Google base的介紹、原理分析與應用實例

時間 2020-04-30

原文原文鏈接

    這幾天使用Google base發佈了一些東西，感受用起來很方便並且頗有用，關於這方面的博客如今基本尚未，這裏就給你們介紹一下Gbase的原理與使用。
    Gbase是一個幫助你發表虛擬類型的任何信息的免費服務，用戶把信息發佈到Gbase上，而後能夠在google網站上搜索。這個服務就頗有用，咱們知道google 的搜索能力很強大，若是咱們把咱們的產品或者服務發佈到Gbase上，就有可能讓全世界的人看到咱們發佈的信息。
    發佈一個項目很簡單，前提是必須得有一個google賬戶，有帳戶的用戶步驟以下：
    1.進入google base網站首頁：http://www.google.com/base/
    2.點擊「One at a time」，就進入了添加item頁面，或者直接登陸進去本身的Gbase首頁，點擊左下角「Add a item」按鈕就能夠添加item。
    3.填完信息後，點擊「Publish」便可。
    這裏添加的信息包括item類別（你能夠選擇已有的類別，或者自定義一個類別），而後填寫可能包含的數量、金額和描述信息等等。上述方法是一次添加一個item的方式，若是你想批量添加，能夠添加一個本地的xml文件，該文件符合google base規定的格式。

    下面介紹如何使用Google base API編寫Gbase應用，主要是給程序開發等編程人員提供參考。
    Data item：在Google base 中描述一個單獨的entry,他包含一組屬性。
    Attribute：描述內容的name/pair對，如

<g:label>kung pao chicken</g:label>
    一個entry的信息以下所示：
 
   
    
    <? 
    xml 
    version 
    ='1.0' 
    ?> 
    
 
    < 
    entry 
    xmlns 
    ='http://www.w3.org/2005/Atom' 
    
         
    xmlns:g 
    ='http://base.google.com/ns/1.0' 
    > 
    
         
    < 
    author 
    > 
    
             
    < 
    name 
    >Jane Doe 
    </ 
    name 
    > 
    
             
    < 
    email 
    >JaneDoe@gmail.com 
    </ 
    email 
    > 
    
         
    </ 
    author 
    > 
    
         
    < 
    category 
    scheme 
    ='http://www.google.com/type' 
    term 
    ='googlebase.item' 
    /> 
    
         
    < 
    title 
    type 
    ='text' 
    >He Jingxian's chicken 
    </ 
    title 
    > 
    
         
    < 
    content 
    type 
    ='xhtml' 
    > 
    
             
    < 
    div 
    xmlns 
    ='http://www.w3.org/1999/xhtml' 
    >Delectable Sichuan specialty 
    </ 
    div 
    > 
    
         
    </ 
    content 
    > 
    
         
    < 
    link 
    rel 
    ='alternate' 
    type 
    ='text/html' 
    href 
    ='http://www.host.com/123456jsh9' 
    /> 
    
         
    < 
    g:item_type 
    >Recipes 
    </ 
    g:item_type 
    > 
    
         
    < 
    g:cooking_time 
    >30 
    </ 
    g:cooking_time 
    > 
    
         
    < 
    g:main_ingredient 
    >chicken 
    </ 
    g:main_ingredient 
    > 
    
         
    < 
    g:main_ingredient 
    >chili peppers 
    </ 
    g:main_ingredient 
    > 
    
         
    < 
    g:main_ingredient 
    >peanuts 
    </ 
    g:main_ingredient 
    > 
    
         
    < 
    g:spices_used 
    >Szechuan peppercorn 
    </ 
    g:spices_used 
    > 
    
         
    < 
    g:cook_technique 
    >blackened 
    </ 
    g:cook_technique 
    > 
    
 
    </ 
    entry 
    > 
    
  

    每個item都有一個URL，或者說一個惟一的ID，用於標識這個item或者說entry，比我添加的一條記錄的URL以下所示：
    http://base.google.com/base/feeds/items/2139682888944988653
    item ID是

2139682888944988653。
    這個URL通常是程序代碼中使用的，item本身生成的URL是http://base.google.com/base/a/6380400/D2139682888944988653，他們的實質都是同樣的。
    每個Googel base API操做跟HTTP方法相同，你可使用HTTP GET、POST、PUT和DELETE方法來操做。
    一個查詢的例子以下所示：

    發送的HTTP請求是：
 
   
   
     GET /base/feeds/snippets?bq=digital+camera 
    
Content-Type: application/atom+xml 
    
Authorization: AuthSub token="" 
    
X-Google-Key: key=ABQIAAAA7VerLsOcLuBYXR7vZI2NjhTRERdeAiwZ9EeJWta3L_JZVS0bOBRIFbhTrQjhHE52fqjZvfabYYyn6A 
    
 
    
  
    因爲響應信息比較多，這裏就不顯示了。

    使用API添加item的代碼以下所示。
InsertExample.java代碼：
 
   
    
    /* Copyright (c) 2006 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 
    
 
    
 
    package cn.edu.xidian; 
    
 
    
 
    import java.io.BufferedReader; 
    
 
    import java.io.IOException; 
    
 
    import java.io.InputStream; 
    
 
    import java.io.InputStreamReader; 
    
 
    import java.io.OutputStream; 
    
 
    import java.net.HttpURLConnection; 
    
 
    import java.net.MalformedURLException; 
    
 
    import java.net.URL; 
    
 
    import java.net.URLEncoder; 
    
 
    import java.util.StringTokenizer; 
    
 
    
 
    /**
 *    Add a new item to Google Base using the Google Base data API server.
 */ 
    
 
    public 
    class InsertExample { 
    
     
    /**
     * URL of the authenticated customer feed.
     */ 
    
     
    private 
    static 
    final String ITEMS_FEED = 
    "http://base.google.com/base/feeds/items";

    /**
     * The data item we are going to insert, in XML/Atom format.
     */
    private static final String DATA_ITEM = 
                "<?xml version='1.0'?>\n" +
                "<entry xmlns='http://www.w3.org/2005/Atom'\n" +
                "        xmlns:g='http://base.google.com/ns/1.0'>\n" +
                "    <g:item_type type='text'>repaceService</g:item_type>\n" +
                "    <title type='text'>EchoService_ID</title>\n" +
                "    <content type='xhtml'>08d8440b82554bad9a7a5ad9a1487</content>\n" +
                "</entry>";

    /**
     * URL used for authenticating and obtaining an authentication token. 
     * More details about how it works:
     * <code>http://code.google.com/apis/accounts/AuthForInstalledApps.html<code>
     */
    private static final String AUTHENTICATION_URL = "https://www.google.com/accounts/ClientLogin";
    
    /**
     * Fill in your Google Account email here.
     */
    private static final String EMAIL = "youremail@gmail.com";
    
    /**
     * Fill in your Google Account password here.
     */
    private static final String PASSWORD = "yourpassword";
    
    /**
     * The main method constructs a <code>InsertExample</code> instance, obtains an 
     * authorization token and posts a new item to Google Base.
     */
    public static void main(String[] args) throws MalformedURLException, IOException {
        InsertExample insertExample = new InsertExample();
        String token = insertExample.authenticate();
        System.out.println("Obtained authorization token: " + token);
        insertExample.postItem(token);
    }

    /**
     * Inserts <code>DATA_ITEM</code> by making a POST request to
     * <code>ITEMS_URL<code>.
     * @param token authentication token obtained using <code>authenticate</code>
     * @throws IOException if an I/O exception occurs while creating/writing/
     *                 reading the request
     */
    public void postItem(String token) throws IOException {
        HttpURLConnection connection = (HttpURLConnection)(new URL(ITEMS_FEED)).openConnection();
        
        connection.setDoInput(true);
        connection.setDoOutput(true);
        
        // Set the properties of the connection: the Http method, the content type
        // of the POST request and the authorization header 
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/atom+xml");
        connection.setRequestProperty("Authorization", "GoogleLogin auth=" + token);

        // Post the data item
        OutputStream outputStream = connection.getOutputStream();
        outputStream.write(DATA_ITEM.getBytes());
        outputStream.close();
    
        // Retrieve the output
        int responseCode = connection.getResponseCode();
        InputStream inputStream;
        if (responseCode == HttpURLConnection.HTTP_CREATED) {
            inputStream = connection.getInputStream();
        } else {
            inputStream = connection.getErrorStream();
        }
        
        // write the output to the console
        System.out.println(toString(inputStream));
        
    }

    /**
     * Retrieves the authentication token for the provided set of credentials.
     * @return the authorization token that can be used to access authenticated
     *                 Google Base data API feeds
     */
    public String authenticate() {
        // create the login request
        String postOutput = null;
        try {
            URL url = new URL(AUTHENTICATION_URL);
            postOutput = makeLoginRequest(url);
        } catch (IOException e) {
            System.out.println("Could not connect to authentication server: " 
                    + e.toString());
            System.exit(1);
        }
    
        // Parse the result of the login request. If everything went fine, the 
        // response will look like
        //            HTTP/1.0 200 OK
        //            Server: GFE/1.3
        //            Content-Type: text/plain 
        //            SID=DQAAAGgA...7Zg8CTN
        //            LSID=DQAAAGsA...lk8BBbG
        //            Auth=DQAAAGgA...dk3fA5N
        // so all we need to do is look for "Auth" and get the token that comes after it
    
        StringTokenizer tokenizer = new StringTokenizer(postOutput, "=\n ");
        String token = null;
        
        while (tokenizer.hasMoreElements()) {
            if (tokenizer.nextToken().equals("Auth")) {
                if (tokenizer.hasMoreElements()) {
                    token = tokenizer.nextToken(); 
                }
                break;
            }
        }
        if (token == null) {
            System.out.println("Authentication error. Response from server:\n" + postOutput);
            System.exit(1);
        }
        return token;
    }

    /**
     * Makes a HTTP POST request to the provided {@code url} given the provided
     * {@code parameters}. It returns the output from the POST handler as a
     * String object.
     * 
     * @param url the URL to post the request
     * @return the output from the handler
     * @throws IOException if an I/O exception occurs while
     *                     creating/writing/reading the request
     */
    private String makeLoginRequest(URL url)
            throws IOException {
        // Create a login request. A login request is a POST request that looks like
        // POST /accounts/ClientLogin HTTP/1.0
        // Content-type: application/x-www-form-urlencoded
        // Email=johndoe@gmail.com&Passwd=north23AZ&service=gbase&source=Insert Example

        // Open connection
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
    
        
        // Set properties of the connection
        urlConnection.setRequestMethod("POST");
        urlConnection.setDoInput(true);
        urlConnection.setDoOutput(true);
        urlConnection.setUseCaches(false);
        urlConnection.setRequestProperty("Content-Type",
                                                                         "application/x-www-form-urlencoded");
    
        // Form the POST parameters
        StringBuilder content = new StringBuilder();
        content.append("Email=").append(URLEncoder.encode(EMAIL, "UTF-8"));
        content.append("&Passwd=").append(URLEncoder.encode(PASSWORD, "UTF-8"));
        content.append("&source=").append(URLEncoder.encode("Repace service example", "UTF-8"));
        content.append("&service=").append(URLEncoder.encode("gbase", "UTF-8"));

        OutputStream outputStream = urlConnection.getOutputStream();
        outputStream.write(content.toString().getBytes("UTF-8"));
        outputStream.close();
    
        // Retrieve the output
        int responseCode = urlConnection.getResponseCode();
        InputStream inputStream;
        if (responseCode == HttpURLConnection.HTTP_OK) {
            inputStream = urlConnection.getInputStream();
        } else {
            inputStream = urlConnection.getErrorStream();
        }
    
        return toString(inputStream);
    }

    /**
     * Writes the content of the input stream to a <code>String<code>.
     */
    private String toString(InputStream inputStream) throws IOException {
        String string;
        StringBuilder outputBuilder = new StringBuilder();
        if (inputStream != null) {
            BufferedReader reader =
                    new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
            while (null != (string = reader.readLine())) {
                outputBuilder.append(string).append('\n');
            }
        }
        return outputBuilder.toString();
    }
}
 
    
  

    若是email和密碼正確，驗證經過，則在你的email賬號下的Gbase下添加了一條item，這個item須要大概1天的時間可以經過google搜索。
QueryExample3.java代碼：
 
   
    
    /* Copyright (c) 2006 Google Inc.                                                                                                                                                                                                                                                                                                                                                                
 *                                                                                                                                                                                                                                                                                                                                                                                                                             
 * Licensed under the Apache License, Version 2.0 (the "License");                                                                                                                                                                                                                                                                                             
 * you may not use this file except in compliance with the License.                                                                                                                                                                                                                                                                                            
 * You may obtain a copy of the License at                                                                                                                                                                                                                                                                                                                                             
 *                                                                                                                                                                                                                                                                                                                                                                                                                             
 *         http://www.apache.org/licenses/LICENSE-2.0                                                                                                                                                                                                                                                                                                                                
 *                                                                                                                                                                                                                                                                                                                                                                                                                             
 * Unless required by applicable law or agreed to in writing, software                                                                                                                                                                                                                                                                                     
 * distributed under the License is distributed on an "AS IS" BASIS,                                                                                                                                                                                                                                                                                         
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.                                                                                                                                                                                                                                                                            
 * See the License for the specific language governing permissions and                                                                                                                                                                                                                                                                                     
 * limitations under the License.                                                                                                                                                                                                                                                                                                                                                                
 */ 
    
 
    
 
    package cn.edu.xidian; 
    
 
    
 
    import java.io.BufferedReader; 
    
 
    import java.io.IOException; 
    
 
    import java.io.InputStream; 
    
 
    import java.io.InputStreamReader; 
    
 
    import java.io.OutputStream; 
    
 
    import java.net.HttpURLConnection; 
    
 
    import java.net.MalformedURLException; 
    
 
    import java.net.URL; 
    
 
    import java.net.URLEncoder; 
    
 
    import java.util.StringTokenizer; 
    
 
    
 
    /**
 * Display all items of a specific customer.
 */ 
    
 
    public 
    class QueryExample3 { 
    
     
    /**
     * URL of the authenticated customer feed.
     */ 
    
     
    private 
    static 
    final String ITEMS_FEED = 
    "http://base.google.com/base/feeds/items/2139682888944988653";

    /**
     * URL used for authenticating and obtaining an authentication token. 
     * More details about how it works:
     * <code>http://code.google.com/apis/accounts/AuthForInstalledApps.html<code>
     */
    private static final String AUTHENTICATION_URL = "https://www.google.com/accounts/ClientLogin";

    /**
     * Fill in your Google Account email here.
     */
    private static final String EMAIL = "youremail@gmail.com";
    
    /**
     * Fill in your Google Account password here.
     */
    private static final String PASSWORD = "yourpassword";
    
    /**
     * Create a <code>QueryExample3</code> instance and call
     * <code>displayMyItems</code>, which displays all items that belong to the
     * currently authenticated user.
     */
    public static void main(String[] args) throws IOException {
        QueryExample3 queryExample = new QueryExample3();
        String token = queryExample.authenticate();
        queryExample.displayMyItems(token);
    }

    /**
     * Retrieves the authentication token for the provided set of credentials.
     * @return the authorization token that can be used to access authenticated
     *                 Google Base data API feeds
     */
    public String authenticate() {
        // create the login request
        String postOutput = null;
        try {
            URL url = new URL(AUTHENTICATION_URL);
            postOutput = makeLoginRequest(url);
        } catch (IOException e) {
            System.out.println("Could not connect to authentication server: " 
                    + e.toString());
            System.exit(1);
        }
    
        // Parse the result of the login request. If everything went fine, the 
        // response will look like
        //            HTTP/1.0 200 OK
        //            Server: GFE/1.3
        //            Content-Type: text/plain 
        //            SID=DQAAAGgA...7Zg8CTN
        //            LSID=DQAAAGsA...lk8BBbG
        //            Auth=DQAAAGgA...dk3fA5N
        // so all we need to do is look for "Auth" and get the token that comes after it
    
        StringTokenizer tokenizer = new StringTokenizer(postOutput, "=\n ");
        String token = null;
        
        while (tokenizer.hasMoreElements()) {
            if (tokenizer.nextToken().equals("Auth")) {
                if (tokenizer.hasMoreElements()) {
                    token = tokenizer.nextToken(); 
                }
                break;
            }
        }
        if (token == null) {
            System.out.println("Authentication error. Response from server:\n" + postOutput);
            System.exit(1);
        }
        return token;
    }

    /**
     * Displays the "items" feed, that is the feed that contains the items that
     * belong to the currently authenticated user.
     * 
     * @param token the authorization token, as returned by
     *                <code>authenticate<code>
     * @throws IOException if an IOException occurs while creating/reading the 
     *                 request
     */
    public void displayMyItems(String token) throws MalformedURLException, IOException {
        HttpURLConnection connection = (HttpURLConnection)(new URL(ITEMS_FEED)).openConnection() ;
        // Set properties of the connection
        connection.setRequestMethod("GET");
        connection.setRequestProperty("Authorization", "GoogleLogin auth=" + token);

        int responseCode = connection.getResponseCode();
        InputStream inputStream;
        if (responseCode == HttpURLConnection.HTTP_OK) {
            inputStream = connection.getInputStream();
        } else {
            inputStream = connection.getErrorStream();
        }
        
        System.out.println(toString(inputStream));
     }
    
    /**
     * Makes a HTTP POST request to the provided {@code url} given the provided
     * {@code parameters}. It returns the output from the POST handler as a
     * String object.
     * 
     * @param url the URL to post the request
     * @return the output from the Google Accounts server, as string
     * @throws IOException if an I/O exception occurs while
     *                     creating/writing/reading the request
     */
    private String makeLoginRequest(URL url)
            throws IOException {
        // Create a login request. A login request is a POST request that looks like
        // POST /accounts/ClientLogin HTTP/1.0
        // Content-type: application/x-www-form-urlencoded
        // Email=johndoe@gmail.com&Passwd=north23AZ&service=gbase&source=Insert Example

        // Open connection
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
    
        
        // Set properties of the connection
        urlConnection.setRequestMethod("POST");
        urlConnection.setDoInput(true);
        urlConnection.setDoOutput(true);
        urlConnection.setUseCaches(false);
        urlConnection.setRequestProperty("Content-Type",
                                                                         "application/x-www-form-urlencoded");
    
        // Form the POST parameters
        StringBuilder content = new StringBuilder();
        content.append("Email=").append(URLEncoder.encode(EMAIL, "UTF-8"));
        content.append("&Passwd=").append(URLEncoder.encode(PASSWORD, "UTF-8"));
        content.append("&service=").append(URLEncoder.encode("gbase", "UTF-8"));
        content.append("&source=").append(URLEncoder.encode("Repace service example", "UTF-8"));

        OutputStream outputStream = urlConnection.getOutputStream();
        outputStream.write(content.toString().getBytes("UTF-8"));
        outputStream.close();
    
        // Retrieve the output
        int responseCode = urlConnection.getResponseCode();
        InputStream inputStream;
        if (responseCode == HttpURLConnection.HTTP_OK) {
            inputStream = urlConnection.getInputStream();
        } else {
            inputStream = urlConnection.getErrorStream();
        }
    
        return toString(inputStream);
    }

    /**
     * Writes the content of the input stream to a <code>String<code>.
     */
    private String toString(InputStream inputStream) throws IOException {
        String string;
        StringBuilder outputBuilder = new StringBuilder();
        if (inputStream != null) {
            BufferedReader reader =
                    new BufferedReader(new InputStreamReader(inputStream));
            while (null != (string = reader.readLine())) {
                outputBuilder.append(string).append('\n');
            }
        }
        return outputBuilder.toString();
    }
}
 
    
  
    
    改代碼的執行結果以下：
 
   
    
    <? 
    xml 
    version 
    ='1.0' 
    encoding 
    ='UTF-8' 
    ?> 
    < 
    entry 
    xmlns 
    ='http://www.w3.org/2005/Atom' 
    xmlns:gm 
    ='http://base.google.com/ns-metadata/1.0' 
    xmlns:g 
    ='http://base.google.com/ns/1.0' 
    xmlns:batch 
    ='http://schemas.google.com/gdata/batch' 
    > 
    < 
    id 
    >http://www.google.com/base/feeds/items/2139682888944988653 
    </ 
    id 
    > 
    < 
    published 
    >2009-08-01T12:55:09.000Z 
    </ 
    published 
    > 
    < 
    updated 
    >2009-08-01T12:55:09.000Z 
    </ 
    updated 
    > 
    < 
    category 
    scheme 
    ='http://base.google.com/categories/itemtypes' 
    term 
    ='repaceService' 
    /> 
    < 
    title 
    type 
    ='text' 
    >EchoService_ID 
    </ 
    title 
    > 
    < 
    content 
    type 
    ='html' 
    >08d8440b82554bad9a7a5ad9a1487 
    </ 
    content 
    > 
    < 
    link 
    rel 
    ='alternate' 
    type 
    ='text/html' 
    href 
    ='http://base.google.com/base/a/6380400/D2139682888944988653' 
    /> 
    < 
    link 
    rel 
    ='self' 
    type 
    ='application/atom+xml' 
    href 
    ='http://www.google.com/base/feeds/items/2139682888944988653' 
    /> 
    < 
    link 
    rel 
    ='edit' 
    type 
    ='application/atom+xml' 
    href 
    ='http://www.google.com/base/feeds/items/2139682888944988653' 
    /> 
    < 
    author 
    > 
    < 
    name 
    >Panpan Zhan 
    </ 
    name 
    > 
    < 
    email 
    >anon-tolts2g0m1kt@base.google.com 
    </ 
    email 
    > 
    </ 
    author 
    > 
    < 
    g:target_country 
    type 
    ='text' 
    >US 
    </ 
    g:target_country 
    > 
    < 
    g:expiration_date 
    type 
    ='dateTime' 
    >2038-01-19T03:14:07Z 
    </ 
    g:expiration_date 
    > 
    < 
    g:customer_id 
    type 
    ='int' 
    >6380400 
    </ 
    g:customer_id 
    > 
    < 
    g:item_language 
    type 
    ='text' 
    >en 
    </ 
    g:item_language 
    > 
    < 
    g:item_type 
    type 
    ='text' 
    >repaceService 
    </ 
    g:item_type 
    > 
    < 
    gd:feedLink 
    xmlns:gd 
    ='http://schemas.google.com/g/2005' 
    rel 
    ='media' 
    href 
    ='http://www.google.com/base/feeds/items/2139682888944988653/media' 
    countHint 
    ='0' 
    /> 
    </ 
    entry 
    >  
    
  
    這樣就完成了一些簡單的Gbase操做的例子。

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