Hi all,
Whilst looking around the guile-user area, I noticed an old question I
posted with regards to returning an image in GNU Guile Web. Sadly, I did
not add closure to this query. As this question comes up on google search I
felt I should respond with a solution. I honestly thought I responded to
this. I can only apologies regarding this -- it is unprofessional.
Regardless, a late reply is better than no reply at all.
I ended up moving to GNU Artanis in the end. At the time, I was just happy
playing around with the Web Example section as presented in the Guile
Reference Manual. My code was becoming similar to Artanis in a number of
ways (atleast the get, post, etc, functions). Obviously, with GNU Artanis
being a much more thought-out framework, it made sense to move over. The
great news is that is was very easy to move my code over.
Below is an example code I use to return an image. You should just be able
to copy-paste the below code - as long as you have artanis installed and
ensured it is pointing to a jpg that exists, just open a browser and type -
localhost:1234/image
(use-modules (artanis artanis)
(rnrs io ports))
(init-server)
(get "/image"
(lambda (rc)
(let* ((port (open-file "s.jpg" "r"))
(bytes (get-bytevector-all port)))
(close-port port)
(response-emit bytes #:headers '((content-type image/jpg))))))
(run #:port 1234)
For my personal website, I pass in an id (ie "/image/{id}") which returns a
record from the database, containing the location of the file in
question... plus other things (tags, uploader, etc) -- once working I
stick it inside an image tag - job done!
Obviously my example does not cover error handling but you get the idea. :-)
I hope this helps
M
On Mon, May 26, 2014 at 5:00 PM, <[email protected]> wrote:
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> Today's Topics:
>
> 1. Learning Guile web. Stuck on returning an image. (Martyn Smith)
> 2. Re: Install Guile 2.0.11 failed on L-Ubuntu 12.04 (Germ?n Arias)
> 3. Re: Learning Guile web. Stuck on returning an image. (Nala Ginrut)
> 4. Re: Learning Guile web. Stuck on returning an image. (Neil Jerram)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 25 May 2014 23:30:33 +0100
> From: Martyn Smith <[email protected]>
> To: [email protected]
> Subject: Learning Guile web. Stuck on returning an image.
> Message-ID:
> <
> ca+dhi3sirax3bq737rk9nrzcqxkdnaoeklgn-giqbmnfzeg...@mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi guys,
>
> I am attempting to create a website as part of a learning experience with
> guile. The code is originally based from ideas in
> https://www.gnu.org/software/guile/manual/html_node/Web-Examples.html. My
> code has progressed since the "Web Examples" page to support a more MVC
> style. So far, so good-ish. :-)
>
> Getting to the point of the email -- I am a bit confused how I would return
> a jpg image. For example: -
> <img src="/load-image?id=1234" />
>
> The "1234" tells me which file to load and return.
>
> Being primarily a .NET developer, I am struggling to understand how to
> achieve such goal in guile. I have tried things like (read-file
> "/location/to/image.jpg" "r") but no luck. Also tried to understand
> converting to bytes in the documentation but again... no luck. Always
> getting a 500 error. Yes, I have included (content-type . (image/jpg)) etc.
>
> Can anyone give me a heads up on how to do such thing? How would I open the
> jpg file? How would it be returned?
>
> I don't think its worth providing any code here. I think the Web-Examples
> page is the best place to review code, and how I would return an image from
> that current codebase, etc.
>
> Thanks for any suggestions.
>
> mart
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>
> ------------------------------
>
> Message: 2
> Date: Sun, 25 May 2014 17:59:08 -0600
> From: Germ?n Arias <[email protected]>
> To: Chris Vine <[email protected]>
> Cc: [email protected]
> Subject: Re: Install Guile 2.0.11 failed on L-Ubuntu 12.04
> Message-ID: <069c51a1d2a956acc5f8f83512f3230c@german-desktop>
> Content-Type: text/plain; charset="iso-8859-1"
>
> On 2014-05-25 03:10:55 -0600 Chris Vine <[email protected]>
> wrote:
>
> [...]
> >
> > Yuck.
>
> This is exactly what one does not expect in a free software list, where is
> supposed the users can share and learn together without being offended.
>
> Germ?n.
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 26 May 2014 08:22:58 +0800
> From: Nala Ginrut <[email protected]>
> To: Martyn Smith <[email protected]>
> Cc: Guile User <[email protected]>
> Subject: Re: Learning Guile web. Stuck on returning an image.
> Message-ID:
> <
> capjozodm7m9sxkjreny3x_pynbkpka2aabmv+cupmqohno0...@mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Martyn!
>
> 2014?5?26? ??6:30? "Martyn Smith" <[email protected]>???
> >
> > Hi guys,
> >
> > I am attempting to create a website as part of a learning experience with
> guile. The code is originally based from ideas in
> https://www.gnu.org/software/guile/manual/html_node/Web-Examples.html. My
> code has progressed since the "Web Examples" page to support a more MVC
> style. So far, so good-ish. :-)
> >
>
> If you want to play web with Guile, I suggest Artanis, which is a web
> framework for it. It's easier than using the lower web api.
>
> www.web-artanis.com
>
> > Getting to the point of the email -- I am a bit confused how I would
> return a jpg image. For example: -
> > <img src="/load-image?id=1234" />
> >
> > The "1234" tells me which file to load and return.
> >
> > Being primarily a .NET developer, I am struggling to understand how to
> achieve such goal in guile. I have tried things like (read-file
> "/location/to/image.jpg" "r") but no luck. Also tried to understand
> converting to bytes in the documentation but again... no luck. Always
> getting a 500 error. Yes, I have included (content-type . (image/jpg)) etc.
> >
>
> Please attache you complete code. But I guess what you need is
> get-bytevector-all which dwells on (rnrs).
> Usually, open file only return a file port, you have to read the content
> then.
>
> > Can anyone give me a heads up on how to do such thing? How would I open
> the jpg file? How would it be returned?
> >
> > I don't think its worth providing any code here. I think the Web-Examples
> page is the best place to review code, and how I would return an image from
> that current codebase, etc.
> >
> > Thanks for any suggestions.
> >
> > mart
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> >
>
> ------------------------------
>
> Message: 4
> Date: Mon, 26 May 2014 10:05:17 +0100
> From: Neil Jerram <[email protected]>
> To: Martyn Smith <[email protected]>
> Cc: [email protected]
> Subject: Re: Learning Guile web. Stuck on returning an image.
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=us-ascii
>
> Martyn Smith <[email protected]> writes:
>
> > Getting to the point of the email -- I am a bit confused how I would
> return a
> > jpg image. For example: -
> > <img src="/load-image?id=1234" />
> >
> > The "1234" tells me which file to load and return.
> >
> > Being primarily a .NET developer, I am struggling to understand how to
> achieve
> > such goal in guile. I have tried things like (read-file "/location/to/
> > image.jpg" "r") but no luck. Also tried to understand converting to
> bytes in
> > the documentation but again... no luck. Always getting a 500 error. Yes,
> I have
> > included (content-type . (image/jpg)) etc.
> >
> > Can anyone give me a heads up on how to do such thing? How would I open
> the jpg
> > file? How would it be returned?
>
> I recently had the same problem, and eventually decided that it would be
> better to use Guile only for my dynamic content, with a standard web
> server for the static content. For the latter I chose lighttpd, and I
> can provide more details of my setup if that would be helpful.
>
> But what specifically was the problem? My handler for an image file
> (and other static content) looked like this:
>
> (lambda (request request-body uri)
> (let* ((fn (apply string-append
> static-root
> (map (lambda (name)
> (string-append "/" name))
> uri)))
> (content (with-input-from-file fn read-string))
> (content-type (cond ((string-match "\\.svg" fn)
> '(image/svg+xml))
> ((string-match "\\.html?" fn)
> '(text/html))
> ((string-match "\\.jpe?g" fn)
> '(image/jpeg))
> ((string-match "\\.png" fn)
> '(image/png))
> ((string-match "\\.css" fn)
> '(text/css))
> ((string-match "\\.js" fn)
> '(application/javascript))
> (else
> '(text/plain)))))
> (trc 'content-type content-type 'length (string-length content))
> (values `((content-type . ,content-type))
> content)))
>
> The problem here that 'content' contains binary data that can't be
> returned as is in an HTTP response. It needs to be encoded in one of
> the HTTP-supported encodings, and a corresponding Content-Encoding
> header added to the response.
>
> I think I investigated a little whether Guile's (web ...) modules could
> do this, or could easily be enhanced, but decided instead on the
> solution described above.
>
> Regards,
> Neil
>
>
>
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> End of guile-user Digest, Vol 138, Issue 9
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