# This file is a demo of using aiocsv and aiofiles libraries to speed up reading and parsing CSV files. # # Start reading this code from the entrypoint function main() below. # import asyncio import aiofiles from csv import QUOTE_NONNUMERIC from typing import AsyncGenerator from aiocsv import AsyncDictWriter, AsyncDictReader async def read_lines(file: str) -> AsyncGenerator[dict, None]: """ Read lines from CSV file. """ async with aiofiles.open(file, "r") as afp: async for row in AsyncDictReader(afp, delimiter=","): yield row async def parse_lines(generator: AsyncGenerator[dict, None]) -> AsyncGenerator[dict, None]: """ Parse lines from generator. """ async for line in generator: # do some parsing here, like that: line = line yield line async def save_lines(file: str, generator: AsyncGenerator[dict, None]): """ Save lines from generator to CSV file. """ async with aiofiles.open( file, mode="w", encoding="utf-8", newline="", ) as afp: rows = [] writer = None async for item in generator: if writer is None: header = list(item.keys()) writer = AsyncDictWriter( afp, header, quoting=QUOTE_NONNUMERIC, ) await writer.writeheader() # gather rows into a list # keep the list size reasonable according to your memory constraints rows.append(item) if len(rows) % 10000 == 0: await writer.writerows(rows) rows = [] await afp.flush() # write the rest of the rows if any if len(rows) > 0: await writer.writerows(rows) async def main(in_file, out_file): """ Main function that reads lines from in_file, parses them and saves to out_file. """ raw_line_generator = read_lines(in_file) parsed_line_generator = parse_lines(generator=raw_line_generator) await save_lines(file=out_file, generator=parsed_line_generator) in_file = "some_input_file.csv" out_file = "some_output_file.csv" asyncio.run(main(in_file, out_file))
Foreword about addiction
I’m an addict and I can’t help myself. At least not in an easy way. I’m addicted to reading idiotic, moronic, hateful, homophobic comments posted by postimees.ee readers to Postimees website. FYI – Postimees is one of the oldest and biggest newspapers in Estonia.
So that’s why I was looking for a solution on how to remove comments or at least these deceptive links to comments by every article on postimees.ee website.
It only works in Firefox because that’s my main browser.
Let’s get hands dirty
First, open about:config (type it into address field). Firefox config opens after a warning.
Find the key
toolkit.legacyUserProfileCustomizations.stylesheets
Make sure the value is “true” (double click on the value). Close config.
Now open config of profiles.
Type about:profiles to address field.
Find your profile (not the development one) and there should be “Root Directory”. At the end of this line is button “Open in Finder” (or open I-dont-know-where in Windows). Whatever, just click it.
Your Firefox profile folder opens.
Inside that folder create a new folder named “chrome” (mind the lowercase name, case matters!).
Inside that “chrome” folder create an empty text file called “userContent.css”. Again – mind the naming.
Into that file add following lines:
@-moz-document domain(postimees.ee) { span.list-article__comment { display: none; } }
Save and close the file. Restart Firefox. Go to postimees.ee. Welcome to your new life!
Add the following aliases to your .bash_profile:
alias socks_on="ssh -D 8666 -C -N -f -M -S ~/.socks.socket $USER@<your_office_gateway>; networksetup -setsocksfirewallproxystate Wi-Fi on;" alias socks_off="networksetup -setsocksfirewallproxystate Wi-Fi off; ssh -S ~/.socks.socket -O exit $USER@<your_office_gateway>;"
Later you can start your tunnel with command
socks_on
and stop it with
socks_off
😉
There’s a good tool for copying ssh keys to remote host under your account: ssh-copy-id. This lets you copy your public key under your account on the remote server.
But what about other accounts? Let’s say you want to log in as root (with key-only auth method, of course)? How to copy key to root user’s .ssh/authorised_keys? One way to do it is to log as your ordinary user, make yourself root with sudo su -, open authorized_keys with editor, paste, save etc… Tedious? Yes.
That’s why there’s a good oneliner:
cat ~/.ssh/id_rsa.pub | ssh your_user@remote.server.com “sudo tee -a /root/.ssh/authorized_keys”
Here’s my experience with SailsJS, Waterline and MongoDB native queries. I like SailsJS and Waterline very much but there’s also room for improvement when things get serious.
There’s limitation in current Waterline that one cannot limit the fields in the output when MongoDB is used. Also the aggregation options are limited with Waterline. MongoDB on the other hand is very-very powerful database engine and once you learn how to aggregate then the possibilities seem endless.
My usecase is that I have to use native queries instead of Waterline’s but I also want the retrieved models have all those nice “instance methods” of Waterline model instances like “model.save()”. This example also gives you overview how to use native queries, aggregation.
So here’s very short guide to this. I hope it helps to save a couple of hours for other guys like me (who spent that time to figure it out:)).
Note! It uses another excellent, wonderful, genius etc pattern called Promises.
Have you ever tried to return custom HTTP headers from your SailsJS backend REST API to your frontend AngularJS application and wondered why they don’t show up in AngularJS?
I had pretty standard case where I wanted to implement server side pagination for my data sets returned by the API. For that you need to return the total number of records in order to implement pagination properly in the frontend. I decided to return the total number of records in a custom header called “X-TotalRecords”. It is returned together with the response but it didn’t show up in AngularJS response:
..... .then(function(response){ $log.debug(response.headers()) //does not show my custom header }) .....
After some googling around I found a solution. You need to create a custom SailsJS policy and send a special header “Access-Control-Expose-Headers” there. Let’s call the policy sendCorsHeaders.
Create a file sendCorsHeaders.js in policies/ folder:
module.exports = function (req, res, next) { res.header('Access-Control-Expose-Headers', sails.config.cors.headers); next(); };
As you can see it re-uses headers defined in your cors.js under config/ folder.
From now on you can retrieve your custom header in AngularJS $http service.
I just struggled with a complex problem of uploading application/bdoc (digital signature container) files to a SailsJS app and I want to share my story. I hope it will make the life easier for those who are working with digidoc and Signwise.
We at Prototypely are creating a solution that heavily uses digital signatures. Signwise is the preferred partner for handling containers and signing process. Signwise process states that they create the container and their system makes a HTTP PUT request to target system to put the newly created container back.
Standard file uploads are handled very nicely in SailsJS by great Skipper library.
However when it comes to uploading quite rare mime types like application/bdoc or application/x-bdoc then it needs some tweaking.
Open config/http.js and add custom body parser there and you’ll be able to accept BDOC files:
bodyParser: function (options) { return function (req, res, next) { if (req.get('content-type') != 'application/bdoc') { return next(); } var bodyParser = require('body-parser').raw({type: 'application/bdoc'}); return bodyParser(req, res, next); } }
After that you’ll be able to save the file in your controller. Mind the req.body – this is the buffer that will be written down.
acceptBdocFile: function(req, res){ var fileId = req.param('fileId'); var tmpFile = process.cwd() + '/.tmp/' + fileId; fs.writeFileSync(tmpFile, req.body); return res.status(201).json(); }
Sometimes Magento gets stuck in “Maintenance mode”. It means that there is maintenance.flag file in Magento’s root folder.
The standard maintenance mode of Magento is a bit “too universal” – it sets Magento backend (admin) to maintenance mode also. Once you’re in maintenance mode, it’s hard to get out of this if you don’t have access server’s shell.
Anyway – there is one option if you have not removed Magento Connect Manager (a.k.a /downloader). This program is be impacted by the maintenance.flag file. Log in to Connect Manager at /downloader and check/uncheck checkbox ““.
That’s it.
Timezones are … difficult. I can say that based on my >20 years programming experience. They pop up here and there and cause a good amount of headache. I won’t spend too much time here for timezones but I just give a quick tip how to set your SailsJS (or any NodeJS) app to use UTC (GMT) timezone by default.
During the years I’ve learn that it’s best to have everything in UTC in the business and DB layers as a rule of thumb (there are exceptions, of course).
It’s really simple to make your NodeJS app to have UTC as default timezone. Just export an environment variable before you run your app:
export TZ="UTC" forever --watchDirectory ./ -l logs/log.log --watch app.js
When you’re packing Magento extensions in Magento admin and want to ignore (or include) a file or directory then there’s a special syntax for it. Let’s say you want to exclude folder “tests” from the tgz package. Number signs (#) are used as wildcard placeholders. Add following line to “Ignore” field:
#tests/#
Your tests folder will be excluded from the tgz package.