image loader working but messy

.gitignore

@@ -1,2 +1,3 @@
 Thumbs.db
 __pycache__/
+cache.txt

image_manager.py

@@ -0,0 +1,83 @@
+# -*- encoding: utf-8 -*-
+
+import os.path
+from threading import Thread
+import urllib.request
+import base64
+import sublime
+
+CACHE_FILE = os.path.join(os.path.dirname(__file__), 'cache.txt')
+TIMEOUT = 20
+
+SEPARATOR = '---%cache%--'
+
+class InternalError(Exception): pass
+
+def to_base64(path=None, content=None):
+    if content is None and path is not None:
+        try:
+            with open(path, 'rb') as fp:
+                content = fp.read()
+        except FileNotFoundError:
+            return to_base64(os.path.join(os.path.dirname(__file__), '404.png'))
+
+    return 'data:image/png;base64,' + ''.join([chr(el) for el in list(base64.standard_b64encode(content))])
+
+def load_and_save_image(url, user_callback):
+    def callback(content):
+        content = to_base64(content=content)
+        with open(CACHE_FILE, 'a') as fp:
+            fp.write(url + SEPARATOR + content)
+            user_callback(content)
+    thread = ImageLoader(url, callback)
+    thread.start()
+    sublime.set_timeout_async(lambda: thread.join(), TIMEOUT)
+
+class ImageLoader(Thread):
+
+    def __init__(self, url, callback):
+        Thread.__init__(self)
+        self.url = url
+        self.callback = callback
+
+    def run(self):
+        page = urllib.request.urlopen(self.url, None, TIMEOUT)
+        self.callback(page.read())
+
+
+class ImageManager(object):
+
+    currently_loading = []
+
+    @staticmethod
+    def get(imageurl, user_callback):
+        if imageurl in ImageManager.currently_loading:
+            return None
+        def callback(content):
+            try:
+                ImageManager.currently_loading.remove(imageurl)
+            except ValueError:
+                sublime.error_message('Internal error: Trying to remove an URL'
+                                      'from loading_url, but not found. Please'
+                                      'report to the issue tracker.')
+                sublime.run_command('open_url', {
+                    'url': 'https://github.com/math2001/MarkdownLivePreview/'
+                           'issues/new'     
+                })
+
+            user_callback(content)
+
+        ImageManager.currently_loading.append(imageurl)
+        try:
+            with open(CACHE_FILE, 'r') as fp:
+                lines = fp.readlines()
+        except FileNotFoundError:
+            pass
+        else:
+            for line in lines:
+                url, base64 = line.split(SEPARATOR, 1)
+                if url == imageurl:
+                    return callback(base64)
+                else:
+                    print(url + '\n' + imageurl)
+        load_and_save_image(imageurl, callback)

md_in_popup.py

@@ -6,6 +6,8 @@ import os.path
 import re
 import base64
 
+from .image_manager import ImageManager
+
 from .escape_amp import *
 from html.parser import HTMLParser
 
@@ -39,7 +41,7 @@ def to_base64(path):
 
     with open(path, 'rb') as fp:
         content = fp.read()
-    return base64.standard_b64encode(content)
+    return 'data:image/png;base64,' + ''.join([chr(el) for el in list(base64.standard_b64encode(content))])
 
 def replace_img_src_base64(html):
     """Really messy, but it works (should be updated)"""
@@ -57,7 +59,7 @@ def replace_img_src_base64(html):
         if index == -1:
             return ''.join(html)
         path, end = get_content_till(html, '"', start=index + len(tag_start))
-        html[index+len(tag_start):end] = 'data:image/png;base64,' + ''.join([chr(el) for el in list(to_base64(''.join(path)))])
+        html[index+len(tag_start):end] = to_base64(''.join(path))
     return ''.join(html)
 
 
@@ -246,3 +248,22 @@ class MarkdownInPopupCommand(sublime_plugin.EventListener):
                     md_view_settings.erase('markdown_preview_enabled')
                     md_view_settings.erase('markdown_preview_id')
                 sublime.set_timeout_async(callback, 250)
+
+class LoadImageCommand(sublime_plugin.ApplicationCommand):
+
+    def run(self):
+        ImageManager.get('https://images.duckduckgo.com/iu/?u=http%3A%2F%2Fi82.photobucket.com%2Falbums%2Fj261%2FOrestesElVerdadero%2Favatar-fenix-100.jpg&f=1',
+                         lambda content: print('got content', len(content)))
+
+class MLPDevListener(sublime_plugin.EventListener):
+
+    def on_post_save(self, view):
+        if not (os.path.dirname(__file__) in view.file_name() and
+            view.file_name().endswith('.py')):
+            return
+        sublime.run_command('reload_plugin', {
+            'main': os.path.join(sublime.packages_path(), 'MarkdownLivePreview',
+                                 'md_in_popup.py'),
+            'scripts': ['image_manager'],
+            'quiet': True
+        })