PyV8Mono

PyV8Mono - python extension for V8 MonoContext library. Commonly intended for rendering fest templates.

Install

Install v8monoctx following instructions on https://github.com/fsitedev/v8monoctx, don't forget to set V8_PREFIX environment variables, e.g.

$ export V8_VERSION=3.27.0
$ export V8_PREFIX=/usr/local/v8-$V8_VERSION

Then install python module as usual:

$ python setup.py build
$ sudo -E bash -c 'python setup.py install'

MonoContext

MonoContext is low-level wrapper above v8monoctx. It contains 2 main methods:

• load_file loads js helpers in V8.

• execute_file renders template. It takes template name, suffix for calling template function and context in JSON format. MonoContext will compile template in V8, as load_file does.

Usage

from PyV8Mono.monocontext import MonoContext
import json

renderer = MonoContext(watch_templates=True)

# load common js helpers
renderer.load_file('context/build.js')

# render templtate
append_str = ';fest["news-detail.xml"]( JSON.parse(__dataFetch()) );'
json_str = json.dumps(context)
html, errors = renderer.execute_file("news-detail/news-detail.xml.js", append_str, json_str)

MonoContext init options

Garbage collector control:

• run_low_memory_notification. Options for running V8::LowMemoryNotification each N iterations. Disabled if 0 (default). run_low_memory_notification = 100 will send notification each 100 renders.
• run_idle_notification_loop. Options for running V8::IdleNotification each N iterations. Disabled if 0 (default).

V8 control:

• cmd_args. String of arguments for V8. Ex: --no_incremental_marking, Default is ''.

Other:

• watch_templates. If set True, MonoContext checks whether template has changed. Useful for development. Default is False.

FestRenderer

FestRenderer provides more convinient use in your project than MonoContext.

Usually you should have one instance on FestRenderer/MonoContext which stores compiled templates in V8 memory. Also be careful if you load common js utils in master process of your web server, it may cause segfaults.

from PyV8Mono.renderer import FestRenderer

renderer = FestRenderer(
	js_root='/path/to/templates/',
	js_files=('context/build.js',),
	js_files_autoload=False
)
json_str = json.dumps(context)
html = renderer.render('news-detail/news-detail.xml.js', json_str)