tasks.py

import json
import os

from binascii import hexlify
from invoke import task
from hyper.http20.hpack import Encoder

@task
def hpack():
 """
 This task generates HPACK test data suitable for use with
 https://github.com/http2jp/hpack-test-case

 The current format defines a JSON object with three keys: 'draft',
 'description' and 'cases'.

 The cases key has as its value a list of objects, with each object
 representing a set of headers and the output from the encoder. The object
 has the following keys:

 - 'header_table_size': the size of the header table used.
 - 'headers': A list of the headers as JSON objects.
 - 'wire': The output from the encoder in hexadecimal.
 """
 # A generator that contains the paths to all the raw data files and their
 # names.
 raw_story_files = (
 (os.path.join('test_fixtures/raw-data', name), name)
 for name in os.listdir('test_fixtures/raw-data')
 )

 # For each file, build our output.
 for source, outname in raw_story_files:
 with open(source, 'rb') as f:
 indata = json.loads(f.read())

 # Prepare the output and the encoder.
 output = {
 'description': 'Encoded by hyper. See github.com/Lukasa/hyper for more information.',
 'cases': []
 }
 e = Encoder()

 for case in indata['cases']:
 outcase = {'header_table_size': e.header_table_size}
 outcase['headers'] = case['headers']
 headers = []

 for header in case['headers']:
 key = header.keys()[0]
 header = (key, header[key])
 headers.append(header)

 outcase['wire'] = hexlify(e.encode(headers))
 output['cases'].append(outcase)

 with open(outname, 'wb') as f:
 f.write(json.dumps(output, sort_keys=True,
 indent=2, separators=(',', ': ')))