01 January 2012

Writing Files to Fluidinfo with Fish 4.21

I pushed a new version of Fish to Github. It includes experimental new functionality to allow files to be written to Fluidinfo using Fish’s tag command.

This functionality is invoked by the -f flag; when this is used, parameter values are taken to be file names. For example, suppose the Fluidinfo user njr has a file in the /tmp directory called spinner.gif and wants to upload this as the tag njr/image/red-spinner.gif on the object whose about tag is abouttag. Assume that we are on a Unix-like system and that the current working directory is /tmp. Then any of the following will work:

$ fish tag -f abouttag image/red-spinner.gif=spinner.gif
$ fish tag -f abouttag image/red-spinner.gif=./spinner.gif
$ fish tag -f abouttag image/red-spinner.gif=/tmp/spinner.gif
$ fish tag -f -M image/gif abouttag image/red-spinner.gif=/tmp/spinner.gif

This red-spinner.gif file has actually been written to this location, using a command similar to those above, and can be viewed at:


Notice that the correct MIME type is served, so the browser can show the image.

Points to note:

  • The -f flag indicates that all tag values in the command are filenames, i.e. you can’t mix file-based values and literals in a single command.
  • The filename has to be included even if it is indentical to the tag name (though this may change at a later date) and there is no recursive option for writing directories as tag bundles at the moment.
  • By default, MIME types for certain common files are inferred from the file extensions as detailed below.
  • If you want to specify the MIME type explicitly, use the -M flag to do this. This will apply to all tags set in the command.
  • Text files are assumed to be encoded as UTF-8.
  • On unix-like systems, tildes will be expanded, so ~ and ~njr etc. may be used.

The file extensions for which MIME types are inferred fall into two groups. First are the textual MIME types (not necessarily types that begin text/, but ones whose contents are textual). These are:

    'txt': None,
    'csv': 'text/plain',
    'html': 'text/html',
    'xml': 'text/xml',
    'htm': 'text/html',
    'css': 'text/css',
    'js': 'text/javascript',
    'vcf': 'text/vcard',
    'plain': 'text/plain',
    'vsg': 'image/svg+xml',
    'ps': 'application/postscript',
    'eps': 'application/postscript',
    'rss': 'application/rss+xml',
    'atom': 'application/atom+xml',
    'xhtml': 'application/xhtml+xml',

Files with these extensions are read as non-binary (open("foo.text")) and interpreted as ‘UTF-8’.

Notice that .txt files are not given a MIME type, meaning that they are written as primitive (unicode) strings to Fluidinfo.

The extensions for which non-textual types are inferred are listed below. These files are read as binary files (open("foo.text", 'rb'))

    'png': 'image/png',
    'jpeg': 'image/jpeg',
    'jpg': 'image/jpg',
    'gif': 'image/gif',
    'tif': 'image/tiff',
    'tiff': 'image/tiff',
    'ico': 'image/vnd.microsoft.icon',
    'pdf': 'application/pdf',
    'zip': 'application/zip',
    'gz': 'application/x-gzip',
    'json': 'application/json',
    'mp3': 'audio/mpeg',
    'mp4': 'audio/mp4',
    'ogg': 'audio/ogg',
    'wav': 'audio/vnd.wave',
    'tar': 'application/x-tar',
    'rar': 'application/x-rar-compressed',

Use the -M flag to set the MIME type where this mapping is not correct or where the MIME type is not listed above.

This feature is experimental and may change in various ways as experience with it is gained.

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