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Re: CGI Question

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  Re: CGI Question "E.D.G." <edgrsprj@ix.netcom.com> - 2012-12-31 06:47 -0600
    Re: CGI Question sfeam <sfeam@users.sourceforge.net> - 2012-12-31 12:38 -0800
      Re: CGI Question "E.D.G." <edgrsprj@ix.netcom.com> - 2013-01-01 09:16 -0600
      Re: CGI Question "E.D.G." <edgrsprj@ix.netcom.com> - 2013-01-01 23:21 -0600

#1562 — Re: CGI Question

"E.D.G." <edgrsprj@ix.netcom.com> wrote in message 
news:zN6dneyLzP8dvULNnZ2dnUVZ_radnZ2d@earthlink.com...

Posted by E.D.G. on December 31, 2012

       This post is a continuation of a CGI programming discussion that I 
started on the Perl Newsgroup a few days ago.

       - The first part of this post has to do with Internet Server CGI 
programs that can create picture files such as PNG files.

       - The second part of this post is a somewhat philosophical computer 
programming discussion that is intended for the people who are developing 
the Perl and Gnuplot languages.

       At the moment I am using ActiveState Perl (both older and newer 
versions), an older version of Gnuplot, and Xampp on my Windows XP and Vista 
PCs.  And I can create and run Perl language CGI programs on my Internet 
Server.

        On my PC, Perl sends Gnuplot plot information through files, and 
command information through Windows pipes.  Those pipes don't appear to be 
very good for sharing large blocks of plotting data.  Things tend to get 
lost.  But they are great for sending relatively small numbers of commands 
to Gnuplot.

CGI PICTURE FILE QUESTIONS

       After preparing for this for quite a few years I am now finally 
starting to create Perl programs for use as CGI programs that will run at my 
Web sites.  The first one that should be running within a few days will be a 
relatively simple variation of Matt Wright's Perl language WWWBoard program. 
It was selected largely because I was able to get it to run with the Xampp 
computer program that makes it possible for a Windows PC to look like an 
Internet Server and respond when an html file SUBMIT button is pressed for 
example.

Question:  What graphics program will work with Perl on an Internet Server 
computer and allow Perl to draw picture files such as charts with a PNG 
extension and store them at the site?

       If Gnuplot will run on an Internet Server and work with Perl then 
that might take care of the matter.  However, after visiting some Web sites 
and doing some reading on the subject I was not able to determine if this is 
actually possible.

Question:  If Gnuplot can be used for Internet Server applications, then can 
anyone point to a Web site where a discussion of that subject can be found 
that would be understandable to an intermediate level programmer?

Question:  If Gnuplot is not recommended for use with Perl for Internet 
Server CGI file work, then what graphics program should be used?

       The following is an indirect URL for the type of picture file work 
that is planned.  And I am not sending people to that Freewebs site to get 
points.  Indirect addresses like that are being used in part in the hopes of 
keeping as much spam mail etc. as possible away from E-mail addresses listed 
on my actual science research Web sites.

http://www.freewebs.com/eq-forecasting/Demo-Program.html


PHILOSOPHICAL PROGRAMMING DISCUSSION FOR PERL AND GNUPLOT DEVELOPERS

      This first part of the following discussion is intended to be 
humorous, not some type of scientific fact.  It has been my experience that 
if that humor statement is not added, some people who might be speaking 
English as a second or third language could get confused.

       When the Great Rain finally ended and his Arc neared land, Noah 
assembled all of the Arc animals on the top deck and said to them,

"Evolve or Perish!"

       Unfortunately, the dinosaurs had been out partying the night before. 
They missed the lecture.  And now they can be found only in Natural History 
museums and paleontological digs.

       Some time ago ago I asked the ActiveState people if they would be 
interested in developing a version of Gnuplot that could be used as a 
downloadable module for Perl and enable Perl programs to use the 
sophisticated Gnuplot chart drawing resources.

       If I remember correctly, they stated that they would rather focus on 
developing chart creation resources for their downloadable version of 
Python.

       What I have recommended in my posts in the past is that some 
combination of Perl and Gnuplot language development personnel create a 
module version of Gnuplot that can be downloaded and used with Perl.  It is 
my understanding that they are both written using one of the C languages. 
So such a module development effort shouldn't be too difficult.  And Gnuplot 
commands in the Perl programs could begin with "gnu" as in "gnuprint" to 
keep them from conflicting with similar Perl commands.

       There are modules that make it possible for Perl programs to interact 
with Gnuplot.  But from what I have seen, data still need to be sent to 
Gnuplot through files or some type of "pipe."  And I am not sure if this 
would work on an Internet Server computer.

       Some of the advantages of having a Perl module version of Gnuplot 
might be the following:

       - This could greatly enhance Perl's chart drawing capabilities.

       - It could greatly enhance Gnuplot's array manipulation and perhaps 
its string manipulation capabilities.

       - Both Perl and Gnuplot would become more attractive to prospective 
users because of their increased power.  And they would both become less 
likely to eventually join the dinosaurs in some museum.

Happy Holiday Season to all,

E.D.G.

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#1564

E.D.G. wrote:

> "E.D.G." <edgrsprj@ix.netcom.com> wrote in message
> news:zN6dneyLzP8dvULNnZ2dnUVZ_radnZ2d@earthlink.com...
> 
> Posted by E.D.G. on December 31, 2012
> 
>        This post is a continuation of a CGI programming discussion that I
> started on the Perl Newsgroup a few days ago.
> 
>        - The first part of this post has to do with Internet Server CGI
> programs that can create picture files such as PNG files.

I have been using cgi + gnuplot to produce analysis pages with embedded PNG
images for many years.  Perl works fine, though I've also used other 
languages for the same purpose.  I'm actually moving away from PNG, however,
since newer gnuplot versions allow you to embed mouseable plots using SVG
or the HTML5 canvas element.

You are welcome to have a look at one of my perl+gnuplot driven servers at
  http://www.bmsc.washington.edu/parvati/
It's a very field-specific application that I won't even try to explain here.
But it does show that you can create and display plots generated by uploading
data from a large file or via a pointer to data in an external public data base.
Hit the "Sample Output" icon, or use the accession code 3CHB to pull the input
data directly from the Protein Data Bank. The pre-cooked output uses PNG;
if you re-calculate you will get a mixture of SVG and PNG.

[snip]
> There are modules that make it possible for Perl programs to interact
> with Gnuplot.  But from what I have seen, data still need to be sent to
> Gnuplot through files or some type of "pipe."  And I am not sure if this
> would work on an Internet Server computer.

Of course it works.  Why wouldn't it?

As to using a tailored Perl module to interface to gnuplot, IMHO this is 
a worse option than just talking to gnuplot directly.  If you rely on 
someone else's Perl module then you are limiting yourself to the subset,
possible a small subset, of gnuplot capabilities that are supported by that
module.  I can pretty much guarantee that no such perl module will keep up
with all of the possible gnuplot options.  In contrast, it is trivially easy
to open a pipe from perl to gnuplot and send any gnuplot command you like.

On the other hand, you need to take care in sandboxing the script + data + 
support programs so that malicious or careless input to the web server does 
not corrupt anything beyond the requested plot output.  
That's a non-trivial requirement, and gnuplot may not be your
best choice from this perspective.  A tailored Perl module sitting in 
between might or might not ameliorate this concern.

	happy gnuplotting (and also Happy New Year)

		Ethan


> 
>        - The second part of this post is a somewhat philosophical computer
> programming discussion that is intended for the people who are developing
> the Perl and Gnuplot languages.
> 
>        At the moment I am using ActiveState Perl (both older and newer
> versions), an older version of Gnuplot, and Xampp on my Windows XP and
> Vista
> PCs.  And I can create and run Perl language CGI programs on my Internet
> Server.
> 
>         On my PC, Perl sends Gnuplot plot information through files, and
> command information through Windows pipes.  Those pipes don't appear to be
> very good for sharing large blocks of plotting data.  Things tend to get
> lost.  But they are great for sending relatively small numbers of commands
> to Gnuplot.
> 
> CGI PICTURE FILE QUESTIONS
> 
>        After preparing for this for quite a few years I am now finally
> starting to create Perl programs for use as CGI programs that will run at
> my
> Web sites.  The first one that should be running within a few days will be
> a relatively simple variation of Matt Wright's Perl language WWWBoard
> program. It was selected largely because I was able to get it to run with
> the Xampp computer program that makes it possible for a Windows PC to look
> like an Internet Server and respond when an html file SUBMIT button is
> pressed for example.
> 
> Question:  What graphics program will work with Perl on an Internet Server
> computer and allow Perl to draw picture files such as charts with a PNG
> extension and store them at the site?
> 
>        If Gnuplot will run on an Internet Server and work with Perl then
> that might take care of the matter.  However, after visiting some Web
> sites and doing some reading on the subject I was not able to determine if
> this is actually possible.
> 
> Question:  If Gnuplot can be used for Internet Server applications, then
> can anyone point to a Web site where a discussion of that subject can be
> found that would be understandable to an intermediate level programmer?
> 
> Question:  If Gnuplot is not recommended for use with Perl for Internet
> Server CGI file work, then what graphics program should be used?
> 
>        The following is an indirect URL for the type of picture file work
> that is planned.  And I am not sending people to that Freewebs site to get
> points.  Indirect addresses like that are being used in part in the hopes
> of keeping as much spam mail etc. as possible away from E-mail addresses
> listed on my actual science research Web sites.
> 
> http://www.freewebs.com/eq-forecasting/Demo-Program.html
> 
> 
> PHILOSOPHICAL PROGRAMMING DISCUSSION FOR PERL AND GNUPLOT DEVELOPERS
> 
>       This first part of the following discussion is intended to be
> humorous, not some type of scientific fact.  It has been my experience
> that if that humor statement is not added, some people who might be
> speaking English as a second or third language could get confused.
> 
>        When the Great Rain finally ended and his Arc neared land, Noah
> assembled all of the Arc animals on the top deck and said to them,
> 
> "Evolve or Perish!"
> 
>        Unfortunately, the dinosaurs had been out partying the night
>        before.
> They missed the lecture.  And now they can be found only in Natural
> History museums and paleontological digs.
> 
>        Some time ago ago I asked the ActiveState people if they would be
> interested in developing a version of Gnuplot that could be used as a
> downloadable module for Perl and enable Perl programs to use the
> sophisticated Gnuplot chart drawing resources.
> 
>        If I remember correctly, they stated that they would rather focus
>        on
> developing chart creation resources for their downloadable version of
> Python.
> 
>        What I have recommended in my posts in the past is that some
> combination of Perl and Gnuplot language development personnel create a
> module version of Gnuplot that can be downloaded and used with Perl.  It
> is my understanding that they are both written using one of the C
> languages.
> So such a module development effort shouldn't be too difficult.  And
> Gnuplot commands in the Perl programs could begin with "gnu" as in
> "gnuprint" to keep them from conflicting with similar Perl commands.
> 
>        There are modules that make it possible for Perl programs to
>        interact
> with Gnuplot.  But from what I have seen, data still need to be sent to
> Gnuplot through files or some type of "pipe."  And I am not sure if this
> would work on an Internet Server computer.
> 
>        Some of the advantages of having a Perl module version of Gnuplot
> might be the following:
> 
>        - This could greatly enhance Perl's chart drawing capabilities.
> 
>        - It could greatly enhance Gnuplot's array manipulation and perhaps
> its string manipulation capabilities.
> 
>        - Both Perl and Gnuplot would become more attractive to prospective
> users because of their increased power.  And they would both become less
> likely to eventually join the dinosaurs in some museum.
> 
> Happy Holiday Season to all,
> 
> E.D.G.

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#1566

"sfeam" <sfeam@users.sourceforge.net> wrote in message 
news:kbst4d$7kl$1@dont-email.me...

Posted by E.D.G. January 1, 2013

Thanks for the comments.  There is enough information there that it is going 
to take a while for me to review and understand it.

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#1569

"sfeam" <sfeam@users.sourceforge.net> wrote in message 
news:kbst4d$7kl$1@dont-email.me...

Posted by E.D.G.  January 1, 2013

Thanks again for the information.

       For the next few days most of my CGI work will involve getting a 
simple Perl bulletin board program organized and running on my Internet 
Server.  It is already running on my PC using Xampp.  Then I might start 
trying to see if I can get gnuplot to run with my Perl programs on the 
server.

       I looked at the Internet application you mentioned and have some very 
basic questions.  They are this basic because I have really only worked with 
Windows PCs, and one UNIX based system years ago am not yet familiar with 
what the Internet Server computers can and cannot do.

       Any answers for the following questions would be helpful.

       If this information is important then I can determine for certain if 
it is accurate.  But without checking on it I am guessing that my Internet 
Server is running what is called an Apache Server.  And the Operating System 
is some version of UNIX.

       The older version of gnuplot that I have been using on my Windows XP 
and Vista PCs is 4.4.  The only gnuplot programs actually being used are 
wgnuplot.exe and pgnuplot.exe.  They work fine for my applications.  And 
being so compact they fit nicely into my specialized computer program zip 
files that are being made available to other researchers around the world.

QUESTIONS:  If I want to use gnuplot with my Perl programs on the Internet 
Server, exactly how is that done?

---  Do I have to store a copy of some gnuplot.exe program on the Internet 
Server in the cgi-bin directory or somewhere else?
            Or would the Internet Server already have gnuplot running on it 
somewhere?

---  How to we get the Internet Server to run gnuplot if a command.gnu file 
is told to run?
          Would the Internet Server already recognize that extension?
          Or does there need to be a special gnuplot location line at the 
start of the command.gnu file as with Perl programs?

---  Are Perl to gnuplot pipes opened on an Internet Server using the same 
type of commands that are used with a Windows PC?

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