X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/3d96b7f10a56fcf826693e98f08b673dad8ac256..ba618a307a30a119b4fafe526ebf7d5f092ba981:/docs/usage_and_configuration/black_as_a_server.md

diff --git a/docs/usage_and_configuration/black_as_a_server.md b/docs/usage_and_configuration/black_as_a_server.md
index 75a4d92..a2d4252 100644
--- a/docs/usage_and_configuration/black_as_a_server.md
+++ b/docs/usage_and_configuration/black_as_a_server.md
@@ -4,10 +4,15 @@
 protocol. The main benefit of using it is to avoid the cost of starting up a new _Black_
 process every time you want to blacken a file.
 
+```{warning}
+`blackd` should not be run as a publicly accessible server as there are no security
+precautions in place to prevent abuse. **It is intended for local use only**.
+```
+
 ## Usage
 
 `blackd` is not packaged alongside _Black_ by default because it has additional
-dependencies. You will need to execute `pip install black[d]` to install it.
+dependencies. You will need to execute `pip install 'black[d]'` to install it.
 
 You can start the server on the default port, binding only to the local interface by
 running `blackd`. You will see a single line mentioning the server's version, and the
@@ -49,8 +54,11 @@ The headers controlling how source code is formatted are:
   command line flag. If present and its value is not the empty string, no string
   normalization will be performed.
 - `X-Skip-Magic-Trailing-Comma`: corresponds to the `--skip-magic-trailing-comma`
-  command line flag. If present and its value is not the empty string, trailing commas
+  command line flag. If present and its value is not an empty string, trailing commas
   will not be used as a reason to split lines.
+- `X-Preview`: corresponds to the `--preview` command line flag. If present and its
+  value is not an empty string, experimental and potentially disruptive style changes
+  will be used.
 - `X-Fast-Or-Safe`: if set to `fast`, `blackd` will act as _Black_ does when passed the
   `--fast` command line flag.
 - `X-Python-Variant`: if set to `pyi`, `blackd` will act as _Black_ does when passed the