Yql Openhackday 2009

YQL
A Query Language for the Web

Nagesh Susarla

Agenda
Why YQL?
YQL Statement Basics
Accessing YQL
Q&A

data manipulation
Application =

data manipulation
Application = +
data visualization

var map = new
YMap(document.getElementById('map'));
…
var currentGeoPoint = new
dev
YGeoPoint( _c.Lat, _c.Lon );
map.addMarker(currentGeoPoint);
…

var map = new
…
dev
…

…
if (flickcurl_prepare(fc,
quot;flickr.photos.geo.correctLocationquot;,
parameters, count)) { … }
…

var map = new
…
dev
…

…
…

http://search.yahooapis.com/
ImageSearchService/V1/imageSearch?
appid=YahooDemo&query=Corvette&results=2

var map = new
…
dev
…

…
…


http://weather.yahooapis.com/
forecastrss?p=FRXX0076&u=c

var map = new
…
dev

?
…

…

?
…

? http://search.yahooapis.com/

?

Yahoo! My Yahoo! Mail Welcome, guest Sign In

Search

var map = new
MY PROJECTS APIs & WEB SERVICES RESOURCES SUPPORT

YDN Maps Suite AJAX Maps

Yahoo! Maps Web Services - AJAX API Getting READY TO GET STARTED?
… You aren't signed in Sign In Help

Started Guide Get an App ID
dev Home The Tour Sign Up Explore Search
Learn the fundamentals of the Yahoo! Maps AJAX API and start creating your own maps. This page contains:
Introduction and Prerequisites Yahoo! Maps Cheatsheets
Flickr Services RECENT BLOG ARTICLES
Yahoo! My Yahoo! Mail
Examples Welcome, guest Sign In

API Documentation Feeds Your API Keys map.addMarker(currentGeoPoint);
Display a Yahoo! Map

?
Apply for a new API Key
Search
Add controls to your Yahoo! Map Leonardo da Vinci: Hacker
… January 24, 2009
Add a logger to a Yahoo! Map
Place a marker on a Yahoo! Map
MY PROJECTS APIs & WEB SERVICES RESOURCES SUPPORT
Draw Polylines on a Yahoo! Map Whaddyathink? & the Yahoo! Application
flickr.places.getPlaceTypes
Place Smart Markers on a Yahoo! Map Platform
YDN Weather RSS Feed
Add multiple custom markers on Yahoo! Map January 22, 2009
Traffic information overlay
Yahoo! Weather RSS Feed
Yahoo! Pipes RSS output information overlay Making the new Yahoo! Currency Converter
Fetches a list of available place types for Flickr.
Yahoo! Pipes JSON output information overlay accessible
YMap
Local search results overlay The Weather RSS feed enables you to get up-to-date weather information for your location. You can save this
January 21, 2009
…
Overlay GeoRSS XML data
feed in My Yahoo! or your favorite feed aggregator, or incorporate the RSS data into your own web site or client
Overlay custom objects at YGeoPoint location
application. The Weather RSSRetrievingdynamically-generatedfrom based on zip code or Location ID.
feed is a and displaying data feed
Authentication
Overlay custom objects at YCoordPoint location
Wikipedia with YQL
Overlay polyline on Yahoo! Map
This page describes the format of the 18, 2009 URL and the RSS response for developers. It contains these
January request

?
Export Yahoo! Map in GeoRSS format
This method does not require authentication.
sections:
GeoRSS overlay with polyline
Get zoom level given radius from center
RSS Request
Arguments
Custom position of controls
Summary
Change Marker Images Dynamically
Request Parameters
Use YMapTypeControl to position map types
…
api_key (Required)
Other Features of the Yahoo! Maps AJAX API RSS Response
YEvent, YGeoRSS, YMarker
Rate Limit Your API application key. See here for moreTop-Level Elements
details.
Terms of Service Channel Elements
Support & Community
Image Elements

?
Example Response Item Elements
Download all of the cheatsheets and example code in the Yahoo
Condition Codes
Maps API Reference Bundle.
<place_types> Examples
For detailed descriptions of the classes and methods in the API, place_type_id=quot;22quot;>neighbourhood</place_type>
<place_type Terms of Use
check out v3.8 Reference Manual. <place_type place_type_id=quot;7quot;>locality</place_type>
<place_type place_type_id=quot;9quot;>county</place_type>
RSS Request
<place_type place_type_id=quot;8quot;>region</place_type>
Remaining, Supporting Classes
<place_type place_type_id=quot;12quot;>country</place_type>
The Weather RSS feed request follows simple HTTP GET syntax: start with a base URL and then add
Introduction and Prerequisites
<place_type place_type_id=quot;29quot;>continent</place_type> (?). Multiple parameters are separated by an ampersand (&).
parameters and values after a question mark
</place_types>
The Yahoo! AJAX Maps API lets developers add maps to their web sites using DHTML and JavaScript®. the Weather RSS feed is
The base URL for Maps
are fully embeddable and scriptable using the JavaScript programming language. Yahoo! Maps AS-Flash API's

?
Error Codes
built-in geocoder means that you can specify a physical address or latitude/longitude coordinates for your map's
http://weather.yahooapis.com/forecastrss
location, as you like.
In this section, Summary shows how to make an RSS request with different parameters; Request Parameters
In order to create and test applications 100: Yahoo! Maps AJAX API, you'll need to use a supported summarizing those parameters.
using Invalid API Key shows a table web
The API key passed was not valid or has expired.
browser: Firefox 2, Internet Explorer 6 or 7, Opera 9 or Safari 3. Newer versions of these browsers are also
supported. You can code your JavaScript applications usingcurrently unavailable
105: Service your favorite text editor or IDE.
SUMMARY
The requested service is temporarily unavailable.
An application ID is required to use the Yahoo! Maps AJAX API. You can get an application ID here.
111: Format quot;xxxquot; not found The Weather RSS feed request follows simple HTTP GET syntax: start with a base URL and then add
parameters and values after a question mark (?). Multiple parameters are separated by an ampersand (&). For
For best results, you should launch your web pagesrequested response format was not found. applications
The from a web server. However, it's possible to run
the Weather RSS feed there are two parameters:
directly from your hard drive by double-clickingMethod This can be donefound
112: on them. quot;xxxquot; not by lowering the security settings in
the Internet Explorer browser or by setting the The requested method was not found. p for location.
UniversalBrowserRead property in Firefox.
u for degrees units (Fahrenheit or Celsius).
114: Invalid SOAP envelope
The SOAP envelope send in the requestlocationnot be parsed. required. Use this parameter to indicate the location for the weather forecast as a
The could parameter p is
Displaying a Yahoo! Map zip code or Location ID.
115: Invalid XML-RPC Method Call
All the API classes and methods necessary to interact with Yahoo! Mapsdocument couldyour application when
The XML-RPC request are availablehttp://weather.yahooapis.com/forecastrss?p=location
to not be parsed.
you include Yahoo! Maps AJAX API library in your web page.This example uses the demonstration application
ID quot;YD-eQRpTl0_JX2E95l_xAFs5UwZUlNQhhn7lj1Hquot;; you cannot use this Application Forand must requestweather for Yahoo! Headquarters in Sunnyvale, CA, use the zip code for Sunnyvale
ID example, to get one
API Explorer
here. (94089):

API Explorer : flickr.places.getPlaceTypes
<html> http://weather.yahooapis.com/forecastrss?p=94089
<head>
Or use the Location ID for Sunnyvale (USCA1116):
<b><script type=quot;text/javascriptquot;
src=quot;http://api.maps.yahoo.com/ajaxymap?v=3.8&appid=YD-

dev

Bindings

YQL
YQL stmt

dev

Bindings

YQL
YQL stmt
select

dev

Bindings

YQL
YQL stmt
select
desc

dev

Bindings

YQL
YQL stmt
select
desc
show

Motivation
Thousands of Web Services that provide valuable
data
Requires developers to read documentation and form
URLs/queries.
Data is isolated
Needs combining, tweaking, shaping even after it
gets to the developer.

YQL
SQL-Like Language
Synonymous with Data access
Familiar to developers
Expressive enough to get the right data.
Self Describing - show, desc table
Allows you to query, ﬁlter and join data across
WebServices.

Verbs

show: lists the supported tables
desc: describes the structure of a table
select: fetches data
use: use an Open Data Table *new*

show tables
desc social.contacts

YQL Statement
Syntax

SELECT what
FROM collection
WHERE filter condition
IN (sub-select)
LIMIT n OFFSET n

Syntax -> Select -> Collection

FROM collection
Yahoo! WebServices
Social Dir, Upcoming, MyblogLog,
Y!Local, Search(BOSS)
External DataSources
XML, Atom, RSS, JSON, CSV, HTML

Syntax -> Select -> WHERE clause

Table data can be filtered in the WHERE
clause either
Remotely by the table data source
Locally by the YQL engine (dot
notation)

Syntax -> WHERE clause -> Remote Filter
WHERE <remote_key>=‘value’
Tables require Keys in where clause
Specified in the describe
<query>
<key name=”guid” required=”true” .../>
</query>

Correspond to query, path or matrix
parameters for the Endpoint

Syntax -> WHERE clause -> Local Filter
WHERE <local_filter> OP ‘value’
Filter an element or an attribute
<movies> Dot notation:
<movie>Star Wars</movie> movies.movie LIKE ‘%Star%’
<movie>StarTrek</movie>
</movies>

<, >, =, LIKE, matches, not matches,
not like
AND, OR binary operator combinations

Syntax -> Select -> Projection
SELECT <what>
Uses the dot notation to project
parts of matching item(s)
<results>
<movie>
<id>101</id>
Projection: (relative to root)
<name>Star Wars</name>
select movie.id, movie.name
</movie> from ...
<movie>...</movie>
</results>

Syntax -> Select -> Sub-Select
IN (SELECT ...)
Join across data sources
field IN (select guid from ...)
Like SELECT but can return only
N leaves

Get the profile for all my connections:

select * from social.profile where guid in
(select guid from social.connections where owner_guid = me)

Syntax -> Select -> Sub-Select
IN (SELECT ...)
(field, ...fieldN) IN (SELECT
f1,...fn from table)

Get the Location name of the given Photo:

select place.name from flickr.places where (lat, lon) in
(select location.latitude, location.longitude from
flickr.photos.info where photo_id='3030238604')

Syntax -> Select -> Table Size
Changing the Table Size
Yahoo! Tables are limited to a
small number by default (10)
select * from local.search where zip=‘94089’
and query=‘pizza’

Increase set size as parameters
to Collection
select * from local.search(100) where
zip=‘94089’ and query=‘pizza’

Syntax -> Post Query Manipulation

Post Select processing using
‘pipe’ symbol.
select ... | sort(field=‘item.pubDate’)
select ... | unique(field=‘item.title’)
select ... | tail(count=10)

Functions operate on return data.
Operations unrelated to table or
data source.

Syntax -> YQL Variables (@var)
Like Prepared Statements for YQL
Substitutes Query parameter
http://<>?q=....&city=Bangalore&state=Karnataka

select * from table where city=@city and state=@state

Can be used in sub-selects

select * from table where city in (@city, @city2,
@city3)

Syntax -> YQL Variables (@var)
Multi Valued variables

http://<>?q=....&city=Bangalore&city=Mumbai

select * from table where city in (@city)

Sounds Good.
But what about my
WebService?

Open Data Tables
Bindings

YQL

Open Data Tables

Map YQL to Endpoint

YQL

Open Data Tables
Schema defines mapping between YQL
and Endpoint
Keys can either be query, path or
matrix parameters
Keys can be marked as required
YQL Compiler validates existence
of required keys

USE Verb
use ‘http://url-to-def.xml’ as tableName;
select * from tableName where key=‘value’...
Imports the Table defintion
Makes it available to following
statements as tableName
desc tableName - describes the def
Acts like a First Class Data
Source just like other YQL Tables.

Accessing YQL
OAuth Endpoint
http://query.yahooapis.com/v1/yql?
q=...
Public Endpoint
http://query.yahooapis.com/v1/
public/yql?q=
YQL Console
http://developer.yahoo.com/yql/
console

Yql Openhackday 2009

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