Add sed() convenience function

copied from fabric1 src

rattail_fabric2/__init__.py

@@ -37,4 +37,4 @@ from .core import (
     set_timezone,
     UNSPECIFIED,
 )
-from .util import exists, contains, append
+from .util import exists, contains, append, sed

rattail_fabric2/util.py

@@ -24,6 +24,8 @@
 Misc. Utilities
 """
 
+import hashlib
+
 
 def exists(c, path, use_sudo=False):
     """
@@ -192,3 +194,77 @@ def get_home_path(c, user=None):
     home = c.run('getent passwd {} | cut -d: -f6'.format(user)).stdout.strip()
     home = home.rstrip('/')
     return home
+
+
+def sed(c, filename, before, after, limit='', use_sudo=False, backup='.bak',
+        flags='',
+        # shell=False,
+):
+    """
+    NOTE: This was copied from the upstream ``fabric.contrib.files`` (v1) module.
+
+    Run a search-and-replace on ``filename`` with given regex patterns.
+
+    Equivalent to ``sed -i<backup> -r -e "/<limit>/ s/<before>/<after>/<flags>g"
+    <filename>``. Setting ``backup`` to an empty string will, disable backup
+    file creation.
+
+    For convenience, ``before`` and ``after`` will automatically escape forward
+    slashes, single quotes and parentheses for you, so you don't need to
+    specify e.g.  ``http:\/\/foo\.com``, instead just using ``http://foo\.com``
+    is fine.
+
+    If ``use_sudo`` is True, will use `sudo` instead of `run`.
+
+    ..
+       The ``shell`` argument will be eventually passed to `run`/`sudo`. It
+       defaults to False in order to avoid problems with many nested levels of
+       quotes and backslashes. However, setting it to True may help when using
+       ``~fabric.operations.cd`` to wrap explicit or implicit ``sudo`` calls.
+       (``cd`` by it's nature is a shell built-in, not a standalone command, so it
+       should be called within a shell.)
+
+    Other options may be specified with sed-compatible regex flags -- for
+    example, to make the search and replace case insensitive, specify
+    ``flags="i"``. The ``g`` flag is always specified regardless, so you do not
+    need to remember to include it when overriding this parameter.
+    """
+    func = use_sudo and c.sudo or c.run
+    # Characters to be escaped in both
+    for char in "/'":
+        before = before.replace(char, r'\%s' % char)
+        after = after.replace(char, r'\%s' % char)
+    # Characters to be escaped in replacement only (they're useful in regexen
+    # in the 'before' part)
+    for char in "()":
+        after = after.replace(char, r'\%s' % char)
+    if limit:
+        limit = r'/%s/ ' % limit
+    context = {
+        'script': r"'%ss/%s/%s/%sg'" % (limit, before, after, flags),
+        'filename': _expand_path(c, filename),
+        'backup': backup
+    }
+    # Test the OS because of differences between sed versions
+
+    # with hide('running', 'stdout'):
+    #     platform = run("uname", shell=False, pty=False)
+    platform = c.run("uname", pty=False, echo=False, hide=True)
+    if platform in ('NetBSD', 'OpenBSD', 'QNX'):
+        # Attempt to protect against failures/collisions
+        hasher = hashlib.sha1()
+        hasher.update(c.host_string) # TODO: what did env.host_string become?
+        hasher.update(filename)
+        context['tmp'] = "/tmp/%s" % hasher.hexdigest()
+        # Use temp file to work around lack of -i
+        expr = r"""cp -p %(filename)s %(tmp)s \
+&& sed -r -e %(script)s %(filename)s > %(tmp)s \
+&& cp -p %(filename)s %(filename)s%(backup)s \
+&& mv %(tmp)s %(filename)s"""
+    else:
+        context['extended_regex'] = '-E' if platform == 'Darwin' else '-r'
+        expr = r"sed -i%(backup)s %(extended_regex)s -e %(script)s %(filename)s"
+    command = expr % context
+    return func(command,
+                # shell=shell
+    )