prerender

# prerender

Render JavaScript-rendered page as HTML/PDF/mhtml/png/jpeg using headless Chrome

## Install Chrome

Headless mode is supported in Chrome stable 59+ and unstable/dev channel, you should be able to install it via:

## Start Chrome Headless

`bash $ google-chrome --headless --remote-debugging-port=9222 --disable-gpu "about:blank"`

To disable image loading, add --blink-settings=imagesEnabled=false argument:

`bash $ google-chrome --headless --remote-debugging-port=9222 --disable-gpu --blink-settings=imagesEnabled=false "about:blank"`

## Install Prerender

`bash $ pip install -U prerender`

## Start Prerender

As standalone application:

`bash $ prerender`

To run it under gunicorn:

`bash $ gunicorn --bind 0.0.0.0:3000 --worker-class sanic.worker.GunicornWorker prerender.app:app`

## How does it work

Say you deployed Prerender under http://prerender.example.com:8000, to render http://example.com you can do:

`bash $ # render HTML $ curl http://prerender.example.com:8000/http://example.com $ curl http://prerender.example.com:8000/html/http://example.com $ # render mhtml $ curl http://prerender.example.com:8000/mhtml/http://example.com $ # render PDF $ curl http://prerender.example.com:8000/pdf/http://example.com $ # render png $ curl http://prerender.example.com:8000/png/http://example.com $ # render jpeg $ curl http://prerender.example.com:8000/jpeg/http://example.com`

## Configuration

Settings are mostly configured by environment variables.

ENV | default value | description |

------------------ | HOST | 0.0.0.0 | Prerender listen host | | PORT | 8000 | Prerender listen port | | DEBUG | false | Toggle debug mode | | PRERENDER_TIMEOUT | 30 | renderring timeout | | PAGE_DONE_CHECK_TIMEOUT | 200 | Number of milliseconds between the interval of checking whether the page is done loading or not | | CONCURRENCY | 2 * CPU count | Chrome pages count | | MAX_ITERATIONS | 200 | Restart Chrome page after rendering this many pages | | CHROME_HOST | localhost | Chrome remote debugging host | | CHROME_PORT | 9222 | Chrome remote debugging port | | USER_AGENT | | Chrome User Agent | | BLOCK_FONTS | 1 | Block web fonts loading, set to 0 to allow fonts loading | | ALLOWED_DOMAINS | | Domains allowed for renderring, comma seperated | | CACHE_BACKEND | dummy | Cache backend, dummy, disk, s3 | | CACHE_LIVE_TIME | 3600 | Disk cache live seconds | | CACHE_ROOT_DIR | /tmp/prerender | Disk cache root directory | | S3_SERVER | s3.amazonaws.com | S3 server address | | S3_ACCESS_KEY | | S3 access key | | S3_SECRET_KEY | | S3 secret key | | S3_REGION | | S3 region | | S3_BUCKET | prerender | S3 bucket name | | SENTRY_DSN | | Sentry DSN, for exception monitoring | | ENABLE_CIRCUIT_BREAKER | false | enable circuit breaker | | CIRCUIT_BREAKER_FAIL_MAX | 5 | maximum failures per browser/bot before circuit breaker open | | CIRCUIT_BREAKER_RESET_TIMEOUT | 60 | circuit breaker reset timeout in seconds |

## Configure client

Please view the original NodeJs version [prerender]() README.

## License

MIT