implementing FileReader/FileWriter (#2)

bonobo/__init__.py

@@ -38,7 +38,7 @@ __all__ = [
     'Bag',
     'FileWriter',
     'Graph',
-    'JsonFileWriter',
+    'JsonWriter',
     'NOT_MODIFIED',
     'NaiveStrategy',
     'ProcessPoolExecutorStrategy',

bonobo/compat/pandas.py

@@ -1,7 +1,7 @@
-from bonobo import FileWriter, JsonFileWriter
+from bonobo import FileWriter, JsonWriter
 
 to_file = FileWriter
-to_json = JsonFileWriter
+to_json = JsonWriter
 
 __all__ = [
     'to_json',

bonobo/ext/console/plugin.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 #
-# Copyright 2012-2014 Romain Dorgueil
+# Copyright 2012-2017 Romain Dorgueil
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

bonobo/ext/jupyter/plugin.py

@@ -3,6 +3,16 @@ from IPython.core.display import display
 from bonobo.core.plugins import Plugin
 from bonobo.ext.jupyter.widget import BonoboWidget
 
+try:
+    import selenium
+except ImportError as e:
+    import logging
+
+    logging.exception(
+        'You must install selenium to use the bonobo selenium extension. Easiest way is to install the '
+        'optional "selenium" dependencies with «pip install bonobo[selenium]», but you can also install a '
+        'specific version by yourself.')
+
 
 class JupyterOutputPlugin(Plugin):
     def initialize(self, context):

bonobo/ext/selenium.py

@@ -1,4 +1,12 @@
-from selenium import webdriver
+try:
+    import selenium
+except ImportError as e:
+    import logging
+
+    logging.exception(
+        'You must install selenium to use the bonobo selenium extension. Easiest way is to install the '
+        'optional "selenium" dependencies with «pip install bonobo[selenium]», but you can also install a '
+        'specific version by yourself.')
 
 from bonobo import service
 
@@ -6,7 +14,7 @@ USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/601.4.
 
 
 def create_profile(use_tor=False):
-    _profile = webdriver.FirefoxProfile()
+    _profile = selenium.webdriver.FirefoxProfile()
     _profile.set_preference("toolkit.startup.max_resumed_crashes", "-1")
 
     if use_tor:
@@ -22,7 +30,7 @@ def create_profile(use_tor=False):
 
 
 def create_browser(profile):
-    _browser = webdriver.Firefox(profile)
+    _browser = selenium.webdriver.Firefox(profile)
     _browser.implicitly_wait(10)
     _browser.set_page_load_timeout(10)
     return _browser

bonobo/io/__init__.py

@@ -1,9 +1,11 @@
 """ Readers and writers for common file formats. """
 
-from .file import FileWriter
+from .file import FileHandler, FileReader, FileWriter
-from .json import JsonFileWriter
+from .json import JsonWriter
 
 __all__ = [
+    'FileHandler',
+    'FileReader',
     'FileWriter',
-    'JsonFileWriter',
+    'JsonWriter',
 ]

bonobo/io/file.py

@@ -1,35 +1,118 @@
+from functools import partial
+
 from bonobo.util.lifecycle import with_context
 
-__all__ = ['FileWriter', ]
+__all__ = [
+    'FileHandler',
+    'FileReader',
+    'FileWriter',
+]
 
 
 @with_context
-class FileWriter:
+class FileHandler:
-    # XXX TODO implement @with_context like this ? Pros and cons ?
+    """
-    class Meta:
+    Abstract component factory for file-related components.
-        contextual = True
+
+    """
+
+    mode = None
 
     def __init__(self, path_or_buf, eol='\n'):
         self.path_or_buf = path_or_buf
         self.eol = eol
 
+    def open(self):
+        return open(self.path_or_buf, self.mode)
+
+    def close(self, fp):
+        """
+        :param file fp:
+        """
+        fp.close()
+
     def initialize(self, ctx):
-        """ todo add lock file ? optional maybe ? """
+        """
-        assert not hasattr(ctx, 'fp'), 'One at a time, baby.'
+        Initialize a
-        ctx.fp = open(self.path_or_buf, 'w+')
+        :param ctx:
-        ctx.first = True
+        :return:
+        """
+        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 write(self, fp, line, prefix=''):
+    def __call__(self, ctx, *args):
-        fp.write(prefix + line)
+        """
+        :param ComponentExecutionContext ctx:
+        :param mixed row:
+        """
+        result = self.handle(ctx, *args)
+        try:
+            yield from result
+        except TypeError:
+            return
 
-    def __call__(self, ctx, row):
+    def handle(self, ctx, *args):
-        if ctx.first:
+        raise NotImplementedError('Abstract.')
-            prefix, ctx.first = '', False
-        else:
-            prefix = self.eol
-
-        self.write(ctx.fp, row, prefix=prefix)
 
     def finalize(self, ctx):
-        ctx.fp.close()
+        self.close(ctx.file)
-        del ctx.fp, ctx.first
+        del ctx.file
+
+
+class FileReader(FileHandler):
+    """
+    Component factory for file-like readers.
+
+    On its own, it can be used to read a file and yield one row per line, trimming the "eol" character at the end if
+    present. Extending it is usually the right way to create more specific file readers (like json, csv, etc.)
+
+    """
+
+    mode = 'r'
+
+    def handle(self, ctx, *args):
+        """
+        Write a row on the next line of file pointed by `ctx.file`.
+        Prefix is used for newlines.
+
+        :param ctx:
+        :param row:
+        """
+        assert not len(args)
+        for line in ctx.file:
+            yield line.rstrip(self.eol)
+
+
+class FileWriter(FileHandler):
+    """
+    Component factory for file or file-like writers.
+
+    On its own, it can be used to write in a file one line per row that comes into this component. Extending it is
+    usually the right way to create more specific file writers (like json, csv, etc.)
+
+    """
+
+    mode = 'w+'
+
+    def initialize(self, ctx):
+        super().initialize(ctx)
+        ctx.line = 0
+
+    def handle(self, ctx, row):
+        """
+        Write a row on the next line of file pointed by fp. Prefix is used for newlines.
+
+        :param file fp:
+        :param str row:
+        :param str prefix:
+        """
+
+        self.write(ctx.file, (self.eol if ctx.line else '') + row)
+        ctx.line += 1
+
+    def write(self, fp, line):
+        return fp.write(line)
+
+    def finalize(self, ctx):
+        del ctx.line
+        super().finalize(ctx)

bonobo/io/json.py

@@ -3,11 +3,11 @@ import json
 from .file import FileWriter
 from bonobo.util.lifecycle import with_context
 
-__all__ = ['JsonFileWriter', ]
+__all__ = ['JsonWriter', ]
 
 
 @with_context
-class JsonFileWriter(FileWriter):
+class JsonWriter(FileWriter):
     def __init__(self, path_or_buf):
         super().__init__(path_or_buf, eol=',\n')
 

docs/reference/modules.rst

@@ -1,3 +0,0 @@
-bonobo
-======
-

examples/opendata_fablabs.py

@@ -2,7 +2,7 @@ import json
 
 from blessings import Terminal
 
-from bonobo import console_run, tee, JsonFileWriter
+from bonobo import console_run, tee, JsonWriter
 from bonobo.ext.opendatasoft import from_opendatasoft_api
 
 try:
@@ -58,5 +58,5 @@ if __name__ == '__main__':
         normalize,
         filter_france,
         tee(display),
-        JsonFileWriter('fablabs.json'),
+        JsonWriter('fablabs.json'),
         output=True, )

tests/io/test_file.py

@@ -0,0 +1,67 @@
+import pytest
+from mock import MagicMock
+
+from bonobo import FileWriter, Bag, FileReader
+from bonobo.core.contexts import ComponentExecutionContext
+from bonobo.util.tokens import BEGIN, END
+
+
+class CapturingComponentExecutionContext(ComponentExecutionContext):
+    send = MagicMock()
+
+
+@pytest.mark.parametrize(
+    'lines,output',
+    [
+        (('ACME', ), 'ACME'),  # one line...
+        (('Foo', 'Bar', 'Baz'), 'Foo\nBar\nBaz'),  # more than one line...
+    ])
+def test_file_writer_in_context(tmpdir, lines, output):
+    file = tmpdir.join('output.txt')
+
+    writer = FileWriter(str(file))
+    context = ComponentExecutionContext(writer, None)
+
+    context.initialize()
+    context.recv(BEGIN, *map(Bag, lines), END)
+    for i in range(len(lines)):
+        context.step()
+    context.finalize()
+
+    assert file.read() == output
+
+    with pytest.raises(AttributeError):
+        getattr(context, 'file')
+
+
+def test_file_writer_out_of_context(tmpdir):
+    file = tmpdir.join('output.txt')
+    writer = FileWriter(str(file))
+    fp = writer.open()
+    fp.write('Yosh!')
+    writer.close(fp)
+
+    assert file.read() == 'Yosh!'
+
+
+def test_file_reader_in_context(tmpdir):
+    file = tmpdir.join('input.txt')
+    file.write('Hello\nWorld\n')
+
+    reader = FileReader(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] == 'Hello'
+    assert args1[0].args[0] == 'World'

tests/io/test_json.py

@@ -1,13 +1,13 @@
 import pytest
 
-from bonobo import Bag, JsonFileWriter
+from bonobo import Bag, JsonWriter
 from bonobo.core.contexts import ComponentExecutionContext
 from bonobo.util.tokens import BEGIN, END
 
 
 def test_write_json_to_file(tmpdir):
     file = tmpdir.join('output.json')
-    json_writer = JsonFileWriter(str(file))
+    json_writer = JsonWriter(str(file))
     context = ComponentExecutionContext(json_writer, None)
 
     context.initialize()
@@ -28,7 +28,7 @@ def test_write_json_to_file(tmpdir):
 
 def test_write_json_without_initializer_should_not_work(tmpdir):
     file = tmpdir.join('output.json')
-    json_writer = JsonFileWriter(str(file))
+    json_writer = JsonWriter(str(file))
 
     context = ComponentExecutionContext(json_writer, None)
     with pytest.raises(AttributeError):