What I've learned from reading RESTful Web APIs

I've recently finished reading the book RESTful Web APIs by Leonard Richardson, Mike Amundsen, Sam Ruby.

Wish I've read this book before building an API. To summarize the things I would have done different (and you've should have done probably too):

• Use standard naming conventions for properties from for example: http://schema.org/docs/schemas.html
• Don't use application/json but a custom format like application/vnd.sameproblemmorecode.blog+json
• Make better use of the default HTTP Headers (e.g. the WWW-Authenticate and Link header)
• Return errors as described in https://tools.ietf.org/html/draft-nottingham-http-problem-06
• Create hypermedia links in the HTTP headers to describe possible links. These links should also have standartized names from for example http://www.iana.org/assignments/link-relations/link-relations.xhtml
• If time allows; event create hypermedia profiles (this allows the server to change without breaking clients). One of the writers is also writing a book on how to create hypermedia driven clients for this.
• Make sure to reuse as much standards as possible, we don't need another new standard. This enables us to reuse webcomponents (or at least parts of) between projects.

Hope this helps.

Cheers,

Luuk

Monitor your Server IP with Python and Pushover

Since I'm running my own web / plex server, I want to be notified when my public IP changes. This is super-easy using python and pushover.

The base of the application is really simple; fetch the IP from http://checkip.dyndns.org/ and check if it's the same as the last time you've runned. If it has changed, send a message with pushover to your mobile phone.

I use crontab every 5 minutes to validate the IP.


Here's the script:

import re
import os
import uuid
import json
import socket
import urllib, urllib2
import time

def get_current_ip():
    req = urllib2.Request('http://checkip.dyndns.org/')
    response = urllib2.urlopen(req)
    the_page = response.read()

    p = re.compile(r'(?P >ip<(?:[0-9]{1,3}\.){3}[0-9]{1,3})')
    m = p.search(the_page)
    return m.group('ip')

# load settings
current_ip = get_current_ip()
uid = ''
computer_name = ''
last_ip = ''

if(os.path.exists('/srv/crontab/oswos.settings')):
    with open('/srv/crontab/oswos.settings', 'r') as f:
        content = f.read()
        decoded = json.loads(content)
        uid = decoded.get('guid')
        computer_name = decoded.get('computer_name')
        last_ip = decoded.get('last_ip')
else:
    uid = str(uuid.uuid1())
    computer_name = socket.gethostname()

data = { 'guid': uid, 'computer_name': computer_name, 'last_ip': current_ip }
with open('/srv/crontab/oswos.settings', 'w') as f:
    json.dump(data, f)

print 'uid          : {0}'.format(uid)
print 'computer_name: {0}'.format(computer_name)
print 'last_ip      : {0}'.format(last_ip)
print 'current ip   : {0}'.format(current_ip)

if(current_ip != last_ip):
    API_URL = "https://api.pushover.net/1/messages.json"
    API_KEY = "api-key-here"
    curUrl = API_URL

    data = urllib.urlencode({
        'token': API_KEY,
        'title': 'Oswos Notification',
        'user': 'user-key-here',
        'message': 'IP Changed from {0} to {1}'.format(last_ip,current_ip).encode('utf-8'),
        'timestamp': int(time.time())
            })

    req = urllib2.Request(curUrl)
    handle = urllib2.urlopen(req, data)
    handle.close()

You see how easy it is to connect to Pushover? Building your own good working Android application is hard, so why not use the tools which are already there!

Just let me know if you have any tips / suggestions to extend this further.

Luuk