Implements JsonReader (#2)

bonobo/__init__.py

@@ -23,7 +23,7 @@ import os
 import sys
 
 from .core import *
-from .io import *
+from .io import FileReader, FileWriter, JsonReader, JsonWriter
 from .util import *
 
 PY35 = (sys.version_info >= (3, 5))
@@ -36,8 +36,10 @@ with open(os.path.realpath(os.path.join(os.path.dirname(__file__), '../version.t
 
 __all__ = [
     'Bag',
+    'FileReader',
     'FileWriter',
     'Graph',
+    'JsonReader',
     'JsonWriter',
     'NOT_MODIFIED',
     'NaiveStrategy',

bonobo/io/__init__.py

@@ -1,11 +1,11 @@
 """ Readers and writers for common file formats. """
 
-from .file import Handler, FileReader, FileWriter
-from .json import JsonWriter
+from .file import FileReader, FileWriter
+from .json import JsonReader, JsonWriter
 
 __all__ = [
-    'Handler',
     'FileReader',
     'FileWriter',
+    'JsonReader',
     'JsonWriter',
 ]

bonobo/io/file.py

@@ -1,14 +1,14 @@
 from bonobo.util.lifecycle import with_context
 
 __all__ = [
-    'Handler',
+    'FileHandler',
     'FileReader',
     'FileWriter',
 ]
 
 
 @with_context
-class Handler:
+class FileHandler:
     """
     Abstract component factory for file-related components.
 
@@ -44,7 +44,7 @@ class Handler:
         del ctx.file
 
 
-class Reader(Handler):
+class Reader(FileHandler):
     def __call__(self, ctx):
         yield from self.handle(ctx)
 
@@ -52,7 +52,7 @@ class Reader(Handler):
         raise NotImplementedError('Abstract.')
 
 
-class Writer(Handler):
+class Writer(FileHandler):
     def __call__(self, ctx, row):
         return self.handle(ctx, row)
 

bonobo/io/json.py

@@ -1,6 +1,6 @@
 import json
 
-from .file import FileWriter
+from .file import FileWriter, FileReader
 
 __all__ = ['JsonWriter', ]
 
@@ -9,9 +9,14 @@ class JsonHandler:
     eol = ',\n'
 
 
+class JsonReader(JsonHandler, FileReader):
+    def handle(self, ctx):
+        for line in json.load(ctx.file):
+            yield line
+
+
 class JsonWriter(JsonHandler, FileWriter):
     def initialize(self, ctx):
-        print('EOL', self.eol)
         super().initialize(ctx)
         ctx.file.write('[\n')
 

bonobo/util/testing.py

@@ -0,0 +1,9 @@
+from unittest.mock import MagicMock
+
+from bonobo.core.contexts import ComponentExecutionContext
+
+
+class CapturingComponentExecutionContext(ComponentExecutionContext):
+    def __init__(self, component, parent):
+        super().__init__(component, parent)
+        self.send = MagicMock()

tests/io/test_file.py

@@ -1,15 +1,11 @@
 import pytest
-from mock import MagicMock
 
 from bonobo import FileWriter, Bag, FileReader
 from bonobo.core.contexts import ComponentExecutionContext
+from bonobo.util.testing import CapturingComponentExecutionContext
 from bonobo.util.tokens import BEGIN, END
 
 
-class CapturingComponentExecutionContext(ComponentExecutionContext):
-    send = MagicMock()
-
-
 @pytest.mark.parametrize(
     'lines,output',
     [

tests/io/test_json.py

@@ -1,7 +1,8 @@
 import pytest
 
-from bonobo import Bag, JsonWriter
+from bonobo import Bag, JsonWriter, JsonReader
 from bonobo.core.contexts import ComponentExecutionContext
+from bonobo.util.testing import CapturingComponentExecutionContext
 from bonobo.util.tokens import BEGIN, END
 
 
@@ -33,3 +34,26 @@ def test_write_json_without_initializer_should_not_work(tmpdir):
     context = ComponentExecutionContext(json_writer, None)
     with pytest.raises(AttributeError):
         json_writer(context, {'foo': 'bar'})
+
+
+def test_read_json_from_file(tmpdir):
+    file = tmpdir.join('input.json')
+    file.write('[{"x": "foo"},{"x": "bar"}]')
+    reader = JsonReader(str(file))
+
+    context = CapturingComponentExecutionContext(reader, None)
+
+    context.initialize()
+    context.recv(BEGIN, Bag(), END)
+    context.step()
+    context.finalize()
+
+    assert len(context.send.mock_calls) == 2
+
+    args0, kwargs0 = context.send.call_args_list[0]
+    assert len(args0) == 1 and not len(kwargs0)
+    args1, kwargs1 = context.send.call_args_list[1]
+    assert len(args1) == 1 and not len(kwargs1)
+
+    assert args0[0].args[0] == {'x': 'foo'}
+    assert args1[0].args[0] == {'x': 'bar'}