@machinateur/the-printer
v1.0.0
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The printer, a prototype. Create PDF documents and images from HTML content using puppeteer and headless-chrome.
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machinateur/the-printer
The printer, a prototype. Create PDF documents and images from HTML content using puppeteer and headless-chrome.
This repository contains the express app (node) and a PHP client implementation with stream support.
The PHP SDK has zero package dependencies, to keep it as simple as possible.
Requirements
- At least PHP
>=8.1
is required- Extensions
ext-json
andext-curl
are reqired
- Extensions
- Node LTS
18
is recommended - Use NPM or Yarn
- Chrome (headless)
Installation
composer require machinateur/the-printer
npm i --save @machinateur/the-printer
Note that the express app is also bundled with the composer package.
Usage
Running the express app
Run
npm start
or
node the-printer.js
to launch the express app. Make sure to install the dependencies first.
Supported CLI args and environment variables
The following arguments are supported, with respective fallback to the env-var.
- Option
--debug
: Control debug output anddumpio
from chromeSTDOUT
/STDERR
.- Fallback:
APP_DEBUG
- Default:
false
- Fallback:
- Option
--connect-to
: Use an existing browser instance at that address, supportsws
andhttp
.- Fallback:
APP_REMOTE
- Default: Launch headless chrome instance locally.
- Fallback:
- Option
--script
: Control JavaScript execution.- Fallback:
APP_ENABLE_JAVASCRIPT
- Default:
false
(JavaScript is not executed)
- Fallback:
- Option
--port
: Set the app port, format\d+
.- Fallback:
APP_PORT
- Default:
3000
- Fallback:
Calling from PHP
From PHP the bundled client provided in this composer package may be used to interact with the express app. It has to be running for this to work.
Create and return a document from php
The following example will render a document (in A5
format without header/footer)
and return it directly to the output buffer.
$configuration = new \Machinateur\ThePrinter\Configuration\DocumentConfiguration();
$configuration->setPageFormat('A5');
$content = '<!-- The HTML document content goes here. -->';
$outputBuffer = \fopen('php://output', 'w', false, null);
$client = new \Machinateur\ThePrinter\Client('http://127.0.0.1:3000/', 10);
\header(\sprintf('%s: %s', 'Content-Type', 'application/pdf'), true, 200);
$client->document($configuration, $content, $outputBuffer);
You can use the \Machinateur\ThePrinter\Client::documentBinary()
method instead, to get the output as a binary string.
It's always possible to write to a stream resource and process/read it later, to save memory.
If no buffer is provided, it is created as temporary stream and has to be closed by the implementor.
The PDF documents do not support JavaScript execution before rendering. This is a engine limitation.
Create and return an image from php
The following example does about the same thing, but with a (full-page) screenshot.
$configuration = new \Machinateur\ThePrinter\Configuration\ImageConfiguration();
$configuration->setCapturePage(true);
$content = '<!-- The HTML document content goes here. -->';
$outputBuffer = \fopen('php://output', 'w', false, null);
$client = new \Machinateur\ThePrinter\Client('http://127.0.0.1:3000/', 10);
\header(\sprintf('%s: %s', 'Content-Type', 'image/png'), true, 200);
$client->image($configuration, $content, $outputBuffer);
As with the \Machinateur\ThePrinter\Client::document()
method, there is
a \Machinateur\ThePrinter\Client::imageBinary()
method to retrieve the buffer as string blob.
The provided HTML content is set as the page content directly. Keep in mind that JavaScript is disabled
in case you rely on it for rendering. That setting can be controlled from the --no-script
option
or using the APP_ENABLE_JAVASCRIPT
env-var.
Calling from other languages
It's totally possible to interact with the express app from other programming languages as well.
Just use the supported endpoints directly via your favourite HTTP client.
The response content will be a binary stream of the mime-type from the response header.
In case of an error (request format or something else) the response will be a json object of
type {Error&{statusCode?:number}}
where trace
is removed when not in debug mode.
Using HTTP files
Find details on the available endpoints and their options in the HTTP files contained in this repository.
TODO
Supported endpoints
POST
/document
Create a PDF document from the provided content string.
{ "configuration": { ... }, "content": "<!-- The HTML document content goes here. -->", "time": 1696091198 }
Configuration:
/** * @typedef {object} DocumentConfiguration * @property {number|null} scale * @property {boolean} displayContentOnly * @property {boolean} displayBackgroundGraphic * @property {boolean} displayTransparent * @property {object|null} template * @property {string|null} template.header * @property {string|null} template.footer * @property {string} pageOrientation * @property {string|null} pageFormat * @property {string|number|undefined} pageWidth * @property {string|number|undefined} pageHeight * @property {string} pageRange * @property {boolean} pageOverride * @property {object|null} margin * @property {string|number|undefined} margin.top * @property {string|number|undefined} margin.right * @property {string|number|undefined} margin.bottom * @property {string|number|undefined} margin.left */
Further reference:
- https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.pdfoptions.md
- https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.pdfmargin.md
- https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.paperformat.md
POST
/image
Create an image from the provided content string.
{ "configuration": { ... }, "content": "<!-- The HTML document content goes here. -->", "time": 1696091198 }
Configuration:
/** * @typedef {object} ImageConfiguration * @property {string|null} type * @property {number|null} quality * @property {number|null} scale * @property {object|null} area * @property {number} area.x * @property {number} area.y * @property {number} area.width * @property {number} area.height * @property {boolean} optimize * @property {boolean} captureViewportOnly * @property {boolean} captureSurface * @property {boolean} capturePage * @property {boolean} displayTransparent */
Further reference:
- https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.screenshotoptions.md
- https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.screenshotclip.md
Development
Setup
To set this project up from scratch for development, run the following commands:
git clone [email protected]:machinateur/the-printer.git
cd the-printer
composer install
Running tests
Execute the PHPUnit test-suite using the following command:
composer run-script --timeout=0 tests
All tests are stored at ./tests
under the \Machinateur\ThePrinter\Tests\...
namespace.
The configuration is stored in phpunit.xml.dist
.
Running tests in multiple PHP versions
It's possible to run the tests in different versions of PHP without the need to install all those versions locally. Thanks to docker, this can be done using a single command:
PHP_VERSION=8.1
docker run --rm -v $(pwd):/app -w /app composer install
docker run --rm -v $(pwd):/app -w /app php:${PHP_VERSION} vendor/bin/phpunit
See this guide for some more details.
Generate coverage
Execute the PHPUnit test-suite and gain coverage insights using the following command:
composer run-script --timeout=0 coverage
This command uses the text UI of PHPUnit exclusively.
About ProcessTestCase
The class \Machinateur\ThePrinter\Tests\ProcessTestCase
is a custom \PHPUnit\Framework\TestCase
that supports
managing a background process that is started and stopped with the test class itself.
While this can impact the test-suite performance quite heavily, if used excessively and depending on the type of background process.
This is utilized to enable a functional test using node
as background process running the the-printer.js
server.
The test is located at `` and holds some other interesting details, discussed below.
About ServerTestCase
The class \Machinateur\ThePrinter\Tests\Server\ServerTestCase
is a variant of the ProcessTestCase
that specifically uses
the PHP built-in webserver. This can be useful, if a test requires a mocked webserver.
This is utilized to mock server responses for actual testing of the curl
calls
within the \Machinateur\ThePrinter\Stream\Connection
.
Embedded PHPT test-suite
The project-level test-suite embeds a separate test-suite as part of the \Machinateur\ThePrinter\Tests\Result\ResultTest
,
where some separate PHPT tests are loaded.
You can find other examples of such tests being used,
for example in the PHP curl
extension
itself.
Thanks to PHPUnit's built-in support for the ancient PHPT format, although somewhat thinly documented, they were really easy to integrate.
The PHPT tests are used to test the accuracy of actual printing results (image and document) using imagick. This comes with some drawbacks and was an experimental approach in the beginning. It can serve as an example for real world use-cases of this "digital print server".
Feel free to browse the code and have a look yourself. Improvements and creative additions are always welcomed.
Managing control files
The comparison (aka. control) files for PHPT tests are stored under tests/Result/res/
.
Running static analysis
To execute PhpStan for static analysis, call the following composer script:
composer run-script lint
This command maps to ./vendor/bin/phpstan analyze
using the phpstan.neon
file from the project root.
License
It's MIT.