httplint

httplint

This Python library lints HTTP messages; it checks them for correctness and reports any issues it finds.

It performs all message-level checks for REDbot, but does not perform any 'active' checks by making requests to the network, and it does not have a Web user interface.

Using httplint as a Library

httplint exposes two classes for linting: HttpRequestLinter and HttpResponseLinter. They expose the following methods for telling the linter about the HTTP message:

• As appropriate:
  • process_request_topline, which takes three bytes arguments: method, uri, and version
  • process_response_topline, which takes three bytes arguments: version, status_code, and status_phrase
• process_headers for the headers, taking a list of (name, value) tuples (both bytes)
• feed_content for the body (which can be called zero to many times), taking an inbytes argument
• finish_content when done, which has two arguments; a bool indicating whether the response was complete, and an optional list of tuples for the trailers, in the same format that process_headers takes.

For example:

from httplint import HttpResponseLinter

linter = HttpResponseLinter()
linter.process_response_topline(b'HTTP/1.1', b'200', b'OK')
linter.process_headers([
  (b'Content-Type', b'text/plain'),
  (b'Content-Length', b'10'),
  (b'Cache-Control', b'max-age=60')
])
linter.feed_content(b'12345')
linter.feed_content(b'67890')
linter.finish_content(True)

Using httplint from the Command Line

httplint can also be used from the command line. For example:

> curl -s -i --raw https://www.mnot.net/ | httplint -n
* The Content-Length header is correct.
* The resource last changed 8 days 6 hr ago.
* This response allows all caches to store it.
* The server's clock is correct.
* This response is fresh until 3 hr from now.
* This response may still be served by a cache once it becomes stale.

Interpreting Notes

Once a message has been linted, the results will appear on the notes property. This is a list of Note objects, each having the following attributes:

• category - the Note's category; see note.categories
• level - see note.levels
• summary - a brief, one-line description of the note
• detail - a longer explanation

Note that summary is textual, and needs to be escaped in a markup environment; detail, however, is already escaped HTML.

Continuing our example:

for note in linter.notes:
  print(note.summary)

and the output should be:

The Content-Length header is correct.
This response allows all caches to store it.
This response doesn't have a Date header.
This response is fresh until 1 min from now.
This response may still be served by a cache once it becomes stale.

Field Descriptions

The description of any field can be found by calling get_field_description. For example:

>>> from httplint import get_field_description
>>> get_field_description("Allow")
'The `Allow` response header advertises the set of methods that are supported by the resource.'

If a description cannot be found it will return None.