Re: SISCweb & File Upload

That's exactly what I did :)
I wrote my own (get-upload-bindings), and I found the util/misc module
which has been very useful!

I just got it to work about a couple of minutes ago.

Some of the problems I had to solve:

1. If the request is not in multipart format then the
ServletFileUpload.parseRequest() throws an exception. So my
(get-upload-bindings) first checks if the request is in multipart
format, and if it isn't then it delegates the work to the standard
(get-bindings). I need this because I have a "Cancel" link on my form
which won't send the request data in multipart format.

2. I have some fields where the name is not in 7 bit ascii (it is a
content management system where the users can define the fields that
need to be entered for each kind of entity, and they assign the names
they want to each field they create), and the file upload library does
not handle those names correctly. To work around this, I wrote some
code to create an "external" name which only uses 7 bit ascii
characters for each field name.

3. The file upload library seems unable to handle multiple checkboxes
with the same name, it just returns the value of the last checked
checkbox. So it is impossible to have (get-upload-bindings) return a
list of values. It turns out I never need to have both file uploads
and multiple checkboxes with identical names in the same web page for
my application. So I did not have to solve this problem :)

On Mon, Jul 21, 2008 at 11:52 PM, Alessandro Colomba <[email protected]> wrote:
> Gerardo,
>
> You're right, I had forgotten that in J2EE the
> HttpServletRequest.getParameter*() methods don't handle multipart
> requests.
>
> The FileUtil library however allows you to read that information with
> the readHeaders() call. It's a bit clunky, with Iterators and the
> such, but consider that:
>
> 1) The (get-bindings) procedure returns a plain Java Map as per [1].
> This is not ever going to change.
>
> 2) You can implement your (get-bindings/multipart) procedure either as
> a wrapper around some Java code that extracts a parameter Map from the
> FileUpload MultiPartstream, or directly, and somewhat naturally, using
> the (iterator/for-each) procedures in the util/misc module. [2]
>
> Sorry this couldn't be any simpler.
> ___
> Alessandro
>
> [1] http://java.sun.com/j2ee/1.4/docs/api/javax/servlet/ServletRequest.html#getParameterMap()
>
> [2] http://siscweb.cvs.sourceforge.net/siscweb/siscweb/scm/util/misc.scm?revision=1.4&view=markup&pathrev=rel-0-6-dev
>
>
>
>
>
> On Mon, Jul 21, 2008 at 3:27 AM, Gerardo Horvilleur <[email protected]> wrote:
>> I've been doing a few tests and I have a problem. In order to be able
>> to upload files y must declare the form's enctype to be
>> multipart/form-data:
>>
>> (form (@ (action ,k-url) (enctype multipart/form-data)) ...
>>
>> But, once I do this, get-bindings isn't able anymore to extract the
>> bindings from the request object. It just returns an empty map.
>>
>> On Sun, Jul 20, 2008 at 11:16 PM, Alessandro Colomba <[email protected]> wrote:
>>> Gerardo,
>>>
>>> The request object returned by the some of the send-*/* procedures is
>>> the actual HttpServletResponset object. You can most certainly place
>>> more than one call to it.
>>>
>>> The response object is also always available through the
>>> (current-response) procedure in the siscweb/response module. [*] So
>>> your file upload module does not technically need to be passed the
>>> response object, and you can keep the (get-bindings) call n place.
>>>
>>> Hope this helps,
>>> ___
>>> Alessandro
>>>
>>> [*] http://siscweb.sourceforge.net/swm/ch08.html#response
>>>
>>>
>>>
>>> On Sun, Jul 20, 2008 at 1:38 AM, Gerardo Horvilleur <[email protected]> wrote:
>>>> The Apache Commons File Upload library is what I have used in other
>>>> projects written in Java.
>>>>
>>>> So, it looks like I''ll have to do something like
>>>>
>>>> (let ((request (send-thml/suspend ...
>>>>
>>>> instead of doing
>>>>
>>>> (let ((bindings (get-bindings (send-html/suspend ...
>>>>
>>>> so I can give the request to the file upload library to extract the data.
>>>>
>>>> What I don't know is if, after I've used the request object with the
>>>> file upload library, I still can do a a
>>>>
>>>> (let ((bindings (get-bindings request))) ...
>>>>
>>>> To extract the values for the parameters which are not file uploads.
>>>>
>>>> All the pages in which I need to support file uploads also have many
>>>> other fields, and I would like to still be able to use get-bindings to
>>>> handle them.
>>>>
>>>> On Sat, Jul 19, 2008 at 8:31 PM, Alessandro Colomba <[email protected]> wrote:
>>>>> Gerardo,
>>>>>
>>>>> Unfortunately file uploads in J2EE are best handled through
>>>>> third-party libraries, and I really did not want to tie SISCweb to
>>>>> one. Apache Commons has a pretty good library (FileUpload), and I
>>>>> wouldn't imagine difficult to write a Scheme wrapper around it.
>>>>>
>>>>> Should you decide to go this route, and encounter any obstacles in
>>>>> SISCweb, please let me know. I'll be glad to clear them out.
>>>>>
>>>>> Regards,
>>>>> ___
>>>>> Alessandro
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Sat, Jul 19, 2008 at 6:14 PM, Gerardo Horvilleur <[email protected]> wrote:
>>>>>> For the application I'm writing, I need to let the user upload images
>>>>>> to the server. I haven't found any straightforward way to handle file
>>>>>> uploads in SISCweb. Has anybody already written some code to handle
>>>>>> this?
>>>>>>
>>>>>> --
>>>>>> Gerardo Horvilleur
>>>>>> [email protected]
>>>>>> 5813-0830
>>>>>>
>>>>>> -------------------------------------------------------------------------
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>>>>>> _______________________________________________
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>>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Gerardo Horvilleur
>>>> [email protected]
>>>> 5813-0830
>>>>
>>>
>>
>>
>>
>> --
>> Gerardo Horvilleur
>> [email protected]
>> 5813-0830
>>
>



-- 
Gerardo Horvilleur
[email protected]
5813-0830

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