[SPARK-11292] [SQL] Python API for text data source

Adds DataFrameReader.text and DataFrameWriter.text.

Author: Reynold Xin <rxin@databricks.com>

Closes #9259 from rxin/SPARK-11292.

python/pyspark/sql/readwriter.py

@@ -23,6 +23,7 @@ if sys.version >= '3':
 from py4j.java_gateway import JavaClass
 
 from pyspark import RDD, since
+from pyspark.rdd import ignore_unicode_prefix
 from pyspark.sql.column import _to_seq
 from pyspark.sql.types import *
 
@@ -193,10 +194,22 @@ class DataFrameReader(object):
         """
         return self._df(self._jreader.parquet(_to_seq(self._sqlContext._sc, paths)))
 
+    @ignore_unicode_prefix
+    @since(1.6)
+    def text(self, path):
+        """Loads a text file and returns a [[DataFrame]] with a single string column named "text".
+
+        Each line in the text file is a new row in the resulting DataFrame.
+
+        >>> df = sqlContext.read.text('python/test_support/sql/text-test.txt')
+        >>> df.collect()
+        [Row(text=u'hello'), Row(text=u'this')]
+        """
+        return self._df(self._jreader.text(path))
+
     @since(1.5)
     def orc(self, path):
-        """
-        Loads an ORC file, returning the result as a :class:`DataFrame`.
+        """Loads an ORC file, returning the result as a :class:`DataFrame`.
 
         ::Note: Currently ORC support is only available together with
         :class:`HiveContext`.
@@ -432,6 +445,16 @@ class DataFrameWriter(object):
             self.partitionBy(partitionBy)
         self._jwrite.parquet(path)
 
+    @since(1.6)
+    def text(self, path):
+        """Saves the content of the DataFrame in a text file at the specified path.
+
+        The DataFrame must have only one column that is of string type.
+        Each row becomes a new line in the output file.
+        """
+        self._jwrite.text(path)
+
+    @since(1.5)
     def orc(self, path, mode=None, partitionBy=None):
         """Saves the content of the :class:`DataFrame` in ORC format at the specified path.
 

python/test_support/sql/text-test.txt

+hello
+this
\ No newline at end of file