Fix/34794/run doc server along with jupyter

src/bin/sage-notebook

@@ -7,19 +7,20 @@ import ast
 import argparse
 import logging
 import textwrap
+
+from contextlib import contextmanager
+
 logging.basicConfig()
 logger = logging.getLogger()
 
 from sage.misc.banner import banner
 
-
 _system_jupyter_url = "https://doc.sagemath.org/html/en/installation/launching.html#setting-up-sagemath-as-a-jupyter-kernel-in-an-existing-jupyter-notebook-or-jupyterlab-installation"
 
 
 class NotebookJupyter():
 
     def print_banner(self):
-        banner()
         print('Please wait while the Sage Jupyter Notebook server starts...')
 
     @classmethod
@@ -45,7 +46,6 @@ class NotebookJupyter():
 
 class NotebookJupyterlab():
     def print_banner(self):
-        banner()
         print('Please wait while the Jupyterlab server starts...')
 
     @classmethod
@@ -71,7 +71,6 @@ class NotebookJupyterlab():
 
 class NotebookNbclassic():
     def print_banner(self):
-        banner()
         print('Please wait while the Jupyterlab server starts...')
 
     @classmethod
@@ -94,7 +93,6 @@ class NotebookNbclassic():
 
 class NotebookRetrolab():
     def print_banner(self):
-        banner()
         print('Please wait while the Jupyterlab server starts...')
 
     @classmethod
@@ -118,7 +116,6 @@ class NotebookRetrolab():
 class SageNBExport(NotebookJupyter):
 
     def print_banner(self):
-        banner()
         print('Please wait while the SageNB export server starts...')
 
     @classmethod
@@ -172,7 +169,6 @@ EXAMPLES:
 
 """
 
-
 notebook_launcher = {
     'default': NotebookJupyter,   # change this to change the default
     'ipython': NotebookJupyter,
@@ -183,7 +179,6 @@ notebook_launcher = {
     'export': SageNBExport,
 }
 
-
 notebook_names = ', '.join(notebook_launcher.keys())
 
 
@@ -230,6 +225,34 @@ def trac_23428_browser_workaround():
         os.environ['BROWSER'] = 'open'
 
 
+@contextmanager
+def sage_doc_server():
+    from sage.env import SAGE_DOC_SERVER_URL
+
+    if SAGE_DOC_SERVER_URL:
+        print(f'Sage doc server running at {SAGE_DOC_SERVER_URL}')
+        yield
+    else:
+        from functools import partial
+        from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
+        from threading import Thread
+
+        from sage.env import SAGE_DOC, SAGE_DOC_LOCAL_PORT as port
+
+        server = ThreadingHTTPServer(('localhost', int(port)),
+            partial(SimpleHTTPRequestHandler, directory=SAGE_DOC))
+        server_thread = Thread(target=server.serve_forever, name="sage_doc_server")
+        server_thread.start()
+        print(f'Sage doc server started running at http://localhost:{port}')
+
+        try:
+            yield
+        finally:
+            server.shutdown()
+            server_thread.join()
+            print(f'Sage doc server stopped runnning at http://localhost:{port}')
+
+
 if __name__ == '__main__':
     parser = make_parser()
     args, unknown = parser.parse_known_args(sys.argv[1:])
@@ -270,4 +293,7 @@ if __name__ == '__main__':
             launcher.print_help()
         sys.exit(0)
 
-    launcher(unknown)
+    banner()
+
+    with sage_doc_server():
+        launcher(unknown)

src/sage/env.py

@@ -185,6 +185,10 @@ def var(key: str, *fallbacks: Optional[str], force: bool = False) -> Optional[st
 SAGE_PKGS = var("SAGE_PKGS", join(SAGE_ROOT, "build", "pkgs"))
 SAGE_ROOT_GIT = var("SAGE_ROOT_GIT", join(SAGE_ROOT, ".git"))
 
+# Sage doc server (local server with PORT if URL is not given)
+SAGE_DOC_SERVER_URL = var("SAGE_DOC_SERVER_URL")
+SAGE_DOC_LOCAL_PORT = var("SAGE_DOC_LOCAL_PORT", "8000")
+
 # ~/.sage
 DOT_SAGE = var("DOT_SAGE", join(os.environ.get("HOME"), ".sage"))
 SAGE_STARTUP_FILE = var("SAGE_STARTUP_FILE", join(DOT_SAGE, "init.sage"))

src/sage/repl/ipython_kernel/kernel.py

@@ -93,40 +93,48 @@ def help_links(self):
             sage: sk = SageKernel.__new__(SageKernel)
             sage: sk.help_links
             [{'text': 'Sage Documentation',
-              'url': 'kernelspecs/sagemath/doc/html/en/index.html'},
+              'url': 'http://localhost:8000/html/en/index.html'},
              ...]
         """
-        from sage.repl.ipython_kernel.install import SageKernelSpec
-        identifier = SageKernelSpec.identifier()
-        kernel_url = lambda x: 'kernelspecs/{0}/{1}'.format(identifier, x)
+        from sage.env import SAGE_DOC_SERVER_URL as url
+
+        if url:
+            def doc_url(path):
+                return '{}/{}'.format(url, path)
+        else:
+            from sage.env import SAGE_DOC_LOCAL_PORT as port
+
+            def doc_url(path):
+                return 'http://localhost:{}/{}'.format(port, path)
+
         return [
             {
                 'text': 'Sage Documentation',
-                'url': kernel_url('doc/html/en/index.html'),
+                'url': doc_url("html/en/index.html"),
             },
             {
                 'text': 'Tutorial',
-                'url': kernel_url('doc/html/en/tutorial/index.html'),
+                'url': doc_url('html/en/tutorial/index.html'),
             },
             {
                 'text': 'Thematic Tutorials',
-                'url': kernel_url('doc/html/en/thematic_tutorials/index.html'),
+                'url': doc_url('html/en/thematic_tutorials/index.html'),
             },
             {
                 'text': 'FAQs',
-                'url': kernel_url('doc/html/en/faq/index.html'),
+                'url': doc_url('html/en/faq/index.html'),
             },
             {
                 'text': 'PREP Tutorials',
-                'url': kernel_url('doc/html/en/prep/index.html'),
+                'url': doc_url('html/en/prep/index.html'),
             },
             {
                 'text': 'Reference',
-                'url': kernel_url('doc/html/en/reference/index.html'),
+                'url': doc_url('html/en/reference/index.html'),
             },
             {
                 'text': "Developer's Guide",
-                'url': kernel_url('doc/html/en/developer/index.html'),
+                'url': doc_url('html/en/developer/index.html'),
             },
             {
                 'text': "Python",