Still working on file handlers... JsonWriter (#2)

bonobo/io/__init__.py

@@ -1,10 +1,10 @@
 """ Readers and writers for common file formats. """
 
-from .file import FileHandler, FileReader, FileWriter
+from .file import Handler, FileReader, FileWriter
 from .json import JsonWriter
 
 __all__ = [
-    'FileHandler',
+    'Handler',
     'FileReader',
     'FileWriter',
     'JsonWriter',

bonobo/io/file.py

@@ -1,26 +1,25 @@
-from functools import partial
-
 from bonobo.util.lifecycle import with_context
 
 __all__ = [
-    'FileHandler',
+    'Handler',
     'FileReader',
     'FileWriter',
 ]
 
 
 @with_context
-class FileHandler:
+class Handler:
     """
     Abstract component factory for file-related components.
 
     """
 
+    eol = '\n'
     mode = None
 
-    def __init__(self, path_or_buf, eol='\n'):
+    def __init__(self, path_or_buf, eol=None):
         self.path_or_buf = path_or_buf
-        self.eol = eol
+        self.eol = eol or self.eol
 
     def open(self):
         return open(self.path_or_buf, self.mode)
@@ -40,26 +39,28 @@ class FileHandler:
         assert not hasattr(ctx, 'file'), 'A file pointer is already in the context... I do not know what to say...'
         ctx.file = self.open()
 
-    def __call__(self, ctx, *args):
-        """
-        :param ComponentExecutionContext ctx:
-        :param mixed row:
-        """
-        result = self.handle(ctx, *args)
-        try:
-            yield from result
-        except TypeError:
-            return
-
-    def handle(self, ctx, *args):
-        raise NotImplementedError('Abstract.')
-
     def finalize(self, ctx):
         self.close(ctx.file)
         del ctx.file
 
 
-class FileReader(FileHandler):
+class Reader(Handler):
+    def __call__(self, ctx):
+        yield from self.handle(ctx)
+
+    def handle(self, ctx):
+        raise NotImplementedError('Abstract.')
+
+
+class Writer(Handler):
+    def __call__(self, ctx, row):
+        return self.handle(ctx, row)
+
+    def handle(self, ctx, row):
+        raise NotImplementedError('Abstract.')
+
+
+class FileReader(Reader):
     """
     Component factory for file-like readers.
 
@@ -70,7 +71,7 @@ class FileReader(FileHandler):
 
     mode = 'r'
 
-    def handle(self, ctx, *args):
+    def handle(self, ctx):
         """
         Write a row on the next line of file pointed by `ctx.file`.
         Prefix is used for newlines.
@@ -78,12 +79,11 @@ class FileReader(FileHandler):
         :param ctx:
         :param row:
         """
-        assert not len(args)
         for line in ctx.file:
             yield line.rstrip(self.eol)
 
 
-class FileWriter(FileHandler):
+class FileWriter(Writer):
     """
     Component factory for file or file-like writers.
 
@@ -100,13 +100,12 @@ class FileWriter(FileHandler):
 
     def handle(self, ctx, row):
         """
-        Write a row on the next line of file pointed by fp. Prefix is used for newlines.
+        Write a row on the next line of opened file in context.
 
         :param file fp:
         :param str row:
         :param str prefix:
         """
-
         self.write(ctx.file, (self.eol if ctx.line else '') + row)
         ctx.line += 1
 

bonobo/io/json.py

@@ -1,23 +1,29 @@
 import json
 
 from .file import FileWriter
-from bonobo.util.lifecycle import with_context
 
 __all__ = ['JsonWriter', ]
 
 
-@with_context
+class JsonHandler:
-class JsonWriter(FileWriter):
+    eol = ',\n'
-    def __init__(self, path_or_buf):
-        super().__init__(path_or_buf, eol=',\n')
 
+
+class JsonWriter(JsonHandler, FileWriter):
     def initialize(self, ctx):
+        print('EOL', self.eol)
         super().initialize(ctx)
-        ctx.fp.write('[\n')
+        ctx.file.write('[\n')
 
-    def write(self, fp, line, prefix=''):
+    def handle(self, ctx, row):
-        fp.write(prefix + json.dumps(line))
+        """
+        Write a json row on the next line of file pointed by ctx.file.
+
+        :param ctx:
+        :param row:
+        """
+        return super().handle(ctx, json.dumps(row))
 
     def finalize(self, ctx):
-        ctx.fp.write('\n]')
+        ctx.file.write('\n]')
         super().finalize(ctx)

tests/io/test_json.py

@@ -20,7 +20,7 @@ def test_write_json_to_file(tmpdir):
 ]'''
 
     with pytest.raises(AttributeError):
-        getattr(context, 'fp')
+        getattr(context, 'file')
 
     with pytest.raises(AttributeError):
         getattr(context, 'first')