Simplicity is a Feature

When you talk to software professionals, you come away with the idea that we have a case of feature-itis. An enormous number of people evaluate software in terms of the length of feature lists and functionality. People dismiss software with fewer features as “underpowered”. And how many times have you heard software devalued because “I could build that”?

And yet, intuitively we know that’s not always true. urllib3 has more features than requests, but people overwhelmingly prefer to use requests. Android has more features than iOS, but Android hasn’t demolished iOS.

The reason for this is that simplicity is a powerful advantage. This talk will explain what is meant by simplicity, how to judge software simplicity, and how to approach building simple tools. It’ll also talk about how to structure your code to give the optimum balance of simplicity and flexibility, to keep yourself and your users happy down the line.

Transcript

1. Simplicity
   Is A Feature
   

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2. Hi!
   

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3. Me
   @lukasaoz
   @lukasa
   

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5. Warning
   Opinions!
   

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6. What Is
   Simplicity?
   

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11. import requests
    r = requests.get(
    ‘https://api.github.com',
    auth=('user', ‘pass')
    )
    

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12. import urllib2
    gh_url = 'https://api.github.com'
    req = urllib2.Request(gh_url)
    password_manager =
    urllib2.HTTPPasswordMgrWithDefaultRealm()
    password_manager.add_password(None, gh_url, 'user',
    'pass')
    auth_manager =
    urllib2.HTTPBasicAuthHandler(password_manager)
    opener = urllib2.build_opener(auth_manager)
    urllib2.install_opener(opener)
    handler = urllib2.urlopen(req)
    

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13. – Justice Potter Stewart
    “I know it when I
    see it.”
    

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14. Simplicity
    ⫫
    Features
    

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15. Simplicity is
    about defaults
    

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16. Why Be
    Simple?
    

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17. – Edsger Dijkstra
    “Simplicity is a
    prerequisite for
    reliability.”
    

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18. – Robert Browning
    “Less is more.”
    

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19. – Henry David Thoreau
    “Our life is
    frittered away by
    detail. Simplify.”
    

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20. How To Be
    Simple
    

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22. How To
    Onion
    

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23. Build In
    Layers
    

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24. Layer 1: Low-level
    

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25. import email.generator
    import http.client
    import io
    import os
    import shutil
    def _encode_multipart_formdata(fields, files):
    boundary = email.generator._make_boundary()
    buf = io.BytesIO()
    textwriter = io.TextIOWrapper(
    buf, 'utf8', newline='', write_through=True)
    for (key, value) in fields.items():
    textwriter.write(
    '--{boundary}\r\n'
    'Content-Disposition: form-data; name="{key}"\r\n\r\n'
    '{value}\r\n'.format(
    boundary=boundary, key=key, value=value))
    for (key, filepath, filename) in files:
    if os.path.isfile(filepath):
    textwriter.write(
    '--{boundary}\r\n'
    'Content-Disposition: form-data; name="{key}"; '
    'filename="{filename}"\r\n'
    'Content-Type: {content_type}\r\n\r\n'.format(
    boundary=boundary, key=key, filename=filename,
    content_type='application/octet-stream'))
    with open(filepath, "rb") as f:
    shutil.copyfileobj(f, buf)
    textwriter.write('\r\n')
    textwriter.write('--{}--\r\n\r\n'.format(boundary))
    content_type = 'multipart/form-data; boundary={}'.format(boundary)
    return content_type, buf.getvalue()
    content_type, data = _encode_multipart_formdata(
    fields={'key': 'value'},
    files=[('filekey', 'test.py', 'test.py')]
    )
    headers = {
    'Accept-Encoding': 'gzip, deflate',
    'Accept': '*/*',
    'Connection': 'keep-alive',
    'User-Agent': 'python-requests/2.7.0 CPython/2.7.10 Darwin 14.5.0',
    'Content-Type': content_type,
    'Content-Length': '{}'.format(len(data)),
    }
    c = http.client.HTTPSConnection('http2bin.org', 443)
    c.request('POST', '/post', body=data, headers=headers)
    resp = c.getresponse()
    print(resp.read())
    

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26. Layer 1: Low-level
    Layer 2: Features
    

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27. import urllib3
    from urllib3.filepost import RequestField
    fields = [
    RequestField(
    'key',
    'value',
    ),
    RequestField(
    'filekey',
    open('test.py').read(),
    filename='test.py',
    ),
    ]
    fields[0].make_multipart()
    fields[1].make_multipart(content_type='application/octet-stream')
    headers = {'User-Agent': 'python-requests/2.7.0 CPython 2.7.10 Darwin/14.5.0'}
    http = urllib3.PoolManager()
    r = http.request('POST', 'http://http2bin.org/post', fields=fields)
    print(r.data)
    

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28. Layer 1: Low-level
    Layer 2: Features
    Layer 3: Simplicity
    

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29. import requests
    r = requests.post(
    'https://http2bin.org/post',
    files={
    'key': 'value',
    'filekey': (
    'test.py',
    open('test.py'),
    'application/octet-stream'
    )
    }
    )
    print(r.text)
    

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30. While We’re
    Here…
    

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31. 80%
    

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33. Thanks!
    ✨✨
    

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