add expiry, and wsgi usage to support that

   The flask dev server seems incapable of using the @timer
   decorator, so we need the whole wsgi implementation, for
   which I've added a script.

   Arbitrary expiration options are available in the config
   file.

11 files changed, 134 insertions, 12 deletions

diff --git a/.gitignore b/.gitignore
index abccb3f..a2e3e4d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,5 @@ env
 pastebin_uwsgi.ini
 config.cfg
 .*.swp
+log/
+*.pid
diff --git a/README-bgstack15.md b/README-bgstack15.md
index e0cd9bc..67b143e 100644
--- a/README-bgstack15.md
+++ b/README-bgstack15.md
@@ -24,17 +24,19 @@ Run server in development mode.
 
     FLASK_APP=pastebin.py FLASK_DEBUG=True flask run --host='0.0.0.0'
 
+Run the server in a full wsgi environment for the cleanup timer to operate.
+
+    ./stackbin.bin
+
 # Improvements
 I still need to work on these tasks:
 
 ## Development
 
 * Protect the /admin/ page
-* Add expiry of pastes? (use existing pubdate value, or just an extra column with desired expiration timestamp)
 
 ## Release
 
-* Read any of my flask projects (fuss is the best one) to learn how to setup prod server
 * Document centos7 dependencies
 * Deploy to prod
 
diff --git a/config.cfg.tpl b/config.cfg.tpl
index 50b4419..23fb072 100644
--- a/config.cfg.tpl
+++ b/config.cfg.tpl
@@ -2,3 +2,16 @@ DEBUG=False
 SQLALCHEMY_DATABASE_URI='sqlite:///pastebin.db'
 SECRET_KEY='development-key'
 SALT='jackson'
+DELETESALT='differentstring'
+APPNAME='stackbin'
+# LOOP_DELAY in seconds is how many seconds between running the expiration cleanup task
+LOOP_DELAY = 5 * 3
+
+# Disable this variable entirely, to disable any choices for expiration
+# Any very simple expression for relative time can be used here. This will be processed by pyparsedate.
+EXPIRATION_OPTIONS = [
+   "never",
+   "1 day",
+   "1 hour",
+   "15 minutes"
+]
diff --git a/initdb.py b/initdb.py
index b56872f..da4f05a 100644
--- a/initdb.py
+++ b/initdb.py
@@ -1,2 +1,3 @@
 from pastebin import db
+no_wsgi = True
 db.create_all()
diff --git a/pastebin.py b/pastebin.py
index 3851d01..d06dc6e 100644..100755
--- a/pastebin.py
+++ b/pastebin.py
@@ -1,7 +1,14 @@
-from datetime import datetime
+from datetime import datetime, timedelta
 from itsdangerous import Signer
 from flask import (Flask, request, url_for, redirect, g, render_template, session, abort)
 from flask_sqlalchemy import SQLAlchemy
+from pytimeparse.timeparse import timeparse # python3-pytimeparse
+# uwsgidecorators load will fail when using initdb.py but is also not necessary
+try:
+   from uwsgidecorators import timer # python3-uwsgidecorators
+except:
+   pass
+import time
 
 ## ripped from https://stackoverflow.com/questions/183042/how-can-i-use-uuids-in-sqlalchemy/812363#812363
 from sqlalchemy import types
@@ -12,6 +19,7 @@ class UUID(types.TypeDecorator):
    impl = MSBinary
    def __init__(self):
       self.impl.length = 16
+      self.cache_ok = False # to shut up some useless warning
       types.TypeDecorator.__init__(self,length=self.impl.length)
    def process_bind_param(self,value,dialect=None):
       if value and isinstance(value,uuid.UUID):
@@ -66,17 +74,27 @@ class Paste(db.Model):
    code = db.Column(db.Text)
    title = db.Column(db.Text)
    pub_date = db.Column(db.DateTime)
+   exp_date = db.Column(db.DateTime)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    is_private = db.Column(db.Boolean)
    parent_id = db.Column(UUID(), db.ForeignKey('paste.id'))
    parent = db.relationship('Paste', lazy=True, backref='children', uselist=False, remote_side=[id])
 
-   def __init__(self, user, code, title, parent=None, is_private=False):
+   def __init__(self, user, code, title, relative_expiration_seconds, parent=None, is_private=False):
       self.user = user
       self.code = code
       self.title = title
       self.is_private = is_private
-      self.pub_date = datetime.utcnow()
+      u = datetime.utcnow()
+      try:
+         # this will fail on POSTed value of "never" for exp
+         b = timedelta(seconds=relative_expiration_seconds)
+      except:
+         # so timedelta() will return 0 seconds, which makes the exp_date = pub_date, which is treated
+         # by the cleanup logic and jinja2 templates as never-expires.
+         b = timedelta()
+      self.pub_date = u
+      self.exp_date = u + b
       self.parent = parent
 
 class User(db.Model):
@@ -99,13 +117,62 @@ def new_paste():
       title = "Untitled paste"
       if request.form['pastetitle'] and request.form['pastetitle'] != "Enter title here":
          title = request.form['pastetitle']
-      paste = Paste(g.user, request.form['code'], title, parent=parent, is_private=is_private)
+      relative_expiration_seconds = 0
+      exp = 0 # start with an empty value
+      if 'exp' in request.form and request.form['exp']:
+         exp_opt = request.form['exp']
+         if exp_opt not in app.config['EXPIRATION_OPTIONS']:
+            try:
+               exp = timeparse(f"+ {app.config['EXPIRATION_OPTIONS'][0]}")
+            except:
+               exp = 60 * 60 # failsafe, 1 hour
+            print(f"WARNING: requested expiration \"{exp_opt}\" is not in the list of options {app.config['EXPIRATION_OPTIONS']}, so will use {exp}")
+         else:
+            try:
+               exp = timeparse(f"+ {exp_opt}")
+            except:
+               exp = 0
+      paste = Paste(
+         g.user,
+         request.form['code'],
+         title,
+         exp,
+         parent=parent,
+         is_private=is_private
+      )
       db.session.add(paste)
       db.session.commit()
       sign = get_signed(paste.id, salt=app.config['SALT']) \
          if is_private else None
       return redirect(url_for('show_paste', paste_id=paste.id, s=sign))
-   return render_template('new_paste.html', parent=parent)
+   try:
+      exp_opts = app.config['EXPIRATION_OPTIONS']
+   except:
+      exp_opts = None
+   return render_template('new_paste.html', parent=parent, exp_opts = exp_opts)
+
+# This @timer is from the uwsgidecorators
+try:
+   @timer(app.config['LOOP_DELAY'])
+   def cleanup_expired_pastes(num):
+      # num is useless.
+      """
+      Every LOOP_DELAY seconds, find any entries that have expired and then delete them.
+      """
+      all1 = Paste.query.all()
+      need_commit = False
+      for p in all1:
+         # the exp_date != pub_date is very important, because anything with "never" expires
+         # is stored in the db as exp_date = pub_date
+         if p.exp_date and p.exp_date != p.pub_date and p.exp_date <= datetime.utcnow():
+            print(f"INFO: deleting paste \"{p.title}\" with expiration {p.exp_date}.")
+            Paste.query.filter(Paste.id == p.id).delete()
+            need_commit = True
+      # only run the commit once!
+      if need_commit:
+         db.session.commit()
+except:
+   pass
 
 @app.route('/<paste_id>/')
 @app.route('/<paste_id>')
@@ -188,6 +255,8 @@ def get_all_pastes():
       p2 = {
          "id": p1.id,
          "title": p1.title,
+         "pub_date": p1.pub_date,
+         "exp_date": p1.exp_date,
          "private": private,
          "user_id": p1.user_id,
          "is_private": p1.is_private,
@@ -203,3 +272,7 @@ def get_all_pastes():
 def admin():
    all_pastes = get_all_pastes()
    return render_template('admin.html', pastes = all_pastes)
+
+if __name__ == "__main__":
+   manager.add_command('runserver', Server(host=app.config["APP_HOST"], port=app.config["APP_PORT"]))
+   app.run()
diff --git a/stackbin.bin b/stackbin.bin
new file mode 100755
index 0000000..d3b2da3
--- /dev/null
+++ b/stackbin.bin
@@ -0,0 +1,9 @@
+#!/bin/sh
+# Reference: fuss.bin from fuss project
+# Startdate: 2022-02-13 19:25
+# Goal: see if uwsgi reacts to the @timer directives in the pastebin.py file, because flask run doesn't.
+thisscript="$( readlink -f "${0}" )"
+COMMAND=""
+grep -qiE 'ID=.*(rhel|centos|fedora)' /etc/os-release && COMMAND="${COMMAND} uwsgi" || \
+   COMMAND="${COMMAND} uwsgi_python39"
+${COMMAND} --ini "$( dirname "${thisscript}" )/$( basename "${thisscript}" | sed -r -e 's/\.bin$//;' ).wsgi.ini"
diff --git a/stackbin.wsgi.ini b/stackbin.wsgi.ini
new file mode 100644
index 0000000..cac4511
--- /dev/null
+++ b/stackbin.wsgi.ini
@@ -0,0 +1,14 @@
+[uwsgi]
+plugins = logfile
+http-socket = 0.0.0.0:5000
+wsgi-file = pastebin.py
+callable = app
+touch-reload = pastebin.py
+touch-reload = config.cfg
+touch-reload = stackbin.wsgi.ini
+req-logger = file:log/req.log
+# to get strftime format fields, you need double percent signs
+logdate = "%%FT%%T"
+logger = file:log/stackbin.log
+# the init script uses a different pidfile owned by root.
+pidfile = stackbin.pid
diff --git a/static/style.css b/static/style.css
index 4507323..874cadf 100644
--- a/static/style.css
+++ b/static/style.css
@@ -9,6 +9,7 @@ a:hover       { color: #c00; }
 .nav li + li:before { content: " // "; }
 h2            { font-weight: normal; color: #222; margin-bottom: 10px; padding-left: 10px}
 .chk-private  { float: right; font-size: 12px; margin-top: 12px}
+.drop-expiration  { float: left; font-size: 12px; margin-top: 12px}
 dl            { overflow: auto; font-size: 14px; padding: 0 10px}
 dl dt         { font-weight: bold; min-width: 70px; float: left; padding-right: 15px;
                 clear: left; }
diff --git a/templates/admin.html b/templates/admin.html
index a815fb5..4991d7c 100644
--- a/templates/admin.html
+++ b/templates/admin.html
@@ -4,13 +4,15 @@
 <h1>Administration for {{ appname }}</h1>
 {% if pastes %}
 <table>
-<tr><th>id</th><th>private</th><th>title</th><th>user</th><th>parent</th><th>children</th><th>Actions</th></tr>
+<tr>{#<th>id</th>#}<th>private</th><th>title</th><th>user</th><th>published</th><th>expires</th><th>parent</th><th>children</th><th>Actions</th></tr>
 {% for p in pastes %}
 <tr>
-<td>{{ p.id }}</td>
+{# <td>{{ p.id }}</td> #}
 <td>{% if p.private %}&#10003;{% endif %}</td>{# magic string is from utf8icons.com #}
 <td><a href="{% if not p.private %}{{ url_for('show_paste', paste_id=p.id) }}{% else %}{{ url_for('show_paste', paste_id=p.id, s=p.private) }}{% endif %}">{{ p.title }}</a></td>
 <td>{% if p.user %}{{ p.user }}{% endif%}</td>
+<td>{{ p.pub_date.strftime('%FT%TZ') }}</td>
+<td>{% if p.exp_date != p.pub_date %}{{ p.exp_date.strftime('%FT%TZ') }}{% endif %}</td>
 <td>{% if p.parent[0] %}<a href="{{ url_for('show_paste', paste_id=p.parent[0]) }}">{{ p.parent[1] }}</a>{% endif %}</td>
 <td>{% if p.children %}{% for c in p.children %}{% if not loop.first %},{% endif %}
 <a href="{{ url_for('show_paste', paste_id=c[0]) }}">{{ c[1] }}</a>{% endfor %}{% endif %}
diff --git a/templates/new_paste.html b/templates/new_paste.html
index 977ef22..b5a78aa 100644
--- a/templates/new_paste.html
+++ b/templates/new_paste.html
@@ -2,11 +2,14 @@
 {% block title %}New Paste{% endblock %}
 {% block body %}
 <form action="" method=post>
-  <h2><div class="pastetitle"><textarea rows="1" name="pastetitle">Enter title here</textarea></div>
+  <h2><div class="pastetitle"><textarea rows="1" name="pastetitle" placeholder="Untitled paste"></textarea></div>
     {%- if parent %}
     - Reply to {{ parent.title }}
     {%- endif %}
-    <span class="chk-private"><input name="is_private" type="checkbox"/>Private</span>
+    <span class="chk-private"><input name="is_private" id="is_private" type="checkbox"/><label for="is_private">Private</label></span>
+    {% if exp_opts %}<span class="drop-expiration"><label for="exp">Expires:</label><select name="exp" id="exp">
+    {% for o in exp_opts %}<option value="{{ o }}">{{ o }}</option>{% endfor %}
+    </select></span>{% endif %}
   </h2>
   <div class=code><textarea name=code cols=60 rows=12>{{ parent.code }}</textarea></div>
   <p><input type=submit value="New Paste">
diff --git a/templates/show_paste.html b/templates/show_paste.html
index 03d57b1..e9ed02a 100644
--- a/templates/show_paste.html
+++ b/templates/show_paste.html
@@ -9,7 +9,9 @@
     <dd>{{ paste.user.display_name }}
     {% endif %}
     <dt>Date
-    <dd>{{ paste.pub_date.strftime('%Y-%m-%dT%H:%M:%SZ') }}
+    <dd>{{ paste.pub_date.strftime('%FT%TZ') }}
+    {% if paste.exp_date and paste.exp_date != paste.pub_date %}<dt>Expires
+    <dd>{{ paste.exp_date.strftime('%FT%TZ') }}{% endif %}
     <dt>Actions
     <dd>
       {% if not paste.is_private %}