Refacotry code with create_app function.

HACKING.md

@@ -13,7 +13,7 @@ Python is a perfect language to develop Qt program and it can call pretty much i
 M-x eaf-open
 ```
 
-    Then type "eaf demo" as input, will pop hello world window in emacs like below:
+    Then type "eaf-demo" as input, will pop hello world window in emacs like below:
 
 ![img](./screenshot/hello_world.png)
 
@@ -34,7 +34,7 @@ from PyQt5.QtGui import QColor
 from PyQt5.QtWidgets import QPushButton
 from core.buffer import Buffer
 
-class DemoBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, True, QColor(0, 0, 0, 255))
 
@@ -56,11 +56,11 @@ class DemoBuffer(Buffer):
 ```Python
 @dbus.service.method(EAF_DBUS_NAME, in_signature="ss", out_signature="s")
 def new_buffer(self, buffer_id, url):
-    if url == "eaf demo":
-        self.create_buffer(buffer_id, DemoBuffer(buffer_id, url))
+    if url == "eaf-demo":
+        return self.create_app(buffer_id, url, "app.demo.buffer")
 ```
 
-    Replace "eaf demo" to "eaf rocks!"
+    Replace "eaf-demo" to "eaf rocks!"
 
 3. Test
 ```
@@ -80,7 +80,9 @@ Above are all you need, happy hacking!
 ### Read user's input
 Below is code example from pdfviewer:
 ```Python
-class PdfViewerBuffer(Buffer):
+...
+
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, False, QColor(0, 0, 0, 255))
 
@@ -93,6 +95,8 @@ class PdfViewerBuffer(Buffer):
     def handle_input_message(self, result_type, result_content):
         if result_type == "jump_page":
             self.buffer_widget.jump_to_page(int(result_content))
+
+...
 ```
 If you want read input from emacs minibuffer then call back to python.
 

app/browser/buffer.py

@@ -27,7 +27,7 @@ from PyQt5.QtWidgets import QApplication
 from PyQt5.QtWebKit import QWebSettings
 from core.buffer import Buffer
 
-class BrowserBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, False, QColor(255, 255, 255, 255))
 

app/camera/buffer.py

@@ -28,7 +28,7 @@ from PyQt5.QtWidgets import QGraphicsScene, QGraphicsView
 from PyQt5.QtWidgets import QWidget, QVBoxLayout
 from core.buffer import Buffer
 
-class CameraBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, True, QColor(0, 0, 0, 255))
 

app/demo/buffer.py

@@ -23,7 +23,7 @@ from PyQt5.QtGui import QColor
 from PyQt5.QtWidgets import QPushButton
 from core.buffer import Buffer
 
-class DemoBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, True, QColor(0, 0, 0, 255))
 

app/imageviewer/buffer.py

@@ -26,7 +26,7 @@ from PyQt5.QtWidgets import QWidget
 import os
 from core.buffer import Buffer
 
-class ImageViewerBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, False, QColor(0, 0, 0, 255))
 

app/pdfviewer/buffer.py

@@ -27,7 +27,7 @@ from PyQt5.QtWidgets import QWidget
 import fitz
 from core.buffer import Buffer
 
-class PdfViewerBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, False, QColor(0, 0, 0, 255))
 

app/videoplayer/buffer.py

@@ -26,7 +26,7 @@ from PyQt5.QtMultimediaWidgets import QGraphicsVideoItem
 from PyQt5.QtWidgets import QWidget, QGraphicsScene, QGraphicsView, QVBoxLayout
 from core.buffer import Buffer
 
-class VideoPlayerBuffer(Buffer):
+class AppBuffer(Buffer):
     def __init__(self, buffer_id, url):
         Buffer.__init__(self, buffer_id, url, True, QColor(0, 0, 0, 255))
 

eaf.py

@@ -25,6 +25,7 @@ from core.utils import file_is_image, file_is_video
 from core.view import View
 from dbus.mainloop.glib import DBusGMainLoop
 from pymediainfo import MediaInfo
+import importlib
 import dbus
 import dbus.service
 import os
@@ -50,17 +51,9 @@ class EAF(dbus.service.Object):
     @dbus.service.method(EAF_DBUS_NAME, in_signature="ss", out_signature="s")
     def new_buffer(self, buffer_id, url):
         if url == "eaf-demo":
-            try:
-                from app.demo.buffer import DemoBuffer
-                self.create_buffer(buffer_id, DemoBuffer(buffer_id, url))
-            except ImportError:
-                return "Something wrong when import app.demo.buffer"
+            return self.create_app(buffer_id, url, "app.demo.buffer")
         elif url == "eaf-camera":
-            try:
-                from app.camera.buffer import CameraBuffer
-                self.create_buffer(buffer_id, CameraBuffer(buffer_id, url))
-            except ImportError:
-                return "Something wrong when import app.camera.buffer"
+            return self.create_app(buffer_id, url, "app.camera.buffer")
         else:
             url = os.path.expanduser(url)
 
@@ -69,46 +62,39 @@ class EAF(dbus.service.Object):
                     (_, extension) = os.path.splitext(url)
 
                     if extension in [".pdf", ".xps", ".oxps", ".cbz", ".epub", ".fb2", "fbz"]:
-                        try:
-                            from app.pdfviewer.buffer import PdfViewerBuffer
-                            self.create_buffer(buffer_id, PdfViewerBuffer(buffer_id, url))
-                        except ImportError:
-                            return "Something wrong when import app.pdfviewer.buffer"
+                        return self.create_app(buffer_id, url, "app.pdfviewer.buffer")
                     else:
                         file_info = MediaInfo.parse(url)
                         if file_is_image(file_info):
-                            try:
-                                from app.imageviewer.buffer import ImageViewerBuffer
-                                self.create_buffer(buffer_id, ImageViewerBuffer(buffer_id, url))
-                            except ImportError:
-                                return "Something wrong when import app.imageviewer.buffer"
+                            return self.create_app(buffer_id, url, "app.imageviewer.buffer")
                         elif file_is_video(file_info):
-                            try:
-                                from app.videoplayer.buffer import VideoPlayerBuffer
-                                self.create_buffer(buffer_id, VideoPlayerBuffer(buffer_id, url))
-                            except ImportError:
-                                return "Something wrong when import app.videoplayer.buffer"
+                            return self.create_app(buffer_id, url, "app.videoplayer.buffer")
                         else:
                             return "Don't know how to open {0}".format(url)
                 else:
                     return "Path {0} not exists.".format(url)
             else:
-                try:
-                    from app.browser.buffer import BrowserBuffer
-                    from urllib.parse import urlparse
-                    result = urlparse(url)
-                    if len(result.scheme) != 0:
-                        self.create_buffer(buffer_id, BrowserBuffer(buffer_id, result.geturl()))
+                from urllib.parse import urlparse
+                result = urlparse(url)
+                if len(result.scheme) != 0:
+                    return self.create_app(buffer_id, result.geturl(), "app.browser.buffer")
+                else:
+                    result = urlparse("{0}:{1}".format("http", url))
+                    if result.scheme != "":
+                        return self.create_app(buffer_id, result.geturl(), "app.browser.buffer")
                     else:
-                        result = urlparse("{0}:{1}".format("http", url))
-                        if result.scheme != "":
-                            self.create_buffer(buffer_id, BrowserBuffer(buffer_id, result.geturl()))
-                        else:
-                            return "{0} is not valid url".format(url)
-                except ImportError:
-                    return "Something wrong when import app.browser.buffer"
+                        return "{0} is not valid url".format(url)
         return ""
 
+    def create_app(self, buffer_id, url, module_path):
+        if importlib.util.find_spec(module_path) is not None:
+            module = importlib.import_module(module_path)
+            self.create_buffer(buffer_id, module.AppBuffer(buffer_id, url))
+
+            return ""
+        else:
+            return "Something wrong when import {0}".format(module_path)
+
     def create_buffer(self, buffer_id, app_buffer):
         global emacs_width, emacs_height