Using Kubernetes to Create Multi-container Pods

Hello, readers! This article will focus on Creating a multi-container pod in Kubernetes with examples and scenarios.

A Kubernetes pod is the smallest instance of a running application. That is, we pack the application within a container. The container represents the configuration files and all the necessary components of the application.

A pod encapsulates the container and runs itself as the live instance of the application altogether. It is the smallest deployable unit of the application within the cluster to function.

#kubernetes 

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Using Kubernetes to Create Multi-container Pods
Christa  Stehr

Christa Stehr

1602964260

50+ Useful Kubernetes Tools for 2020 - Part 2

Introduction

Last year, we provided a list of Kubernetes tools that proved so popular we have decided to curate another list of some useful additions for working with the platform—among which are many tools that we personally use here at Caylent. Check out the original tools list here in case you missed it.

According to a recent survey done by Stackrox, the dominance Kubernetes enjoys in the market continues to be reinforced, with 86% of respondents using it for container orchestration.

(State of Kubernetes and Container Security, 2020)

And as you can see below, more and more companies are jumping into containerization for their apps. If you’re among them, here are some tools to aid you going forward as Kubernetes continues its rapid growth.

(State of Kubernetes and Container Security, 2020)

#blog #tools #amazon elastic kubernetes service #application security #aws kms #botkube #caylent #cli #container monitoring #container orchestration tools #container security #containers #continuous delivery #continuous deployment #continuous integration #contour #developers #development #developments #draft #eksctl #firewall #gcp #github #harbor #helm #helm charts #helm-2to3 #helm-aws-secret-plugin #helm-docs #helm-operator-get-started #helm-secrets #iam #json #k-rail #k3s #k3sup #k8s #keel.sh #keycloak #kiali #kiam #klum #knative #krew #ksniff #kube #kube-prod-runtime #kube-ps1 #kube-scan #kube-state-metrics #kube2iam #kubeapps #kubebuilder #kubeconfig #kubectl #kubectl-aws-secrets #kubefwd #kubernetes #kubernetes command line tool #kubernetes configuration #kubernetes deployment #kubernetes in development #kubernetes in production #kubernetes ingress #kubernetes interfaces #kubernetes monitoring #kubernetes networking #kubernetes observability #kubernetes plugins #kubernetes secrets #kubernetes security #kubernetes security best practices #kubernetes security vendors #kubernetes service discovery #kubernetic #kubesec #kubeterminal #kubeval #kudo #kuma #microsoft azure key vault #mozilla sops #octant #octarine #open source #palo alto kubernetes security #permission-manager #pgp #rafay #rakess #rancher #rook #secrets operations #serverless function #service mesh #shell-operator #snyk #snyk container #sonobuoy #strongdm #tcpdump #tenkai #testing #tigera #tilt #vert.x #wireshark #yaml

Easter  Deckow

Easter Deckow

1655630160

PyTumblr: A Python Tumblr API v2 Client

PyTumblr

Installation

Install via pip:

$ pip install pytumblr

Install from source:

$ git clone https://github.com/tumblr/pytumblr.git
$ cd pytumblr
$ python setup.py install

Usage

Create a client

A pytumblr.TumblrRestClient is the object you'll make all of your calls to the Tumblr API through. Creating one is this easy:

client = pytumblr.TumblrRestClient(
    '<consumer_key>',
    '<consumer_secret>',
    '<oauth_token>',
    '<oauth_secret>',
)

client.info() # Grabs the current user information

Two easy ways to get your credentials to are:

  1. The built-in interactive_console.py tool (if you already have a consumer key & secret)
  2. The Tumblr API console at https://api.tumblr.com/console
  3. Get sample login code at https://api.tumblr.com/console/calls/user/info

Supported Methods

User Methods

client.info() # get information about the authenticating user
client.dashboard() # get the dashboard for the authenticating user
client.likes() # get the likes for the authenticating user
client.following() # get the blogs followed by the authenticating user

client.follow('codingjester.tumblr.com') # follow a blog
client.unfollow('codingjester.tumblr.com') # unfollow a blog

client.like(id, reblogkey) # like a post
client.unlike(id, reblogkey) # unlike a post

Blog Methods

client.blog_info(blogName) # get information about a blog
client.posts(blogName, **params) # get posts for a blog
client.avatar(blogName) # get the avatar for a blog
client.blog_likes(blogName) # get the likes on a blog
client.followers(blogName) # get the followers of a blog
client.blog_following(blogName) # get the publicly exposed blogs that [blogName] follows
client.queue(blogName) # get the queue for a given blog
client.submission(blogName) # get the submissions for a given blog

Post Methods

Creating posts

PyTumblr lets you create all of the various types that Tumblr supports. When using these types there are a few defaults that are able to be used with any post type.

The default supported types are described below.

  • state - a string, the state of the post. Supported types are published, draft, queue, private
  • tags - a list, a list of strings that you want tagged on the post. eg: ["testing", "magic", "1"]
  • tweet - a string, the string of the customized tweet you want. eg: "Man I love my mega awesome post!"
  • date - a string, the customized GMT that you want
  • format - a string, the format that your post is in. Support types are html or markdown
  • slug - a string, the slug for the url of the post you want

We'll show examples throughout of these default examples while showcasing all the specific post types.

Creating a photo post

Creating a photo post supports a bunch of different options plus the described default options * caption - a string, the user supplied caption * link - a string, the "click-through" url for the photo * source - a string, the url for the photo you want to use (use this or the data parameter) * data - a list or string, a list of filepaths or a single file path for multipart file upload

#Creates a photo post using a source URL
client.create_photo(blogName, state="published", tags=["testing", "ok"],
                    source="https://68.media.tumblr.com/b965fbb2e501610a29d80ffb6fb3e1ad/tumblr_n55vdeTse11rn1906o1_500.jpg")

#Creates a photo post using a local filepath
client.create_photo(blogName, state="queue", tags=["testing", "ok"],
                    tweet="Woah this is an incredible sweet post [URL]",
                    data="/Users/johnb/path/to/my/image.jpg")

#Creates a photoset post using several local filepaths
client.create_photo(blogName, state="draft", tags=["jb is cool"], format="markdown",
                    data=["/Users/johnb/path/to/my/image.jpg", "/Users/johnb/Pictures/kittens.jpg"],
                    caption="## Mega sweet kittens")

Creating a text post

Creating a text post supports the same options as default and just a two other parameters * title - a string, the optional title for the post. Supports markdown or html * body - a string, the body of the of the post. Supports markdown or html

#Creating a text post
client.create_text(blogName, state="published", slug="testing-text-posts", title="Testing", body="testing1 2 3 4")

Creating a quote post

Creating a quote post supports the same options as default and two other parameter * quote - a string, the full text of the qote. Supports markdown or html * source - a string, the cited source. HTML supported

#Creating a quote post
client.create_quote(blogName, state="queue", quote="I am the Walrus", source="Ringo")

Creating a link post

  • title - a string, the title of post that you want. Supports HTML entities.
  • url - a string, the url that you want to create a link post for.
  • description - a string, the desciption of the link that you have
#Create a link post
client.create_link(blogName, title="I like to search things, you should too.", url="https://duckduckgo.com",
                   description="Search is pretty cool when a duck does it.")

Creating a chat post

Creating a chat post supports the same options as default and two other parameters * title - a string, the title of the chat post * conversation - a string, the text of the conversation/chat, with diablog labels (no html)

#Create a chat post
chat = """John: Testing can be fun!
Renee: Testing is tedious and so are you.
John: Aw.
"""
client.create_chat(blogName, title="Renee just doesn't understand.", conversation=chat, tags=["renee", "testing"])

Creating an audio post

Creating an audio post allows for all default options and a has 3 other parameters. The only thing to keep in mind while dealing with audio posts is to make sure that you use the external_url parameter or data. You cannot use both at the same time. * caption - a string, the caption for your post * external_url - a string, the url of the site that hosts the audio file * data - a string, the filepath of the audio file you want to upload to Tumblr

#Creating an audio file
client.create_audio(blogName, caption="Rock out.", data="/Users/johnb/Music/my/new/sweet/album.mp3")

#lets use soundcloud!
client.create_audio(blogName, caption="Mega rock out.", external_url="https://soundcloud.com/skrillex/sets/recess")

Creating a video post

Creating a video post allows for all default options and has three other options. Like the other post types, it has some restrictions. You cannot use the embed and data parameters at the same time. * caption - a string, the caption for your post * embed - a string, the HTML embed code for the video * data - a string, the path of the file you want to upload

#Creating an upload from YouTube
client.create_video(blogName, caption="Jon Snow. Mega ridiculous sword.",
                    embed="http://www.youtube.com/watch?v=40pUYLacrj4")

#Creating a video post from local file
client.create_video(blogName, caption="testing", data="/Users/johnb/testing/ok/blah.mov")

Editing a post

Updating a post requires you knowing what type a post you're updating. You'll be able to supply to the post any of the options given above for updates.

client.edit_post(blogName, id=post_id, type="text", title="Updated")
client.edit_post(blogName, id=post_id, type="photo", data="/Users/johnb/mega/awesome.jpg")

Reblogging a Post

Reblogging a post just requires knowing the post id and the reblog key, which is supplied in the JSON of any post object.

client.reblog(blogName, id=125356, reblog_key="reblog_key")

Deleting a post

Deleting just requires that you own the post and have the post id

client.delete_post(blogName, 123456) # Deletes your post :(

A note on tags: When passing tags, as params, please pass them as a list (not a comma-separated string):

client.create_text(blogName, tags=['hello', 'world'], ...)

Getting notes for a post

In order to get the notes for a post, you need to have the post id and the blog that it is on.

data = client.notes(blogName, id='123456')

The results include a timestamp you can use to make future calls.

data = client.notes(blogName, id='123456', before_timestamp=data["_links"]["next"]["query_params"]["before_timestamp"])

Tagged Methods

# get posts with a given tag
client.tagged(tag, **params)

Using the interactive console

This client comes with a nice interactive console to run you through the OAuth process, grab your tokens (and store them for future use).

You'll need pyyaml installed to run it, but then it's just:

$ python interactive-console.py

and away you go! Tokens are stored in ~/.tumblr and are also shared by other Tumblr API clients like the Ruby client.

Running tests

The tests (and coverage reports) are run with nose, like this:

python setup.py test

Author: tumblr
Source Code: https://github.com/tumblr/pytumblr
License: Apache-2.0 license

#python #api 

Chloe  Butler

Chloe Butler

1667425440

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 

Tamale  Moses

Tamale Moses

1669003576

Exploring Mutable and Immutable in Python

In this Python article, let's learn about Mutable and Immutable in Python. 

Mutable and Immutable in Python

Mutable is a fancy way of saying that the internal state of the object is changed/mutated. So, the simplest definition is: An object whose internal state can be changed is mutable. On the other hand, immutable doesn’t allow any change in the object once it has been created.

Both of these states are integral to Python data structure. If you want to become more knowledgeable in the entire Python Data Structure, take this free course which covers multiple data structures in Python including tuple data structure which is immutable. You will also receive a certificate on completion which is sure to add value to your portfolio.

Mutable Definition

Mutable is when something is changeable or has the ability to change. In Python, ‘mutable’ is the ability of objects to change their values. These are often the objects that store a collection of data.

Immutable Definition

Immutable is the when no change is possible over time. In Python, if the value of an object cannot be changed over time, then it is known as immutable. Once created, the value of these objects is permanent.

List of Mutable and Immutable objects

Objects of built-in type that are mutable are:

  • Lists
  • Sets
  • Dictionaries
  • User-Defined Classes (It purely depends upon the user to define the characteristics) 

Objects of built-in type that are immutable are:

  • Numbers (Integer, Rational, Float, Decimal, Complex & Booleans)
  • Strings
  • Tuples
  • Frozen Sets
  • User-Defined Classes (It purely depends upon the user to define the characteristics)

Object mutability is one of the characteristics that makes Python a dynamically typed language. Though Mutable and Immutable in Python is a very basic concept, it can at times be a little confusing due to the intransitive nature of immutability.

Objects in Python

In Python, everything is treated as an object. Every object has these three attributes:

  • Identity – This refers to the address that the object refers to in the computer’s memory.
  • Type – This refers to the kind of object that is created. For example- integer, list, string etc. 
  • Value – This refers to the value stored by the object. For example – List=[1,2,3] would hold the numbers 1,2 and 3

While ID and Type cannot be changed once it’s created, values can be changed for Mutable objects.

Check out this free python certificate course to get started with Python.

Mutable Objects in Python

I believe, rather than diving deep into the theory aspects of mutable and immutable in Python, a simple code would be the best way to depict what it means in Python. Hence, let us discuss the below code step-by-step:

#Creating a list which contains name of Indian cities  

cities = [‘Delhi’, ‘Mumbai’, ‘Kolkata’]

# Printing the elements from the list cities, separated by a comma & space

for city in cities:
		print(city, end=’, ’)

Output [1]: Delhi, Mumbai, Kolkata

#Printing the location of the object created in the memory address in hexadecimal format

print(hex(id(cities)))

Output [2]: 0x1691d7de8c8

#Adding a new city to the list cities

cities.append(‘Chennai’)

#Printing the elements from the list cities, separated by a comma & space 

for city in cities:
	print(city, end=’, ’)

Output [3]: Delhi, Mumbai, Kolkata, Chennai

#Printing the location of the object created in the memory address in hexadecimal format

print(hex(id(cities)))

Output [4]: 0x1691d7de8c8

The above example shows us that we were able to change the internal state of the object ‘cities’ by adding one more city ‘Chennai’ to it, yet, the memory address of the object did not change. This confirms that we did not create a new object, rather, the same object was changed or mutated. Hence, we can say that the object which is a type of list with reference variable name ‘cities’ is a MUTABLE OBJECT.

Let us now discuss the term IMMUTABLE. Considering that we understood what mutable stands for, it is obvious that the definition of immutable will have ‘NOT’ included in it. Here is the simplest definition of immutable– An object whose internal state can NOT be changed is IMMUTABLE.

Again, if you try and concentrate on different error messages, you have encountered, thrown by the respective IDE; you use you would be able to identify the immutable objects in Python. For instance, consider the below code & associated error message with it, while trying to change the value of a Tuple at index 0. 

#Creating a Tuple with variable name ‘foo’

foo = (1, 2)

#Changing the index[0] value from 1 to 3

foo[0] = 3
	
TypeError: 'tuple' object does not support item assignment 

Immutable Objects in Python

Once again, a simple code would be the best way to depict what immutable stands for. Hence, let us discuss the below code step-by-step:

#Creating a Tuple which contains English name of weekdays

weekdays = ‘Sunday’, ‘Monday’, ‘Tuesday’, ‘Wednesday’, ‘Thursday’, ‘Friday’, ‘Saturday’

# Printing the elements of tuple weekdays

print(weekdays)

Output [1]:  (‘Sunday’, ‘Monday’, ‘Tuesday’, ‘Wednesday’, ‘Thursday’, ‘Friday’, ‘Saturday’)

#Printing the location of the object created in the memory address in hexadecimal format

print(hex(id(weekdays)))

Output [2]: 0x1691cc35090

#tuples are immutable, so you cannot add new elements, hence, using merge of tuples with the # + operator to add a new imaginary day in the tuple ‘weekdays’

weekdays  +=  ‘Pythonday’,

#Printing the elements of tuple weekdays

print(weekdays)

Output [3]: (‘Sunday’, ‘Monday’, ‘Tuesday’, ‘Wednesday’, ‘Thursday’, ‘Friday’, ‘Saturday’, ‘Pythonday’)

#Printing the location of the object created in the memory address in hexadecimal format

print(hex(id(weekdays)))

Output [4]: 0x1691cc8ad68

This above example shows that we were able to use the same variable name that is referencing an object which is a type of tuple with seven elements in it. However, the ID or the memory location of the old & new tuple is not the same. We were not able to change the internal state of the object ‘weekdays’. The Python program manager created a new object in the memory address and the variable name ‘weekdays’ started referencing the new object with eight elements in it.  Hence, we can say that the object which is a type of tuple with reference variable name ‘weekdays’ is an IMMUTABLE OBJECT.

Also Read: Understanding the Exploratory Data Analysis (EDA) in Python

Where can you use mutable and immutable objects:

Mutable objects can be used where you want to allow for any updates. For example, you have a list of employee names in your organizations, and that needs to be updated every time a new member is hired. You can create a mutable list, and it can be updated easily.

Immutability offers a lot of useful applications to different sensitive tasks we do in a network centred environment where we allow for parallel processing. By creating immutable objects, you seal the values and ensure that no threads can invoke overwrite/update to your data. This is also useful in situations where you would like to write a piece of code that cannot be modified. For example, a debug code that attempts to find the value of an immutable object.

Watch outs:  Non transitive nature of Immutability:

OK! Now we do understand what mutable & immutable objects in Python are. Let’s go ahead and discuss the combination of these two and explore the possibilities. Let’s discuss, as to how will it behave if you have an immutable object which contains the mutable object(s)? Or vice versa? Let us again use a code to understand this behaviour–

#creating a tuple (immutable object) which contains 2 lists(mutable) as it’s elements

#The elements (lists) contains the name, age & gender 

person = (['Ayaan', 5, 'Male'], ['Aaradhya', 8, 'Female'])

#printing the tuple

print(person)

Output [1]: (['Ayaan', 5, 'Male'], ['Aaradhya', 8, 'Female'])

#printing the location of the object created in the memory address in hexadecimal format

print(hex(id(person)))

Output [2]: 0x1691ef47f88

#Changing the age for the 1st element. Selecting 1st element of tuple by using indexing [0] then 2nd element of the list by using indexing [1] and assigning a new value for age as 4

person[0][1] = 4

#printing the updated tuple

print(person)

Output [3]: (['Ayaan', 4, 'Male'], ['Aaradhya', 8, 'Female'])

#printing the location of the object created in the memory address in hexadecimal format

print(hex(id(person)))

Output [4]: 0x1691ef47f88

In the above code, you can see that the object ‘person’ is immutable since it is a type of tuple. However, it has two lists as it’s elements, and we can change the state of lists (lists being mutable). So, here we did not change the object reference inside the Tuple, but the referenced object was mutated.

Also Read: Real-Time Object Detection Using TensorFlow

Same way, let’s explore how it will behave if you have a mutable object which contains an immutable object? Let us again use a code to understand the behaviour–

#creating a list (mutable object) which contains tuples(immutable) as it’s elements

list1 = [(1, 2, 3), (4, 5, 6)]

#printing the list

print(list1)

Output [1]: [(1, 2, 3), (4, 5, 6)]

#printing the location of the object created in the memory address in hexadecimal format

print(hex(id(list1)))

Output [2]: 0x1691d5b13c8	

#changing object reference at index 0

list1[0] = (7, 8, 9)

#printing the list

Output [3]: [(7, 8, 9), (4, 5, 6)]

#printing the location of the object created in the memory address in hexadecimal format

print(hex(id(list1)))

Output [4]: 0x1691d5b13c8

As an individual, it completely depends upon you and your requirements as to what kind of data structure you would like to create with a combination of mutable & immutable objects. I hope that this information will help you while deciding the type of object you would like to select going forward.

Before I end our discussion on IMMUTABILITY, allow me to use the word ‘CAVITE’ when we discuss the String and Integers. There is an exception, and you may see some surprising results while checking the truthiness for immutability. For instance:
#creating an object of integer type with value 10 and reference variable name ‘x’ 

x = 10
 

#printing the value of ‘x’

print(x)

Output [1]: 10

#Printing the location of the object created in the memory address in hexadecimal format

print(hex(id(x)))

Output [2]: 0x538fb560

#creating an object of integer type with value 10 and reference variable name ‘y’

y = 10

#printing the value of ‘y’

print(y)

Output [3]: 10

#Printing the location of the object created in the memory address in hexadecimal format

print(hex(id(y)))

Output [4]: 0x538fb560

As per our discussion and understanding, so far, the memory address for x & y should have been different, since, 10 is an instance of Integer class which is immutable. However, as shown in the above code, it has the same memory address. This is not something that we expected. It seems that what we have understood and discussed, has an exception as well.

Quick checkPython Data Structures

Immutability of Tuple

Tuples are immutable and hence cannot have any changes in them once they are created in Python. This is because they support the same sequence operations as strings. We all know that strings are immutable. The index operator will select an element from a tuple just like in a string. Hence, they are immutable.

Exceptions in immutability

Like all, there are exceptions in the immutability in python too. Not all immutable objects are really mutable. This will lead to a lot of doubts in your mind. Let us just take an example to understand this.

Consider a tuple ‘tup’.

Now, if we consider tuple tup = (‘GreatLearning’,[4,3,1,2]) ;

We see that the tuple has elements of different data types. The first element here is a string which as we all know is immutable in nature. The second element is a list which we all know is mutable. Now, we all know that the tuple itself is an immutable data type. It cannot change its contents. But, the list inside it can change its contents. So, the value of the Immutable objects cannot be changed but its constituent objects can. change its value.

FAQs

1. Difference between mutable vs immutable in Python?

Mutable ObjectImmutable Object
State of the object can be modified after it is created.State of the object can’t be modified once it is created.
They are not thread safe.They are thread safe
Mutable classes are not final.It is important to make the class final before creating an immutable object.

2. What are the mutable and immutable data types in Python?

  • Some mutable data types in Python are:

list, dictionary, set, user-defined classes.

  • Some immutable data types are: 

int, float, decimal, bool, string, tuple, range.

3. Are lists mutable in Python?

Lists in Python are mutable data types as the elements of the list can be modified, individual elements can be replaced, and the order of elements can be changed even after the list has been created.
(Examples related to lists have been discussed earlier in this blog.)

4. Why are tuples called immutable types?

Tuple and list data structures are very similar, but one big difference between the data types is that lists are mutable, whereas tuples are immutable. The reason for the tuple’s immutability is that once the elements are added to the tuple and the tuple has been created; it remains unchanged.

A programmer would always prefer building a code that can be reused instead of making the whole data object again. Still, even though tuples are immutable, like lists, they can contain any Python object, including mutable objects.

5. Are sets mutable in Python?

A set is an iterable unordered collection of data type which can be used to perform mathematical operations (like union, intersection, difference etc.). Every element in a set is unique and immutable, i.e. no duplicate values should be there, and the values can’t be changed. However, we can add or remove items from the set as the set itself is mutable.

6. Are strings mutable in Python?

Strings are not mutable in Python. Strings are a immutable data types which means that its value cannot be updated.

Join Great Learning Academy’s free online courses and upgrade your skills today.


Original article source at: https://www.mygreatlearning.com

#python 

Rupert  Beatty

Rupert Beatty

1666454701

Fully Customizable & Extensible Action Sheet Controller

XLActionController

By XMARTLABS.

XLActionController is an extensible library to quickly create any custom action sheet controller.

Examples

demo_spotify.gifdemo_twitter.gifdemo_tweetbot.gif
demo_periscope.gifdemo_youtube.gifdemo_skype.gif

The action sheet controllers shown above were entirely created using XLActionController and are included in the Examples. To run the Example project: clone XLActionController repository, open XLActionController workspace and run the Example project.

The code snippet below shows how to present the Tweetbot action sheet controller:

let actionController = TweetbotActionController()

actionController.addAction(Action("View Details", style: .default, handler: { action in
  // do something useful
}))
actionController.addAction(Action("View Retweets", style: .default, handler: { action in
  // do something useful
}))
actionController.addAction(Action("View in Favstar", style: .default, handler: { action in
  // do something useful
}))
actionController.addAction(Action("Translate", style: .default, executeImmediatelyOnTouch: true, handler: { action in
  // do something useful
}))

actionController.addSection(Section())
actionController.addAction(Action("Cancel", style: .cancel, handler:nil))

present(actionController, animated: true, completion: nil)

As you may have noticed, the library usage looks pretty similar to UIAlertController.

Actions' handlers are executed after the alert controller is dismissed from screen. If you want, you can change this passing true to the action's constructor to the argument executeImmediatelyOnTouch.

Behind the scenes XLActionController uses a UICollectionView to display the action sheet.

Usage

First create a custom action sheet view controller by extending from the ActionController generic class. For details on how to create a custom action sheet controller look at the Extensibility section.

For instance, let's suppose we've already created TwitterActionController.

// Instantiate custom action sheet controller
let actionSheet = TwitterActionController()
// set up a header title
actionSheet.headerData = "Accounts"
// Add some actions, note that the first parameter of `Action` initializer is `ActionData`.
actionSheet.addAction(Action(ActionData(title: "Xmartlabs", subtitle: "@xmartlabs", image: UIImage(named: "tw-xmartlabs")!), style: .default, handler: { action in
   // do something useful
}))
actionSheet.addAction(Action(ActionData(title: "Miguel", subtitle: "@remer88", image: UIImage(named: "tw-remer")!), style: .default, handler: { action in
   // do something useful
}))
// present actionSheet like any other view controller
present(actionSheet, animated: true, completion: nil)

As the code above illustrates, there are no relevant differences compared to the UIAlertController API.

The main difference is that XLActionController works with any header data type and not only the standard UIAlertController title and message properties. Similarly XLActionController's Action works with any data Type and not only the title string.

// XLActionController:
xlActionController.headerData = SpotifyHeaderData(title: "The Fast And The Furious Soundtrack Collection", subtitle: "Various Artists", image: UIImage(named: "sp-header-icon")!)

// vs UIAlertController:
uiActionController.title = "The Fast And The Furious Soundtrack Collection" // no way to pass an image
uiActionController.message = "Various Artists"
// XLActionController:
let xlAction = Action(ActionData(title: "Save Full Album", image: UIImage(named: "sp-add-icon")!), style: .default, handler: { action in })
// notice that we are able to pass an image in addition to the title
xlActionController.addAction(xlAction)

// vs UIAlertController:
let uiAction = UIAlertAction(title: "Xmartlabs", style: .default, handler: { action in }))
uiActionController.addAction(uiAction)

This can be accomplished because XLActionController is a generic type.

Another important difference is that XLActionController provides a way to add action sections as illustrated in the code below:

  actionController.addSection(Section())

and also each section has a data property. This property is generic, so that it can hold any type. This data will be used to create this section's header view.

let section = actionController.addSection(Section())
section.data = "String" // assuming section data Type is String

Each section contains a set of actions. We typically use sections to show a header view above a set of actions.

Extensibility

ActionController uses a UICollectionView to show actions and headers on screen. Actions will be rendered as instances of UICollectionViewCell. You can use your own subclass of UICollectionViewCell by specifying it in the action controller declaration. Additionally, ActionController allows you to specify a global header and a section header. Headers are shown as collection view's supplementary views.

The ActionController class is a generic type that works with any cell, header, section header type and its associated data types.

Create your custom action sheet controller

XLActionController provides extension points to specify a whole new look and feel to our custom sheet controller and to tweak present and dismiss animations. Let's see an example:

// As first step we should extend the ActionController generic type
public class PeriscopeActionController: ActionController<PeriscopeCell, String, PeriscopeHeader, String, UICollectionReusableView, Void> {

    // override init in order to customize behavior and animations
    public override init(nibName nibNameOrNil: String? = nil, bundle nibBundleOrNil: Bundle? = nil) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        // customizing behavior and present/dismiss animations
        settings.behavior.hideOnScrollDown = false
        settings.animation.scale = nil
        settings.animation.present.duration = 0.6
        settings.animation.dismiss.duration = 0.5
        settings.animation.dismiss.options = .curveEaseIn
        settings.animation.dismiss.offset = 30

        // providing a specific collection view cell which will be used to display each action, height parameter expects a block that returns the cell height for a particular action.
        cellSpec = .nibFile(nibName: "PeriscopeCell", bundle: Bundle(for: PeriscopeCell.self), height: { _ in 60})
        // providing a specific view that will render each section header.
        sectionHeaderSpec = .cellClass(height: { _ in 5 })
        // providing a specific view that will render the action sheet header. We calculate its height according the text that should be displayed.
        headerSpec = .cellClass(height: { [weak self] (headerData: String) in
            guard let me = self else { return 0 }
            let label = UILabel(frame: CGRect(x: 0, y: 0, width: me.view.frame.width - 40, height: CGFloat.greatestFiniteMagnitude))
            label.numberOfLines = 0
            label.font = .systemFontOfSize(17.0)
            label.text = headerData
            label.sizeToFit()
            return label.frame.size.height + 20
        })

        // once we specify the views, we have to provide three blocks that will be used to set up these views.
        // block used to setup the header. Header view and the header are passed as block parameters
        onConfigureHeader = { [weak self] header, headerData in
            guard let me = self else { return }
            header.label.frame = CGRect(x: 0, y: 0, width: me.view.frame.size.width - 40, height: CGFloat.greatestFiniteMagnitude)
            header.label.text = headerData
            header.label.sizeToFit()
            header.label.center = CGPoint(x: header.frame.size.width  / 2, y: header.frame.size.height / 2)
        }
        // block used to setup the section header
        onConfigureSectionHeader = { sectionHeader, sectionHeaderData in
            sectionHeader.backgroundColor = UIColor(white: 0.95, alpha: 1.0)
        }
        // block used to setup the collection view cell
        onConfigureCellForAction = { [weak self] cell, action, indexPath in
            cell.setup(action.data, detail: nil, image: nil)
            cell.separatorView?.isHidden = indexPath.item == self!.collectionView.numberOfItems(inSection: indexPath.section) - 1
            cell.alpha = action.enabled ? 1.0 : 0.5
            cell.actionTitleLabel?.textColor = action.style == .destructive ? UIColor(red: 210/255.0, green: 77/255.0, blue: 56/255.0, alpha: 1.0) : UIColor(red: 0.28, green: 0.64, blue: 0.76, alpha: 1.0)
        }
    }
}

ActionController type declaration:

public class ActionController<ActionViewType: UICollectionViewCell, ActionDataType, HeaderViewType: UICollectionReusableView, HeaderDataType, SectionHeaderViewType: UICollectionReusableView, SectionHeaderDataType>

When extending ActionController we must specify the following view types ActionViewType, HeaderViewType, SectionHeaderViewType. These types are the cell type used to render an action, the view used to render the action sheet header and the view used to render the section header.

Each view type has its associated data: ActionDataType, HeaderDataType, SectionHeaderDataType respectively.

If your custom action sheet doesn't have a header view we can use UICollectionReusableView as HeaderViewType and Void as HeaderDataType. If it doesn't have a section header view you can use UICollectionReusableView as SectionHeaderViewType and Void as SectionHeaderDataType.

The code below shows how we specify these types for the action controllers provided in the example project:

class PeriscopeActionController: ActionController<PeriscopeCell, String, PeriscopeHeader, String, UICollectionReusableView, Void> { ... } // doesn't need to show a section header
class SpotifyActionController: ActionController<SpotifyCell, ActionData, SpotifyHeaderView, SpotifyHeaderData, UICollectionReusableView, Void> { ... } // doesn't need to show a section header
class TwitterActionController: ActionController<TwitterCell, ActionData, TwitterActionControllerHeader, String, UICollectionReusableView, Void> { ... } // doesn't need to show a section header
class YoutubeActionController: ActionController<YoutubeCell, ActionData, UICollectionReusableView, Void, UICollectionReusableView, Void>

Tweaking default style and animation parameters

By following the previous section steps you should already be able to play with your custom action controller. It happens quite often that we need some other customization such as zooming out the presenting view, changing the status bar color or customizing the default present and dismiss animation.

ActionController class defines the settings property of type ActionSheetControllerSettings to tweak all these.

UICollectionView's behavior

// Indicates if the action controller must be dismissed when the user taps the background view. `true` by default.
settings.behavior.hideOnTap: Bool
// Indicates if the action controller must be dismissed when the user scrolls down the collection view. `true` by default.
settings.behavior.hideOnScrollDown: Bool
// Indicates if the collectionView's scroll is enabled. `false` by default.
settings.behavior.scrollEnabled: Bool
// Controls whether the collection view scroll bounces past the edge of content and back again. `false` by default.
settings.behavior.bounces: Bool
// Indicates if the collection view layout will use UIDynamics to animate its items. `false` by default.
settings.behavior.useDynamics: Bool
// Determines whether the navigation bar is hidden when action controller is being presented. `true` by default
settings.hideCollectionViewBehindCancelView: Bool

UICollectionView Style

// Margins between the collection view and the container view's margins. `0` by default
settings.collectionView.lateralMargin: CGFloat
// Cells height when UIDynamics is used to animate items. `50` by default.
settings.collectionView.cellHeightWhenDynamicsIsUsed: CGFloat

Animation settings

Struct that contains all properties related to presentation & dismissal animations

// Used to scale the presenting view controller when the action controller is being presented. If `nil` is set, then the presenting view controller won't be scaled. `(0.9, 0.9)` by default.
settings.animation.scale: CGSize? = CGSize(width: 0.9, height: 0.9)

Present animation settings

// damping value for the animation block. `1.0` by default.
settings.animation.present.damping: CGFloat
// delay for the animation block. `0.0` by default.
settings.animation.present.delay: TimeInterval
// Indicates the animation duration. `0.7` by default.
settings.animation.present.duration: TimeInterval
// Used as `springVelocity` for the animation block. `0.0` by default.
settings.animation.present.springVelocity: CGFloat
// Present animation options. `UIViewAnimationOptions.curveEaseOut` by default.
settings.animation.present.options: UIViewAnimationOptions

Dismiss animation settings

// damping value for the animation block. `1.0` by default.
settings.animation.dismiss.damping: CGFloat
// Used as delay for the animation block. `0.0` by default.
settings.animation.dismiss.delay: TimeInterval
// animation duration. `0.7` by default.
settings.animation.dismiss.duration: TimeInterval
// springVelocity for the animation block. `0.0` by default
settings.animation.dismiss.springVelocity: CGFloat
// dismiss animation options. `UIViewAnimationOptions.curveEaseIn` by default
settings.animation.dismiss.options: UIViewAnimationOptions

StatusBar Style

// Indicates if the status bar should be visible or hidden when the action controller is visible. Its default value is `true`
settings.statusBar.showStatusBar: Bool
// Determines the style of the device’s status bar when the action controller is visible. `UIStatusBarStyle.LightContent` by default.
settings.statusBar.style: UIStatusBarStyle
// Determines whether the action controller takes over control of status bar appearance from the presenting view controller. `true` by default.
settings.statusBar.modalPresentationCapturesStatusBarAppearance: Bool

Cancel view style

Sometimes we need to show a cancel view below the collection view. This is the case of the SpotifyActionController. These properties have nothing to do with the actions added to an action Controller nor with the actions with .Cancel as style value.

 // Indicates if the cancel view is shown. `false` by default.
settings.cancelView.showCancel: Bool
 // Cancel view's title. "Cancel" by default.
settings.cancelView.title: String?
 // Cancel view's height. `60` by default.
settings.cancelView.height: CGFloat
 // Cancel view's background color. `UIColor.black.withAlphaComponent(0.8)` by default.
settings.cancelView.backgroundColor: UIColor
// Indicates if the collection view is partially hidden by the cancelView when it is pulled down.
settings.cancelView.hideCollectionViewBehindCancelView: Bool

Advanced animations

If tweaking previous settings is not enough to make the animations work like you want, XLActionController allows you to change the present/dismiss animation by overriding some functions.

Presentation

open func presentView(_ presentedView: UIView, presentingView: UIView, animationDuration: Double, completion: ((_ completed: Bool) -> Void)?)

The function above is responsible for making the present animation. It encapsulates how the presentation is performed and invokes onWillPresentView, performCustomPresentationAnimation and onDidPresentView to allow you to change a specific point of the animation.

Typically we don't need to override presentView function because overriding either onWillPresentView, performCustomPresentationAnimation or onDidPresentView is enough.

open func onWillPresentView()

onWillPresentView is called before the animation block starts. Any change here won't be animated. It's intended to set the initial animated properties values.

open func performCustomPresentationAnimation(_ presentedView: UIView, presentingView: UIView)

performCustomPresentationAnimation is called from within the main animation block.

open func onDidPresentView()

After the present animation is completed, presentView calls onDidPresentView from within completion callback.

onWillPresentView, performCustomPresentationAnimation, onDidPresentView won't be invoked if you override presentView implementation.

Dismissal

Dismissal animation can be customized in the same way as presentation animation.

open func dismissView(_ presentedView: UIView, presentingView: UIView, animationDuration: Double, completion: ((_ completed: Bool) -> Void)?)

The function above is responsible for making the dismissal animation. It encapsulates how the dismissal animation is performed and invokes onWillDismissView, performCustomDismissingAnimation and onDidDismissView to allow you to change an specific point of the animation.

Typically we don't need to override dismissView method because overriding either onWillDismissView, performCustomDismissingAnimationoronDidDismissView` is enough.

open func onWillDismissView()

Overrides onWillDismissView to perform any set up before the animation begins.

open func performCustomDismissingAnimation(_ presentedView: UIView, presentingView: UIView)

performCustomDismissingAnimation function is invoked from within the main animation block.

open func onDidDismissView()

After the dismissal animation completes, dismissView calls onDidDismissView from within completion callback.

onWillDismissView, performCustomDismissingAnimation, onDidDismissView won't be invoked if you override dismissView implementation.

To show how simple and powerful XLActionController is and give several examples of how to extend ActionController we have mimicked the Skype, Tweetbot, Twitter, Youtube, Periscope and Spotify action controllers.

Requirements

  • iOS 9.3+
  • Xcode 10.2+
  • Swift 5.0+

Getting involved

  • If you want to contribute please feel free to submit pull requests.
  • If you have a feature request please open an issue.
  • If you found a bug or need help please check older issues before submitting an issue.

If you use XLActionController in your app we would love to hear about it! Drop us a line on twitter.

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects.

Specify XLActionController into your project's Podfile:

source 'https://github.com/CocoaPods/Specs.git'
use_frameworks!

target '<Your App Target>' do
  # This will install just the library's core, won't include any examples
  pod 'XLActionController'

  # Uncomment depending on the examples that you want to install
  #pod 'XLActionController/Periscope'
  #pod 'XLActionController/Skype'
  #pod 'XLActionController/Spotify'
  #pod 'XLActionController/Tweetbot'
  #pod 'XLActionController/Twitter'
  #pod 'XLActionController/Youtube'
end

Then run the following command:

$ pod install

Carthage

Carthage is a simple, decentralized dependency manager for Cocoa.

Specify XLActionController into your project's Carthage:

github "xmartlabs/XLActionController" ~> 5.1.0

Manually as Embedded Framework

Clone XLActionController as a git submodule by running the following command from your project root git folder.

$ git submodule add https://github.com/xmartlabs/XLActionController.git

Open XLActionController folder that was created by the previous git submodule command and drag the XLActionController.xcodeproj into the Project Navigator of your application's Xcode project.

Select the XLActionController.xcodeproj in the Project Navigator and verify the deployment target matches with your application deployment target.

Select your project in the Xcode Navigation and then select your application target from the sidebar. Next select the "General" tab and click on the + button under the "Embedded Binaries" section.

Select XLActionController.framework and we are done!

Download Details:

Author: xmartlabs
Source Code: https://github.com/xmartlabs/XLActionController 
License: MIT license

#swift #ios