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Chapter 1
Introduction to Client-Server Networking

This is a directory of program listings from Chapter 1 of the book:

Foundations of Python Network Programming

Third Edition, October 2014
by Brandon Rhodes and John Goerzen

You can learn more about the book by visiting the root of this GitHub source code repository.

All the scripts in this chapter have been tested successfully under Python 2. Simply use 3to2 to convert them to the older syntax.

The four scripts in this chapter with “search” in their name perform exactly the same Google geocoding query, but at four different levels of abstraction in the network protocol hierarchy. This lets the chapter launch an introduction of each level that the book will be discussing.

$ python search1.py
(41.521954, -84.306691)

$ python search2.py
{'lat': 41.521954, 'lng': -84.306691}

$ python search3.py
{'lat': 41.521954, 'lng': -84.306691}

$ python search4.py
HTTP/1.1 200 OK
Content-Type: application/json; charset=UTF-8
Date: Tue, 21 Oct 2014 22:50:21 GMT
Expires: Wed, 22 Oct 2014 22:50:21 GMT
Cache-Control: public, max-age=86400
Vary: Accept-Language
Access-Control-Allow-Origin: *
Server: mafe
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN
Alternate-Protocol: 80:quic,p=0.01
Connection: close

{
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "207",
               "short_name" : "207",
               "types" : [ "street_number" ]
            },
            {
               "long_name" : "North Defiance Street",
               "short_name" : "N Defiance St",
               "types" : [ "route" ]
            },
            {
               "long_name" : "Archbold",
               "short_name" : "Archbold",
               "types" : [ "locality", "political" ]
            },
            {
               "long_name" : "German",
               "short_name" : "German",
               "types" : [ "administrative_area_level_3", "political" ]
            },
            {
               "long_name" : "Fulton County",
               "short_name" : "Fulton County",
               "types" : [ "administrative_area_level_2", "political" ]
            },
            {
               "long_name" : "Ohio",
               "short_name" : "OH",
               "types" : [ "administrative_area_level_1", "political" ]
            },
            {
               "long_name" : "United States",
               "short_name" : "US",
               "types" : [ "country", "political" ]
            },
            {
               "long_name" : "43502",
               "short_name" : "43502",
               "types" : [ "postal_code" ]
            }
         ],
         "formatted_address" : "207 North Defiance Street, Archbold, OH 43502, USA",
         "geometry" : {
            "location" : {
               "lat" : 41.521954,
               "lng" : -84.306691
            },
            "location_type" : "ROOFTOP",
            "viewport" : {
               "northeast" : {
                  "lat" : 41.5233029802915,
                  "lng" : -84.3053420197085
               },
               "southwest" : {
                  "lat" : 41.5206050197085,
                  "lng" : -84.30803998029151
               }
            }
         },
         "types" : [ "street_address" ]
      }
   ],
   "status" : "OK"
}

The remaining two scripts are quite tiny. The first shows how a hostname is turned into an IP address, and the second illustrates the basic string decoding and encoding maneuvers that Python 3 is careful to require of network programmers.

$ python getname.py
The IP address of maps.google.com is 74.125.228.105

$ python stringcodes.py && cat eagle.txt
'413 is in.'
We copy you down, Eagle.