Re: Html/jpg from db to client?

[john-paul delaney]

Are there any examples of these techniques available?
thanks
/j-p.


On Mon, 22 Apr 2002, Jeffrey Bonevich wrote:

> Nope.  Only need two at most.  Each of them sets their own content type 
> (image streamer sets it to "image/jpg", HTML producer to "text/html"). 
> And in answer to your other question, yes, this could be reduced to just 
> one servlet that does conditional setting of content-type and content. 
> But you will then need a querystring (or other) key/value pair to do the 
> conditional on.  Suppose your HTML page url is /servlets/showimage/1. 
> Suppose the "1" in the subpath is the id for the image.  Then you need 
> to have a switch in the URL to tell it whether you are getting html or 
> image: /servlets/showimage/1?show=1
> 
> SO now your HTML page is accessed with the URL /servlets/showimage/1 and 
> inside that page is embedded an  height=" + image height + " width=" + image width + " ...>.
> 
> Then in your showimage servlet, you grab the "show" request parameter 
> and, if it is present/equals 1, then set content type to image and 
> stream the image, otherwise set content type to html and output HTML (or 
> forward to JSP - just be sure to stick the image info somewhere in a 
> context so you can access it in the JSP page).
> 
> Make sense?
> 
> jeff
> 
> john-paul delaney wrote:
> 
> > On Mon, 22 Apr 2002, Nikola Milutinovic wrote:
> > 
> > Thanks Nix... then I'm thinking I need three servlets to handle for each page sent 
>to the client... 1. Write the html header, 2. Get image from db and send the image, 
>3.Add in dimensions to  & add the footer.  
> > 
> > Is this correct?
> > 
> > regards
> > /j-p.
> >  
> > 
> >>If you wish to send BOTH html and the image in the same invocation of the servlet, 
>then you're mistaken. HTTP/HTML, in general, doesn't work that way. You should make a 
>servlet which can retrieve a single picture, something like:
> >>
> >>/servlets/showImage?src=my_test_pic.gif
> >>
> >>Then make your servlet accept "src" parameter, retrive the image from the 
>database. Based on the extension you should set the correct MIME type, in this case 
>"image/gif" and send it. You should set Response->contentType to your MIME type and 
>open a servlet output stream in the Response and just splash your image into it.
> >>
> > 
> > 
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RE: Html/jpg from db to client?

[Ozgur Sahoglu]

how do you store your image files in your DB? as BLOB objects or as
references to image files at some location?

Ozgur.

> -Original Message-
> From: john-paul delaney [mailto:[EMAIL PROTECTED]]
> Sent: Monday, April 22, 2002 3:15 AM
> To: Tomcat Users List
> Subject: Re: Html/jpg from db to client?
>
>
> On Mon, 22 Apr 2002, Nikola Milutinovic wrote:
>
> Thanks Nix... then I'm thinking I need three servlets to handle
> for each page sent to the client... 1. Write the html header, 2.
> Get image from db and send the image, 3.Add in dimensions to  tag> & add the footer.
>
> Is this correct?
>
> regards
> /j-p.
>
> > If you wish to send BOTH html and the image in the same
> invocation of the servlet, then you're mistaken. HTTP/HTML, in
> general, doesn't work that way. You should make a servlet which
> can retrieve a single picture, something like:
> >
> > /servlets/showImage?src=my_test_pic.gif
> >
> > Then make your servlet accept "src" parameter, retrive the
> image from the database. Based on the extension you should set
> the correct MIME type, in this case "image/gif" and send it. You
> should set Response->contentType to your MIME type and open a
> servlet output stream in the Response and just splash your image into it.
>
>
> ---
>  JUSTATEST Art Online
>   www.justatest.com
>
>
>
>
> --
> To unsubscribe:   <mailto:[EMAIL PROTECTED]>
> For additional commands: <mailto:[EMAIL PROTECTED]>
> Troubles with the list: <mailto:[EMAIL PROTECTED]>
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Re: Html/jpg from db to client?

[Jeffrey Bonevich]

Nope.  Only need two at most.  Each of them sets their own content type 
(image streamer sets it to "image/jpg", HTML producer to "text/html"). 
And in answer to your other question, yes, this could be reduced to just 
one servlet that does conditional setting of content-type and content. 
But you will then need a querystring (or other) key/value pair to do the 
conditional on.  Suppose your HTML page url is /servlets/showimage/1. 
Suppose the "1" in the subpath is the id for the image.  Then you need 
to have a switch in the URL to tell it whether you are getting html or 
image: /servlets/showimage/1?show=1

SO now your HTML page is accessed with the URL /servlets/showimage/1 and 
inside that page is embedded an .

Then in your showimage servlet, you grab the "show" request parameter 
and, if it is present/equals 1, then set content type to image and 
stream the image, otherwise set content type to html and output HTML (or 
forward to JSP - just be sure to stick the image info somewhere in a 
context so you can access it in the JSP page).

Make sense?

jeff

john-paul delaney wrote:

> On Mon, 22 Apr 2002, Nikola Milutinovic wrote:
> 
> Thanks Nix... then I'm thinking I need three servlets to handle for each page sent 
>to the client... 1. Write the html header, 2. Get image from db and send the image, 
>3.Add in dimensions to  & add the footer.  
> 
> Is this correct?
> 
> regards
> /j-p.
>  
> 
>>If you wish to send BOTH html and the image in the same invocation of the servlet, 
>then you're mistaken. HTTP/HTML, in general, doesn't work that way. You should make a 
>servlet which can retrieve a single picture, something like:
>>
>>/servlets/showImage?src=my_test_pic.gif
>>
>>Then make your servlet accept "src" parameter, retrive the image from the database. 
>Based on the extension you should set the correct MIME type, in this case "image/gif" 
>and send it. You should set Response->contentType to your MIME type and open a 
>servlet output stream in the Response and just splash your image into it.
>>
> 
> 
> ---
>  JUSTATEST Art Online
>   www.justatest.com
> 
> 
> 
> 
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Re: Html/jpg from db to client?

[john-paul delaney]

On Mon, 22 Apr 2002, Nikola Milutinovic wrote:

Thanks Nix... then I'm thinking I need three servlets to handle for each page sent to 
the client... 1. Write the html header, 2. Get image from db and send the image, 3.Add 
in dimensions to  & add the footer.  

Is this correct?

regards
/j-p.
 
> If you wish to send BOTH html and the image in the same invocation of the servlet, 
>then you're mistaken. HTTP/HTML, in general, doesn't work that way. You should make a 
>servlet which can retrieve a single picture, something like:
> 
> /servlets/showImage?src=my_test_pic.gif
> 
> Then make your servlet accept "src" parameter, retrive the image from the database. 
>Based on the extension you should set the correct MIME type, in this case "image/gif" 
>and send it. You should set Response->contentType to your MIME type and open a 
>servlet output stream in the Response and just splash your image into it.


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Re: Html/jpg from db to client?

[john-paul delaney]

On Sun, 21 Apr 2002, Jeffrey Bonevich wrote:

Thanks Jeff... I'll try this out - following your suggestion, I was thinking to put 
the dimensions of the image (jpg) in the database too and to retrieve it along with 
the image - the html will be a combination of includes and dynamic written by the 
servlet.
Don't know if this is really a relevant question - from a design point of view, is it 
better to use one servlet to handle all of this or multiple chained servlets?

regards
/j-p.



> http://mydomain.com/mywebapp/imagestreamservlet?imageID=xxx";>
> 
> The only sticking point is that you do not know the image dimensions 
> before grabbing the image (duh!), so if you need width/height info for 
> the image in the page, it may be worthwhile having the HTML page also 
> produced by a servlet that also looks up the image, but only retrieves 
> metadata about it and sticks it in the appropriate places.



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Re: Html/jpg from db to client?

[Nikola Milutinovic]

> Hello List...
> 
> Using a servlet, I retrieve an image from a database, but I want to send it in
> a formatted html page to the client... any suggestions on how to approach
> this (combining html and streaming images) appreciated.

If you wish to send BOTH html and the image in the same invocation of the servlet, 
then you're mistaken. HTTP/HTML, in general, doesn't work that way. You should make a 
servlet which can retrieve a single picture, something like:

/servlets/showImage?src=my_test_pic.gif

Then make your servlet accept "src" parameter, retrive the image from the database. 
Based on the extension you should set the correct MIME type, in this case "image/gif" 
and send it. You should set Response->contentType to your MIME type and open a servlet 
output stream in the Response and just splash your image into it.

Nix.

Re: Html/jpg from db to client?

[Jeffrey Bonevich]

Yes, make the image element's src attribute a call to a servlet that 
just streams out the image.  So for example, in your HTML page you have:

http://mydomain.com/mywebapp/imagestreamservlet?imageID=xxx";>

Then the 'imagestreamservlet' does the image lookup and streams it out 
to the response writer (i.e. response.setContentType("image/gif") or 
image/jpeg, or whatever, then grab response.getWriter() and start 
writing bytes from a reader on the image file to it).

The only sticking point is that you do not know the image dimensions 
before grabbing the image (duh!), so if you need width/height info for 
the image in the page, it may be worthwhile having the HTML page also 
produced by a servlet that also looks up the image, but only retrieves 
metadata about it and sticks it in the appropriate places.

jeff

john-paul delaney wrote:

> Hello List...
> 
> Using a servlet, I retrieve an image from a database, but I want to send it in a 
>formatted html page to the client... any suggestions on how to approach this 
>(combining html and streaming images) appreciated.
> 
> thanks
> /j-p.
> 
> 
> ---
>  JUSTATEST Art Online
>   www.justatest.com
> 
> 
> 
> 
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> For additional commands: 
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> 
> 
> 


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Jeffrey Bonevich
Ann Arbor, Michigan
[EMAIL PROTECTED]
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Html/jpg from db to client?

[john-paul delaney]

Hello List...

Using a servlet, I retrieve an image from a database, but I want to send it in a 
formatted html page to the client... any suggestions on how to approach this 
(combining html and streaming images) appreciated.

thanks
/j-p.


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