Merge pull request #257 from CycloneDX/fix/256-no-default-file-when-n…

…o-input-on-stdin

FIX: Fallback to default manifest names in current directory when no `-i` supplied and nothing piped in via STDIN

README.md

@@ -135,7 +135,26 @@ You can then run `cyclonedx-bom` as follows:
 cyclonedx-bom -p -i PATH/TO/poetry.lock -o sbom.xml
 ```
 
-#### Pip / Requirements
+If your `poetry.lock` is in the current working directory, you can also shorten this to:
+```
+cyclonedx-bom -p -o sbom.xml
+```
+
+#### Pip
+
+We currently support `Pipfile.lock` manifest files.
+
+You can then run `cyclonedx-bom` as follows:
+```
+cyclonedx-bom -pip -i PATH/TO/Pipfile.lock -o sbom.xml
+```
+
+If your `Pipfile.lock` is in the current working directory, you can also shorten this to:
+```
+cyclonedx-bom -pip -o sbom.xml
+```
+
+#### Requirements
 
 We currently support `requirements.txt` manifest files. Note that a BOM such as CycloneDX expects exact version numbers, 
 therefore if you wish to generate a BOM from a `requirements.txt`, these must be frozen. This can be accomplished via:
@@ -144,11 +163,16 @@ therefore if you wish to generate a BOM from a `requirements.txt`, these must be
 pip freeze > requirements.txt
 ```
 
-You can then run `cyclonedx-py` as follows:
+You can then run `cyclonedx-bom` as follows:
 ```
 cyclonedx-bom -r -i PATH/TO/requirements.txt -o sbom.xml
 ```
 
+If your `requirements.txt` is in the current working directory, you can also shorten this to:
+```
+cyclonedx-bom -r -o sbom.xml
+```
+
 This will generate a CycloneDX and output to STDOUT in XML using the latest schema version `1.3` by default.
 
 **Note:** If you failed to freeze your dependencies before passing the `requirements.txt` data to `cyclonedx-bom`, 

cyclonedx_py/client.py

@@ -33,6 +33,14 @@
 from cyclonedx.parser.requirements import RequirementsParser
 
 
+class CycloneDxCmdException(Exception):
+    pass
+
+
+class CycloneDxCmdNoInputFileSupplied(CycloneDxCmdException):
+    pass
+
+
 class CycloneDxCmd:
     # Whether debug output is enabled
     _DEBUG_ENABLED: bool = False
@@ -49,7 +57,14 @@ def __init__(self, args: argparse.Namespace):
             self._debug_message('Parsed Arguments: {}'.format(self._arguments))
 
     def get_output(self) -> BaseOutput:
-        parser = self._get_input_parser()
+        try:
+            parser = self._get_input_parser()
+        except CycloneDxCmdNoInputFileSupplied as e:
+            print(f'ERROR: {str(e)}')
+            exit(1)
+        except CycloneDxCmdException as e:
+            print(f'ERROR: {str(e)}')
+            exit(1)
 
         if parser.has_warnings():
             print('')
@@ -186,6 +201,29 @@ def _get_input_parser(self) -> BaseParser:
             return EnvironmentParser()
 
         # All other Parsers will require some input - grab it now!
+        if not self._arguments.input_source:
+            # Nothing passed via STDIN, and no FILENAME supplied, let's assume a default by input type for ease
+            current_directory = os.getcwd()
+            try:
+                if self._arguments.input_from_conda_explicit:
+                    raise CycloneDxCmdNoInputFileSupplied('When using input from Conda Explicit, you need to pipe input'
+                                                          'via STDIN')
+                elif self._arguments.input_from_conda_json:
+                    raise CycloneDxCmdNoInputFileSupplied('When using input from Conda JSON, you need to pipe input'
+                                                          'via STDIN')
+                elif self._arguments.input_from_pip:
+                    self._arguments.input_source = open(os.path.join(current_directory, 'Pipfile.lock'), 'r')
+                elif self._arguments.input_from_poetry:
+                    self._arguments.input_source = open(os.path.join(current_directory, 'poetry.lock'), 'r')
+                elif self._arguments.input_from_requirements:
+                    self._arguments.input_source = open(os.path.join(current_directory, 'requirements.txt'), 'r')
+                else:
+                    raise CycloneDxCmdException('Parser type could not be determined.')
+            except FileNotFoundError as e:
+                raise CycloneDxCmdNoInputFileSupplied(
+                    f'No input file was supplied and no input was provided on STDIN:\n{str(e)}'
+                )
+
         input_data_fh = self._arguments.input_source
         with input_data_fh:
             input_data = input_data_fh.read()
@@ -202,7 +240,7 @@ def _get_input_parser(self) -> BaseParser:
         elif self._arguments.input_from_requirements:
             return RequirementsParser(requirements_content=input_data)
         else:
-            raise ValueError('Parser type could not be determined.')
+            raise CycloneDxCmdException('Parser type could not be determined.')
 
 
 def main():