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[Music]
so just before we begin the actual video
today I'd just like to say that an early
access copy of my book hello Swift IOS
app programming for kids and other
beginners has been released you can find
it on many bookstores online such as
Amazon chapters and Indigo as well as
the Publishers website I really do hope
it helps you along your journey of
learning the Swift programming language
for iOS development all right so let's
get into the tutorial now so hello there
and welcome to another tutorial my name
is Tammy bakshi and this time we're
going to be going over how you can code
and use Bridges between different
programming languages all right so to
begin today I'd like to say a big thank
you to retesh for sending in this
question on Twitter uh and so basically
what we're going to be doing today is we
are going to be using the following
programming language programming
language combinations and I'm going to
be telling you how to create Bridges
between Java and Ruby Swift and python
as well as Swift PHP and
MySQL all right so let's begin with the
very first topic of this video today
which is how you can create Bridges
between Java and Ruby all right so now
the main way that you should be doing
this or at least the main way that I
believe uh is quite simple to actually
do uh is using shell let me explain uh
so let's say we've got two little bricks
here okay these bricks are respectively
Java and of course we've
got we too big of a box there but we've
also got
Ruby has another programming language so
we've got jav and
Ruby now let's say you've got a very
very simple Ruby script uh that takes
two numbers all right uh two and three
for example and we'll add them together
and print the screen five and that's in
Ruby and let's just say that you'd like
to call that code from java what would
you do well first of all let's take a
look how you regularly run this Ruby
script now what you would usually do is
you would go to your terminal
and this signifies your terminal this
dollar sign and you would type in
Ruby script
script.
RB and then you give it your parameters
like 2
three okay and what's going to happen is
it'll run the Ruby command on script. RB
and it'll give it the two and three
arguments and then those arguments can
then be used to add and then it'll give
you the result five and then you have
your terminal again now this is
something called a shell command and
well now we've actually determined that
Ruby is basically just sitting on top of
this shell
platform okay we're basically running
Ruby off of shell in this case now the
thing is the exact same logic applies to
Java we're calling Java off of
shell more specifically we're running
the Java Das jar function and we're
running our jar our Java
jar now let's just ignore how we
actually call Ruby FAL okay but we're
basically what what my what the idea is
in order to get uh these two programming
languages Bridge together is the fact
that both of these are not only based
off of shell but can then in turn call
Shell
commands as most most programming
languages can so Java can call Shell
commands and can get output from them
and so can
Ruby
shell okay and since these both are
based off of shell and can run shell
commands it becomes so so e easy to
bridge them the reason is because all we
need to do is let's just say we want to
call that Ruby script from java what we
do is since Ruby's based off of shell
and we can call Shell from java all we
need to do is tell Java to call Shell
Shell then calls that Ruby shell
script
okay and once shell once this shell has
called our Ruby script and once Ruby has
given those instructions back to
Shell this shell is able to give output
to
Java the shell Handler
more
specifically and then what happens is
we're able to get our output into
Java then once Java has the output it's
free to do whatever it actually wants to
with that output and this is actually
quite a simple way of having a
programming language bridge and it works
the exact same way if you like to
contact from Ruby to Shell in fact now
let's cut over to the Mac part where I'm
going to show you how you can actually
implement this so let's cut over to a
short code part and then we'll be back
to the Whiteboard part to discuss how
you can Bridge Swift and python all
right so now I'm going to be showing you
how you can implement the bridge between
Java and Ruby all right so let's take a
look so to begin let me show you the
extremely simple Ruby script that we're
going to be using today now first of all
just before I actually get to the Ruby
script though I like to show you I have
this little Java project ready called
Call Ruby code and this Java project uh
is actually quite simple and what I've
done is I've actually gone into a
terminal window and cded into this
directory if you seen the list here uh
we've got of course as you know by
default the bin and Source directories
uh but we've also got this script called
add to numbers. RB if I open it up as
you can see it's a very very simple Ruby
script inside of the Java projects
directory uh and basically all we do
here is we print to the screen or put to
the screen uh the first argument that it
was given to an integer plus the second
argument that was given to an integer
now basically what this means uh is
we're taking both of the arguments that
was given via the command line and we
are converting them to integers adding
them together and putting them back onto
the
screen once that's done you should have
a very simple Ruby script that can do
this so if you type in Ruby add to
numbers. rb23 it should give you five if
you were to write 50,000 maybe 25,000 it
should give you 7500 uh 75,000 sorry uh
so you can just you know add in put any
two numbers here and it will add them up
uh except for decimals you have to put
in integers uh and it should be able to
add them up and give you your
output now basically let's just say you
wanted to call this code from java how
would you do that well it's actually
quite simple now the first thing you
need to do is make Java available to ACC
actually access the shell environment
and the way we can do that is by
implementing my very own little run
shell function and the Run shell
function returns a string but it also
takes a string called command and this
is the actual shell command that you'd
like to run and this function can throw
an
exception now inside here as you can see
I'm defining the output variable and
this is basically a string that contains
the final output for the
user or technically what came from our
shell command
once that's done I'm creating a new
process called execution process and
we're setting this execution process to
a new runtime execution process and
we're giving it the command that you
gave for that shell command then what
we're doing is we're telling it to wait
for this process to be done because what
we've just gone ahead and done is we've
given that uh I guess you could say
execution Handler uh to a different
process but what we're doing is we're
telling this process to wait for itself
to be done and then we'll continue with
the rest of the Java code and so once
that is done we take that execution
process and we get it input stream and
we put that into a new variable called
is we then create a new input stream
reader called is reader uh based off of
that input stream and then we create a
buffered reader called reader from that
input stream reader uh and this is a new
buffered reader instance then there's a
little bit of logic that we use in order
to extract all of the lines from our
buffered read reader into our output
variable now this is a little bit of I
guess you could say work around is logic
uh and it's not recommended for your
applications necessarily but it should
work in really every single circumstance
so I'm not exactly uh I mean it's not
bad basically uh but the way this works
uh is essentially we are using
exceptions to our advantage I guess you
could say uh so inside of our try catch
here uh I have inside of the tri block
uh an infinite Loop a while true Loop
which is infinitely going on it'll never
ever stop and inside of this we've
basically got our output variable which
uh starts off as a blank string as you
can see here and we're basically telling
setting it to whatever it already was
plus uh the next line in from the
iterator of the lines of our buffer
reader and then we're adding a new line
basically what this means is infinitely
we'll keep you know using this iterator
from the reader and we'll keep getting
the next line and the next line and the
next line the next line however when
there is no next line then what's going
to happen is the next function will
actually just throw a no such element
exception and once it throws this
exception we're going to be out of scope
of this while and we're going to be
inside of our catch block and since
there's no code in our catch block we're
basically catching our exception and
then dropping
we ignore it completely because we know
that's basically how we're stopping our
Loop and then we're able to return the
output variable and that means we are
completely finished executing our code
and now we have run the shell command
successfully and gotten our output and
then that can be used to do really
anything we would like to and so then in
the main static function all I do is I
print out to the screen the output of
the Run shell function when I run the
root be add two numbers on rb23 command
so now if I run this as you should see
uh it says five to me in this little
console here uh and I mean just for
example if I were to say a few different
numbers maybe uh through four and three
uh it should give me uh I'm just going
to save my file and then as you can see
it gives me seven and I could type in
any two numbers any two numbers I'd like
to and it should be able to give me the
output for that uh for that addition
problem and that is how you can call
Ruby code from java now though let's get
back to the Whiteboard part where I'm
going to show you how you can create a
Swift and python code Bridge let's get
to it all right so welcome back to the
whiteo part and now that you've seen how
you can Bridge Java and Ruby now let's
take a look at how you can Bridge Swift
and python code now quite surprisingly
and quite uh amazingly and quite um I
guess you could say easy easily for us
developers or it's quite convenient how
guess what all we need to do in order to
Swift Java I mean uh Swift uh sorry uh
Bridge Swift and python code is replace
Java and Ruby with
Swift and
python but why is this well let's take a
look now let's say we've got a python
scrip that again add the numbers two and
three now the way you would run this is
you would go to your terminal and you
would type in
Python uh let's just say
script.py and you would say 2 3 then it
would output five and then you're back
to a
terminal so this proves that python is
based off of
bash now something else that's very
interesting here is you're saying hey
what well Swift isn't based off of bash
well that's why I'm here to talk to you
about Mac iOS apps or uh sorry Mac uh
Swift apps now you can actually create
command line tools or you can create
command line applications in Swift for
Mac OS and so the way you would run
those is you would have your terminal
and you would say Swift for example um
some binary file like uh Swift my
app okay and then you would say
23 and then 2 three will be the input
and the application can use that input
and then of course you would receive
five from Swift and then you can
continue dot dot dot do whatever you
want to in your
shell uh and so uh that's basically what
we're going to be doing today we're
going to compile some of our Swift code
into a binary uh or at least we could
compile it into a binary and have python
call it using its shell capability uh
but in this case what I'm going to do is
I'm actually going to be using using our
python script and I'm going to be
calling my python script from my Swift
code from my iOS sorry my Mac OS Swift
Code so now let's get right back over to
the code part where I'm going to be
showing you how you can create a bridge
between Swift and python let's get to
that all right so now I'm going to be
showing you how you can implement the
bridge between Java and Ruby all right
so let's take a look so to begin let me
show you the extremely simple Ruby
script that we're going to be using
today now first of all just we actually
get to the Ruby script though I like to
show you I have this little Java project
ready called Call Ruby code and this
Java product uh is actually quite simple
and what I've done is I've actually gone
into a terminal window and cded into
this directory if you've seen the list
here uh we've got of course as you know
by default the bin and Source Direct R
uh but we've also got this script called
add to numbers. RB if I open it up as
you can see it's a very very simple Ruby
script inside of the Java projects
directory uh and basically all we do
here is we print to the screen or put to
the screen uh the first argument that it
was given to an integer plus the second
argument it was given to an integer now
basically what this means uh is we're
taking both of the arguments that was
given via the command line and we are
converting them to integers adding them
together and putting them back onto the
screen once that's done you should have
a very simple Ruby script that can do
this so if you type in Ruby add2
numbers. rb23 it should give you five if
you were to write 50,000 maybe 25,000
which should give you 7500 uh 75,000
sorry uh so you can just you know add in
put any two numbers here and it will add
them up uh except for decimals you have
to put in integers uh and it should be
able to add them up and give you your
output now basically let's just say you
wanted to call this code from java how
would you do that well it's actually
quite simple now the first thing you
need to do is make Java available to ACC
actually access the shell environment
and the way we can do that is by
implementing my very own little run
shell function the Run shell function
returns a string but it also takes a
string called command and this is the
actual shell command that you'd like to
run and this function can throw an
exception
now inside here as you can see I'm
defining the output variable and this is
basically a string that contains the
final output for the
user or technically what came from our
shell command once that's done I'm
creating a new process called execution
process and we're setting this execution
process to a new runtime execution
process and we're giving it the command
that you gave for that shell command
then what we're doing is we're telling
it to wait for this process to be done
because what we've just gone ahead and
done is we've given that I guess you
could say execution Handler uh to a
different process but what we're doing
is we're telling this process to wait
for itself to be done and then we'll
continue with the rest of the Java code
and so once that is done we take that
execution process and we get it input
stream and we put that into a new
variable called is we then create a new
input stream reader called is reader uh
based off of that input stream and then
we create a buffered reader called
reader from that input stream reader uh
and this is a new buffer reader instance
then there's a little bit of logic that
we use in order to extract all of the
lines from our buffer reader into our
output
variable now this is a little bit of I
guess you could say workaround each
logic uh and it's not recommended for
your applications necessarily but it
should work in really every single
circumstance so I'm not exactly uh I
mean it
it's not bad basically uh but the way
this works uh is essentially we are
using exceptions to our advantage I
guess you could say uh so inside of our
Tri catch here uh I have inside of the
tri block uh an infinite Loop a while
true Loop which is infinitely going on
it'll never ever stop and inside of this
we've basically got our output variable
which uh starts off as a blank string as
you can see here and we're basically
telling setting it to whatever it
already was
plus uh the next line in from the
iterator of the lines of our buffered
reader and then we're adding a new line
basically what this means is infinitely
we'll keep you know using this iterator
from the reader and we'll keep getting
the next line and the next line and the
next line the next line however when
there is no next line then what's going
to happen is the next function will
actually just throw a no such element
exception
and once it throws this exception we're
going to be out of scope of this while
and we're going to be inside of our
catch block and since there's no code in
our catch block we're basically catching
our exception and then dropping it we
ignore it completely because we know
that's basically how we're stopping our
Loop and then we're able to return the
output variable and that means we are
completely finished executing our code
and now we have run the shell command
successfully and gotten our output and
then that can be used to do really
anything we would like to and so then in
the main static function all I do is I
print out to the screen the output of
the Run shell function when I run the
Ruby add to numbers on rb23 command so
now if I run this as you should see uh
it says five to me in this little
console here uh and I mean just for
example if I were to say a few different
numbers maybe uh four and three uh it
should give me uh I'm just going to save
my file and then as you can see gives me
seven and I could type in any two
numbers any two numbers I'd like to and
it should be able to give me the output
for that uh for that addition
problem and that is how you can call
Ruby code from java now though let's get
back to the Whiteboard part where I'm
going to show you how you can create a
Swift and python code Bridge let's get
to it all right so now that you've seen
how you can Bridge Java and Ruby as well
as Swift and python we are now ready to
move to the last and argu arguably the
most important Bridge of them all how
you can use Swift to bridge with myql
using PHP in between let's talk about
that now we're basically using in this
case MySQL for things like user data
okay uh or really anything any storage
for your application uh in this case
would be handled by
MySQL uh and essentially the point here
uh is that we
are sorry uh so basically what we're
going to do is let's just say we've got
Swift and this Swift is running on an
IOS app and this IOS app is something
like a chatting app okay uh and
basically you've
got all the messages and everything of
that sort on my my
SQL okay got messages user data
everything about your application on
MySQL now you need to find a way to
communicate between Swift and MySQL but
there's no direct way to do that so you
have to use a programming language
bridge and the way that I like to do
this is well a very simple PHP bridge
now what does this mean well basically
what this means is that with PHP we can
easily get a direct connection to myql
up and running in no time and that means
that PHP is capable of very very easily
communicating to and from my
SQL and I can very easily again make
Swift communicate with PHP as well but
how would we do that it's quite simple
all we need to do is set up a rest and
point Point such as
get I mean you could use post request
delete request put request anything I'm
using get in this case since it's the
simplest to create so a get request for
slash maybe you know insert or you know
register and this would take a few
parameters like username password date
of birth etc etc etc and then what would
happen is we would use Swift and we
would basically
contact PHP using this endpoint and PHP
would you know do its MySQL logic go to
mySQL do whatever it needs to then MySQL
is going to come back to PHP and Swift
will get the result to get that uh uh
get the result of that rest call that it
made to PHP and in this way it basically
becomes a rest API that your application
is based off of and it becomes extremely
extremely convenient to work with and so
that is basically how this bridge Works
uh in fact if you'd actually like to see
a live example of how this works with a
friend list app uh then of course you
can actually visit my video in fact one
of my one of my first video is called
Swift databases uh and I've actually
created an entire series about this with
then they all highlight how you can use
that Swift PHP MySQL bridge in fact I've
even created I guess you could say this
framework called tql kit and there will
be a link to that video as well in the
description and that basically allows
you to skip the worrying and the logic
of that PHP Bridge it allows you to run
native MySQL code on inside of Swift
that will go through PHP in the
background and will hit a remote MySQL
server and get back to you with a
response it's really really interesting
what it does and of course I really do
recommend that you check the those all
out and links to those will be in the
description all right so that's what
this video consisted of today I really
do hope you enjoyed and of course I
really do hope I was able to answer your
question ratesh all right so thank you
very much for watching today of course
if you like the video please do consider
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your friends or family please do
consider sharing the video as well of
course if you have any other questions
suggestions or feedback you can leave
them down in the comment section below
email them to me at tajim Manny
gmail.com or tweet them to me at tajim
Manny of course though if you really
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for watching today that's going to be it
for this tutorial goodbye