gulp-etl-tap-mime

This plugin converts MIME (Email) files to gulp-etl Message Stream files; originally adapted from the gulp-etl-handlelines model plugin. It is a gulp-etl wrapper for mailparser.

This is a gulp-etl plugin, and as such it is a gulp plugin. gulp-etl plugins work with ndjson data streams/files which we call Message Streams and which are compliant with the Singer specification. In the gulp-etl ecosystem, taps tap into an outside format or system (in this case, a MIME file) and convert their contents/output to a Message Stream, and targets convert/output Message Streams to an outside format or system. In this way, these modules can be stacked to convert from one format or system to another, either directly or with tranformations or other parsing in between. Message Streams look like this:

{"type": "SCHEMA", "stream": "users", "key_properties": ["id"], "schema": {"required": ["id"], "type": "object", "properties": {"id": {"type": "integer"}}}}
{"type": "RECORD", "stream": "users", "record": {"id": 1, "name": "Chris"}}
{"type": "RECORD", "stream": "users", "record": {"id": 2, "name": "Mike"}}
{"type": "SCHEMA", "stream": "locations", "key_properties": ["id"], "schema": {"required": ["id"], "type": "object", "properties": {"id": {"type": "integer"}}}}
{"type": "RECORD", "stream": "locations", "record": {"id": 1, "name": "Philadelphia"}}
{"type": "STATE", "value": {"users": 2, "locations": 1}}

Usage

gulp-etl plugins accept a configObj as the first parameter; the configObj will contain any info the plugin needs. For this plugin the configObj is the "options" object (OPTIONAL) for mailparser

Sample gulpfile.js

/* parse all .MIME files in a folder into Message Stream files in a different folder */

let gulp = require('gulp')
var rename = require('gulp-rename')
var tapCsv = require('gulp-etl-tap-mime').tapMime

exports.default = function() {
    return gulp.src('data/*.eml')
    .pipe(tapMime({}))
    .pipe(rename({ extname: ".ndjson" })) // rename to *.ndjson
    .pipe(gulp.dest('output/'));
}

Quick Start for Coding on This Plugin

• Dependencies:
  • git
  • nodejs - At least v6.3 (6.9 for Windows) required for TypeScript debugging
  • npm (installs with Node)
  • typescript - installed as a development dependency
• Clone this repo and run npm install to install npm packages
• Debug: with VScode use Open Folder to open the project folder, then hit F5 to debug. This runs without compiling to javascript using ts-node
• Test: npm test or npm t
• Compile to javascript: npm run build

Testing

We are using Jest for our testing. Each of our tests are in the test folder.

• Run npm test to run the test suites

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