Shall I Use ADD or COPY in the Dockerfile, and What's the Difference?

Every developer and every team faces confusion about COPY and ADD in the Dockerfile at some point. When I get this question, first I usually give the technical background, which is this:

Both **ADD** and **COPY** copy files and directories from the host machine into a Docker image, the difference is that **ADD** can also extract and copy local tar archives and it can also download files from URLs (a.k.a. the internet), and copy them into the Docker image. The best practice is to use **COPY**.

So COPY equals ADD minus the unpacking and URL fetching features. COPY is the preferred way, except if you unpack a local tar archive into a Docker image and you are certain that the local archive has the right format.

You can understand why this is the case looking at some background info. Read on…

Why COPY is Preferred

The core purpose of ADD and COPY is to let Dockerfile developers copy files and directories from the host machine into the Docker image during image build.

Extracting archives and downloading files from the internet are common use-cases, these features are built into ADD.

The uncompression feature is described in the official documentation as follows:

If  <src> is a local tar archive in a recognized compression format (identity, gzip, bzip2 or xz) then it is unpacked as a directory.

The following note on the same page further explains the behavior:

Note: Whether a file is identified as a recognized compression format is done solely based on the contents of the file, not the name of the file. For example, if an empty file happens to end with  .tar.gz this will not be recognized as a compressed file, and will not generate any kind of decompression error message, rather the file will simply be copied to the destination.

This means that your final outcome depends on the contents of the file you intend to copy, and you don’t get warnings if something goes wrong. This may make your build pipeline unpredictable.

_To make life more reliable, we have the _**_COPY_**_ instruction, which is __"the same as _[**_ADD_**](https://github.com/moby/moby/blob/670c8696a29825b23208496bd4d8e88b5faa7773/builder/dispatchers.go#L77), but without the tar and URL handling". **COPY** does one thing and it does it well.

#docker #kubernetes #cloud native #add #copy #cloud

What is GEEK

Buddha Community

Pdf2gerb: Perl Script Converts PDF Files to Gerber format

pdf2gerb

Perl script converts PDF files to Gerber format

Pdf2Gerb generates Gerber 274X photoplotting and Excellon drill files from PDFs of a PCB. Up to three PDFs are used: the top copper layer, the bottom copper layer (for 2-sided PCBs), and an optional silk screen layer. The PDFs can be created directly from any PDF drawing software, or a PDF print driver can be used to capture the Print output if the drawing software does not directly support output to PDF.

The general workflow is as follows:

1. Design the PCB using your favorite CAD or drawing software.
2. Print the top and bottom copper and top silk screen layers to a PDF file.
3. Run Pdf2Gerb on the PDFs to create Gerber and Excellon files.
4. Use a Gerber viewer to double-check the output against the original PCB design.
5. Make adjustments as needed.
6. Submit the files to a PCB manufacturer.

Please note that Pdf2Gerb does NOT perform DRC (Design Rule Checks), as these will vary according to individual PCB manufacturer conventions and capabilities. Also note that Pdf2Gerb is not perfect, so the output files must always be checked before submitting them. As of version 1.6, Pdf2Gerb supports most PCB elements, such as round and square pads, round holes, traces, SMD pads, ground planes, no-fill areas, and panelization. However, because it interprets the graphical output of a Print function, there are limitations in what it can recognize (or there may be bugs).

See docs/Pdf2Gerb.pdf for install/setup, config, usage, and other info.

---

pdf2gerb_cfg.pm

#Pdf2Gerb config settings:
#Put this file in same folder/directory as pdf2gerb.pl itself (global settings),
#or copy to another folder/directory with PDFs if you want PCB-specific settings.
#There is only one user of this file, so we don't need a custom package or namespace.
#NOTE: all constants defined in here will be added to main namespace.
#package pdf2gerb_cfg;

use strict; #trap undef vars (easier debug)
use warnings; #other useful info (easier debug)


##############################################################################################
#configurable settings:
#change values here instead of in main pfg2gerb.pl file

use constant WANT_COLORS => ($^O !~ m/Win/); #ANSI colors no worky on Windows? this must be set < first DebugPrint() call

#just a little warning; set realistic expectations:
#DebugPrint("${\(CYAN)}Pdf2Gerb.pl ${\(VERSION)}, $^O O/S\n${\(YELLOW)}${\(BOLD)}${\(ITALIC)}This is EXPERIMENTAL software.  \nGerber files MAY CONTAIN ERRORS.  Please CHECK them before fabrication!${\(RESET)}", 0); #if WANT_DEBUG

use constant METRIC => FALSE; #set to TRUE for metric units (only affect final numbers in output files, not internal arithmetic)
use constant APERTURE_LIMIT => 0; #34; #max #apertures to use; generate warnings if too many apertures are used (0 to not check)
use constant DRILL_FMT => '2.4'; #'2.3'; #'2.4' is the default for PCB fab; change to '2.3' for CNC

use constant WANT_DEBUG => 0; #10; #level of debug wanted; higher == more, lower == less, 0 == none
use constant GERBER_DEBUG => 0; #level of debug to include in Gerber file; DON'T USE FOR FABRICATION
use constant WANT_STREAMS => FALSE; #TRUE; #save decompressed streams to files (for debug)
use constant WANT_ALLINPUT => FALSE; #TRUE; #save entire input stream (for debug ONLY)

#DebugPrint(sprintf("${\(CYAN)}DEBUG: stdout %d, gerber %d, want streams? %d, all input? %d, O/S: $^O, Perl: $]${\(RESET)}\n", WANT_DEBUG, GERBER_DEBUG, WANT_STREAMS, WANT_ALLINPUT), 1);
#DebugPrint(sprintf("max int = %d, min int = %d\n", MAXINT, MININT), 1); 

#define standard trace and pad sizes to reduce scaling or PDF rendering errors:
#This avoids weird aperture settings and replaces them with more standardized values.
#(I'm not sure how photoplotters handle strange sizes).
#Fewer choices here gives more accurate mapping in the final Gerber files.
#units are in inches
use constant TOOL_SIZES => #add more as desired
(
#round or square pads (> 0) and drills (< 0):
    .010, -.001,  #tiny pads for SMD; dummy drill size (too small for practical use, but needed so StandardTool will use this entry)
    .031, -.014,  #used for vias
    .041, -.020,  #smallest non-filled plated hole
    .051, -.025,
    .056, -.029,  #useful for IC pins
    .070, -.033,
    .075, -.040,  #heavier leads
#    .090, -.043,  #NOTE: 600 dpi is not high enough resolution to reliably distinguish between .043" and .046", so choose 1 of the 2 here
    .100, -.046,
    .115, -.052,
    .130, -.061,
    .140, -.067,
    .150, -.079,
    .175, -.088,
    .190, -.093,
    .200, -.100,
    .220, -.110,
    .160, -.125,  #useful for mounting holes
#some additional pad sizes without holes (repeat a previous hole size if you just want the pad size):
    .090, -.040,  #want a .090 pad option, but use dummy hole size
    .065, -.040, #.065 x .065 rect pad
    .035, -.040, #.035 x .065 rect pad
#traces:
    .001,  #too thin for real traces; use only for board outlines
    .006,  #minimum real trace width; mainly used for text
    .008,  #mainly used for mid-sized text, not traces
    .010,  #minimum recommended trace width for low-current signals
    .012,
    .015,  #moderate low-voltage current
    .020,  #heavier trace for power, ground (even if a lighter one is adequate)
    .025,
    .030,  #heavy-current traces; be careful with these ones!
    .040,
    .050,
    .060,
    .080,
    .100,
    .120,
);
#Areas larger than the values below will be filled with parallel lines:
#This cuts down on the number of aperture sizes used.
#Set to 0 to always use an aperture or drill, regardless of size.
use constant { MAX_APERTURE => max((TOOL_SIZES)) + .004, MAX_DRILL => -min((TOOL_SIZES)) + .004 }; #max aperture and drill sizes (plus a little tolerance)
#DebugPrint(sprintf("using %d standard tool sizes: %s, max aper %.3f, max drill %.3f\n", scalar((TOOL_SIZES)), join(", ", (TOOL_SIZES)), MAX_APERTURE, MAX_DRILL), 1);

#NOTE: Compare the PDF to the original CAD file to check the accuracy of the PDF rendering and parsing!
#for example, the CAD software I used generated the following circles for holes:
#CAD hole size:   parsed PDF diameter:      error:
#  .014                .016                +.002
#  .020                .02267              +.00267
#  .025                .026                +.001
#  .029                .03167              +.00267
#  .033                .036                +.003
#  .040                .04267              +.00267
#This was usually ~ .002" - .003" too big compared to the hole as displayed in the CAD software.
#To compensate for PDF rendering errors (either during CAD Print function or PDF parsing logic), adjust the values below as needed.
#units are pixels; for example, a value of 2.4 at 600 dpi = .0004 inch, 2 at 600 dpi = .0033"
use constant
{
    HOLE_ADJUST => -0.004 * 600, #-2.6, #holes seemed to be slightly oversized (by .002" - .004"), so shrink them a little
    RNDPAD_ADJUST => -0.003 * 600, #-2, #-2.4, #round pads seemed to be slightly oversized, so shrink them a little
    SQRPAD_ADJUST => +0.001 * 600, #+.5, #square pads are sometimes too small by .00067, so bump them up a little
    RECTPAD_ADJUST => 0, #(pixels) rectangular pads seem to be okay? (not tested much)
    TRACE_ADJUST => 0, #(pixels) traces seemed to be okay?
    REDUCE_TOLERANCE => .001, #(inches) allow this much variation when reducing circles and rects
};

#Also, my CAD's Print function or the PDF print driver I used was a little off for circles, so define some additional adjustment values here:
#Values are added to X/Y coordinates; units are pixels; for example, a value of 1 at 600 dpi would be ~= .002 inch
use constant
{
    CIRCLE_ADJUST_MINX => 0,
    CIRCLE_ADJUST_MINY => -0.001 * 600, #-1, #circles were a little too high, so nudge them a little lower
    CIRCLE_ADJUST_MAXX => +0.001 * 600, #+1, #circles were a little too far to the left, so nudge them a little to the right
    CIRCLE_ADJUST_MAXY => 0,
    SUBST_CIRCLE_CLIPRECT => FALSE, #generate circle and substitute for clip rects (to compensate for the way some CAD software draws circles)
    WANT_CLIPRECT => TRUE, #FALSE, #AI doesn't need clip rect at all? should be on normally?
    RECT_COMPLETION => FALSE, #TRUE, #fill in 4th side of rect when 3 sides found
};

#allow .012 clearance around pads for solder mask:
#This value effectively adjusts pad sizes in the TOOL_SIZES list above (only for solder mask layers).
use constant SOLDER_MARGIN => +.012; #units are inches

#line join/cap styles:
use constant
{
    CAP_NONE => 0, #butt (none); line is exact length
    CAP_ROUND => 1, #round cap/join; line overhangs by a semi-circle at either end
    CAP_SQUARE => 2, #square cap/join; line overhangs by a half square on either end
    CAP_OVERRIDE => FALSE, #cap style overrides drawing logic
};
    
#number of elements in each shape type:
use constant
{
    RECT_SHAPELEN => 6, #x0, y0, x1, y1, count, "rect" (start, end corners)
    LINE_SHAPELEN => 6, #x0, y0, x1, y1, count, "line" (line seg)
    CURVE_SHAPELEN => 10, #xstart, ystart, x0, y0, x1, y1, xend, yend, count, "curve" (bezier 2 points)
    CIRCLE_SHAPELEN => 5, #x, y, 5, count, "circle" (center + radius)
};
#const my %SHAPELEN =
#Readonly my %SHAPELEN =>
our %SHAPELEN =
(
    rect => RECT_SHAPELEN,
    line => LINE_SHAPELEN,
    curve => CURVE_SHAPELEN,
    circle => CIRCLE_SHAPELEN,
);

#panelization:
#This will repeat the entire body the number of times indicated along the X or Y axes (files grow accordingly).
#Display elements that overhang PCB boundary can be squashed or left as-is (typically text or other silk screen markings).
#Set "overhangs" TRUE to allow overhangs, FALSE to truncate them.
#xpad and ypad allow margins to be added around outer edge of panelized PCB.
use constant PANELIZE => {'x' => 1, 'y' => 1, 'xpad' => 0, 'ypad' => 0, 'overhangs' => TRUE}; #number of times to repeat in X and Y directions

# Set this to 1 if you need TurboCAD support.
#$turboCAD = FALSE; #is this still needed as an option?

#CIRCAD pad generation uses an appropriate aperture, then moves it (stroke) "a little" - we use this to find pads and distinguish them from PCB holes. 
use constant PAD_STROKE => 0.3; #0.0005 * 600; #units are pixels
#convert very short traces to pads or holes:
use constant TRACE_MINLEN => .001; #units are inches
#use constant ALWAYS_XY => TRUE; #FALSE; #force XY even if X or Y doesn't change; NOTE: needs to be TRUE for all pads to show in FlatCAM and ViewPlot
use constant REMOVE_POLARITY => FALSE; #TRUE; #set to remove subtractive (negative) polarity; NOTE: must be FALSE for ground planes

#PDF uses "points", each point = 1/72 inch
#combined with a PDF scale factor of .12, this gives 600 dpi resolution (1/72 * .12 = 600 dpi)
use constant INCHES_PER_POINT => 1/72; #0.0138888889; #multiply point-size by this to get inches

# The precision used when computing a bezier curve. Higher numbers are more precise but slower (and generate larger files).
#$bezierPrecision = 100;
use constant BEZIER_PRECISION => 36; #100; #use const; reduced for faster rendering (mainly used for silk screen and thermal pads)

# Ground planes and silk screen or larger copper rectangles or circles are filled line-by-line using this resolution.
use constant FILL_WIDTH => .01; #fill at most 0.01 inch at a time

# The max number of characters to read into memory
use constant MAX_BYTES => 10 * M; #bumped up to 10 MB, use const

use constant DUP_DRILL1 => TRUE; #FALSE; #kludge: ViewPlot doesn't load drill files that are too small so duplicate first tool

my $runtime = time(); #Time::HiRes::gettimeofday(); #measure my execution time

print STDERR "Loaded config settings from '${\(__FILE__)}'.\n";
1; #last value must be truthful to indicate successful load


#############################################################################################
#junk/experiment:

#use Package::Constants;
#use Exporter qw(import); #https://perldoc.perl.org/Exporter.html

#my $caller = "pdf2gerb::";

#sub cfg
#{
#    my $proto = shift;
#    my $class = ref($proto) || $proto;
#    my $settings =
#    {
#        $WANT_DEBUG => 990, #10; #level of debug wanted; higher == more, lower == less, 0 == none
#    };
#    bless($settings, $class);
#    return $settings;
#}

#use constant HELLO => "hi there2"; #"main::HELLO" => "hi there";
#use constant GOODBYE => 14; #"main::GOODBYE" => 12;

#print STDERR "read cfg file\n";

#our @EXPORT_OK = Package::Constants->list(__PACKAGE__); #https://www.perlmonks.org/?node_id=1072691; NOTE: "_OK" skips short/common names

#print STDERR scalar(@EXPORT_OK) . " consts exported:\n";
#foreach(@EXPORT_OK) { print STDERR "$_\n"; }
#my $val = main::thing("xyz");
#print STDERR "caller gave me $val\n";
#foreach my $arg (@ARGV) { print STDERR "arg $arg\n"; }

---

Download Details:

Author: swannman
Source Code: https://github.com/swannman/pdf2gerb

License: GPL-3.0 license

#perl 

Shall I Use ADD or COPY in the Dockerfile, and What's the Difference?

Every developer and every team faces confusion about COPY and ADD in the Dockerfile at some point. When I get this question, first I usually give the technical background, which is this:

Both **ADD** and **COPY** copy files and directories from the host machine into a Docker image, the difference is that **ADD** can also extract and copy local tar archives and it can also download files from URLs (a.k.a. the internet), and copy them into the Docker image. The best practice is to use **COPY**.

So COPY equals ADD minus the unpacking and URL fetching features. COPY is the preferred way, except if you unpack a local tar archive into a Docker image and you are certain that the local archive has the right format.

You can understand why this is the case looking at some background info. Read on…

Why COPY is Preferred

The core purpose of ADD and COPY is to let Dockerfile developers copy files and directories from the host machine into the Docker image during image build.

Extracting archives and downloading files from the internet are common use-cases, these features are built into ADD.

The uncompression feature is described in the official documentation as follows:

If  <src> is a local tar archive in a recognized compression format (identity, gzip, bzip2 or xz) then it is unpacked as a directory.

The following note on the same page further explains the behavior:

Note: Whether a file is identified as a recognized compression format is done solely based on the contents of the file, not the name of the file. For example, if an empty file happens to end with  .tar.gz this will not be recognized as a compressed file, and will not generate any kind of decompression error message, rather the file will simply be copied to the destination.

This means that your final outcome depends on the contents of the file you intend to copy, and you don’t get warnings if something goes wrong. This may make your build pipeline unpredictable.

_To make life more reliable, we have the _**_COPY_**_ instruction, which is __"the same as _[**_ADD_**](https://github.com/moby/moby/blob/670c8696a29825b23208496bd4d8e88b5faa7773/builder/dispatchers.go#L77), but without the tar and URL handling". **COPY** does one thing and it does it well.

#docker #kubernetes #cloud native #add #copy #cloud

matrix multiplication in python user input

Given two user input matrix. Our task is to display the addition of two matrix. In these problem we use nested List comprehensive.

matrix multiplication in python user input

Algorithm

Step1: input two matrix.

Step 2: nested for loops to iterate through each row and each column.

Step 3: take one resultant matrix which is initially contains all 0. Then we multiply each row elements of first matrix with each elements of second matrix, then add all multiplied value. That is the value of resultant matrix.

Example Code

# Program to multiply two matrices
A=[]
n=int(input("Enter N for N x N matrix: "))         
print("Enter the element ::>")
for i in range(n): 
   row=[]                                      #temporary list to store the row
   for j in range(n): 
      row.append(int(input()))           #add the input to row list
      A.append(row)                      #add the row to the list
print(A)
# [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
#Display the 2D array
print("Display Array In Matrix Form")
for i in range(n):
   for j in range(n):
      print(A[i][j], end=" ")
   print()                                        #new line
B=[]
n=int(input("Enter N for N x N matrix : "))           #3 here
#use list for storing 2D array
#get the user input and store it in list (here IN : 1 to 9)
print("Enter the element ::>")
for i in range (n): 
   row=[]                                      #temporary list to store the row
   for j in range(n): 
      row.append(int(input()))           #add the input to row list
      B.append(row)                       #add the row to the list
print(B)
# [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
#Display the 2D array
print("Display Array In Matrix Form")
for i in range(n):
   for j in range(n):
      print(B[i][j], end=" ")
   print()                                           
result = [[0,0,0], [0,0,0], [0,0,0]] 
for i in range(len(A)): 
   for j in range(len(B[0])): 
      for k in range(len(B)): 
         result[i][j] += A[i][k] * B[k][j] 
print("The Resultant Matrix Is ::>")
for r in result: 
   print(r) 

Output

Enter N for N x N matrix: 3
Enter the element ::>
2
1
4
2
1
2
3
4
3
[[2, 1, 4], [2, 1, 2], [3, 4, 3]]
Display Array In Matrix Form
2 1 4 
2 1 2 
3 4 3 
Enter N for N x N matrix : 3
Enter the element ::>
1
2
3
4
5
6
7
8
9
[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Display Array In Matrix Form
1 2 3 
4 5 6 
7 8 9 
The Resultant Matrix Is ::>
[34, 41, 48]
[20, 25, 30]
[40, 50, 60]

https://www.pakainfo.com/python-program-multiplication-of-two-matrix-from-user-input/

Top 6 Python Packages You Should be Using in Every Django Web App

There are countless Python packages easily added to any project. But there are some packages you can't help but use in every Django web app because they've proven to be extremely beneficial and time-saving.

We decided to focus on those packages, the ones you'll end up installing regularly, and explain the installation and configurations needed to get them up and running. 

While some Python packages offer cool functionality needed for one specific project, the packages discussed below are the bread-and-butter of the Django packages.

Django Web Framework

But we can't jump into Django packages by talking about the Django web framework.

A web framework is comprised of modules or packages that allow developers to quickly write web applications without having to handle the precise details of the protocol and other web app management.

Django is considered a full-stack web framework in which a database, application server, template engine, authentication module, and dispatcher are all neatly combined to create a high-level framework. These individual components are included upon package installation and often just need some minor configurations for them to function correctly. 

macOS Terminal

(env)User-Macbook:env user$ pip install django

Windows Command Prompt

(env)C:\Users\Owner\desktop\env> pip install django

At the time of this article, the latest version of Django is 3.0.8. To install the latest version, all you need is the command pip install django.

If you wish to install a different version, then specify the version number as demonstrated in the command pip install django==2.1.15. Please note that there are two equal signs after the package name, not one. 

Once the installation is complete, you will need to start configuring your Django web app with a project and an application. If you want to jump right into building your Django web app, check out the quick start guides to Django Installation and Django Configuration. Or if you are just getting started and need a step-by-step tutorial, see the Beginner's Guide to Django Web Apps. 

But we are here to talk about Python Packages meant for Django web apps, not basic Django configurations so we'll keep moving.

We have a lot to cover.

1. Django TinyMCE4 Lite
2. Pillow
3. Django Crispy Forms
4. Django Tables
5. Django Filter
6. Python Decouple

 

---

 

(1) Django TinyMCE4 Lite

macOS Terminal

(env)User-Macbook:mysite user$ pip install django-tinymce4-lite

Windows Command Prompt

(env) C:\Users\Owner\Desktop\Code\env\mysite>pip install django-tinymce4-lite

Once you have finished the basic configurations of your web app, you can install a cool Python package named django-tinymce4-lite. This package is actually a smaller version of the Django application django-tinymce4 that contains a widget to render Django form fields as TinyMCE editors.

TinyMCE is a WYSIWYG ("what you see is what you get") text editor that converts HTML elements into editor instances or "plain text".  This python package is highly recommended if you are looking to create a blog as you can easily edit text that is then formatted to HTML within the actual template.

 

env > mysite > mysite > settings.py

INSTALLED_APPS = [
    ...
    ...
    'tinymce',
]


TINYMCE_DEFAULT_CONFIG = {
    'height': 400,
    'width': 1000,
    'cleanup_on_startup': True,
    'custom_undo_redo_levels': 20,
    'selector': 'textarea',
    'browser_spellcheck': 'True',
    'theme': 'modern',
    'plugins': '''
            textcolor save link image media preview codesample contextmenu
            table code lists fullscreen  insertdatetime  nonbreaking
            contextmenu directionality searchreplace wordcount visualblocks
            visualchars code fullscreen autolink lists  charmap print  hr
            anchor pagebreak
            ''',
    'toolbar1': '''
            fullscreen preview bold italic underline | fontselect,
            fontsizeselect  | forecolor backcolor | alignleft alignright |
            aligncenter alignjustify | indent outdent | bullist numlist table |
            | link image media | codesample
            ''',
    'toolbar2': '''
            visualblocks visualchars |
            charmap hr pagebreak nonbreaking anchor |  code |
            ''',
    'contextmenu': 'formats | link image',
    'menubar': True,
    'statusbar': True,
    }

After installation, you will need to add tinymce to the list of installed apps in the settings file then add the default configurations below.  The default configurations define the height, weight, spellcheck, and toolbars. 

 

env > mysite > mysite > urls.py

"""mysite URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path, include


urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include ('main.urls')),
    path('tinymce/', include('tinymce.urls')), #add this

]

Then add the TinyMCE path to the project URLs.

 

env > mysite > main > models.py

from django.db import models
from tinymce import HTMLField

class MyModel(models.Model):
    ...
    content = HTMLField()

Finally, you can quickly add TinyMCE to the Django model by importing HTMLField at the top of the page then calling it in the model field. If you are unsure of how to use Django models, check out the article, How to use Django Models for more information. 

 

---

 

(2) Pillow

macOS Terminal

(env)User-Macbook:mysite user$ pip install Pillow

Windows Command Prompt

(env) C:\Users\Owner\Desktop\Code\env\mysite>pip install Pillow

So, this package is not specific to Django but is needed for image and file uploads to work correctly in a Django project.  If you are looking to have a media upload field in your Django model for let's say an article cover image, you need to install Pillow. It's a Python Imaging Library fork for uploading files correctly. 

 

env > mysite > mysite > settings.py

MEDIA_URL = '/media/'

MEDIA_ROOT = os.path.join(BASE_DIR, 'media')

Once installed, you need to add a media folder URL and ROOT directory to your settings file. 

 

env > mysite > mysite > urls.py

from django.contrib import admin
from django.urls import path, include
from django.conf import settings #add this
from django.conf.urls.static import static #add this

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include ('main.urls')),
]

if settings.DEBUG: #add this
    urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

Then you need to add the necessary imports at the top of your project's URL file and specify the URL pattern to the media folder. Keep in mind that the media upload will not work in production given the if condition. You will need to reconfigure your media upload location when you are ready to deploy.

 

env > mysite > main > models.py

from django.db import models

class MyModel(models.Model):
    ...
    image = models.ImageField(upload_to='images/')

Now to upload an image, go to your models file and add an ImageField with the upload location as 'images/'. The uploaded images will then be added to a media  > images folder that will automatically be created upon the upload. 

For more information about correctly creating a model, accessing the upload location in the Django admin, and rendering the model in a template, refer to How to use Django Models.

 

---

 

(3) Django Crispy Forms

macOS Terminal

(env)User-Macbook:mysite user$ pip install django-crispy-forms

Windows Command Prompt

(env) C:\Users\Owner\desktop\code\env\mysite>pip install django-crispy-forms

Let's talk about Django forms. Their functionality is great but their appearance isn't the best. You can choose to install django-crispy-forms in your project to quickly solve this issue.

 

env > mysite > mysite > settings.py

INSTALLED_APPS = [
    ...
    'crispy_forms',
]

CRISPY_TEMPLATE_PACK = 'uni_form'

For it to function correctly, you will need to go to the settings file and add crispy_forms to the installed apps list. Keep in mind that there is an underscore between crispy and forms.

Then you need to specify the crispy template pack. The one listed below is the default but if you are using the Bootstrap CSS framework, check out how to integrate Bootstrap with django-crispy-forms. 

 

env > mysite > main > templates > main > contact.html

{% load crispy_forms_tags %}

<form method="post">
    {% csrf_token %}
       {{form|crispy}}
       <button type="submit">Submit</button>
</form>

The package django-crispy-forms is added to the project in the form of a filter added within the Django template language {{form}}. This format will not only call all of the form fields but also format each field according to the crispy form template pack specified in the settings.

Refer to the article Render Forms with Django Crispy Forms for more information regarding the form rendering process using crispy forms and the article Build a Django Contact Form with Email Backend for more general information on how to build a Django form. 

 

---

 

(4) Django Tables

macOS Terminal

(env)User-Macbook:mysite user$ pip install django-tables2

Windows Command Prompt

(env) C:\Users\Owner\desktop\code\env\mysite>pip install django-tables2

Now let's say you want to create a dynamic table in your Django project that connects to a model. Install django-tables2, a Django-specific package for table rendering.

 

env > mysite > mysite > settings.py

INSTALLED_APPS = [
    ...
    'django_tables2',
]

Add Django tables to the installed apps.

 

env > mysite > main > models.py

from django.db import models


class MyModel(models.Model):
    name = models.CharField(max_length=100, verbose_name="full name")
    email = models.EmailField(max_length=200)

Then create the model you wish to use in the table.

After you have created the model, you will need to run the commands python manage.py makemigrations and python manage.py migrate to add the model to the database and add your model objects via the Django admin. For more instruction, see How to Use Django Models. 

 

env > mysite > main > (New File) tables.py

import django_tables2 as tables
from .models import MyModel

class MyTable(tables.Table):
    class Meta:
        model = MyModel
        fields = ("name", "email", )

 

Now, create a new file called tables.py in the application folder, main, and import tables from django_tables2 at the top of the file. Then create a class that specifies the model and field names. 

 

env > mysite > main > views.py (Class-based views)

...
from django_tables2 import SingleTableView

from .models import MyModel
from .tables import MyTable


class ListView(SingleTableView):
    model = MyModel
    table_class = MyTable
    template_name = 'main/table.html'

 

If you are looking to use class-based views, go to the views file and add the view class specifying the model, table, and template. Again, you will need to import the necessary variables from their appropriate files at the top of the file.

 

env > mysite > main > urls.py (Class-based views)

from django.urls import path
from . import views

app_name = "main"   


urlpatterns = [
     path("table", views.ListView.as_view()),
]

Then make sure there is a tables URL in the app urls.py file. If you are looking to learn more about class-based views, check out the article Django Class-based Views.

 

env > mysite > main > views.py (Function-based views)

...
from django_tables2 import SingleTableView

from .models import MyModel
from .tables import MyTable


def list(request):
	model = MyModel.objects.all()
	table = MyTable(model)
	return render(request=request, template_name="main/table.html", context={"model":model, "table":table})

 

Or you can choose to do function-based views in the views.py file. Either one will work, but the format is different. 

 

env > mysite > main > urls.py (Function-based views)

from django.urls import path
from . import views

app_name = "main"   


urlpatterns = [
    path("table", views.list, name="list"),
]

Then add the table URL in the app urls.py file. 

 

env > mysite > main > templates > main > (New File) table.html

{% load render_table from django_tables2 %}

<div>
    {% render_table table %}
</div>

With the views and URLs configured, you can render the table in the template by loading in render_table from django_tables2 at the top of the file then calling render_table and the context of the table passed in the view.

By default, the class-based view passes the table context as just table, and in the function-based view, we also chose to specify the context of the table as table. 

 

If you want to add Bootstrap CSS to the table:

env > mysite > main > tables.py

import django_tables2 as tables
from .models import MyModel

class MyTable(tables.Table):
    class Meta:
        model = MyModel
        template_name = "django_tables2/bootstrap4.html"
        fields = ("name", "email",)

 

Add a template name to the tables.py file connecting to the Bootstrap template. This and other template files can be found in the Lib > site-packages > django_tables2 > templates > django_tables2 folder of your project.

 

env > mysite > main > templates > main > (New File) table.html

{% extends "main/header.html" %}

{% block content %}

{% load render_table from django_tables2 %}

<div class="container">
    {% render_table table %}
</div>

{% endblock %}

Then you can extend to a header that loads in the Bootstrap CDNs. This is the easiest way of adding Bootstrap to all of your templates using the same piece of code.

If you are unsure of how to use the extends tag with the Bootstrap CDNs, check out the Django extends tag and block content section in the Beginner's Guide to Django Web Apps. 

 

---

 

(5) Django Filter

macOS Terminal

(env)User-Macbook:mysite user$  pip install django-filter

Windows Command Prompt

(env) C:\Users\Owner\desktop\code\env\mysite>  pip install django-filter

Now that you have a table, you probably want the ability to search for specific content within the rows and filter the table by its results. The django-filter package can easily be used on top of the django-tables2 package to accomplish this.

 

env > mysite > mysite > settings.py

INSTALLED_APPS = [
    ...
    'django_filters',
]

Add Django filters to the installed apps. Note that is django_filters not django_filter.

 

env > mysite > main > (New File) filters.py

import django_filters
from .models import MyModel


class MyFilter(django_filters.FilterSet):
	name = django_filters.CharFilter(lookup_expr='icontains')

	class Meta:
		model = MyModel
		fields = {'name', 'email'}

 

Now, create a new file called filters.py in the application folder, main, and import django_filters. Then list the model and the model fields you wish to filter by.

You can also choose to add django_filters.CharFilter to the class. In the example above, the filter displays any rows where the name column contains the query specified. 

You can also choose to do django_filters.CharFilter(lookup_expr='iexact') if you are looking to filter only by an exact query match.

 

env > mysite > main > views.py (Class-based views)

...
from django_tables2 import SingleTableMixin
from django_filters.views import FilterView

from .models import MyModel
from .tables import MyTable
from .filters import MyFilter


class ListView(SingleTableMixin, FilterView):
    model = MyModel
    table_class = MyTable
    template_name = 'main/table.html'
    filterset_class = MyFilter

 

Then for a class-based view, import FilterView from django_filters.views at the top of the file and change django_tables2 import from SingleTableView to SingleTableMixin. You will also need to import your custom filter from the filter.py file.

In the class view, ListView will now inherit SingleTableMixin and FilterView and list the filterset_class as the custom filter within it. 

 

env > mysite > main > templates > main > table.html

{% load render_table from django_tables2 %}

<div>
    <br>
    <form action="" method="GET">
        {{filter.form}}
        <button type="submit">Filter</button>
    </form>
    <br>
    {% render_table table %}
</div>

With class-based views, the URL will stay the same but you will need to add a form HTML element and the Django Template language calling the filter and the form within the template. You also need a submit button within the form to submit your filter queries. Nothing changes about the way the table renders.

 

env > mysite > main > views.py (Function-based views)

...
from django_tables2.views import SingleTableMixin
from django_filter import FilterView

from .models import MyModel
from .tables import MyTable


def list(request):
	model = MyModel.objects.all()
	filterset_class = MyFilter(request.GET, model)
	table = MyTable(filterset_class.qs)
	return render(request=request, template_name="main/table.html", context={"model":model, "table":table, "filterset_class":filterset_class})

 

If using function-based views, make the same imports and the class-based views, then create an instance of the MyFilter class and pass in a GET request and model as arguments. Pass in the filterset_class as a queryset argument in the table then lists the filterset_class as context in the return render. 

 

env > mysite > main > templates > main > table.html

{% load render_table from django_tables2 %}

<div>
    <br>
    <form action="" method="GET">
        {{filterset_class.form}}
        <button type="submit">Filter</button>
    </form>
    <br>
    {% render_table table %}
</div>

With function-based views, you will need to specify the filterset_class, or the context declared, as the filter on the form. Everything else is the same format as the class-based template.

If you are looking to style the form, either scroll back up to the Django Crispy Forms section or click at the article mentioned earlier, Render Forms with Django Crispy Forms.

 

---

 

(6) Python Decouple

macOS Terminal

(env)User-Macbook:mysite user$ pip install python-decouple

Windows Command Prompt

(env) C:\Users\Owner\desktop\code\env\mysite> pip install python-decouple

The last and arguably most important Python package we will discuss is python-decouple. This package hides your sensitive configuration keys and information from hackers. It was created for Django but it is now considered a "generic tool" for separating configuration settings.

 

env > mysite > (New File) .env

SECRET_KEY =sdjioerb43buobnodhioh4i34hgip
DEBUG =True

env > mysite > mysite > settings.py

from decouple import config

SECRET_KEY = config('SECRET_KEY')
DEBUG = config('DEBUG', cast=bool)

Create a new file named .env in the project folder then import config in the settings.py file. Then transfer all of the configuration settings and variables you wish to hide to the .env file and call each variable using the python-decouple format of config('variable').

#programming #django #python

Why Use WordPress? What Can You Do With WordPress?

Can you use WordPress for anything other than blogging? To your surprise, yes. WordPress is more than just a blogging tool, and it has helped thousands of websites and web applications to thrive. The use of WordPress powers around 40% of online projects, and today in our blog, we would visit some amazing uses of WordPress other than blogging.
What Is The Use Of WordPress?

WordPress is the most popular website platform in the world. It is the first choice of businesses that want to set a feature-rich and dynamic Content Management System. So, if you ask what WordPress is used for, the answer is – everything. It is a super-flexible, feature-rich and secure platform that offers everything to build unique websites and applications. Let’s start knowing them:

1. Multiple Websites Under A Single Installation
WordPress Multisite allows you to develop multiple sites from a single WordPress installation. You can download WordPress and start building websites you want to launch under a single server. Literally speaking, you can handle hundreds of sites from one single dashboard, which now needs applause.
It is a highly efficient platform that allows you to easily run several websites under the same login credentials. One of the best things about WordPress is the themes it has to offer. You can simply download them and plugin for various sites and save space on sites without losing their speed.

2. WordPress Social Network
WordPress can be used for high-end projects such as Social Media Network. If you don’t have the money and patience to hire a coder and invest months in building a feature-rich social media site, go for WordPress. It is one of the most amazing uses of WordPress. Its stunning CMS is unbeatable. And you can build sites as good as Facebook or Reddit etc. It can just make the process a lot easier.
To set up a social media network, you would have to download a WordPress Plugin called BuddyPress. It would allow you to connect a community page with ease and would provide all the necessary features of a community or social media. It has direct messaging, activity stream, user groups, extended profiles, and so much more. You just have to download and configure it.
If BuddyPress doesn’t meet all your needs, don’t give up on your dreams. You can try out WP Symposium or PeepSo. There are also several themes you can use to build a social network.

3. Create A Forum For Your Brand’s Community
Communities are very important for your business. They help you stay in constant connection with your users and consumers. And allow you to turn them into a loyal customer base. Meanwhile, there are many good technologies that can be used for building a community page – the good old WordPress is still the best.
It is the best community development technology. If you want to build your online community, you need to consider all the amazing features you get with WordPress. Plugins such as BB Press is an open-source, template-driven PHP/ MySQL forum software. It is very simple and doesn’t hamper the experience of the website.
Other tools such as wpFoRo and Asgaros Forum are equally good for creating a community blog. They are lightweight tools that are easy to manage and integrate with your WordPress site easily. However, there is only one tiny problem; you need to have some technical knowledge to build a WordPress Community blog page.

4. Shortcodes
Since we gave you a problem in the previous section, we would also give you a perfect solution for it. You might not know to code, but you have shortcodes. Shortcodes help you execute functions without having to code. It is an easy way to build an amazing website, add new features, customize plugins easily. They are short lines of code, and rather than memorizing multiple lines; you can have zero technical knowledge and start building a feature-rich website or application.
There are also plugins like Shortcoder, Shortcodes Ultimate, and the Basics available on WordPress that can be used, and you would not even have to remember the shortcodes.

5. Build Online Stores
If you still think about why to use WordPress, use it to build an online store. You can start selling your goods online and start selling. It is an affordable technology that helps you build a feature-rich eCommerce store with WordPress.
WooCommerce is an extension of WordPress and is one of the most used eCommerce solutions. WooCommerce holds a 28% share of the global market and is one of the best ways to set up an online store. It allows you to build user-friendly and professional online stores and has thousands of free and paid extensions. Moreover as an open-source platform, and you don’t have to pay for the license.
Apart from WooCommerce, there are Easy Digital Downloads, iThemes Exchange, Shopify eCommerce plugin, and so much more available.

6. Security Features
WordPress takes security very seriously. It offers tons of external solutions that help you in safeguarding your WordPress site. While there is no way to ensure 100% security, it provides regular updates with security patches and provides several plugins to help with backups, two-factor authorization, and more.
By choosing hosting providers like WP Engine, you can improve the security of the website. It helps in threat detection, manage patching and updates, and internal security audits for the customers, and so much more.

Read More

#use of wordpress #use wordpress for business website #use wordpress for website #what is use of wordpress #why use wordpress #why use wordpress to build a website