Trigger MC CGI with nothing to StandardOut

[andu]

Sivakatirswami wrote:
> 
> Aloha,
> 
> Since my knowledge of CGI fills a small thimble... this question, ( which
> perhaps it more appropriately sent to the Apache listserver/forum, but since
> I want to do it from within MC....)
> 
> I have a little mc cgi that "rotates" an image by randomly selecting one
> from a set of 15 and reading a gif as binary and writing out the file again
> under a standard name which is the tag in the HTML that is served. (see
> script below). I can trigger the CGI "from home" from within MC using "get
> url..." and it works fine. I can also put
> 
> www.gurudeva.org/cgi-bin/rotate_taka_art.cgi
> 
> into my browser  and it works fine.  But, if I comment out the part  that
> serves the image to the browser...(the last three lines of this script) I
> will get an apache error... obviously on a GET Apache "demands' that
> something be sent to standardOut. What I want to do is eliminate the last
> three lines and still be able to trigger the CGI remotely.
> 
> Another way to state the problem is: from with MC/REV how to tell a CGI to
> execute where that CGI doesn't return anything.. it simply performs an
> operation on site.
> 
> OK, some context in case there is an entire better strategy: the goal is to
> include a statement in the html form of a index.shtml that is served that
> would trigger the CGI
> <!--#exec cgi="/cgi-bin/rotate_taka_art.cgi"-->  But, this doesn't work... I
> get binary code for the GIF in the place where this is entered, not a .GIF
> image... So, I want to "lop off" the last three lines so that when the page
> is hit, put the statement at the top of the page and have a normal img src
> tag, which goes for the same image, but the CGI will have swapped it for a
> new one each time, i.e. the art is "rotated and the next person who uses the
> page gets a different image... but, if I lop of the last three lines, apache
> doesn't like this either.  I actually solved the problem with a work around
> by sending nothing out the pipe... but there are other situations where I
> don't want to be forced to send anything to standardOut...

One thing to do is to have index.html replaced with a script which would
do 2 things: do whatever you want with the image and load and pass to
the server the *real* index.html page.
Also you may be able to do this using the redirect Apache function to
trigger the script but I don't know details on that.

> 
> ########## rotate_taka_art.cgi ##########
> on startup
>    set the directory to "../images"
>    put random(15) into AumNo
>    put "taka_aum_" &AumNo&".gif" into nextAum
>    put URL ("binfile:aums/"&nextAum) into temp_image
>    put temp_image into URL ("binfile:taka_header_art.gif")
>    put "Content-Type: image/gif" & cr
>    put "Content-Length:" && the length of temp_image & cr & cr
>    put temp_image
> end startUp
> 
> Wants to become:
> 
> on startup
>    set the directory to "../images"
>    put random(15) into AumNo
>    put "taka_aum_" &AumNo&".gif" into nextAum
>    put URL ("binfile:aums/"&nextAum) into temp_image
>    put temp_image into URL ("binfile:taka_header_art.gif")
> end startUp
> 
> this work around works also, where send nothing to standard out except a
> header and then you can include the exec statement at the top of the HTML
> page... but this is very "hokey"
> :
> #!/export/vhost/org/g/gurudeva/www/public_html/cgi-bin/mc
> on startup
>    set the directory to "../images"
>    put random(15) into AumNo
>    put "taka_aum_" &AumNo&".gif" into nextAum
>    put URL ("binfile:aums/"&nextAum) into temp_image
>    put temp_image into URL ("binfile:taka_header_art.gif")
>  put empty into dummyOut
>   put "Content-Type: image/gif" & cr
>    put "Content-Length:" && the length of dummyOut & cr & cr
>    put dummyOut
> end startUp
> 
> Hinduism Today
> 
> Sivakatirswami
> Editor's Assistant/Production Manager
> katir at hindu.org
> www.HinduismToday.com, www.HimalayanAcademy.com,
> www.Gurudeva.org, www.hindu.org
> 
> Read The Master Course Lesson of the Day at
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> 
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____________________
Regards, Andu Novac