Add get_server_address() and simplify starting the ete server.

We changed start_server() so that it automatically tracks the created server in g_threads (unless we set track=False).

It also sets the compression (with the compress argument) to use when communicating. So we do not have to do it somewhere else. I think it makes sense here.

Finally, with the new get_server_address() which returns (host, port),
we can simplify quite a bit of code, and make it look independent of
the kind of server that we use (wsgiref.simple_server, cheroot,
whatever).

Author: jordibc

ete4/core/tree.pyx

@@ -1083,7 +1083,7 @@ cdef class Tree:
 
         # Add tree and start a server.
         name = explorer.add_tree(self, layouts=layouts)
-        thread, server = explorer.start_server()
+        thread_server = explorer.start_server(track=False)
 
         # Use selenium to make a screenshot.
         w = w or 2560  # width
@@ -1100,7 +1100,7 @@ cdef class Tree:
 
         driver = webdriver.Chrome(options=options)
 
-        host, port = server.bind_addr
+        host, port = explorer.get_server_address()
         driver.get(f'http://{host}:{port}/static/gui.html?tree={name}')
 
         time.sleep(2)  # wait, kind of a hack
@@ -1110,7 +1110,7 @@ cdef class Tree:
         driver.quit()
 
         # Stop the server (and close its thread), and remove the tree.
-        explorer.stop_server((thread, server), remove_trees=False)
+        explorer.stop_server(thread_server, remove_trees=False)
         explorer.remove_tree(name)
 
     def copy(self, method="cpickle"):

ete4/smartview/explorer.py

@@ -659,27 +659,29 @@ def explore(tree, name=None, layouts=None,
     """Run the web server, add tree and open a browser to visualize it."""
     add_tree(tree, name, layouts, kwargs)
 
-    if compress is not None:
-        g_config['compress'] = compress  # global configuration
-
     # Launch the thread with the http server (if not already running).
     if 'server' not in g_threads:
-        thread, server = start_server(host, port, verbose, keep_server,
-                                      server_args)
-        g_threads['server'] = (thread, server)
-        host, port = server.bind_addr  # port may have changed
-        print(f'Explorer now available at http://{host}:{port}')
+        print('Creating new server.')
+        start_server(host, port, verbose, compress, keep_server, server_args)
     else:
-        _, server = g_threads['server']
-        host, port = server.bind_addr
-        print(f'Existing explorer available at http://{host}:{port}')
+        print('Using existing server.')
+
+    host, port = get_server_address()
+    print(f'Explorer available at http://{host}:{port}')
 
     if open_browser:
-        _, server = g_threads['server']
-        host, port = server.bind_addr
         open_browser_window(host, port)
 
 
+def get_server_address():
+    """Return (host, port) where the server is listening."""
+    if 'server' in g_threads:
+        _, server = g_threads['server']
+        return server.bind_addr  # (host, port)
+    else:
+        return None, None
+
+
 def add_tree(tree, name=None, layouts=None, extra_style=None):
     """Add tree, layouts, etc to the global variables, and return its name."""
     name = name or make_name()  # in case we didn't receive one
@@ -705,18 +707,21 @@ def remove_tree(name):
     g_layouts.pop(name)
 
 
-def start_server(host='127.0.0.1', port=None, verbose=False, keep_server=False,
-                 server_args=None):
+def start_server(host='127.0.0.1', port=None, verbose=False, compress=None,
+                 keep_server=False, server_args=None, track=True):
     """Create a thread running the web server and return it and the server."""
-    server_args = server_args or {}  # extra server arguments
-    server_args.setdefault('numthreads', 100)
-
     port = port or get_next_available_port(host)
     assert port, 'could not find any port available'
 
     if verbose:
         default_app().install(log_requests)
 
+    if compress is not None:
+        g_config['compress'] = compress  # global configuration
+
+    server_args = server_args or {}  # extra server arguments
+    server_args.setdefault('numthreads', 100)
+
     server = Server((host, port), default_app(), **server_args)
 
     thread = Thread(
@@ -725,6 +730,9 @@ def start_server(host='127.0.0.1', port=None, verbose=False, keep_server=False,
 
     thread.start()
 
+    if track:  # we normally want to keep track of the server in g_threads
+        g_threads['server'] = (thread, server)
+
     return thread, server
 
 
@@ -810,15 +818,12 @@ def stop_server(thread_server=None, remove_trees=True):
             g_trees[name] = t
             g_layouts[name] = [BASIC_LAYOUT]
 
-        # Set the global config options.
-        g_config['compress'] = args.compress
-
         # Launch the http server in a thread and open the browser.
-        _, server = start_server('127.0.0.1', args.port, args.verbose)
-        port = server.bind_addr[1]
-        open_browser_window(port=port)
+        start_server('127.0.0.1', args.port, args.verbose, args.compress)
+        host, port = get_server_address()
+        open_browser_window(host, port)
 
-        print(f'Explorer available at http://127.0.0.1:{port}')
+        print(f'Explorer available at http://{host}:{port}')
         input('Press enter to stop the server and finish.\n')
     except (FileNotFoundError, newick.NewickError, ValueError) as e:
         sys.exit(f'Error using tree from {args.FILE}: {e}')

examples/explorer/ete_server.py

@@ -10,7 +10,7 @@
 import ete4.smartview.explorer as ex  # to get all the server functions
 
 
-# Add NameLayout, a simple example of a layout, that we will use in /load_custom.
+# Add NameLayout, an example layout that we will use in /load_custom.
 
 def draw_node(node):
     yield TextFace(node.name)
@@ -45,9 +45,9 @@ def callback():
 
 # Run the server and show where it is.
 
-_, server = ex.start_server(verbose=True)  # just to show what is going on
+ex.start_server(verbose=True)  # just to show what is going on
 
-host, port = server.bind_addr
+host, port = ex.get_server_address()
 print(f'Explorer available at http://{host}:{port}')
 
 print('Press enter to stop the server and finish.')