hi everybody I am Thomas Bethany and I
try to briefly explain what the point of
Oracle is so we keep talking about the
potentials of smart contracts but one of
the main limitations of smart contracts
is that we have to rely on on chain data
only so in the previous presentations
they already seen something like BTC
relay or other prize feeds which are
essentially from contracts from where
you can get some data which should be
updated by an external data provider so
essentially this means that there is a
party an external centralized party that
is pushing some data in with some
cryptographic proof to this contract so
that you can fetch this information from
another contract so the approach of
Oracle eyes is rightly different what we
are built here is a contract interface
so that you can use from your own
contract our service to fetch API is and
data feeds from the internet so since we
are a centralized party because the
fetching cannot be done on chain and
directly with some of course all things
are dead how can you trust us we are
sending TLS natori proof which is
proving that a center a certain content
was given as a result by a certain
server at a specified time so in this
way you don't have to trust us not to
alter your data and you are 100% sure
that the data coming from us is not
altered so to explain with some code
with what they just said oops
I just show that acne on the website so
if you go through this subdomain def dot
or alkalis dot a here there are some
sample codes that awfully now will be
loading and calling your class is very
easy because essentially we are
providing a solidity file to to import
directly in your code and after that you
have a base contract which is called
using oracle eyes so essentially you can
write your code we and in the definition
you can extend you can inherit our
contract by just typing is using oracle
eyes so this is providing some functions
such as oracle eyes underscore query the
code is not loading so this is a little
bit difficult to explain let's see if at
least a documentation is working yeah so
essentially you are sending us an
asynchronous request and this is the
syntax so you just type oracle eyes
underscore it and as first argument you
specify the data source the data source
in this case is Wolfram Alpha but
obviously you can get even you can use
directly any HTTP API you want just by
typing as data source URL so this is a
synchronous and then I'm say we are
sending back a transaction which is
calling a callback method in your
contract so the only thing you have to
do is to implement a callback method
which is described in the documentation
here callback function and then here you
decide what to do with this data
so essentially you can write in just ten
lines or something like a data feed
which is always keeping updated the
price of either taking the price from
tracking or things like that there are
even some utilities you can use because
obviously
we are sending back this as string so we
have some JSON and XML helpers so you
can just fetch some fields if you don't
need the old response back from the API
and there are some Alpers so that you
can do string comparison string
concatenation and all this kind of stuff
thank you for your attention