googlec查询调用

以上代码的主要功能子程序是DisplaySearchResults(),它将调用web服务，把结果
绑定到DataList中去，并且它还将显示各色各样的信息，比如估计匹配数，查询要求
运行的时间等等。这个子程序还将决定以前的LinkButton是激活还是不激活。

还有一点要注意的就是，当调用google搜索的web服务时，我们必须规定起始的
索引和在一页中将看见多少结果。那就是说，为了看见一个搜索的前十个记录，我们
应当设定0作为开始标记，而将10作为返回的记录数。为了看见接下来的十个记录，
我们最好将10作为开始标记(让10作为返回的记录数)。需要注意的就是，ViewState
被用来去维持开始页的标记数。每一页要显示的记录数被常数PAGE_SIZE所表示。

考虑到分页，将有两个LinkButton被使用，当点击它们的时候，nextRecs和
prevRecs事件将被触发。这些事件仅仅更新可以看见的开始记录数并且调用
DisplaySearchResults().

在这篇文章中我们探究了如何去调用google搜索的web服务。为了调用这个web
服务，我们首先下载了downloading the Google Web API Developer's Kit，接下来我们
在google站里建立了一个帐号可以得到一个许可证。这些都做完以后，我们建立了一个
基于google web服务WSDL文件(GoogleSearch.wsdl, 被包含在被下载的Developer's Kit
里）的代理类。建立了代理类以后，我们仅仅就需要几行简单的ASP.NET代码就可以去调用这个
web服务了。

Introduction
Did you know that Google provides a Web service for searching through Google's database, retrieving cached versions of Web pages, and performing spelling checks? Using Google's Web service you can provide Google's search functionality on your own Web site. Over the next month or so I plan on authoring two to three articles describing how to utilize Google's Web services. In this first article, we'll look at how to use the Web service to search through Google's database.

Licensing Terms of the Google Web Service
The Google Web Service API is currently in Beta testing, and is only available for personal use. To limit excessive use, Google requires that those who wish to use the Google Web service acquire a unique license key (which is free to obtain). This license key is used to limit individuals to no more than 1,000 calls to the Google Web service per day. Please be sure to read the license terms.

A Quick Primer on Web Services
A Web service is an external interface provided by a Web site that can be called from other Web sites. Think of Web services as a self-contained component with one or more methods. This component can reside anywhere on the Internet, and can have its methods invoked by remote clients. For example, the Google Web service provides three methods: doGoogleSearch(), doGetCachedPage(), and doSpellingSuggestion(). The doGoogleSearch(), which we'll be examining in this article, has a number of input parameters that specify the search query. The method then returns an instance of the GoogleSearchResult object, which has the results of the search.

Web services are built on open protocols and standards. For example, the communication between a client that wishes to consume a Web service, and the Web service itself, happens over HTTP, a well-known, open protocol. The parameters and return values being passed back and forth are packaged using SOAP, a well-known, open protocol for data-marshalling. The relevant point here is that Web services can be exposed on, say, a Microsoft IIS Web server and be consumed by PHP Web pages running on Apache, by ASP.NET Web pages running on IIS 6.0, or even by a desktop application.

When consuming a Web service, typically a proxy class is created to shield the client from the complexity involved in invoking the Web service. A proxy class is a class that itself contains all of the methods and objects that the Web service exposes. These methods, when called from the client program, handle the marshalling of the parameters into SOAP, sending the SOAP request over HTTP, receiving the response from the Web service, and unmarshalling the return value. The proxy class allows the client program to call a Web service as if the Web service was a local component.

If you are unfamiliar with Web services, this primer serves as a good introduction, but you should definitely take the time to read Creating a Web Service and then Creating and Consuming a Web Service.

The Google Web Service API
The Google Web Service information can be found online at http://www.google.com/apis/. To start using the Google Web Service you will first need to download the Google Web API Developer's Kit. This 666K file includes the WSDL (Web Service Description Language) file that fully describes the Web service, and examples of accessing the Google Web Service in both Java and VB.NET/C#.

After downloading the Google Web API Developer's Kit, you will need to create an account with Google. This can be done at: https://www.google.com/accounts/NewAccount?continue=http://api.google.com/createkey. Once you create one of these free accounts, you will be assigned a unique license number. This license number must be used whenever a Google Web service method is called. The purpose of this license is to limit the number of calls to the Google Web service to 1,000 invocations per license key per day.

Creating the Proxy Class
Once you have a license key and the Google API Developer's Kit, the next step is to create the proxy class that we'll use to call the Web service. To accomplish this, we first need to get our hands on the WSDL file, which is an XML-formatted file that describes the services provided by the Google Web service. This WSDL file, GoogleSearch.wsdl is located in the Google Web API Developer's Kit.

If you are using Visual Studio .NET, copy this file to the ASP.NET Web directory (like C:/Inetpub/wwwroot/WebApplication1). Then, in Visual Studio .NET, go to the Project menu and select the Add Web Reference option. Then, in the dialog box, enter the URL to the WSDL file, which will look like: http://localhost/WebApplication1/GoogleSearch.wsdl (see the screenshot to the right). To complete the process, click the Add Reference button. This will create the proxy class using the namespace localhost (which you can change if you like).

If you do not have Visual Studio .NET, you can create the proxy class through a command-line program called wsdl.exe. Wsdl.exe will create a C# or VB.NET file, which you'll then need to compile. To run wsdl.exe, drop to the command-line and enter:

wsdl /protocol:SOAP /namespace:google /out:GoogleProxy.cs C:/google/GoogleSearch.wsdl

This will create a C# file named GoogleProxy.cs with the namespace google. To compile this class, use the C# command-line compiler, csc, like so:

csc /t:library /out:GoogleProxy.dll GoogleProxy.cs

This will create a file named GoogleProxy.dll. Be sure to copy this file to your Web application's /bin directory!

For More Information on `Wsdl.exe`
For more information on creating a proxy class without using Visual Studio .NET, be sure to read the PowerPoint presentation: Calling a Web Service from an ASP.NET Web Page.

Creating an ASP.NET Web Page that Calls the Google Web Service
Now that we have created the proxy class, calling the Google Web Service through an ASP.NET Web page is a breeze. Before we examine how, precisely, to do this, we need to first examine what parameters the Web service methods expect. Fortunately, these methods and their input parameters are detailed in the reference section on Google's Web site. Since, in this article, we'll focus on simply performing a search via the Google Web services, let's examine the parameters for the doGoogleSearch() method.

This method takes in 10 parameters:

Name	Description
key	Provided by Google, this is required for you to access the Google service. Google uses the key for authentication and logging.
q	(See Query Terms section for details on query syntax.)
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. Filtering tends to improve the end user experience on Google, but for your application you may prefer to turn it off. (See Automatic Filtering section for more details.)
restricts	Restricts the search to a subset of the Google Web index, such as a country like "Ukraine" or a topic like "Linux." (See Restricts for more details.)
safeSearch	A Boolean value which enables filtering of adult content in the search results. See SafeSearch for more details.
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. (See Input and Output Encodings section for details.)
oe	Output Encoding - this parameter has been deprecated and is ignored. All requests to the APIs should be made with UTF-8 encoding. (See Input and Output Encodings for details.)

The doGoogleSearch() method returns an instance of the GoogleSearchResult object. This object has a resultElements property, which is an array of ResultElement objects. Each ResultElement object has a number of properties, such as title, snippet, URL, summary, and so on.

Now, let's create a simple ASP.NET Web page that will display the first 10 search results for the search query ASP. This can be accomplished using the following code:

 


  
    
      <%# Container.DataItem.title %>
    

    <%# Container.DataItem.summary %>

    [
        <%# Container.DataItem.URL %>
     ]

[ View a Live Demo!]

The bolded text shows the code necessary to call the Google Web service's doGoogleSearch() method. Such little code is needed thanks to the proxy class. The search results are displayed in a DataList, with each result displaying the title, summary, and the URL to access the page.

While the previous live demo illustrates how to call the Google Web service to perform a search, it is fairly limited in that it only displays the first 10 records of a predefined search query. In Part 2 we'll see how to create a more useful ASP.NET Web page that employs the Google search Web service.

While the previous live demo illustrates how to call the Google Web service to perform a search, it is fairly limited in that it only displays the first 10 records of a predefined search query. In this second part we'll examine how to build a "pseudo Google" search engine, by creating a page that the user can enter a search query for and page through the search results.

Building a More Functional Search Engine
In order to create a more functional search through Google's Web service search API, let's create an ASP.NET Web page that allows the user to input the search term and provides pagination through the data. One way to accomplish this would be to mimic Google's own approach, meaning that search terms and page numbers would be placed in the querystring. That is, if the user searched for "ASP" and was viewing records 10 through 20, the URL requested might be:

http://www.yourserver.com/Search.aspx?q=ASP&first=10&last=20

Or something to that effect. Another option is to use postback forms. The postback approach lends itself to ASP.NET moreso than the querystring approach. However, the querystring approach has the benefit that a user can bookmark a particular search query (note that with the postback form, the postback occurs via the HTTP POST headers, meaning the actual querystring does not change when searching or paging through the search results).

Despite the querystring approach's bookmarking advantage, I decided to implement this live demo using the postback approach. You are encouraged to implement the querystring approach if you so wish. The source code for the postback approach can be seen below:

 


Enter your search term: 



  

  
    
  
  

  

    
      
        <%# Container.DataItem.title %>
      

      <%# Container.DataItem.snippet %>

      [<%# Container.DataItem.URL %>]
    
  
    
       
    

  

  
  
     |

[ View a Live Demo!]

The main workhorse subroutine in the above code listing is DisplaySearchResults(), which makes the Web service call, binds the results to the DataList, and displays miscellaneous information, such as the estimated number of matches found, the time to run the query, etc. This subroutine also determines whether or not the Prev. LinkButton should be enabled or not.

Realize that when calling the Google search Web service, we must specify the starting result index and how many results we want to see in the page. That is, to view the first 10 records of a search, we would pass in 0 as the starting index and 10 as the number of records to return. To view the next 10 records, we'd simply pass in 10 as the starting index (leaving 10 as the number of records to return). Notice that the ViewState is used to maintain what the starting index number. The number of records to display per page is denoted by the constant PAGE_SIZE.

To allow for pagination, two LinkButtons are used, which, when clicked, cause the nextRecs and prevRecs event handlers to fire. These event handlers simply update the starting record number to view and then call DisplaySearchResults().

Conclusion
In this article we saw how to call the Google search Web service. To use the Google Web services, we started by downloading the Google Web API Developer's Kit and then creating an account to obtain a license key. Following that, we created a proxy class based on the Google Web service's WSDL file (GoogleSearch.wsdl, which is included in the Developer's Kit download). Armed with this proxy class, we could then access the Web service with just a few lines of code from our ASP.NET Web page.

Happy Programming!

Google SOAP Search API ReferenceOverview

You may also find the following files from the Google SOAP Search API developer kit to be helpful:

For comments or questions, please use the Google SOAP Search API discussion group.

Special Query Capability	Example Query	Description
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.
Boolean OR Search	vacation london OR paris	Google search supports the Boolean I 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. Note: The exclusion operator ("-") can be applied to this query term to remove a web site from consideration in the search. Note: Only one site: term per query is supported.
Date Restricted Search	Star Wars daterange:2452122-2452234	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:- where = Julian date indicating the start of the date range = Julian date indicating the end of the date range The Julian date is calculated by the number of days since January 1, 4713 BC. For example, the Julian date for August 1, 2001 is 2452122.
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. Note: Putting "intitle:" in front of every word in your query is equivalent to putting "allintitle:" at the front of your query.
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. Note: "inurl:" works only on words , not URL components. In particular, it ignores punctuation and uses only the first word following the "inurl:" operator. 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. Note: "allinurl:" works only on words, not URL components. In particular, it ignores punctuation. Thus, "allinurl: foo/bar" restricts the results to pages with the words "foo" and "bar"" in the URL, but does not require that they be separated by a slash within that URL, that they be adjacent, or that they be in that particular word order. There is currently no way to enforce these constraints.
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. Note: Multiple file types can be included in a filtered search by adding more "filetype:" terms to the search query.
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. Note: Multiple file types can be excluded in a filtered search by adding more "-filetype:" terms to the search query.
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. Note: No other query terms can be specified when using this special query term.
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. Note: No other query terms can be specified when using this special query term.
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 "related:" and the web page URL. Note: No other query terms can be specified when using this special query term.
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. If you include other words in the query, Google will highlight those words within the cached document.

Boolean Operator	Sample Usage	Description
Boolean NOT [ - ]	-lang_fr	Removes all results which are defined as part of the sub-collection immediately following the "-" operator. The example restrict value would remove all results in French.
Boolean AND [ . ]	linux.countryFR	Returns results which are in the intersection of the results returned by the sub-collection to either side of the "." operator. The example restrict value would return all results which are from both the "linux" subtopic and identified as being located in France.
Boolean OR [ \| ]	lang_en\|lang_fr	Returns results which are in either of the results returned by the sub-collection to either side of the "\|" operator. The example restrict value would return all results matching the query that are in either the French or English sub-collections.
Parentheses [ ( ) ]	(linux).(-(conutryUK\|countryUS))	All terms within the innermost set of parentheses in a sub-collection string will be evaluated before terms outside the parentheses are evaluated. Use parentheses to adjust the order of term evaluation. The example restrict value would return all results in the "linux" custom sub-collection that are not in either the United States or United Kingdom sub-collections.

googlec查询调用

Searching Google Using the Google Web Service

Google SOAP Search API ReferenceOverview