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Introduction to Google API… By Pratheepan Raveendranathan.

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1 Introduction to Google API… By Pratheepan Raveendranathan

2 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 users program and Google API. Programming environments such as Java, Perl, Visual Studio.NET are compatible with Google API. Definitions from What is Google API?

3 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, URLs, Snippets, Query Time etc. access information in the Google cache, and check the spelling of words.

4 To start using the API You need to, Download API Package from 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 dont need to get it. IT is not on UB or Bulldog.

5 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/

6 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.

7 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

8 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.

9 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;

10 Search Contd… $result = $service -> doGoogleSearch( $key, # key $query, # search query 0, # start results 10, # max results "false", # filter: boolean "", # restrict (string) "false", # safeSearch: boolean "", # lr "", # ie "" # oe );

11 NameDescription key Provided by Google, this is required for you to access the Google service. Google uses the key for authentication and logging. q Query Phrase. start 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.

12 restrict Restricts the search to a subset of the Google Web index, such as a country like "Ukraine" or a topic like "Linux." safeSearch 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.

13 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

14 Search.pl Output Found: University of Minnesota Duluth Welcomes You The University of Minnesota Duluth Homepage: an overview of academic prog rams, campus life, resources, news and events, with extensive links to other web sites... The search took The estimated Number of results for your query is:

15 Or, to get all elements: foreach $temp { print $temp->{snippet}; } foreach $temp { print $temp->{URL}; } foreach $temp { $title_array[$count++]=$temp->{title}; }

16 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);

17 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";

18 Spelling output Enter a word dulut The suggested spelling for Duluth is: duluth

19 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,

20 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);

21 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

22 Search with other options: Google has four topic restricts: Topic value US. Governmentunclesam Linuxlinux Macintoshmac FreeBSDbsd

23 Search with Restrictions: $result = $service -> doGoogleSearch( $key, # key $query, # search query 0, # start results 10, # max results "false", # filter: boolean "linux", # restrict (string) "false", # safeSearch: boolean "", # lr "", # ie "" # oe );

24 Search with Language Restrictions $result = $service -> doGoogleSearch( $key, # key $query, # search query 0, # start results 10, # max results "false", # filter: boolean "", # restrict (string) "false", # safeSearch: boolean "lang_de", # 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

25 Search with Language Restrictions Contd… Please Enter Search Item der sturm The search took The estimated Number of results for your query is: Found: SK STURM GRAZ - Willkommen beim Sk Sturm Eintreten. Puntigamer das bierige Bier, Steiermark.com, Puma, Tipp3, Autohaus Jakob Prügger, Graz - Hausmannstätten. © 2003 SkSturm...

26 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)

27 (The following Special Query table can be found in the API Reference Section in your Google API download)

28 Special Query Capability Example QueryDescription Include Query Term 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. Exclude Query Term 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. Phrase Search "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.

29 Boolean OR 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. Site Restricted Search 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. Date Restricted Search Star Wars daterange: 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: -

30 Title Search (term) intitle:Google search 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. Title Search (all) allintitle: Google search Starting a query with the term "allintitle:" restricts the results to those with all of the query words in the title. URL Search (term) inurl:Google search 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. 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

31 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. File Type Filtering 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.

32 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 Links 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. Cached Results Page 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..

33 Other Interesting Issues 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.

34 Conclusion… The API can be used as means of retrieving information and Text from the web. Some interesting examples:


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