feedtr fetches feed sources (Atom, RSS or anything using XML), transforms them using XSLT and saves the outputs.

feedtr is implemented in Go as a library with a command line front end.

The source code for the command line interface can be found in cmd/feedtr/main.go.

After building, run with feedtr --config-file=config.json or feedtr < config.json.

The config file specifies a number of outputs to be produced. Each output is created by fetching a source and transforming it.

For example, fetching the GitHub public timeline and filtering it to only include fork events:

config.json:

{
  "outputs": [
    {
      "name": "github-fork-events.atom",
      "source": "https://github.com/timeline",
      "transforms": ["github-fork-events.xslt"]
    }
  ]
}

If using the --config-file option, the files referenced in "transforms" should be placed in a directory named transforms located in the same directory as the config file. If loading the config from standard input, the transforms directory should be in the current directory.

transforms/github-fork-events.xslt:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:atom="http://www.w3.org/2005/Atom">
  <!-- Copy everything unless explicitly handled below -->
  <xsl:template match="@*|*|processing-instruction()|comment()">
    <xsl:copy>
      <xsl:apply-templates select="*|@*|text()|processing-instruction()|comment()"/>
    </xsl:copy>
  </xsl:template>

  <!-- Adjust the title -->
  <xsl:template match="//atom:feed/atom:title">
    <atom:title>GitHub Public Timeline Fork Events Feed</atom:title>
  </xsl:template>

  <!-- Exclude any <entry>s that don't relate to ForkEvents -->
  <xsl:template match="atom:entry[not(contains(atom:id, ':ForkEvent/'))]"/>
</xsl:stylesheet>

When feedtr runs, it will create a cache directory to store feeds that have been fetched and a outputs directory to store the transformed outputs.

In the above example, a file named github-fork-events.atom will be created in the outputs directory. This will contain the result of running the XSLT transform.

Transforms will only be run if the source has changed (based on the date returned over HTTP) since the last output file was written. If the configuration or transforms are changed, the relevant outputs should be manually deleted.

Please refer to the code documentation along with the cmd/feedtr/main.go source code for example usage.