In [1]:

    

import pickle
pickle.dumps([5, 6, 7])


    

    
Out[1]:





b'\x80\x03]q\x00(K\x05K\x06K\x07e.'

In [2]:

    

pickle.loads(b'\x80\x03]q\x00(K\x05K\x06K\x07e.')


    

    
Out[2]:





[5, 6, 7]

In [3]:

    

pickle.loads(b'\x80\x03]q\x00(K\x05K\x06K\x07e.blahblahblah')


    

    
Out[3]:





[5, 6, 7]

In [4]:

    

# how many bytes it processed in order to reload the pickle ?


    

In [5]:

    

from io import BytesIO


    

In [7]:

    

f = BytesIO(b'\x80\x03]q\x00(K\x05K\x06K\x07e.blahblahblah')


    

In [9]:

    

pickle.load(f)


    

    
Out[9]:





[5, 6, 7]

In [10]:

    

f.tell()


    

    
Out[10]:





14

In [11]:

    

f.read()


    

    
Out[11]:





b'blahblahblah'

In [12]:

    

import json


    

In [13]:

    

json.dumps([51, 'Namárië!'])


    

    
Out[13]:





'[51, "Nam\\u00e1ri\\u00eb!"]'

In [14]:

    

json.dumps([51, 'Namárië!'], ensure_ascii=False)


    

    
Out[14]:





'[51, "Namárië!"]'

In [17]:

    

json.loads('{"name": "Gaurav", "quest":"Grail"}')


    

    
Out[17]:





{'name': 'Gaurav', 'quest': 'Grail'}

In [21]:

    

json.loads('{"name": "Gaurav", "age":12}')


    

    
Out[21]:





{'age': 12, 'name': 'Gaurav'}

In [22]:

    

# Compresiion


    

In [23]:

    

import zlib


    

In [24]:

    

data = zlib.compress(b'Python') + b'.' + zlib.compress(b'zlib') + b'.'


    

In [25]:

    

data


    

    
Out[25]:





b'x\x9c\x0b\xa8,\xc9\xc8\xcf\x03\x00\x08\x97\x02\x83.x\x9c\xab\xca\xc9L\x02\x00\x04d\x01\xb2.'

In [26]:

    

len(data)


    

    
Out[26]:





28

In [27]:

    

# Imagine that these 28 bytes arrive at their destination in 8-byte packets.


    

In [28]:

    

d = zlib.decompressobj()


    

In [29]:

    

d.decompress(data[0:8]), d.unused_data


    

    
Out[29]:





(b'Pytho', b'')

In [30]:

    

# as unused_data is empty, there is more data


    

In [31]:

    

d.decompress(data[8:16]), d.unused_data


    

    
Out[31]:





(b'n', b'.x')

In [33]:

    

"""Since here you are expecting further compressed data, you will feed the 'x' to a fresh decompress
object to which you can then feed the final 8-byte “packets”"""


    

    
Out[33]:





"Since here you are expecting further compressed data, you will feed the 'x' to a fresh decompress\nobject to which you can then feed the final 8-byte “packets”"

In [34]:

    

d = zlib.decompressobj()


    

In [35]:

    

d.decompress(b'x'), d.unused_data


    

    
Out[35]:





(b'', b'')

In [36]:

    

d.decompress(data[16:24]), d.unused_data


    

    
Out[36]:





(b'zlib', b'')

In [38]:

    

d.decompress(data[24:]), d.unused_data


    

    
Out[38]:





(b'', b'.')

In [39]:

    

import socket


    

In [40]:

    

s = socket.socket()


    

In [44]:

    

try:
    s.connect(('nonexistent.n.c', 80))
except socket.gaierror as e :
    print(e.errno)
    print(e.strerror)
    raise


    

    




-2
Name or service not known






    




---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
<ipython-input-44-ee415639d9bb> in <module>()
      1 try:
----> 2     s.connect(('nonexistent.n.c', 80))
      3 except socket.gaierror as e :
      4     print(e.errno)
      5     print(e.strerror)

gaierror: [Errno -2] Name or service not known

In [45]:

    

import http.client


    

In [47]:

    

connection = http.client.HTTPConnection('nonexistent.foo.bar.com')


    

In [48]:

    

connection.request('GET', '/')


    

    




---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
<ipython-input-48-0869f11f846a> in <module>()
----> 1 connection.request('GET', '/')

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in request(self, method, url, body, headers, encode_chunked)
   1237                 encode_chunked=False):
   1238         """Send a complete request to the server."""
-> 1239         self._send_request(method, url, body, headers, encode_chunked)
   1240 
   1241     def _send_request(self, method, url, body, headers, encode_chunked):

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in _send_request(self, method, url, body, headers, encode_chunked)
   1283             # default charset of iso-8859-1.
   1284             body = _encode(body, 'body')
-> 1285         self.endheaders(body, encode_chunked=encode_chunked)
   1286 
   1287     def getresponse(self):

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in endheaders(self, message_body, encode_chunked)
   1232         else:
   1233             raise CannotSendHeader()
-> 1234         self._send_output(message_body, encode_chunked=encode_chunked)
   1235 
   1236     def request(self, method, url, body=None, headers={}, *,

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in _send_output(self, message_body, encode_chunked)
   1024         msg = b"\r\n".join(self._buffer)
   1025         del self._buffer[:]
-> 1026         self.send(msg)
   1027 
   1028         if message_body is not None:

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in send(self, data)
    962         if self.sock is None:
    963             if self.auto_open:
--> 964                 self.connect()
    965             else:
    966                 raise NotConnected()

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in connect(self)
    934         """Connect to the host and port specified in __init__."""
    935         self.sock = self._create_connection(
--> 936             (self.host,self.port), self.timeout, self.source_address)
    937         self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
    938 

~/.pyenv/versions/3.6.1/lib/python3.6/socket.py in create_connection(address, timeout, source_address)
    702     host, port = address
    703     err = None
--> 704     for res in getaddrinfo(host, port, 0, SOCK_STREAM):
    705         af, socktype, proto, canonname, sa = res
    706         sock = None

~/.pyenv/versions/3.6.1/lib/python3.6/socket.py in getaddrinfo(host, port, family, type, proto, flags)
    741     # and socket type values to enum constants.
    742     addrlist = []
--> 743     for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
    744         af, socktype, proto, canonname, sa = res
    745         addrlist.append((_intenum_converter(af, AddressFamily),

gaierror: [Errno -5] No address associated with hostname

In [49]:

    

import urllib.request


    

In [51]:

    

urllib.request.urlopen('http://nonexistent.foo.bar.com')


    

    




---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
   1317                 h.request(req.get_method(), req.selector, req.data, headers,
-> 1318                           encode_chunked=req.has_header('Transfer-encoding'))
   1319             except OSError as err: # timeout error

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in request(self, method, url, body, headers, encode_chunked)
   1238         """Send a complete request to the server."""
-> 1239         self._send_request(method, url, body, headers, encode_chunked)
   1240 

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in _send_request(self, method, url, body, headers, encode_chunked)
   1284             body = _encode(body, 'body')
-> 1285         self.endheaders(body, encode_chunked=encode_chunked)
   1286 

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in endheaders(self, message_body, encode_chunked)
   1233             raise CannotSendHeader()
-> 1234         self._send_output(message_body, encode_chunked=encode_chunked)
   1235 

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in _send_output(self, message_body, encode_chunked)
   1025         del self._buffer[:]
-> 1026         self.send(msg)
   1027 

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in send(self, data)
    963             if self.auto_open:
--> 964                 self.connect()
    965             else:

~/.pyenv/versions/3.6.1/lib/python3.6/http/client.py in connect(self)
    935         self.sock = self._create_connection(
--> 936             (self.host,self.port), self.timeout, self.source_address)
    937         self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)

~/.pyenv/versions/3.6.1/lib/python3.6/socket.py in create_connection(address, timeout, source_address)
    703     err = None
--> 704     for res in getaddrinfo(host, port, 0, SOCK_STREAM):
    705         af, socktype, proto, canonname, sa = res

~/.pyenv/versions/3.6.1/lib/python3.6/socket.py in getaddrinfo(host, port, family, type, proto, flags)
    742     addrlist = []
--> 743     for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
    744         af, socktype, proto, canonname, sa = res

gaierror: [Errno -5] No address associated with hostname

During handling of the above exception, another exception occurred:

URLError                                  Traceback (most recent call last)
<ipython-input-51-d40eb86e6453> in <module>()
----> 1 urllib.request.urlopen('http://nonexistent.foo.bar.com')

~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in urlopen(url, data, timeout, cafile, capath, cadefault, context)
    221     else:
    222         opener = _opener
--> 223     return opener.open(url, data, timeout)
    224 
    225 def install_opener(opener):

~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in open(self, fullurl, data, timeout)
    524             req = meth(req)
    525 
--> 526         response = self._open(req, data)
    527 
    528         # post-process response

~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in _open(self, req, data)
    542         protocol = req.type
    543         result = self._call_chain(self.handle_open, protocol, protocol +
--> 544                                   '_open', req)
    545         if result:
    546             return result

~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in _call_chain(self, chain, kind, meth_name, *args)
    502         for handler in handlers:
    503             func = getattr(handler, meth_name)
--> 504             result = func(*args)
    505             if result is not None:
    506                 return result

~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in http_open(self, req)
   1344 
   1345     def http_open(self, req):
-> 1346         return self.do_open(http.client.HTTPConnection, req)
   1347 
   1348     http_request = AbstractHTTPHandler.do_request_

~/.pyenv/versions/3.6.1/lib/python3.6/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
   1318                           encode_chunked=req.has_header('Transfer-encoding'))
   1319             except OSError as err: # timeout error
-> 1320                 raise URLError(err)
   1321             r = h.getresponse()
   1322         except:

URLError: <urlopen error [Errno -5] No address associated with hostname>

In [ ]: