[MRG + 1] Add suppress_warnings flag (#155)

* Add suppress_warnings flag

* Add --quiet flag to cli (to suppress warnings)

* Remove TODO and update comment

camelot/cli.py

@@ -38,6 +38,7 @@ pass_config = click.make_pass_decorator(Config)
               ' font size. Useful to detect super/subscripts.')
 @click.option('-M', '--margins', nargs=3, default=(1.0, 0.5, 0.1),
               help='PDFMiner char_margin, line_margin and word_margin.')
+@click.option('-q', '--quiet', is_flag=True, help='Suppress warnings.')
 @click.pass_context
 def cli(ctx, *args, **kwargs):
     """Camelot: PDF Table Extraction for Humans"""
@@ -89,6 +90,7 @@ def lattice(c, *args, **kwargs):
     output = conf.pop('output')
     f = conf.pop('format')
     compress = conf.pop('zip')
+    suppress_warnings = conf.pop('quiet')
     plot_type = kwargs.pop('plot_type')
     filepath = kwargs.pop('filepath')
     kwargs.update(conf)
@@ -99,7 +101,8 @@ def lattice(c, *args, **kwargs):
     kwargs['copy_text'] = None if not copy_text else copy_text
     kwargs['shift_text'] = list(kwargs['shift_text'])
 
-    tables = read_pdf(filepath, pages=pages, flavor='lattice', **kwargs)
+    tables = read_pdf(filepath, pages=pages, flavor='lattice',
+                      suppress_warnings=suppress_warnings, **kwargs)
     click.echo('Found {} tables'.format(tables.n))
     if plot_type is not None:
         for table in tables:
@@ -134,6 +137,7 @@ def stream(c, *args, **kwargs):
     output = conf.pop('output')
     f = conf.pop('format')
     compress = conf.pop('zip')
+    suppress_warnings = conf.pop('quiet')
     plot_type = kwargs.pop('plot_type')
     filepath = kwargs.pop('filepath')
     kwargs.update(conf)
@@ -143,7 +147,8 @@ def stream(c, *args, **kwargs):
     columns = list(kwargs['columns'])
     kwargs['columns'] = None if not columns else columns
 
-    tables = read_pdf(filepath, pages=pages, flavor='stream', **kwargs)
+    tables = read_pdf(filepath, pages=pages, flavor='stream',
+                      suppress_warnings=suppress_warnings, **kwargs)
     click.echo('Found {} tables'.format(tables.n))
     if plot_type is not None:
         for table in tables:

camelot/io.py

@@ -1,10 +1,12 @@
 # -*- coding: utf-8 -*-
+import warnings
 
 from .handlers import PDFHandler
 from .utils import validate_input, remove_extra
 
 
-def read_pdf(filepath, pages='1', flavor='lattice', **kwargs):
+def read_pdf(filepath, pages='1', flavor='lattice', suppress_warnings=False,
+             **kwargs):
     """Read PDF and return extracted tables.
 
     Note: kwargs annotated with ^ can only be used with flavor='stream'
@@ -20,6 +22,8 @@ def read_pdf(filepath, pages='1', flavor='lattice', **kwargs):
     flavor : str (default: 'lattice')
         The parsing method to use ('lattice' or 'stream').
         Lattice is used by default.
+    suppress_warnings : bool, optional (default: False)
+        Prevent warnings from being emitted by Camelot.
     table_area : list, optional (default: None)
         List of table area strings of the form x1,y1,x2,y2
         where (x1, y1) -> left-top and (x2, y2) -> right-bottom
@@ -85,6 +89,10 @@ def read_pdf(filepath, pages='1', flavor='lattice', **kwargs):
         raise NotImplementedError("Unknown flavor specified."
                                   " Use either 'lattice' or 'stream'")
 
+    with warnings.catch_warnings():
+        if suppress_warnings:
+            warnings.simplefilter("ignore")
+
         validate_input(kwargs, flavor=flavor)
         p = PDFHandler(filepath, pages)
         kwargs = remove_extra(kwargs, flavor=flavor)

tests/test_cli.py

@@ -77,3 +77,17 @@ def test_cli_output_format():
         result = runner.invoke(cli, ['--zip', '--format', 'csv', '--output', outfile.format('csv'),
                                      'stream', infile])
         assert result.exit_code == 0
+
+def test_cli_quiet_flag():
+    with TemporaryDirectory() as tempdir:
+        infile = os.path.join(testdir, 'blank.pdf')
+        outfile = os.path.join(tempdir, 'blank.csv')
+        runner = CliRunner()
+
+        result = runner.invoke(cli, ['--format', 'csv', '--output', outfile,
+                                     'stream', infile])
+        assert 'No tables found on page-1' in result.output
+
+        result = runner.invoke(cli, ['--quiet', '--format', 'csv',
+                                     '--output', outfile, 'stream', infile])
+        assert 'No tables found on page-1' not in result.output

tests/test_errors.py

@@ -43,11 +43,20 @@ def test_stream_equal_length():
 
 def test_no_tables_found():
     filename = os.path.join(testdir, 'blank.pdf')
-    # TODO: use pytest.warns
     with warnings.catch_warnings():
         warnings.simplefilter('error')
-        try:
+        with pytest.raises(UserWarning) as e:
             tables = camelot.read_pdf(filename)
-        except Exception as e:
+        assert str(e.value) == 'No tables found on page-1'
-            assert type(e).__name__ == 'UserWarning'
+
-            assert str(e) == 'No tables found on page-1'
+
+def test_no_tables_found_warnings_supressed():
+    filename = os.path.join(testdir, 'blank.pdf')
+    with warnings.catch_warnings():
+        # the test should fail if any warning is thrown
+        warnings.simplefilter('error')
+        try:
+            tables = camelot.read_pdf(filename, suppress_warnings=True)
+        except Warning as e:
+            warning_text = str(e)
+            pytest.fail('Unexpected warning: {}'.format(warning_text))