Need help

[Anjali Abraham <an...@aztec.soft.net>]

Hi All,
            I have a scenario wherein in my html, I have a code something
like this:
<input type="file" jwcid="upload1" name="upload1"/>
            
            I have a requirement of giving a filter to only .gif files can
be shown by default to the dialog box which get opened on click of "browse"
button of the type file. For that to do I need to modify my above html code
to something like this:
<input type="file" jwcid="upload1" name="upload1" accept="image/gif"/>
            But here there is a problem, as in my input tag I am using
jwcid, I ignores all the attributes particular to html's.
 
            That's the reason we need to enable javascripting for these
tags. How to do the same.......???????
 
            How can I achieve the same "accept" attribute functionality
through Tapestry4...????????
 
Please respond with reply,
Thanks in advance,
 
Regards,
Anjali
 

Re: Need help

[Andreas Andreou <an...@di.uoa.gr>]

Ok, here's the validator I mentioned before.
I'll ask if it can be included in directly into Tapestry.
For the moment, you have to add edit your hivemodule.xml, and add this 
contribution:

  <contribution configuration-id="tapestry.form.validator.Validators">
    <validator name="accept" class="ebyz.web.validator.Accept"/>
  </contribution>   

Then you have to add an unsupported-file-type entry in 
ValidationString.properties. Here's mine:
unsupported-file-type={0} only supports files of type {1}.

Then you can define your Upload component like this:

    <component id="file" type="Upload">
        <binding name="file" value="file"/>
        <binding name="validators" value="validators:accept=jpeg-jpg-png"/>
        <binding name="displayName" value="literal:Choose file"/>        
       
    </component>

And here is the java source. Note that it does both client side and 
server side validation...

package ebyz.web.validator;

import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.TapestryUtils;
import org.apache.tapestry.form.FormComponentContributorContext;
import org.apache.tapestry.form.IFormComponent;
import org.apache.tapestry.form.ValidationMessages;
import org.apache.tapestry.form.validator.BaseValidator;
import org.apache.tapestry.multipart.UploadPart;
import org.apache.tapestry.util.RegexpMatcher;
import org.apache.tapestry.valid.ValidationConstraint;
import org.apache.tapestry.valid.ValidatorException;

public class Accept extends BaseValidator
{
    private String accept;
   
    public Accept()
    {       
    }
   
    public Accept(String initializer)
    {
        super(initializer);
    }
   
    public void setAccept(String acc)
    {
        accept = acc;
    }

    public void validate(IFormComponent field, ValidationMessages messages,
            Object object) throws ValidatorException
    {
        UploadPart part = (UploadPart) object;
        String name = part.getFileName();
        String ext = name.toLowerCase();
        int pos = ext.lastIndexOf(".");
        if (pos >=0)
        {
            ext = ext.substring(pos+1);
        }
       
        if (accept.indexOf(ext) >= 0)
        {
            return;
        }       
        throw new ValidatorException(buildMessage(messages, field),
                ValidationConstraint.PATTERN_MISMATCH);       
    }
   
    private String buildMessage(ValidationMessages messages, 
IFormComponent field)
    {
        return messages.formatValidationMessage(
                getMessage(),
                "unsupported-file-type",
                new Object[]
                { field.getDisplayName(), accept });
    }   
   
    public void renderContribution(IMarkupWriter writer, IRequestCycle 
cycle,
            FormComponentContributorContext context, IFormComponent field)
    {
        
context.includeClasspathScript("/org/apache/tapestry/form/validator/RegExValidator.js");

        String toReg = accept.replace('-','|');
        toReg = ".*\\.(" + toReg + ")$";
        String pattern = new RegexpMatcher().getEscapedPatternString(toReg);
        String message = buildMessage(context, field);

        StringBuffer buffer = new StringBuffer("function(event) { 
Tapestry.validate_regex(event, '");
        buffer.append(field.getClientId());
        buffer.append("', '");
        buffer.append(pattern);
        buffer.append("', ");
        buffer.append(TapestryUtils.enquote(message));
        buffer.append("); }");

        context.addSubmitHandler(buffer.toString());
    }   

}


---------------------------------------------------------------------
To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tapestry-user-help@jakarta.apache.org

Re: Need help

[Andreas Andreou <an...@di.uoa.gr>]

The @Upload component allows informal parameters, but
are you sure that the accept attribute is valid html and recognized by
browsers.

In general, it's difficult to change the <input type="file"> control's 
appearance
and (clientside) behavior due to security reasons. Maybe it's better to 
create your
own Upload component and do the filtering server-side.

Also, take a look at:
http://www.irt.org/script/561.htm
http://www.irt.org/script/1154.htm

If the method in the first link works, you have to write some javascript
which will check the filename and which will get triggered on form submit.
A generic solution to implement this (in Tap4) would be to write an 
AcceptValidator
, contributing the correct javascript to the onSubmit handler of your 
form and bind
it to the @Upload component, i.e.

  <component id="file" type="Upload">
    <binding name="file" value="file"/>
    <binding name="displayName" value="message:filename"/>
    <binding name="validators" value="validators:accept=gif-jpeg-other"/>
  </component>

Since I'm interested in this, i'll also look into it and report my findings.

Anjali Abraham wrote:

>Hi All,
>            I have a scenario wherein in my html, I have a code something
>like this:
><input type="file" jwcid="upload1" name="upload1"/>
>            
>            I have a requirement of giving a filter to only .gif files can
>be shown by default to the dialog box which get opened on click of "browse"
>button of the type file. For that to do I need to modify my above html code
>to something like this:
><input type="file" jwcid="upload1" name="upload1" accept="image/gif"/>
>            But here there is a problem, as in my input tag I am using
>jwcid, I ignores all the attributes particular to html's.
> 
>            That's the reason we need to enable javascripting for these
>tags. How to do the same.......???????
> 
>            How can I achieve the same "accept" attribute functionality
>through Tapestry4...????????
> 
>Please respond with reply,
>Thanks in advance,
> 
>Regards,
>Anjali
> 
>
>  
>

---------------------------------------------------------------------
To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tapestry-user-help@jakarta.apache.org