Merge pull request #331 from hartym/302_csv_skip_headers_option

CSV skip headers option

bonobo/nodes/io/csv.py

@@ -54,16 +54,10 @@ class CsvHandler(FileHandler):
 @use_context
 class CsvReader(FileReader, CsvHandler):
     """
-    Reads a CSV and yield the values as dicts.
+    Reads a CSV and yield the values.
     """
 
-    skip = Option(
-        int,
-        default=0,
-        __doc__="""
-        If set and greater than zero, the reader will skip this amount of lines.
-    """,
-    )
+    skip = Option(int, default=0, __doc__="If set and greater than zero, the reader will skip this amount of lines.")
 
     @Method(
         positional=False,
@@ -96,6 +90,8 @@ class CsvReader(FileReader, CsvHandler):
 
 @use_context
 class CsvWriter(FileWriter, CsvHandler):
+    skip_header = Option(bool, default=False, __doc__="If true, the writer will not produce a file header.")
+
     @Method(
         __doc__="""
             Builds the CSV writer, a.k.a an object we can pass a field collection to be written as one line in the
@@ -114,7 +110,7 @@ class CsvWriter(FileWriter, CsvHandler):
         if not context.lineno:
             context.writer = self.writer_factory(file)
 
-            if fields:
+            if fields and not self.skip_header:
                 context.writer(fields)
                 context.lineno += 1
 

tests/nodes/io/test_csv.py

@@ -89,6 +89,22 @@ class CsvWriterTest(Csv, WriterTest, TestCase):
 
         assert self.readlines() == ("foo,bar", "a,b", "c,d")
 
+    @incontext(skip_header=False)
+    def test_fields_with_headers(self, context):
+        context.set_input_fields(["foo", "bar"])
+        context.write_sync(("a", "b"), ("c", "d"))
+        context.stop()
+
+        assert self.readlines() == ("foo,bar", "a,b", "c,d")
+
+    @incontext(skip_header=True)
+    def test_fields_without_headers(self, context):
+        context.set_input_fields(["foo", "bar"])
+        context.write_sync(("a", "b"), ("c", "d"))
+        context.stop()
+
+        assert self.readlines() == ("a,b", "c,d")
+
     @incontext()
     def test_fields_from_type(self, context):
         context.set_input_type(namedtuple("Point", "x y"))