This answer was extremely helpful: https://stackoverflow.com/a/9695045/353878.

I needed to not initialize the db right away.

    from app.database import Base
    
    class User(Base):
    __tablename__ = &#39;users&#39;

Shouldn it be this way ??


Say I have a list of dicts that looks like this:

    [{1: &quot;a&quot;}, {2: &quot;b&quot;}]

What is the pythonic way to indicate if a certain key is in one of the dicts in the list?

How can I check if key exists in list of dicts in python?

For instance, is there a way to nest my &quot;**i18n**&quot; helper inside another helper&#39;s hash variable? 

    {{view &quot;SearchView&quot; placeholder=&quot;{{t &#39;search.root&#39;}}&quot; ref=&quot;search&quot; url=&quot;/pages/search&quot; className=&#39;home-search&#39;  polyfill=true}}


Is it possible to nest helpers inside the options hash with handlebars?

Many examples for Flask apps that I have seen have the models stored directly in the main app file (http://pythonhosted.org/Flask-SQLAlchemy/quickstart.html, http://maximebf.com/blog/2012/10/building-websites-in-python-with-flask/). Other ones (http://flask.pocoo.org/docs/patterns/sqlalchemy/) have a &quot;models.py&quot; file in which models are placed.

How can I have my Flask app import models from separate files, e.x. &quot;User.py&quot;? When I try creating a User.py file with these contents:

    from app import db

    class User(db.Model):
        [...]

I get the following error:

    File &quot;/Users/stackoverflow/myapp/models/User.py&quot;, line 1, in &lt;module&gt;
    from app import db
    ImportError: No module named app

When I insert `from models import User` in my module file.

Separate SQLAlchemy models by file in Flask

Many examples for Flask apps that I have seen have the models stored directly in the main app file (<a href="http://pythonhosted.org/Flask-SQLAlchemy/quickstart.html" target="_blank" rel="noopener noreferrer">http://pythonhosted.org/Flask-SQLAlchemy/quickstart.html</a>, <a href="http://maximebf.com/blog/2012/10/building-websites-in-python-with-flask/" target="_blank" rel="noopener noreferrer">http://maximebf.com/blog/2012/10/building-websites-in-python-with-flask/</a>). Other ones (<a href="http://flask.pocoo.org/docs/patterns/sqlalchemy/" target="_blank" rel="noopener noreferrer">http://flask.pocoo.org/docs/patterns/sqlalchemy/</a>) have a "models.py" file in which models are placed.
How can I have my Flask app import models from separate files, e.x. "User.py"? When I try creating a User.py file with these contents:
<pre><code class="hljs language-javascript">from app import db

class User(db.Model):
 [...]
</code></pre>
I get the following error:
<pre><code class="hljs language-arduino">File "/Users/stackoverflow/myapp/models/User.py", line 1, in &#x3C;module>
from app import db
ImportError: No module named app
</code></pre>
When I insert <code>from models import User</code> in my module file.

When using PyCharm IDE the use of `except:` without an exception type triggers a reminder from the IDE that this exception clause is `Too broad`. 

Should I be ignoring this advice? Or is it Pythonic to always specific the exception type?

Should I always specify an exception type in `except` statements?

I want to open a series of subfolders in a folder and find some text files and print some lines of the text files. I am using this:

    configfiles = glob.glob(&#39;C:/Users/sam/Desktop/file1/*.txt&#39;)

But this cannot access the subfolders as well. Does anyone know how I can use the same command to access subfolders as well?

How can I search sub-folders using glob.glob module?

I want to find the minimum of a list of tuples sorting by a given column.  I have some data arranged as a list of 2-tuples for example.

    data = [ (1, 7.57), (2, 2.1), (3, 1.2), (4, 2.1), (5, 0.01), 
             (6, 0.5), (7, 0.2), (8, 0.6)]

How may I find the min of the dataset by the comparison of the second number in the tuples only?

i.e. 

    data[0][1] = 7.57
    data[1][1] = 2.1

min( data ) = `(5, 0.01)`


`min( data )` returns `(1, 7.57)`, which I accept is correct for the minimum of index 0, but I want minimum of index 1.



Tuple pairs, finding minimum using python

Hello when I attempt to install pylibmc on OSX Lion using pip I get the following error:

    ./_pylibmcmodule.h:42:10: fatal error: &#39;libmemcached/memcached.h&#39; file not found

    #include &lt;libmemcached/memcached.h&gt;

             ^

    1 error generated.

    error: command &#39;clang&#39; failed with exit status 1

Any clues at how to solve this issue?

Error when install pylibmc using pip

How can I add an element to an Enum field in an alembic migration when using a version of PostgreSQL older than 9.1 (which adds the ALTER TYPE for enums)? [This](https://stackoverflow.com/questions/1771543/postgresql-updating-an-enum-type) SO question explains the direct process, but I&#39;m not quite sure how best to translate that using alembic.

This is what I have:

    new_type = sa.Enum(&#39;nonexistent_executable&#39;, &#39;output_limit_exceeded&#39;,
                       &#39;signal&#39;, &#39;success&#39;, &#39;timed_out&#39;, name=&#39;status&#39;)
    old_type = sa.Enum(&#39;nonexistent_executable&#39;, &#39;signal&#39;, &#39;success&#39;, &#39;timed_out&#39;,
                       name=&#39;status&#39;)
    tcr = sa.sql.table(&#39;testcaseresult&#39;,
                       sa.Column(&#39;status&#39;, new_type, nullable=False))
    
    
    def upgrade():
        op.alter_column(&#39;testcaseresult&#39;, u&#39;status&#39;, type_=new_type,
                        existing_type=old_type)
    
    
    def downgrade():
        op.execute(tcr.update().where(tcr.c.status==u&#39;output_limit_exceeded&#39;)
                   .values(status=&#39;timed_out&#39;))
        op.alter_column(&#39;testcaseresult&#39;, u&#39;status&#39;, type_=old_type,
                        existing_type=new_type)

The above unfortunately only produces `ALTER TABLE testcaseresult ALTER COLUMN status TYPE status` upon upgrade, which essentially does nothing.

Altering an Enum field using Alembic

Looking at the output of `select * from pg_stat_activity;`, I see a column called `application_name`, described [here](http://www.postgresql.org/docs/current/static/monitoring-stats.html#PG-STAT-ACTIVITY-VIEW).

I see psql sets this value correctly (to `psql`...), but my application code (psycopg2/SQLAlchemy) leaves it blank.

I&#39;d like to set this to something useful, like `web.1`, `web.2`, etc, so I could later on correlate what I see in `pg_stat_activity` with what I see in my application logs.

I couldn&#39;t find how to set this field using SQLAlchemy (and if push comes to shove - even with raw sql; I&#39;m using PostgresSQL 9.1.7 on Heroku, if that matters).

Am I missing something obvious?

Setting application_name on Postgres/SQLAlchemy

Let&#39;s say I have a `User` model with fields `popularity` and `date_created`. I want to do the following query:

    SELECT * FROM user ORDER BY popularity DESC, date_created DESC LIMIT 10

In SQLAlchemy, for a single one this works:

    User.query.order_by(User.popularity.desc()).limit(10).all()

Should I just add another `order_by()`? Or put both `popularity` and `date_created` in my current `order_by()`?

I want `popularity` to have priority on `date_created` for ordering.

How can I do multiple &quot;order_by&quot; in Flask-SQLAlchemy?

I can query my `Seat` table for all seats where there is no invite assigned:

    seats = Seat.query.filter_by(invite=None).all()

However, when querying for all seats that have an invite assigned, I get a `NameError`:

    seats = Seat.query.filter_by(invite!=None).all()

&lt;!-- language: lang-none --&gt;

    NameError: name &#39;invite&#39; is not defined

Here is my `Seat` class:

    class Seat(db.Model):
        id = db.Column(db.Integer, primary_key=True)

        invite_id = db.Column(db.Integer, db.ForeignKey(&#39;invite.id&#39;))
        invite = db.relationship(&#39;Invite&#39;,
            backref=db.backref(&#39;folks&#39;, lazy=&#39;dynamic&#39;))

How can I query for all seats where the owner is not blank?

Flask SQLAlchemy querying a column with &quot;not equals&quot;

I&#39;m working on forum template using Flask. When I attempt creating a new thread in the browser using forms, SQLAlchemy throws an AttributeError. The problem showed up when I tried implementing a one-to-many relationship with Forum-to-Thread and a one-to-many relationship with Thread-to-User.

models.py

    class User(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      username = db.Column(db.String(32), index=True, unique=True)
      password = db.Column(db.String(32), index=True)
      email = db.Column(db.String(120), index=True, unique=True)
      role = db.Column(db.SmallInteger, default=ROLE_USER)
    
      posts = db.relationship(&#39;Post&#39;, backref=&#39;author&#39;, lazy=&#39;dynamic&#39;)

    class Forum(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      title = db.Column(db.String(128))
      description = db.Column(db.Text)
    
      threads = db.relationship(&#39;Thread&#39;, backref=&#39;forum&#39;, lazy=&#39;dynamic&#39;)
    	  
    class Thread(db.Model):
      
      id = db.Column(db.Integer, primary_key=True)
      title = db.Column(db.String(128))
      author= db.Column(db.String(32))
      timestamp = db.Column(db.DateTime)
      forum_id = db.Column(db.Integer, db.ForeignKey(&#39;forum.id&#39;))
    
      posts = db.relationship(&#39;Post&#39;, backref=&#39;thread&#39;, lazy=&#39;dynamic&#39;)
    	
    class Post(db.Model):
      
      id = db.Column(db.Integer, primary_key=True)
      body = db.Column(db.Text)
      timestamp = db.Column(db.DateTime)
      thread_id = db.Column(db.Integer, db.ForeignKey(&#39;thread.id&#39;))
      user_id = db.Column(db.Integer, db.ForeignKey(&#39;user.id&#39;))

All the new posts/threads and handled within views.py

views.py

    @app.route(&#39;/forum/id=&lt;id&gt;/submit&#39;, methods=[&#39;GET&#39;,&#39;POST&#39;])
    @login_required
    def new_thread(id):
      form = ThreadForm()
      forum = Forum.query.filter_by(id=id).first()
      if form.validate_on_submit():
        thread = Thread(title=form.title.data,
                        author=g.user.username,
                        timestamp=datetime.utcnow())
        db.session.add(thread)
        db.session.flush()
        post = Post(body=form.body.data,
                    timestamp=datetime.utcnow(),
                    thread=thread.id,
                    author=g.user.id)
        db.session.add(post)
        db.session.commit()
        flash(&#39;Post successful.&#39;)
        return redirect(url_for(&#39;forum_index&#39;, id=id))
      return render_template(&#39;forum/thread_submit.html&#39;, title=forum.title, form=form) 

AttributeError: &#39;int&#39; object has no attribute &#39;_sa_instance_state&#39;

I am using `url_for` to generate a redirect URL when a user has logged out:

    return redirect(url_for(&#39;.index&#39;, _external=True))

However, when I changed the page to a *https* connection, the `url_for` still gives me *http*.

I would like to explicitly ask `url_for` to add *https* at the beginning of a URL.

Can you point me how to change it? I looked at Flask docs, without luck.

Flask url_for generating http URL instead of https

I know I can link Flask with Apache or other web servers. But, I was thinking of running Flask as a standalone server serving multiple clients simultaneously.

Is this possible? Do I have to handle spawning multiple threads and managing them?

Can I serve multiple clients using just Flask app.run() as standalone?

I have a Flask server running in standalone mode (using `app.run()`). But, I don&#39;t want any messages in the console, like

    127.0.0.1 - - [15/Feb/2013 10:52:22] &quot;GET /index.html HTTP/1.1&quot; 200 -
    ...

How do I disable verbose mode?

Disable console messages in Flask server

I&#39;m having trouble getting data POSTed from jquery ajax.

    $(&#39;#clickme&#39;).click( function() {
    	var data = save_input(); // data
    
    	data[&#39;_sid&#39;] = $survey_id;  // survey_id injected from flask
    	data[&#39;_uip&#39;] = $user_ip; // user_ip injected from flask, request.remote_addr
    
    	$.ajax({
    		type : &quot;POST&quot;,
    		url : &quot;{{ url_for(&#39;mod.load_ajax&#39;) }}&quot;,
    		data: JSON.stringify(data),
    		contentType: &#39;application/json;charset=UTF-8&#39;,
    		success: function(result) {
    			console.log(result);
    		}
    	});
    
    	console.log(data);
    });

from the code, `data` is a javascript object like


    {
        &#39;foo&#39; : &#39;foo&#39;,
        &#39;bar&#39; : &#39;bar&#39;,
        &#39;fo_&#39; : 42,
    }

what I&#39;m trying to do in flask is :


    @mod.route(&#39;/load_ajax&#39;, methods=[&quot;GET&quot;, &quot;POST&quot;])
    def load_ajax():
        if request.method == &quot;POST&quot;:
            # load _sid and _uip from posted JSON and save other data
            # but request.form is empty.
            # &gt;&gt;&gt; request.form
            # ImmutableMultiDict([]) 
            return str(request.form)

see, the ajax request is made but no data is submitted. I do `console.log(data)` with ajax so I can see that I really have some meaningful data in `data` variable in jquery. but request.form in ajax view is empty. Where is my data submitted? 

how can I use data posted from ajax in flask?

I love Flask&#39;s error catching.  It&#39;s beautifully simple:

    @app.errorhandler(404)
    def pageNotFound(error):
    	return &quot;page not found&quot;

works like charm.  But it doesn&#39;t work for the 500 error code.  I want to catch Python errors when something goes wrong an exception is raised in the code.  Is that possible?

I should note that if I explicitly call `return abort(500)` in a view then the 500 errorhandler does work.  So this is explicitly for when the Python code fails.

Is this possible?

Catching a 500 server error in Flask

I&#39;m following the flask-sqlalchemy tutorial on [declaring models][1] regarding one-to-many relationship. The example code is as follows:

    class Person(db.Model):
        id = db.Column(db.Integer, primary_key=True)
        name = db.Column(db.String(50))
        addresses = db.relationship(&#39;Address&#39;, backref=&#39;person&#39;,
                                    lazy=&#39;dynamic&#39;)
    
    class Address(db.Model):
        id = db.Column(db.Integer, primary_key=True)
        email = db.Column(db.String(50))
        person_id = db.Column(db.Integer, db.ForeignKey(&#39;person.id&#39;))

Now I&#39;m wondering how to insert new records into DB using such model. I assume I need a constructor __init__, but I have difficulties to understand how it should be implemented and used. The main problem for me here is that Person depends on Address and Address has ForeignKey to Person, so it should know about the Person in advance.

Plase help me to understand how it should be performed.

Thank you in advance.

  [1]: http://flask-sqlalchemy.pocoo.org/2.1/models/

Inserting new records with one-to-many relationship in sqlalchemy

I&#39;m using Flask-SQLAlchemy to query from a database of users; however, while

    user = models.User.query.filter_by(username=&quot;ganye&quot;).first()

will return

    &lt;User u&#39;ganye&#39;&gt;

doing

    user = models.User.query.filter_by(username=&quot;GANYE&quot;).first()

returns

    None

I&#39;m wondering if there&#39;s a way to query the database in a case insensitive way, so that the second example will still return

    &lt;User u&#39;ganye&#39;&gt;

Content Type	Original Author	Original Content on Stackoverflow
Question	element119	View Question on Stackoverflow
Solution 1 - Python	element119	View Answer on Stackoverflow
Solution 2 - Python	Redian	View Answer on Stackoverflow

Separate SQLAlchemy models by file in Flask

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Is it possible to nest helpers inside the options hash with handlebars?

How can I check if key exists in list of dicts in python?

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