ef9b2daf6d
As soon as the plugin is reloaded, or the editor restarted, the images must be reloaded. Maybe we could use a file cache...
101 lines
3.9 KiB
Python
101 lines
3.9 KiB
Python
import concurrent.futures
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import urllib.request
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import base64
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import os.path
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from functools import lru_cache, partial
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from bs4 import BeautifulSoup
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from .lib.markdown2 import Markdown
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__all__ = ('markdown2html', )
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markdowner = Markdown()
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# FIXME: how do I choose how many workers I want? Does thread pool reuse threads or
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# does it stupidly throw them out? (we could implement something of our own)
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executor = concurrent.futures.ThreadPoolExecutor(max_workers=5)
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# FIXME: put a nice picture please :^)
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BASE64_LOADING_IMAGE = 'loading image!'
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BASE64_404_IMAGE = '404 not found :-('
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images_cache = {}
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class LoadingError(Exception):
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pass
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def markdown2html(markdown, basepath, re_render):
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""" converts the markdown to html, loads the images and puts in base64 for sublime
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to understand them correctly. That means that we are responsible for loading the
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images from the internet. Hence, we take in re_render, which is just a function we
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call when an image has finished loading to retrigger a render (see #90)
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"""
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html = markdowner.convert(markdown)
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soup = BeautifulSoup(html, "html.parser")
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for img_element in soup.find_all('img'):
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src = img_element['src']
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# already in base64, or something of the like
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# FIXME: what other types are possible? Are they handled by ST? If not, could we
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# convert it into base64? is it worth the effort?
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if src.startswith('data:image/'):
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continue
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if src.startswith('http://') or src.startswith('https://'):
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path = src
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elif src.startswith('file://'):
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path = src[len('file://'):]
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else:
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# expanduser: ~ -> /home/math2001
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# realpath: simplify that paths so that we don't have duplicated caches
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path = os.path.realpath(os.path.expanduser(os.path.join(basepath, src)))
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try:
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base64 = get_base64_image(path, re_render)
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except FileNotFoundError as e:
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print("{!r} not found {!r}".format(path, e))
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base64 = BASE64_404_IMAGE
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except LoadingError:
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# the image is loading
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base64 = BASE64_LOADING_IMAGE
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img_element['src'] = base64
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# FIXME: how do tables look? should we use ascii tables?
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return str(soup)
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def get_base64_image(path, re_render):
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def callback(url, future):
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# this is "safe" to do because callback is called in the same thread as
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# add_done_callback:
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# > Added callables are called in the order that they were added and are always
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# > called in a thread belonging to the process that added them
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# > --- Python docs
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images_cache[url] = future.result()
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# we render, which means this function will be called again, but this time, we
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# will read from the cache
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re_render()
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if path.startswith('http://') or path.startswith('https://'):
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if path in images_cache:
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return images_cache[path]
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executor.submit(load_image, path).add_done_callback(partial(callback, path))
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return 'loading of the internet!'
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with open(path, 'rb') as fp:
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return 'data:image/png;base64,' + base64.b64encode(fp.read()).decode('utf-8')
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# FIXME: This is an in memory cache. 20 seems like a fair bit of images... Should it be
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# bigger? Should the user be allowed to chose? There definitely should be a limit
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# because we don't wanna use to much memory, we're a simple markdown preview plugin
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# NOTE: > The LRU feature performs best when maxsize is a power-of-two. --- python docs
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@lru_cache(maxsize=2 ** 4)
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def load_image(url):
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with urllib.request.urlopen(url, timeout=60) as conn:
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content_type = conn.info().get_content_type()
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if 'image' not in content_type:
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raise ValueError("{!r} doesn't point to an image, but to a {!r}".format(url, content_type))
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return 'data:image/png;base64,' + base64.b64encode(conn.read()).decode('utf-8') |