Pipeprint

This is a proof-of-concept repo for now, so there is not much documentation just yet. It's a spin-off project from Enveloper. To see how's it's useful, and why it exists, see here. To be updated when on new changes and docs, follow along on twitter.**

Pipeprint has two modes of operation, as an HTTP server, and as a command line tool. Both of these rely on docker to simplify setup, running and updating.

Let's create a few templates to get started. For this simple example, we'll create a PDF using a template built with Twig. The HTML will be generated from Markdown.

Here is invoice.pdf.md.twig:

# Sales invoice. Order no {{ order.number }}

| Item | Price | Qty | Total |
| ---- | ----- | --- | ----- | 
{% for item in order.items %}
    | {{ item.title }} | {{ item.price }} | {{ item.qty }} | {{ item.total }} |
{% endfor %}

Using the CLI

This is in the design stage right now. The CLI does not yet exist! See this issue for progress or to submit ideas.

Using the HTTP server

Start the HTTP server:

docker run \
    -e PIPEPRINT_ENGINE_CONFIG='{"markdown": "http://markdown", "mjml": "http://pdf"}' \
    outstack/pipeprint

The URLs in the PIPEPRINT_ENGINE_CONFIG are the URLs of the template engines we will request next. They must be available to the docker container at these addresses.

The HTTP server has a single endpoint, /render/pipeline. You POST to it with a JSON-encoded array like this:

{
    'files': {
        'invoice.pdf.md.twig': '.. file contents'.
    ],
    'pipeline': [
        {'engine': 'twig', 'template': 'invoice.pdf.md.twig' },
        {'engine': 'markdown' },
        {'engine': 'pdf'},
    ],
    'parameters': {
        "order": {
            "number": "14", 
            "items": [
                {"title": "widget",   "price": "£5.00", "qty": 4, "total": "£20.00"}
                {"title": "widget 2", "price": "£9.20", "qty": 2, "total": "£18.40"}
            ]
        }
}

Building a pipeprint compatible engine

For each stage in the pipeline, the engine (whose endpoint is retrieved from PIPEPRINT_ENGINE_CONFIG) will be called with files and parameters as above.

Additionally, it will receive a template parameter indicating which of the files is the template to be rendered. In the case that this is the first pipeline stage, this would be e.g. invoice.pdf.twig. In any following stages, it would be _previous - a special file added to the list of files passed.

See the MJML engine for a JS example, or the Twig engine for a PHP example.