Introduction to Google API…
By Pratheepan Raveendranathan
What is Google API?

The Google Web APIs service is a beta web program that enables developers to
easily find and manipulate information on the web.

Google Web APIs are for developers and researchers interested in using
Google as a resource in their applications.

The Google Web APIs service allows software developers to query more
than 3 billion web documents directly from their own computer programs.

Google uses the SOAP and WSDL standards to act as an interface between
the user’s program and Google API.

Programming environments such as Java, Perl, Visual Studio .NET are
compatible with Google API.
Definitions from http:// www.google.com/apis/
What can you do with the API

Developers can issue search requests to
Google's index of more than 3 billion web
pages.

and receive results as

structured data,



Estimated number of results, URL’s, Snippets, Query Time
etc.
access information in the Google cache,
and check the spelling of words.
To start using the API

You need to,




Download API Package from
http://www.google.com/apis/
Create an account and get your license key
Install kit in your UMD account
And also need Soap::Lite

However, it is on all the csdev machines, so you don’t
need to get it. IT is not on UB or Bulldog.
Contents of this package:

googleapi.jar - Java library for accessing the Google Web APIs
service.

GoogleAPIDemo.java - Example program that uses googleapi.jar.
dotnet/

Example .NET - programs that uses Google Web APIs.

APIs_Reference.html - Reference doc for the API. Describes
semantics of all calls and fields.

Javadoc - Documentation for the example Java libraries.

Licenses - Licenses for Java code that is redistributed in this package.

GoogleSearch.wsdl -WSDL description for Google SOAP API.

soap-samples/
WSDL
Web Services Description Language



The standard format for describing a web
service.
Expressed in XML, a WSDL definition
describes how to access a web service and
what operations it will perform.
This is the most important file (only) to use
the API with Perl.
SOAP –
Simple Object Access Protocol









SOAP stands for Simple Object Access Protocol
SOAP is a communication protocol
SOAP is for communication between applications
SOAP is a format for sending messages
SOAP is designed to communicate via Internet
SOAP is platform independent
SOAP is language independent
SOAP is based on XML
SOAP will be developed as a W3C standard
Google API for Perl
SOAP:Lite
SOAP:Lite for Perl is a collection of Perl
modules which provides a simple and
lightweight interface to the SOAP both on
client and server side.
So How do I Query Google?
#!/usr/local/bin/perl –w
use SOAP::Lite;
# Configuration
$key = "Your Key Goes Here";
# Initialize with local SOAP::Lite file
$service = SOAP::Lite
-> service('file:GoogleSearch.wsdl');
$query= “duluth”;
Search Contd…
$result = $service
-> doGoogleSearch(
$key,
$query,
0,
10,
"false",
"",
"false",
"",
"",
""
);
# key
# search query
# start results
# max results
# filter: boolean
# restrict (string)
# safeSearch: boolean
# lr
# ie
# oe
Name
key
q
start
Description
Provided by Google, this is required for you to access the
Google service. Google uses the key for authentication and
logging.
Query Phrase.
Zero-based index of the first desired result.
maxResults
Number of results desired per query. The maximum value per
query is 10.
Note: If you do a query that doesn't have many matches, the
actual number of results you get may be smaller than what you
request.
filter
Activates or deactivates automatic results filtering, which hides
very similar results and results that all come from the same
Web host.
restrict
safeSearch
Restricts the search to a subset of the Google Web
index, such as a country like "Ukraine" or a topic like
"Linux."
A Boolean value which enables filtering of adult
content in the search results.
lr
Language Restrict - Restricts the search to documents
within one or more languages.
ie
Input Encoding - this parameter has been deprecated
and is ignored. All requests to the APIs should be
made with UTF-8 encoding.
oe
Output Encoding - this parameter has been
deprecated and is ignored. All requests to the APIs
should be made with UTF-8 encoding.
Now to Retrieve the Search
Results
if(defined($result->{resultElements})) {
print join "\n",
"Found:",
$result->{resultElements}->[0]->{title},
$result->{resultElements}->[0]->{URL},
$result->{resultElements}->[0]->{snippet} . "\n"
}
print "\n The search took ";
print $result->{searchTime};
print "\n\n";
print "The estimated Number of results for your query is: ";
print $result->{estimatedTotalResultsCount};
print "\n\n";
What you need for
your program
Search.pl Output
Found:
University of Minnesota <b>Duluth</b> Welcomes You
http://www.d.umn.edu/
The University of Minnesota <b>Duluth</b> Homepage: an overview of academic
prog
rams, campus<br> life, resources, news and events, with extensive links to other
web sites <b>...</b>
The search took 0.159791
The estimated Number of results for your query is: 881000
Or, to get all elements:
foreach $temp (@{$result->{resultElements}}) {
print $temp->{snippet};
}
foreach $temp (@{$result->{resultElements}}) {
print $temp->{URL};
}
foreach $temp (@{$result->{resultElements}}) {
$title_array[$count++]=$temp->{title};
}
How to get a spelling suggestion?
#!/usr/local/bin/perl -w
use SOAP::Lite;
# Configuration
$key = "Your Key Goes Here";
# Initialize with local SOAP::Lite file
$service = SOAP::Lite
-> service('file:GoogleSearch.wsdl');
$correction = $service->doSpellingSuggestion($key,$searchString);
How do I get the results?

Easy,


The variable Correction will contain the spelling
suggestion, if Google has one, or it would be
empty if there is no suggestion
So Retrieving the result would be as easy as:
print "\n The suggested spelling for $searchString is
$correction \n\n";
Spelling output
Enter a word
dulut
The suggested spelling for “Duluth” is:
duluth
How do I get a cached web page?

Google has this feature that given a URL, it
will try to retrieve the web page from its
“cache”.


So the actual contents of the page might be
somewhat old, relative to when the web crawlers
or Google did an update on the site
Example,
Example Contd…
#!/usr/local/bin/perl –w
use SOAP::Lite;
# Configuration
$key = "Your Key Goes Here";
# Initialize with local SOAP::Lite file
$service = SOAP::Lite
-> service('file:GoogleSearch.wsdl');
$url="http://www.d.umn.edu";
$cachedPage=$service->doGetCachedPage($key,$url);
How do I retrieve the results?

This is going to be the same as the spelling
suggestion,



So if the web page does exist you will have the
whole web page HTML in the “cachedWebpage”
variable.
Otherwise, you would get a message from Google
which says
“ This web page has not been
updated…blah…blah…blah
“
Search with other options:
Google has four topic restricts:
Topic<restrict>
value
US. Government
Linux
Macintosh
unclesam
linux
mac
FreeBSD
bsd
Search with Restrictions:
$result = $service
-> doGoogleSearch(
$key,
$query,
0,
10,
"false",
"linux",
"false",
"",
"",
""
);
# key
# search query
# start results
# max results
# filter: boolean
# restrict (string)
# safeSearch: boolean
# lr
# ie
# oe
Search with Language
Restrictions
$result = $service
-> doGoogleSearch(
$key,
$query,
0,
10,
"false",
"",
"false",
"lang_de",
"",
""
);
# key
# search query
# start results
# max results
# filter: boolean
# restrict (string)
# safeSearch: boolean
# lr
# ie
# oe
print "\n The search took ";
print $result->{searchTime};
print "\n\n";
print "The estimated Number of results for your query is: ";
print $result->{estimatedTotalResultsCount};
print "\n\n";
if(defined($result->{resultElements})) {
print join "\n",
"Found:",
$result->{resultElements}->[0]->{title},$result->{resultElements}->[0]->{URL},
$result->{resultElements}->[0]->{snippet} . "\n"
}
lang_de = Gernman
Search with Language
Restrictions Contd…
Please Enter Search Item
der sturm
The search took 0.309039
The estimated Number of results for your query is: 206000
Found:
SK <b>STURM</b> GRAZ - Willkommen beim Sk <b>Sturm</b>
http://www.sksturm.at/
Eintreten. Puntigamer das bierige Bier, Steiermark.com, Puma, Tipp3,<br>
Autohaus Jakob Prügger, Graz - Hausmannstätten. © 2003 SkSturm
<b>...</b>
Tips on Querying Google
Default Search
By default, Google only returns pages that include all of the terms in the query string.
Stop Words
Google ignores common words and characters such as "where" and "how," as well as certain single digits and single
letters. Common words that are ignored are known as stop words.
However, you can prevent Google from ignoring stop words by enclosing them in quotes, such as in the phrase "to be
or not to be".
Special Characters
By default, all non-alphanumeric characters that are included in a search query are treated as word separators.
The only exceptions are the following: double quote mark ("), plus sign (+), minus sign or hyphen (-), and ampersand
(&).
The ampersand character (&) is treated as another character in the query term in which it is included, while the
remaining exception characters correspond to search features listed in the section below.
Special Query Terms
Google supports the use of several special query terms that allow the user or search administrator to access additional
capabilities of the Google search engine.
(The same Explanations can be found in the API Reference Section in your Google API download)
(The following Special Query table can
be found in the API Reference Section in
your Google API download)
Special Query
Capability
Include Query Term
Exclude Query Term
Phrase Search
Example Query
Description
Star Wars Episode +I
If a common word is essential to
getting the results you want, you can
include it by putting a "+" sign in front
of it.
bass -music
You can exclude a word from your
search by putting a minus sign ("-")
immediately in front of the term you
want to exclude from the search
results.
"yellow pages"
Search for complete phrases by
enclosing them in quotation marks or
connecting them with hyphens. Words
marked in this way will appear
together in all results exactly as
entered.
Note: You may need to use a "+" to
force inclusion of common words in a
phrase.
Boolean OR Search
Site Restricted
Search
Date Restricted
Search
vacation london OR paris
Google search supports the Boolean "OR" operator.
To retrieve pages that include either word A or word
B, use an uppercase OR between terms.
admission
site:www.stanford.edu
If you know the specific web site you want to search
but aren't sure where the information is located within
that site, you can use Google to search only within a
specific web site.
Do this by entering your query followed by the string
"site:" followed by the host name.
Star Wars
daterange:24521222452234
If you want to limit your results to documents
that were published within a specific date
range, then you can use the "daterange: "
query term to accomplish this. The
"daterange:" query term must be in the
following format:
daterange:<start_date>-<end date>
Title Search
(term)
intitle:Google
search
Title Search (all)
allintitle: Google
search
URL Search
(term)
If you prepend "intitle:" to a query term, Google search
restricts the results to documents containing that
word in the title. Note there can be no space between
the "intitle:" and the following word.
Starting a query with the term "allintitle:" restricts the results to
those with all of the query words in the title.
If you prepend "inurl:" to a query term, Google search restricts
the results to documents containing that word in the result
URL. Note there can be no space between the "inurl:" and the
following word.
inurl:Google
search
To find multiple words in a result URL, use the "inurl:"
operator for each word.
Note: Putting "inurl:" in front of every word in your query is
equivalent to putting "allinurl:" at the front of your query
URL Search
(all)
allinurl: Google search
Starting a query with the term "allinurl:" restricts the results
to those with all of the query words in the result URL.
Text Only
Search (all)
allintext: Google search
Starting a query with the term "allintext:" restricts the results
to those with all of the query words in only the body
text, ignoring link, URL, and title matches.
Links Only
Search (all)
allinlinks: Google search
Starting a query with the term "allinlinks:" restricts the
results to those with all of the query words in the
URL links on the page.
Google filetype:doc OR
filetype:pdf
The query prefix "filetype:" filters the results returned to
include only documents with the extension
specified immediately after. Note there can be no
space between "filetype:" and the specified
extension.
File Type
Filtering
File Type
Exclusion
Google -filetype:doc filetype:pdf
The query prefix "-filetype:" filters the results to exclude
documents with the extension specified immediately
after. Note there can be no space between "-filetype:" and
the specified extension.
Web Document
Info
info:www.google.com
The query prefix "info:" returns a single result for the specified
URL if it exists in the index.
Back Links
link:www.google.com
The query prefix "link:" lists web pages that have links to the
specified web page. Note there can be no space between
"link:" and the web page URL.
related:www.google.com
The query prefix "related:" lists web pages that are similar to the
specified web page. Note there can be no space between
"link:" and the web page URL.
cache:www.google.com web
The query prefix "cache:" returns the cached HTML version of
the specified web document that the Google search
crawled. Note there can be no space between "cache:" and
the web page URL.
.
Related Links
Cached Results
Page
Other Interesting Issues

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

Search for say “yahoo”, and look at the
estimated number of results.
Wait for like a minute or so.
Search again for “yahoo” and look at the
estimated number of results.
The result, 5 out of 10 times, will be different.
Conclusion…
The API can be used as means of retrieving “information” and “Text” from the web.
Some interesting examples:
http://www.googleduel.com/original.php
http://douweosinga.com/projects/googlehacks
http://www.researchbuzz.org/archives/001418.shtml
http://cgi.sfu.ca/~gpeters/cgi-bin/pear/gender.php