Add cli options "check" and "in-place"

README.md

@@ -34,25 +34,13 @@ This project can be used as either a command line utility or a Python library.
 
 ### Command line interface
 
-Print detailed help
+    Stdin -> Disk : cat input.toml | toml-sort
 
-    toml-sort --help
+    Disk -> Disk  : toml-sort -o output.toml input.toml
 
-Read from stdin, write to stdout:
+    Linting       : toml-sort --check input.toml
 
-    cat input.toml | toml-sort
-
-Read from file on disk, write to file on disk:
-
-    toml-sort -o output.toml input.toml
-
-Read from file on disk, write to stdout
-
-    toml-sort input.toml
-
-Read from stdin, write to file on disk
-
-    cat input.toml | toml-sort -o output.toml
+    Inplace Disk  : toml-sort --in-place input.toml
 
 ## Example
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "poetry.masonry.api"
 
 [tool.poetry]
 name = "toml-sort"
-version = "0.15.1"
+version = "0.16.0"
 description = "Toml sorting library"
 authors = ["Sam Roeca <[email protected]>"]
 readme = "README.md"
@@ -44,7 +44,7 @@ commands =
   poetry run black --check --diff toml_sort tests
   poetry run mypy toml_sort
   poetry run pylint toml_sort tests
-  poetry run pytest
+  poetry run pytest -vv
 """
 
 [tool.black]

toml_sort/cli.py

@@ -5,13 +5,33 @@
 
 from . import TomlSort
 
+# The standard stream
+STD_STREAM = "-"
+
+
+def read_file(path: str) -> str:
+    """Read contents from a file"""
+    if path == STD_STREAM:
+        return sys.stdin.read()
+    with open(path, "r") as fileobj:
+        return fileobj.read()
+
+
+def write_file(path: str, content: str) -> None:
+    """Write content to a path"""
+    if path == STD_STREAM:
+        click.echo(content, nl=False)
+        return
+    with open(path, "w") as fileobj:
+        fileobj.write(content)
+
 
 @click.command()
 @click.option(
     "-o",
     "--output",
-    type=click.File("w"),
-    default="-",
+    type=click.Path(file_okay=True, writable=True, allow_dash=True),
+    default=STD_STREAM,
     show_default=True,
     help="The output filepath. Choose stdout with '-'.",
 )
@@ -25,27 +45,54 @@
         "Default is to only sort non-inline 'tables and arrays of tables'."
     ),
 )
+@click.option(
+    "-i",
+    "--in-place",
+    is_flag=True,
+    help=(
+        "Makes changes to the original input file. "
+        "Note: you cannot redirect from a file to itself in Bash. "
+        "POSIX shells process redirections first, then execute the command."
+    ),
+)
 @click.option(
     "--no-header",
     is_flag=True,
     help="Do not keep a document's leading comments.",
 )
-@click.argument("filename", type=click.File("r"), default="-")
+@click.option(
+    "--check",
+    is_flag=True,
+    help=(
+        "Check if an original file is changed by the formatter. "
+        "Return code 0 means it would not change. "
+        "Return code 1 means it would change. "
+    ),
+)
+@click.argument(
+    "filename",
+    type=click.Path(
+        exists=True, file_okay=True, readable=True, allow_dash=True
+    ),
+    default=STD_STREAM,
+)
 @click.version_option()
-def cli(output, _all, no_header, filename) -> None:
+def cli(output, _all, in_place, no_header, check, filename) -> None:
     """Sort toml file FILENAME, saving results to a file, or stdout (default)
 
     FILENAME a filepath or standard input (-)
 
     Examples (non-exhaustive list):
 
-        Read from stdin, write to stdout: cat input.toml | toml-sort
+        Stdin -> Disk : cat input.toml | toml-sort
+
+        Disk -> Disk  : toml-sort -o output.toml input.toml
 
-        Read from disk, write to disk   : toml-sort -o output.toml input.toml
+        Linting       : toml-sort --check input.toml
 
-        Read from disk, write to stdout : toml-sort input.toml
+        Inplace Disk  : toml-sort --in-place input.toml
     """
-    if filename.isatty():
+    if filename == "-" and sys.stdin.isatty():
         error_message_if_terminal = """
 toml-sort: missing FILENAME, and no stdin
 Usage: toml-sort [OPTIONS] [FILENAME]
@@ -54,9 +101,24 @@ def cli(output, _all, no_header, filename) -> None:
 """.strip()
         click.echo(error_message_if_terminal, err=True)
         sys.exit(1)
+    elif in_place and filename == STD_STREAM:
+        click.echo("Cannot format stdin in-place", err=True)
+        sys.exit(1)
+    elif in_place and output != STD_STREAM:
+        click.echo("Cannot specify output file with in-place", err=True)
+        sys.exit(1)
+    original_toml = read_file(filename)
     sorted_toml = TomlSort(
-        input_toml=filename.read(),
+        input_toml=original_toml,
         only_sort_tables=not bool(_all),
         no_header=bool(no_header),
     ).sorted()
-    output.write(sorted_toml)
+    if check:
+        if original_toml != sorted_toml:
+            click.echo("File would be re-formatted", err=True)
+            sys.exit(1)
+        return
+    if in_place:
+        write_file(filename, sorted_toml)
+        return
+    write_file(output, sorted_toml)