✨ Add initial support for browsing gemtext in file system

Author: davep

src/rogallo/preflight.py

@@ -2,6 +2,7 @@
 
 ##############################################################################
 # Python imports.
+from pathlib import Path
 from urllib.parse import urlparse
 
 ##############################################################################
@@ -41,4 +42,39 @@ def is_likely_capsule(uri: str) -> bool:
         return is_likely_page_relative(uri)
 
 
+##############################################################################
+def path_from_uri(uri: str) -> Path:
+    """Get the path from a URI.
+
+    Args:
+        uri: The URI to get the path from.
+
+    Returns:
+        The path from the URI.
+    """
+
+    if (parsed := urlparse(uri)).scheme == "file":
+        return Path(parsed.path)
+    elif not parsed.scheme and not parsed.netloc:
+        return Path(uri)
+    raise ValueError(f"URI is not a local file: {uri}")
+
+
+##############################################################################
+def is_likely_local_file(uri: str) -> bool:
+    """Determine if a URI is likely a local file.
+
+    Args:
+        uri: The URI to check.
+
+    Returns:
+        `True` if the URI is likely a local file, `False` otherwise.
+    """
+    try:
+        candidate = path_from_uri(uri)
+    except ValueError:
+        return False
+    return candidate.exists() and candidate.is_file()
+
+
 ### location_tests.py ends here

src/rogallo/screens/main.py

@@ -3,6 +3,7 @@
 ##############################################################################
 # Python imports.
 from argparse import Namespace
+from pathlib import Path
 from webbrowser import open as open_in_browser
 
 ##############################################################################
@@ -50,6 +51,7 @@
     update_configuration,
 )
 from ..messages import OpenLocation, OpenText, OpenURI
+from ..preflight import is_likely_local_file, path_from_uri
 from ..providers import MainCommands
 from ..widgets import CommandLine, HistoryViewer, Viewer
 
@@ -305,6 +307,27 @@ async def _load_from_capsule(self, request: OpenLocation) -> None:
         finally:
             self._command_line.working = False
 
+    @work(thread=True)
+    def _load_from_filesystem(self, request: OpenLocation) -> None:
+        """Load a document from the filesystem.
+
+        Args:
+            request: The request to load the document from.
+        """
+        assert isinstance(request.location, Path)
+        try:
+            self.post_message(
+                OpenText(request.location.read_text(encoding="utf-8"), request.location)
+            )
+            # TODO: Remember in history.
+        except IOError as error:
+            self.notify(
+                f"Error loading {request.location}:\n\n{error}",
+                severity="error",
+                title="Filesystem Error",
+            )
+            return
+
     @on(OpenText)
     def open_text(self, message: OpenText) -> None:
         """Open text in the viewer.
@@ -324,6 +347,8 @@ def open_location(self, message: OpenLocation) -> None:
         """
         if isinstance(message.location, GeminiURI):
             self._load_from_capsule(message)
+        else:
+            self._load_from_filesystem(message)
 
     @on(OpenURI)
     def open_uri(self, message: OpenURI) -> None:
@@ -340,7 +365,10 @@ def open_uri(self, message: OpenURI) -> None:
         except URIError:
             pass
 
-        # TODO: Handle gmi files in the filesystem.
+        # Perhaps it's a local file?
+        if is_likely_local_file(message.uri):
+            self.post_message(OpenLocation(path_from_uri(message.uri)))
+            return
 
         # Otherwise, try to open it in the system browser.
         open_in_browser(message.uri)

src/rogallo/widgets/command_line/open_file.py

@@ -0,0 +1,37 @@
+"""Provides a command for opening a gemtext file in the local filesystem."""
+
+##############################################################################
+# Textual imports.
+from textual.widget import Widget
+
+##############################################################################
+# Local imports.
+from ...messages import OpenLocation
+from ...preflight import is_likely_local_file, path_from_uri
+from .base_command import InputCommand
+
+
+##############################################################################
+class OpenFileCommand(InputCommand):
+    """Open `<file>` in your external browser"""
+
+    COMMAND = "`<file>`"
+
+    @classmethod
+    def handle(cls, text: str, for_widget: Widget) -> bool:
+        """Handle the command.
+
+        Args:
+            text: The text of the command.
+            for_widget: The widget to handle the command for.
+
+        Returns:
+            `True` if the command was handled; `False` if not.
+        """
+        if is_likely_local_file(text):
+            for_widget.post_message(OpenLocation(path_from_uri(text)))
+            return True
+        return False
+
+
+### open_file.py ends here

src/rogallo/widgets/command_line/widget.py

@@ -33,13 +33,15 @@
 from ...data import CommandLineHistory
 from .base_command import InputCommand
 from .general import HelpCommand, QuitCommand
+from .open_file import OpenFileCommand
 from .open_gemini_uri import OpenGeminiURICommand
 from .open_other_uri import OpenOtherURICommand
 
 ##############################################################################
 COMMANDS: Final[tuple[type[InputCommand], ...]] = (
     OpenGeminiURICommand,
     OpenOtherURICommand,
+    OpenFileCommand,
     HelpCommand,
     QuitCommand,
 )

src/rogallo/widgets/viewer/gemtext_blocks.py

@@ -4,6 +4,7 @@
 # Python imports.
 from collections.abc import Callable
 from functools import cache
+from pathlib import Path
 from typing import Final
 from urllib.parse import urlparse
 
@@ -226,6 +227,8 @@ def normalise_uri(self, base_uri: GeminiLocation | None) -> None:
             return
         if isinstance(base_uri, GeminiURI):
             self._normalised_uri = str(base_uri.resolve(self._link.uri))
+        elif isinstance(base_uri, Path):
+            self._normalised_uri = (base_uri.parent / self._link.uri).resolve().as_uri()
 
     def _watch__normalised_uri(self) -> None:
         """Watch for changes to the normalised URI."""