Attachments as TML, available programmatically

If attachments could have an alternate rendering handler we might get a clean way of supporting FunkyNewActions on them. e.g. attached excel files could be pushed through CPAN:Spreadsheet::ParseExcel to produce a TXT, XML, HTML or TML rendering.

So this could allow someone to upload an excel file and for TWiki to get a TML representation of it.

This would be like a dynamic version of the BeforeAttachmentSaveHandler, dynamic in the sense that (1) the alternate representation is not stored and (2) extra renderers can retrospectively apply to attachments loaded in the past.

A process could suck a TML rendering from the attachment and push that TML representation through the TWiki::Data::DelimitedFile class. As well as allowing BulkRegistration to occur from a native excel tile this would facilitate conversion of spreadsheets of data into pages containing the data.

-- MartinCleaver - 13 Jul 2005

Good idea

-- CrawfordCurrie - 14 Jul 2005

Ok, what would the API look like? Is there an object on a particular attachment?

I'm thinking something like:

topic("web.topic")->attachment("tables.xls")->worksheet(1)->asTML()

-- MartinCleaver - 15 Jul 2005

Why can't you use the document MIME type, in the same way as the browser does? Register renderers for different MIME types? Have a mapping for standard document types based on extension? Allow that mapping to be overridden using a meta-data setting in %META:FILEATTACHMENT?

-- CrawfordCurrie - 15 Jul 2005

Hmm. I didn't think of that.

View::_suffixToMimeType seems to be the only MIME hook at the moment. Am I correct?

-- MartinCleaver - 15 Jul 2005

AFAIK yes

-- CrawfordCurrie - 15 Jul 2005

Ok, so we'd like plugins to register what pairs of conversions they are capable of providing. e.g. during plugin registration of ExcelToTmlPlugin:

registerConverter("application/x-excel", "TML", &ExcelToTmlPlugin::convertXexcel);
registerConverter("application/x-excel", "XML", &ExcelToTmlPlugin::convertXexcel);

ContentAccessSyntax could be extended for allow for attachment renderings too:

Web.Topic.Attachments{attachmentName}.AsHtml or similar.

The registration of handlers for rendering would be extremely simple and fairly quick to to implement. The MsOfficeAttachmentsAsHTMLPluginDev beta has a converters hash that illustrates the principle.

-- MartinCleaver - 18 Jul 2005