understanding google api
DESCRIPTION
Understand How Google APIs work, and how to use them in your applicationTRANSCRIPT
UnderstandingGoogle APIsBuilding application that uses Google APIs
Fethi DILMI
Active Member at Scientific Club of ESI – CSE
Technical Manager at GDG Algiers
Microsoft Student Partner
What's Google APIs?
What's Google APIsWhat's Google APIs
● Google offers a variety of APIs, mostly web APIs for web developers and mobile developers.
● The APIs are based on popular Google consumer products, including Google Maps, Google Earth, AdSense, Adwords, Google Apps and YouTube.
Example:● YOU use Google+ from your web browser.● Your Android application uses Google+ through
Google+ API.● i.e: Google APIs are the tools we need to build
applications that can use Google Products.
What's Google APIsWhat's Google APIs
How Google APIs work behind the scenes?
How Google APIs work behind the scenes ?How Google APIs work behind the scenes ?
● Most of Google APIs are web-based APIs.● This kind of APIs are called RESTFUL APIs (because they
are based on REST architecture).● REST is a style of software architecture that is based on
HTTP protocol to retrieve data.
How Google APIs work behind the scenes ?How Google APIs work behind the scenes ?
● Most of Google APIs are web-based APIs.● This kind of APIs are called RESTFUL APIs (because they
are based on REST architecture).● REST is a style of software architecture that is based on
HTTP protocol to retrieve data.
Simply, in order to use Google APIs , you only need to make HTTP requests to get
data ☺
How Google APIs work behind the scenes ?How Google APIs work behind the scenes ?
Example: “Google Places API”
https://maps.googleapis.com/maps/api/place/nearbysearch/xml?
location=36.825,2.3257&radius=50000&sensor=false&key=AddYourOwnKey
Here
Global Structure of an API HTTPrequest:
Global Structure of an API HTTP requestGlobal Structure of an API HTTP request
Each HTTP request is composed of 4 parts:– API Scope– Action– Output format– Parameters
To understand these parts, we'll take the previous example:
https://maps.googleapis.com/maps/api/place/nearbysearch/xml?
location=36.825,2.3257&radius=50000&sensor=false&key=AddYourOwnKeyHere
Global Structure of an API HTTP requestGlobal Structure of an API HTTP request
1- API Scope:● A scope is the main part of the HTTP request.● In our case it's: https://maps.googleapis.com/maps/api/place
● A scope defines the web address of the API.● For example, the scope of Google Latitude API is:
https://www.googleapis.com/latitude/
NB: Some API Scopes defines an API version, just like the Latitude API
Global Structure of an API HTTP requestGlobal Structure of an API HTTP request
2- Output formats:● There are 2 possible output formats for an API request.
– JSON – XML
● In the previous example, we could get the same results in JSON format:
https://maps.googleapis.com/maps/api/place/nearbysearch/jsonjson ?
location=36.825,2.3257&radius=50000&sensor=false&key=AddYourOwnKeyHere
Global Structure of an API HTTP requestGlobal Structure of an API HTTP request
3- ACTION:● Each Google web API gives you a set of possibilities
called ACTIONS.● In our example, we specified for the Google Places API
the action “nearbysearch” to search places in a radius of 50Km.
● We could also search a place's detail.
Global Structure of an API HTTP requestGlobal Structure of an API HTTP request
4- Parameters:● Each action has a set of parameters.● Action Parameters let you customize the results you
want to get.● In our example, we could add the parameter
“type=food” to search only for restaurants.
Types of Google web APIs
Types of Google web APIsTypes of Google web APIs
● There are 2 kinds of Google web APIs:– Public APIs.– Private APIs.
Types of Google web APIsTypes of Google web APIs
1- Public APIs● Interact with public content: Google Maps API, Google
Places API ..● Need an authentication key to be able to retrieve data.
Types of Google web APIsTypes of Google web APIs
2- Private APIs● Interact with user private date: Google+ API, Google
Latitude API, Google Drive SDK ..● Need an authorization process before accessing to user
data.
Public APIs and Authentication:What's THAT !!
AuthenticationAuthentication
● Public APIs use authentication key to identify your application.● This means, in our previous example we would not be able to
make a search using Google Places API without specifying an authentication key.
● Each device type has a different kind of key:– Android application authentication key.– Web application authentication key.– Web Service authentication key – ..
AuthenticationAuthentication
But Why ?
AuthenticationAuthentication
● Identify from which device your application is making API request: i.e: You can't make an API request from a web browser using an Android application authentication key.
● Limit the quota of requests per day: Each API has a limited number of requests per day. Since your application makes request using an authentication key, Google Servers will be able to stop your application when it exceeds its daily quota.
● Limit the number of requests per second for a single user: Your application may be used by millions of people at the same time, and since we're talking about a daily quota, we have to limit the number of requests/second for a single user.
AuthenticationAuthentication
● Identify from which device your application is making API request: i.e: You can't make an API request from a web browser using an Android application authentication key.
● Limit the quota of requests per day: Each API has a limited number of requests per day. Since your application makes request using an authentication key, Google Servers will be able to stop your application when it exceeds its daily quota.
● Limit the number of requests per second for a single user: Your application may be used by millions of people at the same time, and since we're talking about a daily quota, we have to limit the number of requests/second for a single user.
AuthenticationAuthentication
● Identify from which device your application is making API request: i.e: You can't make an API request from a web browser using an Android application authentication key.
● Limit the quota of requests per day: Each API has a limited number of requests per day. Since your application makes request using an authentication key, Google Servers will be able to stop your application when it exceeds its daily quota.
● Limit the number of requests per second for a single user: Your application may be used by millions of people at the same time, and since we're talking about a daily quota, we have to limit the number of requests/second for a single user.
Private APIs and Authorization:What's THAT !!
Authorization:Authorization:
● Private APIs try to fetch user data.● This cannot be done without the permission of the user.● So we need a tool to demand permissions from the user
in order to perform action on his/her private data.
Authorization:Authorization:
● Private APIs try to fetch user data.● This cannot be done without the permission of the user.● So we need a tool to demand permissions from the user
in order to perform action on his/her private data.
THIS TOOL IS CALLED “OAuth2.0”
It is trying to solve a tricky problem.
What is OAuth2.0 ?What is OAuth2.0 ?
If you, the developer, are building an application.
What is OAuth2.0 ?What is OAuth2.0 ?
And your users
What is OAuth2.0 ?What is OAuth2.0 ?
have data in another service that your application needs to function
What is OAuth2.0 ?What is OAuth2.0 ?
such as their tasks list, or their photos
What is OAuth2.0 ?What is OAuth2.0 ?
HOW DO YOU GO ABOUT GETTING IT?
???
What is OAuth2.0 ?What is OAuth2.0 ?
You could ask the user for their name and password.
NO !!NO !!
But then the user has given your application access to all their data on that service. That's not safe. Don't do that.
NO !!NO !!
The user's name and password are like keys to their digital kingdom, you should never ask for them.
NO !!NO !!
What we really want is a special key, one that only allows access to a limited set of data in the API.
Better ☺Better ☺
A special key that the User can let the App acquire and use without the use of their name and password.
Better ☺Better ☺
But for that to work, everyone has to confirm that everyone else is who they say they are.
That's OAuth2.0 ☺That's OAuth2.0 ☺
That looks simple after all this
That's OAuth2.0 ☺That's OAuth2.0 ☺
But actually, it's a little more complicated than even that, because that special key (Code)
That's OAuth2.0 ☺That's OAuth2.0 ☺
can change over time to keep things secure.
That's OAuth2.0 ☺That's OAuth2.0 ☺
How to create Authentication andAuthorization keys ?
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● To get authentication/authorization keys, you have to register your application.
● Registering your application is signing its name, type, package, and extra info.
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● To get authentication/authorization keys, you have to register your application.
● Registering your application is signing its name, type, package, and extra info.
Please focus on the following steps ☺
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● Connect to your Google account.● Go to: https://code.google.com/apis/console/ ● Click on “Create Project”
● Now there is a list of all Google APIs, choose for example the "Google Places API", and check it up:
● Register your organization like shown in the image and click submit:
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● Agree & Accept
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● You can now notice that the Google Places API is activated:
● Click on "Overview", then click on "Register" in order to register your project:
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● Type a unique project ID
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● You've created automatically an authentication key for browser applications
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● You can click on:– Create New Server Key: To create an authentication key for
a server application– Create New Server Key: To create an authentication key for
an Android application.● You can create many authentication keys for the same
application type (example: 3 authentication keys for Android Applications)
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● And Now ..
How To Create Authorization Keys ?
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● Click on “Create an OAuth 2.0 Client ID”. This dialog will show up:
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● Click on “Create an OAuth 2.0 Client ID”. This dialog will show up:
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
Now please focus with me, it's so important ! In the following dialog, you'll be asked to specify your
application type !!
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
1- Web Applications: ● If you choose this type of application, you'll be asked to
specify your application URL. Than Google will generate a redirect URI according to what you've entered.
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
2- Server Applications: ● Applications of this type run on server. ● They're a little bit different, so I invite you to read this
article to understand more: https://developers.google.com/accounts/docs/OAuth2#serviceaccount
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
3- Installed Applications:● This could be:
– Android application: You'll have to specify you're application package (it must be unique)
– iOS application.– Chrome extension. – A Desktop application .– etc...
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● I'll take the example of a Desktop Application
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● When you click “Create Client ID”, this dialog will show up:
How to create Authentication and Authorization keys ?
How to create Authentication and Authorization keys ?
● You can create many authorization keys for many projects.
● We'll see how to use the “Client ID” and the “Client Secret” to make authorized API calls.
Some demonstration:Step By Step ☺
Google APIs Client LibrariesGoogle APIs Client Libraries
● It's not easy to construct manually authorized HTTP requests.
● It's much harder to parse the XML/JSON results in order to extract information.
Google APIs Client LibrariesGoogle APIs Client Libraries
● Google created some libraries to do those tasks for you: It's Google API Client Libraries.
● Google API Client Libraries are available in many languages (e.g: PHP, Python, C# and .NET, Java ..)
● In this Demo, we'll be using the Google API Client for Python.
Now that we know what OAuth 2.0 looks like. How does it work in the Google API Client for Python?
Let's Start !!Let's Start !!
The key is held in a Credentials object.
CredentialsCredentials
All the steps needed to go through getting Credentials is in a Flow object.
FlowFlow
Storage
And finally, because keys can change over time there is a Storage object for storing and retrieving keys.
StorageStorage
Flow Credentials Storage
You set up and run a Flow, which in the end produces Credentials, which you store in a Storage.
The ModelThe Model
Later, when you need the key, you take it out of Storage and use it.
From PythonFrom Python
So let's look at actual code.
Step By StepStep By Step
First, create a Flow.
FLOW = OAuth2WebServerFlow( client_id='<CLIENT ID HERE>', client_secret='<CLIENT SECRET HERE>', redirect_uri='https://.../oauth2callback', scope='https://.../tasks', user_agent='my-sample/1.0')
Step By StepStep By Step
Fill your Client ID, Client Secret and redirect URI
FLOW = OAuth2WebServerFlow( client_id='<CLIENT ID HERE>', client_secret='<CLIENT SECRET HERE>', redirect_uri='https://.../oauth2callback', scope='https://.../tasks', user_agent='my-sample/1.0')
Step By StepStep By Step
We request and authorization URL
authorize_url = FLOW.step1_get_authorize_url()self.redirect(authorize_url)
Step By StepStep By Step
We get redirected to the generate URL
authorize_url = FLOW.step1_get_authorize_url()self.redirect(authorize_url)
Step By StepStep By Step
We get Credentials when the Flow finishes, which we save in a Storage.
credentials = flow.step2_exchange(self.request.params)storage = StorageByKeyName( Credentials, user.user_id(), 'credentials' )storage.put(credentials)
Step By StepStep By Step
To use Credentials we retrieve them from the Storage and apply them to an httplib2.Http() object.
user = users.get_current_user()storage = StorageByKeyName( Credentials, user.user_id(), 'credentials' )credentials = storage.get()
http = httplib2.Http()http = credentials.authorize(http)
Step By StepStep By Step
user = users.get_current_user()storage = StorageByKeyName( Credentials, user.user_id(), 'credentials' )credentials = storage.get()
http = httplib2.Http()http = credentials.authorize(http)
Now any HTTP requests made with http will be authorized with those Credentials.
Step By StepStep By Step
Thanks everyone ☺
ReferencesReferences
● “OAuth 2.0 and the Google API Client for Python”.● “Understanding Google APIs” :
http://fethidilmi.blogspot.com ● Google Developers portal:
http://developers.google.com