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karludkarlud
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Flask-based forum!
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-94
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8 files changed

+185
-94
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‎vagrant/Vagrantfile‎

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Original file line numberDiff line numberDiff line change
@@ -5,7 +5,6 @@ VAGRANTFILE_API_VERSION = "2"
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Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
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config.vm.provision "shell", path: "pg_config.sh"
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# config.vm.box = "hashicorp/precise32"
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config.vm.box = "ubuntu/trusty32"
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config.vm.network "forwarded_port", guest: 8000, host: 8000
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config.vm.network "forwarded_port", guest: 8080, host: 8080

‎vagrant/forum/forum.py‎

Lines changed: 26 additions & 68 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,13 @@
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#
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# DB Forum - a buggy web forum server backed by a good database
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#
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#!/usr/bin/env python3
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#
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# A buggy web service in need of a database.
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# The forumdb module is where the database interface code goes.
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import forumdb
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import datetime
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from flask import Flask, request, redirect, url_for
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# Other modules used to run a web server.
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import cgi
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from wsgiref.simple_server import make_server
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from wsgiref import util
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from forumdb import get_posts, add_post
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app = Flask(__name__)
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# HTML template for the forum page
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HTML_WRAP = '''\
@@ -21,14 +20,14 @@
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textarea { width: 400px; height: 100px; }
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div.post { border: 1px solid #999;
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padding: 10px 10px;
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margin: 10px 20%%; }
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margin: 10px 20%%; }
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hr.postbound { width: 50%%; }
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em.date { color: #999 }
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</style>
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</head>
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<body>
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<h1>DB Forum</h1>
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<form method=post action="/post">
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<form method=post>
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<div><textarea id="content" name="content"></textarea></div>
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<div><button id="go" type="submit">Post message</button></div>
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</form>
@@ -40,68 +39,27 @@
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# HTML template for an individual comment
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POST = '''\
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<div class=post><em class=date>%(time)s</em><br>%(content)s</div>
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<div class=post><em class=date>%s</em><br>%s</div>
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'''
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## Request handler for main page
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def View(env, resp):
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'''View is the 'main page' of the forum.
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It displays the submission form and the previously posted messages.
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'''
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# get posts from database
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posts = forumdb.GetAllPosts()
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# send results
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headers = [('Content-type', 'text/html')]
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resp('200 OK', headers)
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return [HTML_WRAP % ''.join(POST % p for p in posts)]
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## Request handler for posting - inserts to database
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def Post(env, resp):
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'''Post handles a submission of the forum's form.
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The message the user posted is saved in the database, then it sends a 302
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Redirect back to the main page so the user can see their new post.
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'''
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# Get post content
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input = env['wsgi.input']
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length = int(env.get('CONTENT_LENGTH', 0))
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# If length is zero, post is empty - don't save it.
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if length > 0:
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postdata = input.read(length)
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fields = cgi.parse_qs(postdata)
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content = fields['content'][0]
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# If the post is just whitespace, don't save it.
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content = content.strip()
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if content:
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# Save it in the database
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forumdb.AddPost(content)
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# 302 redirect back to the main page
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headers = [('Location', '/'),
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('Content-type', 'text/plain')]
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resp('302 REDIRECT', headers)
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return ['Redirecting']
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@app.route('/', methods=['GET'])
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def main():
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'''Main page of the forum.'''
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posts = "".join(POST % (date, text) for text, date in get_posts())
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html = HTML_WRAP % posts
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return html
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## Dispatch table - maps URL prefixes to request handlers
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DISPATCH = {'': View,
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'post': Post,
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}
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## Dispatcher forwards requests according to the DISPATCH table.
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def Dispatcher(env, resp):
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'''Send requests to handlers based on the first path component.'''
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page = util.shift_path_info(env)
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if page in DISPATCH:
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return DISPATCH[page](env, resp)
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else:
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status = '404 Not Found'
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headers = [('Content-type', 'text/plain')]
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resp(status, headers)
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return ['Not Found: ' + page]
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@app.route('/', methods=['POST'])
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def post():
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'''New post submission.'''
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message = request.form['content']
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add_post(message)
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return redirect(url_for('main'))
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# Run this bad server only on localhost!
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httpd = make_server('', 8000, Dispatcher)
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print "Serving HTTP on port 8000..."
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httpd.serve_forever()
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if __name__ == '__main__':
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app.run(host='0.0.0.0', port=8000)
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app.run(debug=True)
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‎vagrant/forum/forumdb.py‎

Lines changed: 9 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -1,31 +1,15 @@
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#
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# Database access functions for the web forum.
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#
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# "Database code" for the DB Forum.
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import time
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import datetime
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## Database connection
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DB = []
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POSTS = [("This is the first post.", datetime.datetime.now())]
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## Get posts from database.
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def GetAllPosts():
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'''Get all the posts from the database, sorted with the newest first.
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def get_posts():
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"""Return all posts from the 'database', most recent first."""
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return reversed(POSTS)
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Returns:
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A list of dictionaries, where each dictionary has a 'content' key
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pointing to the post content, and 'time' key pointing to the time
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it was posted.
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'''
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posts = [{'content': str(row[1]), 'time': str(row[0])} for row in DB]
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posts.sort(key=lambda row: row['time'], reverse=True)
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return posts
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def add_post(content):
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"""Add a post to the 'database' with the current timestamp."""
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POSTS.append((content, datetime.datetime.now()))
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## Add a post to the database.
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def AddPost(content):
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'''Add a new post to the database.
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Args:
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content: The text content of the new post.
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'''
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t = time.strftime('%c', time.localtime())
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DB.append((t, content))

‎vagrant/forum/solution/forum.py‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,65 @@
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#!/usr/bin/env python3
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#
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# A buggy web service in need of a database.
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import datetime
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from flask import Flask, request, redirect, url_for
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from forumdb_initial import get_posts, add_post
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app = Flask(__name__)
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# HTML template for the forum page
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HTML_WRAP = '''\
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<!DOCTYPE html>
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<html>
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<head>
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<title>DB Forum</title>
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<style>
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h1, form { text-align: center; }
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textarea { width: 400px; height: 100px; }
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div.post { border: 1px solid #999;
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padding: 10px 10px;
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margin: 10px 20%%; }
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hr.postbound { width: 50%%; }
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em.date { color: #999 }
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</style>
27+
</head>
28+
<body>
29+
<h1>DB Forum</h1>
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<form method=post>
31+
<div><textarea id="content" name="content"></textarea></div>
32+
<div><button id="go" type="submit">Post message</button></div>
33+
</form>
34+
<!-- post content will go here -->
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%s
36+
</body>
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</html>
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'''
39+
40+
# HTML template for an individual comment
41+
POST = '''\
42+
<div class=post><em class=date>%s</em><br>%s</div>
43+
'''
44+
45+
46+
@app.route('/', methods=['GET'])
47+
def main():
48+
'''Main page of the forum.'''
49+
posts = "".join(POST % (date, text) for text, date in get_posts())
50+
html = HTML_WRAP % posts
51+
return html
52+
53+
54+
@app.route('/', methods=['POST'])
55+
def post():
56+
'''New post submission.'''
57+
message = request.form['content']
58+
add_post(message)
59+
return redirect(url_for('main'))
60+
61+
62+
if __name__ == '__main__':
63+
app.run(host='0.0.0.0', port=8000)
64+
app.run(debug=True)
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‎vagrant/forum/solution/forumdb_initial.py‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
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# "Database code" for the DB Forum.
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3+
import datetime
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5+
POSTS = [("This is the first post.", datetime.datetime.now())]
6+
7+
def get_posts():
8+
"""Return all posts from the 'database', most recent first."""
9+
return reversed(POSTS)
10+
11+
def add_post(content):
12+
"""Add a post to the 'database' with the current timestamp."""
13+
POSTS.append((content, datetime.datetime.now()))
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15+

‎vagrant/forum/solution/forumdb_solved.py‎

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@@ -0,0 +1,22 @@
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# Database code for the DB Forum, full solution!
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3+
import psycopg2, bleach
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5+
DBNAME = "forum"
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7+
def get_posts():
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"""Return all posts from the 'database', most recent first."""
9+
db = psycopg2.connect(database=DBNAME)
10+
c = db.cursor()
11+
c.execute("select content, time from posts order by time desc")
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return c.fetchall()
13+
db.close()
14+
15+
def add_post(content):
16+
"""Add a post to the 'database' with the current timestamp."""
17+
db = psycopg2.connect(database=DBNAME)
18+
c = db.cursor()
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c.execute("insert into posts values (%s)", (bleach.clean(content),)) # good
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db.commit()
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db.close()
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‎vagrant/forum/solution/forumdb_stepone.py‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,24 @@
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# Database code for the DB Forum.
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#
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# This is NOT the full solution!
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import psycopg2
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7+
DBNAME = "forum"
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9+
def get_posts():
10+
"""Return all posts from the 'database', most recent first."""
11+
db = psycopg2.connect(database=DBNAME)
12+
c = db.cursor()
13+
c.execute("select content, time from posts order by time desc")
14+
return c.fetchall()
15+
db.close()
16+
17+
def add_post(content):
18+
"""Add a post to the 'database' with the current timestamp."""
19+
db = psycopg2.connect(database=DBNAME)
20+
c = db.cursor()
21+
c.execute("insert into posts values (%s)" % content) # Almost but not quite.
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db.commit()
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db.close()
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‎vagrant/forum/solution/forumdb_steptwo.py‎

Lines changed: 24 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,24 @@
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# Database code for the DB Forum.
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#
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# This is still NOT the full solution!
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5+
import psycopg2, bleach
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7+
DBNAME = "forum"
8+
9+
def get_posts():
10+
"""Return all posts from the 'database', most recent first."""
11+
db = psycopg2.connect(database=DBNAME)
12+
c = db.cursor()
13+
c.execute("select content, time from posts order by time desc")
14+
return c.fetchall()
15+
db.close()
16+
17+
def add_post(content):
18+
"""Add a post to the 'database' with the current timestamp."""
19+
db = psycopg2.connect(database=DBNAME)
20+
c = db.cursor()
21+
c.execute("insert into posts values (%s)", (content,)) # Better, but ...
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db.commit()
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db.close()
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