Detect and inform to user if the website is down

This will detect and inform to user if website is down.
It detects the status by checking if constant username
which is probably taken forever is available.

Closes manu-chroma#66

templates/status.html

@@ -29,7 +29,9 @@
             })
             .then((result) => {
                 var res = result;
-                if (!res['possible'])
+                if (!res['usable'])
+                    $("#" + site)[0].innerHTML = 'Website Down';
+                else if (!res['possible'])
                     $("#" + site)[0].innerHTML = 'Impossible';
                 else if (res['status'] == '404' || res['status'] == '301')
                     $("#" + site)[0].innerHTML = 'Available';

tests/test_username_api.py

@@ -80,6 +80,7 @@ def get_response(app, website, user):
 def get_expected_response(website, user, status):
     return {
         'possible': True,
+        'usable': True,
         'status': status,
         'url': username_api.get_profile_url(website, user),
         'avatar': username_api.get_avatar(website, user) if status == 200
@@ -157,5 +158,6 @@ def test_format_checking(self, website, username):
         url = username_api.get_profile_url(website, username)
         assert {
             'possible': False,
+            'usable': True,
             'url': url
         } == json_resp

username_api.py

@@ -5,13 +5,16 @@
 from bs4 import BeautifulSoup
 from flask import Flask, jsonify
 from flask.ext.cors import CORS, cross_origin
+from werkzeug.contrib.cache import SimpleCache
 
 app = Flask(__name__)
 cors = CORS(app)
 app.config['CORS_HEADERS'] = 'Content-Type'
 
 patterns = yaml.load(open('websites.yml'))
 
+cache = SimpleCache()
+
 
 def get_profile_url(website, username):
     return patterns['urls'].get(website, 'https://{w}.com/{u}').format(
@@ -63,36 +66,58 @@ def get_avatar(website, username):
     return result
 
 
+def get_status_code(website, username):
+    url = get_profile_url(website, username)
+
+    if website in patterns['content_verification']:
+        res = r.get(url)
+        phrase = patterns['content_verification'][website].format(u=username)
+        if bytes(phrase, encoding='utf-8') in res.content:
+            return 200
+        else:
+            return 404
+
+    else:
+        return r.get(url).status_code
+
+
 def check_username(website, username):
     url = get_profile_url(website, username)
 
+    usable = check_usable(website)
+
     possible = check_format(website, username)
 
+    if not usable:
+        return {
+            'url': url,
+            'possible': possible,
+            'usable': usable,
+        }
+
     if not possible:
         return {
             'url': url,
             'possible': possible,
+            'usable': usable,
         }
 
+    code = get_status_code(website, username)
+
     if website in patterns['content_verification']:
-        res = r.get(url)
-        phrase = patterns['content_verification'][website].format(u=username)
-        if bytes(phrase, encoding='utf-8') in res.content:
-            code = 200
-        else:
-            code = 404
 
         return {
             'status': code,
             'url': url,
             'avatar': get_avatar(website, username) if code == 200
             else None,
             'possible': possible,
+            'usable': usable,
         }
 
     elif website == 'facebook':
         res = r.get(url)
-        code = res.status_code
+
         # Using mfacebook for checking username,
         # when a username exists but hidden from
         # search engines, it gives a login redirect
@@ -110,6 +135,7 @@ def check_username(website, username):
             'avatar': get_avatar(website, username),
             'possible': possible,
             'profile': profile,
+            'usable': usable,
         }
 
     else:
@@ -118,9 +144,35 @@ def check_username(website, username):
             'url': url,
             'avatar': get_avatar(website, username),
             'possible': possible,
+            'usable': usable,
         }
 
 
+def check_usable(website):
+    """
+        Check if the website is usable.
+        It works by checking if known taken username is shown as available.
+        The checking will be cached in memory for 10 minutes.
+    """
+
+    identifier = 'usable_{}'.format(website)
+
+    usable = cache.get(identifier)
+    if usable is not None:
+        return usable
+
+    constant_username = patterns['constant_usernames'][website]
+
+    code = get_status_code(website, constant_username)
+
+    if code == 404 or code == 301:
+        usable = False
+    usable = True
+    cache.set(identifier, usable, timeout=60*10)
+
+    return usable
+
+
 def check_format(website, username):
     """Check the format of a username depending on the website
     """

websites.yml

@@ -12,6 +12,20 @@ content_verification:
   gitlab: "Snippets"
   opensuse: "About me"
   pinterest: "{u}"
+constant_usernames:
+  asciinema: "john"
+  behance: "seeeturtle"
+  deviantart: "joshua"
+  facebook: "gyanlakhwani"
+  github: "seeeturtle"
+  gitlab: "andrewda"
+  instagram: "ElonMusk"
+  openhub: "seeeturtle"
+  opensuse: "biscuitsnake"
+  pinterest: "steve"
+  soundcloud: "postmalone"
+  tumblr: "steve"
+  twitter: "ElonMusk"
 username_patterns:
   asciinema:
     characters: a-zA-Z0-9-