at my site.
>
>Cool.
>
>--
>L.J. Johnson, Slightly Tilted Software
>Microsoft MVP (Visual Basic)
>LJJohnsn@Flash.Net or LJJohnson@mvps.org
><http://www.flash.net/~ljjohnsn>
>Ask The NT Pro at <http://www.inquiry.com>
>
>
>


Thanks for all your help!

[L.J. Johnson]

Christopher,

> After going through the various white papers, code snippets, and L.J.
Johnson's
> vb console application (VBPJ March 1998), I can dynamically create a
console
> window, write text out to it and receive user key input (using the
AllocConsole(),
> WriteConsole(), etc... APIs ). However I can not figure out how to
"scrape"
> static text outputed by a dos application in this console window.


> If anyone knows of an API, or has done this and give me a quick hint. (I'm
> not looking for a complete solution, I just need a quick hint to point me
> in the right direction so I can puzzle it out myself and learn something
> in the process)

I haven't done this, but according to MS documentation, you would need to
use the CreateFile API to get a handle of the console's active screen buffer
(it can have many buffers, but the active screen buffer is the one you see
on the screen). The screen buffer has its own 2-dimmed array of character
info records, and each record is stored in a CHAR_INFO structure (which
consists of two items -- see below). So, you should be able to iterate thru
the records and reconstruct the screen, particularly if you use the
GetConsoleScreenBufferInfo call to figure out the "size" of the console (#
lines, #columns, etc).

Char
Specifies either the Unicode (wide-character) or ANSI character of a screen
buffer character cell, depending on whether the Unicode or ANSI version of
the function is used.
Attributes
Specifies the foreground (text) and background colors in which a screen
buffer character cell is drawn. This member can be zero, or it can be any
combination of the following values:
BACKGROUND_BLUE
FOREGROUND_BLUE
BACKGROUND_GREEN
FOREGROUND_GREEN
BACKGROUND_RED
FOREGROUND_RED
BACKGROUND_INTENSITY
FOREGROUND_INTENSITY

--
L.J. Johnson, Slightly Tilted Software
Microsoft MVP (Visual Basic)
LJJohnsn@Flash.Net or LJJohnson@mvps.org
<http://www.flash.net/~ljjohnsn>
Ask The NT Pro at <http://www.inquiry.com>

[Mattias Sjögren]

Christopher,

>If anyone knows of an API, or has done this and give me a quick hint. (I'm
>not looking for a complete solution, I just need a quick hint to point me
>in the right direction so I can puzzle it out myself and learn something
>in the process)

I have a sample of how to redirect the output from a console app into
a VB string at my site. If it's too much of a "complete solution" for
you, you could start looking at the CreatePipe API, and the
STARTUPINFO structure used in a call to CreateProcess.


Mattias

____________________________________________
Mattias Sjögren - mattiass @ hem.passagen.se
http://hem.spray.se/mattias.sjogren/
Docendo discimus

[L.J. Johnson]

Mattias,

> I have a sample of how to redirect the output from a console app into
> a VB string at my site.

Cool.

--
L.J. Johnson, Slightly Tilted Software
Microsoft MVP (Visual Basic)
LJJohnsn@Flash.Net or LJJohnson@mvps.org
<http://www.flash.net/~ljjohnsn>
Ask The NT Pro at <http://www.inquiry.com>

[Christopher Lutz]

"L.J. Johnson" <ljjohnsn@flash.net> wrote:
>Mattias,
>
>> I have a sample of how to redirect the output from a console app into
>> a VB string at my site.
>
>Cool.
>
>--
>L.J. Johnson, Slightly Tilted Software
>Microsoft MVP (Visual Basic)
>LJJohnsn@Flash.Net or LJJohnson@mvps.org
><http://www.flash.net/~ljjohnsn>
>Ask The NT Pro at <http://www.inquiry.com>
>
>
>


Thanks for all your help!