[IMPL] - added support for sass and scss stylesheet languages

- better checking of stylesheets to be compiled
 - added support for sass and scss stylesheet languages
 - the stylesheets files are now copied to ".web/styles/" at compile time
 - relock poetry file for libsass deps
 - stylesheet compiler unit tests also check the contents of the file

pyproject.toml

@@ -59,6 +59,7 @@ twine = ">=4.0.0,<6.0"
 tomlkit = ">=0.12.4,<1.0"
 lazy_loader = ">=0.4"
 reflex-chakra = ">=0.6.0"
+libsass = "0.23.0"
 
 [tool.poetry.group.dev.dependencies]
 pytest = ">=7.1.2,<9.0"

reflex/compiler/compiler.py

@@ -4,8 +4,12 @@ from __future__ import annotations
 
 from datetime import datetime
 from pathlib import Path
+from re import IGNORECASE as RE_IGNORECASE
+from re import compile as re_compile
 from typing import TYPE_CHECKING, Dict, Iterable, Optional, Tuple, Type, Union
 
+from sass import compile as sass_compile
+
 from reflex import constants
 from reflex.compiler import templates, utils
 from reflex.components.base.fragment import Fragment
@@ -24,6 +28,8 @@ from reflex.utils.imports import ImportVar
 from reflex.utils.prerequisites import get_web_dir
 from reflex.vars.base import LiteralVar, Var
 
+RE_SASS_SCSS_EXT = re_compile(r"\.s(c|a)ss", flags=RE_IGNORECASE)
+
 
 def _compile_document_root(root: Component) -> str:
     """Compile the document root.
@@ -189,18 +195,66 @@ def _compile_root_stylesheet(stylesheets: list[str]) -> str:
         if get_config().tailwind is not None
         else []
     )
-    for stylesheet in stylesheets:
+
+    while len(stylesheets):
+        stylesheet = stylesheets.pop(0)
         if not utils.is_valid_url(stylesheet):
             # check if stylesheet provided exists.
-            stylesheet_full_path = (
+            assets_app_path = Path.cwd() / constants.Dirs.APP_ASSETS
-                Path.cwd() / constants.Dirs.APP_ASSETS / stylesheet.strip("/")
+            stylesheet_full_path = assets_app_path / stylesheet.strip("/")
-            )
+
             if not stylesheet_full_path.exists():
                 raise FileNotFoundError(
                     f"The stylesheet file {stylesheet_full_path} does not exist."
                 )
-            stylesheet = f"../{constants.Dirs.PUBLIC}/{stylesheet.strip('/')}"
+            elif not stylesheet_full_path.is_file():
+                if stylesheet_full_path.is_dir():
+                    # NOTE: this can create an infinite loop, for example:
+                    # assets/
+                    #   | dir_a/
+                    #   |   | dir_c/ (symlink to "assets/dir_a")
+                    #   | dir_b/
+                    # so to avoid the infinite loop, we don't include symbolic links
+                    stylesheets += [
+                        str(p.relative_to(assets_app_path))
+                        for p in stylesheet_full_path.iterdir()
+                        if not p.is_symlink()
+                    ]
+                    continue
+                else:
+                    raise FileNotFoundError(
+                        f'The stylesheet path "{stylesheet_full_path}" is not a valid path.'
+                    )
+            elif (
+                stylesheet_full_path.suffix[1:]
+                not in constants.Reflex.STYLESHEETS_SUPPORTED
+            ):
+                raise FileNotFoundError(
+                    f'The stylesheet file "{stylesheet_full_path}" is not a valid file.'
+                )
+
+            if (
+                stylesheet_full_path.suffix[1:]
+                in constants.Reflex.STYLESHEETS_SUPPORTED
+            ):
+                target = (
+                    Path.cwd()
+                    / f"{constants.Dirs.WEB}/{constants.Dirs.STYLES}/{RE_SASS_SCSS_EXT.sub(".css", str(stylesheet)).strip('/')}"
+                )
+                target.parent.mkdir(parents=True, exist_ok=True)
+                target.write_text(
+                    data=sass_compile(
+                        filename=str(stylesheet_full_path), output_style="compressed"
+                    ),
+                    encoding="utf8",
+                )
+            else:
+                pass
+
+            stylesheet = f"./{RE_SASS_SCSS_EXT.sub(".css", str(stylesheet)).strip('/')}"
+
         sheets.append(stylesheet) if stylesheet not in sheets else None
+
     return templates.STYLE.render(stylesheets=sheets)
 
 

reflex/constants/base.py

@@ -80,6 +80,9 @@ class Reflex(SimpleNamespace):
 
     RELEASES_URL = "https://api.github.com/repos/reflex-dev/templates/releases"
 
+    # The reflex stylesheet language supported
+    STYLESHEETS_SUPPORTED = ["css", "sass", "scss"]
+
 
 class ReflexHostingCLI(SimpleNamespace):
     """Base constants concerning Reflex Hosting CLI."""

reflex/utils/build.py

@@ -220,6 +220,9 @@ def setup_frontend(
     path_ops.cp(
         src=str(root / constants.Dirs.APP_ASSETS),
         dest=str(root / prerequisites.get_web_dir() / constants.Dirs.PUBLIC),
+        ignore=tuple(
+            f"*.{ext}" for ext in constants.Reflex.STYLESHEETS_SUPPORTED
+        ),  # ignore stylesheet files precompiled in the compiler
     )
 
     # Set the environment variables in client (env.json).

reflex/utils/path_ops.py

@@ -28,13 +28,19 @@ def rm(path: str | Path):
         path.unlink()
 
 
-def cp(src: str | Path, dest: str | Path, overwrite: bool = True) -> bool:
+def cp(
+    src: str | Path,
+    dest: str | Path,
+    overwrite: bool = True,
+    ignore: tuple[str, ...] | None = None,
+) -> bool:
     """Copy a file or directory.
 
     Args:
         src: The path to the file or directory.
         dest: The path to the destination.
         overwrite: Whether to overwrite the destination.
+        ignore: Ignoring files and directories that match one of the glob-style patterns provided
 
     Returns:
         Whether the copy was successful.
@@ -46,7 +52,11 @@ def cp(src: str | Path, dest: str | Path, overwrite: bool = True) -> bool:
         return False
     if src.is_dir():
         rm(dest)
-        shutil.copytree(src, dest)
+        shutil.copytree(
+            src,
+            dest,
+            ignore=shutil.ignore_patterns(*ignore) if ignore is not None else ignore,
+        )
     else:
         shutil.copyfile(src, dest)
     return True

tests/units/compiler/test_compiler.py

@@ -106,7 +106,7 @@ def test_compile_imports(import_dict: ParsedImportDict, test_dicts: List[dict]):
         assert sorted(import_dict["rest"]) == test_dict["rest"]  # type: ignore
 
 
-def test_compile_stylesheets(tmp_path, mocker):
+def test_compile_stylesheets(tmp_path: Path, mocker):
     """Test that stylesheets compile correctly.
 
     Args:
@@ -119,25 +119,50 @@ def test_compile_stylesheets(tmp_path, mocker):
     assets_dir = project / "assets"
     assets_dir.mkdir()
 
-    (assets_dir / "styles.css").touch()
+    assets_preprocess_dir = project / "assets" / "preprocess"
+    assets_preprocess_dir.mkdir()
+
+    (assets_dir / "styles.css").write_text(
+        "button.rt-Button {\n\tborder-radius:unset !important;\n}"
+    )
+    (assets_preprocess_dir / "styles_a.sass").write_text(
+        "button.rt-Button\n\tborder-radius:unset !important"
+    )
+    (assets_preprocess_dir / "styles_b.scss").write_text(
+        "button.rt-Button {\n\tborder-radius:unset !important;\n}"
+    )
     mocker.patch("reflex.compiler.compiler.Path.cwd", return_value=project)
 
     stylesheets = [
         "https://fonts.googleapis.com/css?family=Sofia&effect=neon|outline|emboss|shadow-multiple",
         "https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css",
         "/styles.css",
+        "/preprocess/styles_a.sass",
+        "/preprocess/styles_b.scss",
         "https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap-theme.min.css",
     ]
 
     assert compiler.compile_root_stylesheet(stylesheets) == (
         str(Path(".web") / "styles" / "styles.css"),
-        "@import url('./tailwind.css'); \n"
+        f"@import url('./tailwind.css'); \n"
-        "@import url('https://fonts.googleapis.com/css?family=Sofia&effect=neon|outline|emboss|shadow-multiple'); \n"
+        f"@import url('https://fonts.googleapis.com/css?family=Sofia&effect=neon|outline|emboss|shadow-multiple'); \n"
-        "@import url('https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css'); \n"
+        f"@import url('https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css'); \n"
-        "@import url('../public/styles.css'); \n"
+        f"@import url('./styles.css'); \n"
-        "@import url('https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap-theme.min.css'); \n",
+        f"@import url('./preprocess/styles_a.css'); \n"
+        f"@import url('./preprocess/styles_b.css'); \n"
+        f"@import url('https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap-theme.min.css'); \n",
     )
 
+    # NOTE: the css file is also inserted into the s(a|c)ss preprocessor, which compressed the result, which means we don't have the tab, return,... characters.
+    expected_result = "button.rt-Button{border-radius:unset !important}\n"
+    assert (project / ".web" / "styles" / "styles.css").read_text() == expected_result
+    assert (
+        project / ".web" / "styles" / "preprocess" / "styles_a.css"
+    ).read_text() == expected_result
+    assert (
+        project / ".web" / "styles" / "preprocess" / "styles_b.css"
+    ).read_text() == expected_result
+
 
 def test_compile_stylesheets_exclude_tailwind(tmp_path, mocker):
     """Test that Tailwind is excluded if tailwind config is explicitly set to None.
@@ -165,7 +190,7 @@ def test_compile_stylesheets_exclude_tailwind(tmp_path, mocker):
 
     assert compiler.compile_root_stylesheet(stylesheets) == (
         str(Path(".web") / "styles" / "styles.css"),
-        "@import url('../public/styles.css'); \n",
+        "@import url('./styles.css'); \n",
     )