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從Google App Engine上傳文件到Google雲端存儲（Java）

2016-12-19 658 views
3

如何將文件從谷歌應用引擎中的servlet上傳到谷歌雲存儲？從Google App Engine上傳文件到Google雲端存儲（Java）

當我這樣做時，Google雲存儲並不知道文件的類型，即我從HTML表單發送的文件。編寫HTML/JavaScript和servlet以將文件上傳到雲存儲的正確方法是什麼？

來源

2016-12-19 user2354982

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有一個使用Google Cloud Storage JavaScript客戶端庫的Google示例。它通過JavaScript將文件上傳到雲存儲，因此它不通過AppEngine使用，但是隻要文件上傳到雲存儲，您就可以調用AppEngine servlet。其實我在互聯網上找不到這樣的例子......但它運行得很好，如果你有興趣，我可以在這裏發佈它。 –

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是的，我有興趣 – user2354982

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您是否閱讀了文章[讀寫雲存儲]（https://cloud.google.com/appengine/docs/java/googlecloudstorageclient/read-write-to-cloud-storage#writing_to_cloud_storage ）？它提供了一個簡單的示例並鏈接到工作[Github servlet文件]（https://github.com/GoogleCloudPlatform/appengine-gcs-client/blob/master/java/example/src/main/java/com/google/appengine /demos/GcsExampleServlet.java）。我會建議先嚐試一下，並報告和尋求堆棧溢出與具體的錯誤和挑戰，而不是一般的答案***如何***。 – Nicholas

回答

2

下面是Google用於與Java Script中的雲存儲交互的代碼示例。它不僅僅是上傳，也就是說你可以下載，創建新的存儲桶等等。下面我添加了我用來上傳的函數，它是從這個例子中派生出來的。

<!DOCTYPE html> 
<html> 
<head lang="en"> 
    <meta charset='utf-8' /> 
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script> 
    <script src="https://apis.google.com/js/client.js"></script> 
    <script type="text/javascript"> 
     /** 
     * The Project ID of your Google Cloud Storage Project. 
     */ 
     var PROJECT = 'abcd'; 
     /** 
     * Enter a client ID for a web application from the Google Developers 
     * Console on the "APIs & auth", "Credentials" page. 
     * In your Developers Console project add a JavaScript origin 
     * that corresponds to the domain from where you will be running the 
     * script. For more info see: 
     * https://developers.google.com/console/help/new/#generatingoauth2 
     */ 
     var clientId = '701111116470-55bj2lkjlkkjkljhe97di22gus5hs3.apps.googleusercontent.com'; 
     /** 
     * Enter the API key from the Google Developers Console, by following these 
     * steps: 
     * 1) Visit https://cloud.google.com/console and select your project 
     * 2) Click on "APIs & auth" in the left column and then click 「Credentials」 
     * 3) Find section "Public API Access" and use the "API key." If sample is 
     * being run on localhost then delete all "Referers" and save. Setting 
     * should display "Any referer allowed." For more info see: 
     * https://developers.google.com/console/help/new/#generatingdevkeys 
     */ 
     var apiKey = 'JHJhhguy8786875hghgjbS0nYjcMY'; 
     /** 
     * To enter one or more authentication scopes, refer to the documentation 
     * for the API. 
     */ 
     var scopes = 'https://www.googleapis.com/auth/devstorage.full_control'; 
     /** 
     * Constants for request parameters. Fill these values in with your custom 
     * information. 
     */ 
     var API_VERSION = 'v1'; 
     /** 
     * Enter a unique bucket name to create a new bucket. The guidelines for 
     * bucket naming can be found here: 
     * https://developers.google.com/storage/docs/bucketnaming 
     */ 
     //var BUCKET = 'code-sample-bucket-' + Date.now(); 
     var BUCKET = 'testbucket'; 
     /** 
     * The name of the object inserted via insertObject method. 
     */ 
     var object = ""; 
     /** 
     * Get this value from the Developers Console. Click on the 
     * 「Cloud Storage」 service in the Left column and then select 
     * 「Project Dashboard」. Use one of the Google Cloud Storage group IDs 
     * listed and combine with the prefix 「group-」 to get a string 
     * like the example below. 
     */ 
     var GROUP = 
       'group-kjhHJKHJKH897897878jgjghg8728f21c3ff22597efbfc63ccdb8f2294d8fd2561cb9'; 
     /** 
     * Valid values are user-userId, user-email, group-groupId, group-email, 
     * allUsers, allAuthenticatedUsers 
     */ 
     var ENTITY = 'allUsers'; 
     /** 
     * Valid values are READER, OWNER 
     */ 
     var ROLE = 'READER'; 
     /** 
     * Valid values are READER, OWNER 
     */ 
     var ROLE_OBJECT = 'READER'; 
     /** 
     * A list of example calls to the Google Cloud Storage JavaScript client 
     * library, as well as associated explanations of each call. 
     */ 
     var listApiRequestExplanations = { 
      'listBuckets': 'This API call queries the Google Cloud Storage API ' + 
      'for a list of buckets in your project, and returns the result as ' + 
      'a list of Google Cloud Storage buckets.', 
      'listObjects': 'This API call queries the Google Cloud Storage API ' + 
      'for a list of objects in your bucket, and returns the result as ' + 
      'a list of Google Cloud Storage objects.', 
      'listBucketsAccessControls': 'This API call queries the Google Cloud ' + 
      'Storage API for the list of access control lists on buckets in your ' + 
      'project and returns the result as a list of Google Cloud Storage ' + 
      'Access Control Lists.', 
      'listObjectsAccessControls': 'This API call queries the Google Cloud ' + 
      'Storage API for the list of access control lists on objects in your ' + 
      'bucket and returns the result as a list of Google Cloud Storage ' + 
      'Access Control Lists.', 
      'getBucket': 'This API call queries the Google Cloud Storage API ' + 
      'for a bucket in your project, and returns the result as a ' + 
      'Google Cloud Storage bucket.', 
      'getBucketAccessControls': 'This API call queries the Google Cloud ' + 
      'Storage API for the access control list on a specific bucket ' + 
      'and returns the result as a Google Cloud Storage Access Control List.', 
      'getObjectAccessControls': 'This API call queries the Google Cloud ' + 
      'Storage API for the access control list on a specific object ' + 
      'and returns the result as a Google Cloud Storage Access Control List.', 
      'insertBucket': 'This API call uses the Google Cloud Storage API ' + 
      'to insert a bucket into your project.', 
      'insertObject': 'This API call uses the Google Cloud Storage API ' + 
      'to insert an object into your bucket.', 
      'insertBucketAccessControls': 'This API uses the Google Cloud ' + 
      'Storage API to insert an access control list on a specific bucket ' + 
      'and returns the result as a Google Cloud Storage Access Control List.', 
      'insertObjectAccessControls': 'This API uses the Google Cloud ' + 
      'Storage API to insert an access control list on a specific object ' + 
      'and returns the result as a Google Cloud Storage Access Control List.', 
      'deleteBucket': 'This API uses the Google Cloud Storage API to delete ' + 
      'an empty bucket and returns an empty response to indicate success.', 
      'deleteObject': 'This API uses the Google Cloud Storage API to delete ' + 
      'an object and returns an empty response to indicate success.' 
     }; 
     /** 
     * Google Cloud Storage API request to retrieve the list of buckets in 
     * your Google Cloud Storage project. 
     */ 
     function listBuckets() { 
      var request = gapi.client.storage.buckets.list({ 
       'project': PROJECT 
      }); 
      executeRequest(request, 'listBuckets'); 
     } 
     /** 
     * Google Cloud Storage API request to retrieve the list of objects in 
     * your Google Cloud Storage project. 
     */ 
     function listObjects() { 
      var request = gapi.client.storage.objects.list({ 
       'bucket': BUCKET 
      }); 
      executeRequest(request, 'listObjects'); 
     } 
     /** 
     * Google Cloud Storage API request to retrieve the access control list on 
     * a bucket in your Google Cloud Storage project. 
     */ 
     function listBucketsAccessControls() { 
      var request = gapi.client.storage.bucketAccessControls.list({ 
       'bucket': BUCKET 
      }); 
      executeRequest(request, 'listBucketsAccessControls'); 
     } 
     /** 
     * Google Cloud Storage API request to retrieve the access control list on 
     * an object in your Google Cloud Storage project. 
     */ 
     function listObjectsAccessControls() { 
      var request = gapi.client.storage.objectAccessControls.list({ 
       'bucket': BUCKET, 
       'object': object 
      }); 
      executeRequest(request, 'listObjectsAccessControls'); 
     } 
     /** 
     * Google Cloud Storage API request to retrieve a bucket in 
     * your Google Cloud Storage project. 
     */ 
     function getBucket() { 
      var request = gapi.client.storage.buckets.get({ 
       'bucket': BUCKET 
      }); 
      executeRequest(request, 'getBucket'); 
     } 
     /** 
     * Google Cloud Storage API request to retrieve a bucket's Access Control 
     * List in your Google Cloud Storage project. 
     */ 
     function getBucketAccessControls() { 
      var request = gapi.client.storage.bucketAccessControls.get({ 
       'bucket': BUCKET, 
       'entity': GROUP 
      }); 
      executeRequest(request, 'getBucketAccessControls'); 
     } 
     /** 
     * Google Cloud Storage API request to retrieve an object's Access Control 
     * List in your Google Cloud Storage project. 
     */ 
     function getObjectAccessControls() { 
      var request = gapi.client.storage.objectAccessControls.get({ 
       'bucket': BUCKET, 
       'object': object, 
       'entity': GROUP 
      }); 
      executeRequest(request, 'getObjectAccessControls'); 
     } 
     /** 
     * Google Cloud Storage API request to insert a bucket into 
     * your Google Cloud Storage project. 
     */ 
     function insertBucket() { 
      resource = { 
       'name': BUCKET 
      }; 
      var request = gapi.client.storage.buckets.insert({ 
       'project': PROJECT, 
       'resource': resource 
      }); 
      executeRequest(request, 'insertBucket'); 
     } 
     /** 
     * Google Cloud Storage API request to insert an object into 
     * your Google Cloud Storage bucket. 
     */ 
     function insertObject(event) { 
      try{ 
       var fileData = event.target.files[0]; 
      } 
      catch(e) { 
       //'Insert Object' selected from the API Commands select list 
       //Display insert object button and then exit function 
       filePicker.style.display = 'block'; 
       return; 
      } 
      const boundary = '-------314159265358979323846'; 
      const delimiter = "\r\n--" + boundary + "\r\n"; 
      const close_delim = "\r\n--" + boundary + "--"; 
      var reader = new FileReader(); 
      reader.readAsBinaryString(fileData); 
      reader.onload = function(e) { 
       var contentType = fileData.type || 'application/octet-stream'; 
       var metadata = { 
        'name': fileData.name, 
        'mimeType': contentType 
       }; 
       var base64Data = btoa(reader.result); 
       var multipartRequestBody = 
         delimiter + 
         'Content-Type: application/json\r\n\r\n' + 
         JSON.stringify(metadata) + 
         delimiter + 
         'Content-Type: ' + contentType + '\r\n' + 
         'Content-Transfer-Encoding: base64\r\n' + 
         '\r\n' + 
         base64Data + 
         close_delim; 
       //Note: gapi.client.storage.objects.insert() can only insert 
       //small objects (under 64k) so to support larger file sizes 
       //we're using the generic HTTP request method gapi.client.request() 
       var request = gapi.client.request({ 
        'path': '/upload/storage/' + API_VERSION + '/b/' + BUCKET + '/o', 
        'method': 'POST', 
        'params': {'uploadType': 'multipart'}, 
        'headers': { 
         'Content-Type': 'multipart/mixed; boundary="' + boundary + '"' 
        }, 
        'body': multipartRequestBody}); 
       //Remove the current API result entry in the main-content div 
       listChildren = document.getElementById('main-content').childNodes; 
       if (listChildren.length > 1) { 
        listChildren[1].parentNode.removeChild(listChildren[1]); 
       } 
       try{ 
        //Execute the insert object request 
        executeRequest(request, 'insertObject'); 
        //Store the name of the inserted object 
        object = fileData.name; 
       } 
       catch(e) { 
        alert('An error has occurred: ' + e.message); 
       } 
      } 
     } 
     /** 
     * Google Cloud Storage API request to insert an Access Control List into 
     * your Google Cloud Storage bucket. 
     */ 
     function insertBucketAccessControls() { 
      resource = { 
       'entity': ENTITY, 
       'role': ROLE 
      }; 
      var request = gapi.client.storage.bucketAccessControls.insert({ 
       'bucket': BUCKET, 
       'resource': resource 
      }); 
      executeRequest(request, 'insertBucketAccessControls'); 
     } 
     /** 
     * Google Cloud Storage API request to insert an Access Control List into 
     * your Google Cloud Storage object. 
     */ 
     function insertObjectAccessControls() { 
      resource = { 
       'entity': ENTITY, 
       'role': ROLE_OBJECT 
      }; 
      var request = gapi.client.storage.objectAccessControls.insert({ 
       'bucket': BUCKET, 
       'object': object, 
       'resource': resource 
      }); 
      executeRequest(request, 'insertObjectAccessControls'); 
     } 
     /** 
     * Google Cloud Storage API request to delete a Google Cloud Storage bucket. 
     */ 
     function deleteBucket() { 
      var request = gapi.client.storage.buckets.delete({ 
       'bucket': BUCKET 
      }); 
      executeRequest(request, 'deleteBucket'); 
     } 
     /** 
     * Google Cloud Storage API request to delete a Google Cloud Storage object. 
     */ 
     function deleteObject() { 
      var request = gapi.client.storage.objects.delete({ 
       'bucket': BUCKET, 
       'object': object 
      }); 
      executeRequest(request, 'deleteObject'); 
     } 
     /** 
     * Removes the current API result entry in the main-content div, adds the 
     * results of the entry for your function. 
     * @param {string} apiRequestName The name of the example API request. 
     */ 
     function updateApiResultEntry(apiRequestName) { 
      listChildren = document.getElementById('main-content') 
        .childNodes; 
      if (listChildren.length > 1) { 
       listChildren[1].parentNode.removeChild(listChildren[1]); 
      } 
      if (apiRequestName != 'null') { 
       window[apiRequestName].apply(this); 
      } 
     } 
     /** 
     * Determines which API request has been selected, and makes a call to add 
     * its result entry. 
     */ 
     function runSelectedApiRequest() { 
      var curElement = document.getElementById('api-selection-options'); 
      var apiRequestName = curElement.options[curElement.selectedIndex].value; 
      updateApiResultEntry(apiRequestName); 
     } 
     /** 
     * Binds event listeners to handle a newly selected API request. 
     */ 
     function addSelectionSwitchingListeners() { 
      document.getElementById('api-selection-options') 
        .addEventListener('change', 
        runSelectedApiRequest, false); 
     } 
     /** 
     * Template for getting JavaScript sample code snippets. 
     * @param {string} method The name of the Google Cloud Storage request 
     * @param {string} params The parameters passed to method 
     */ 
     function getCodeSnippet(method, params) { 
      var objConstruction = "// Declare your parameter object\n"; 
      objConstruction += "var params = {};"; 
      objConstruction += "\n\n"; 
      var param = "// Initialize your parameters \n"; 
      for (i in params) { 
       param += "params['" + i + "'] = "; 
       param += JSON.stringify(params[i], null, '\t'); 
       param += ";"; 
       param += "\n"; 
      } 
      param += "\n"; 
      var methodCall = "// Make a request to the Google Cloud Storage API \n"; 
      methodCall += "var request = gapi.client." + method + "(params);"; 
      return objConstruction + param + methodCall; 
     } 
     /** 
     * Executes your Google Cloud Storage request object and, subsequently, 
     * inserts the response into the page. 
     * @param {string} request A Google Cloud Storage request object issued 
     * from the Google Cloud Storage JavaScript client library. 
     * @param {string} apiRequestName The name of the example API request. 
     */ 
     function executeRequest(request, apiRequestName) { 
      request.execute(function(resp) { 
       console.log(resp); 
       var apiRequestNode = document.createElement('div'); 
       apiRequestNode.id = apiRequestName; 
       var apiRequestNodeHeader = document.createElement('h2'); 
       apiRequestNodeHeader.innerHTML = apiRequestName; 
       var apiRequestExplanationNode = document.createElement('div'); 
       apiRequestExplanationNode.id = apiRequestName + 'RequestExplanation'; 
       var apiRequestExplanationNodeHeader = document.createElement('h3'); 
       apiRequestExplanationNodeHeader.innerHTML = 'API Request Explanation'; 
       apiRequestExplanationNode.appendChild(apiRequestExplanationNodeHeader); 
       var apiRequestExplanationEntry = document.createElement('p'); 
       apiRequestExplanationEntry.innerHTML = 
         listApiRequestExplanations[apiRequestName]; 
       apiRequestExplanationNode.appendChild(apiRequestExplanationEntry); 
       apiRequestNode.appendChild(apiRequestNodeHeader); 
       apiRequestNode.appendChild(apiRequestExplanationNode); 
       var apiRequestCodeSnippetNode = document.createElement('div'); 
       apiRequestCodeSnippetNode.id = apiRequestName + 'CodeSnippet'; 
       var apiRequestCodeSnippetHeader = document.createElement('h3'); 
       apiRequestCodeSnippetHeader.innerHTML = 'API Request Code Snippet'; 
       apiRequestCodeSnippetNode.appendChild(apiRequestCodeSnippetHeader); 
       var apiRequestCodeSnippetEntry = document.createElement('pre'); 
       //If the selected API command is not 'insertObject', pass the request 
       //paramaters to the getCodeSnippet method call as 'request.wc.wc.params' 
       //else pass request paramaters as 'request.wc.wc' 


/*    if (apiRequestName != 'insertObject') { 
        apiRequestCodeSnippetEntry.innerHTML = 
          getCodeSnippet(request.wc.wc.method, request.wc.wc.params); 
        //Selected API Command is not 'insertObject' 
        //hide insert object button 
        filePicker.style.display = 'none'; 
       } else { 
        apiRequestCodeSnippetEntry.innerHTML = 
          getCodeSnippet(request.wc.wc.method, request.wc.wc); 
       }*/ 


       apiRequestCodeSnippetNode.appendChild(apiRequestCodeSnippetEntry); 
       apiRequestNode.appendChild(apiRequestCodeSnippetNode); 
       var apiResponseNode = document.createElement('div'); 
       apiResponseNode.id = apiRequestName + 'Response'; 
       var apiResponseHeader = document.createElement('h3'); 
       apiResponseHeader.innerHTML = 'API Response'; 
       apiResponseNode.appendChild(apiResponseHeader); 
       var apiResponseEntry = document.createElement('pre'); 
       apiResponseEntry.innerHTML = JSON.stringify(resp, null, ' '); 
       apiResponseNode.appendChild(apiResponseEntry); 
       apiRequestNode.appendChild(apiResponseNode); 
       var content = document.getElementById('main-content'); 
       content.appendChild(apiRequestNode); 
      }); 
     } 
     /** 
     * Set required API keys and check authentication status. 
     */ 
     function handleClientLoad() { 
      gapi.client.setApiKey(apiKey); 
      window.setTimeout(checkAuth, 1); 
     } 
     /** 
     * Authorize Google Cloud Storage API. 
     */ 
     function checkAuth() { 
      gapi.auth.authorize({ 
       client_id: clientId, 
       scope: scopes, 
       immediate: true 
      }, handleAuthResult); 
     } 
     /** 
     * Handle authorization. 
     */ 
     function handleAuthResult(authResult) { 
      var authorizeButton = document.getElementById('authorize-button'); 
      if (authResult && !authResult.error) { 
       authorizeButton.style.visibility = 'hidden'; 
       initializeApi(); 
       filePicker.onchange = insertObject; 
      } else { 
       authorizeButton.style.visibility = ''; 
       authorizeButton.onclick = handleAuthClick; 
      } 
     } 
     /** 
     * Handle authorization click event. 
     */ 
     function handleAuthClick(event) { 
      gapi.auth.authorize({ 
       client_id: clientId, 
       scope: scopes, 
       immediate: false 
      }, handleAuthResult); 
      return false; 
     } 
     /** 
     * Load the Google Cloud Storage API. 
     */ 
     function initializeApi() { 
      gapi.client.load('storage', API_VERSION); 
     } 
     /** 
     * Driver for sample application. 
     */ 
     $(window) 
       .bind('load', function() { 
        addSelectionSwitchingListeners(); 
        handleClientLoad(); 
       }); 
    </script> 
</head> 
<body> 
<!--Add a button for the user to click to initiate auth sequence --> 
<button id="authorize-button" style="visibility: hidden">Authorize</button> 
<header> 
    <h1>Google Cloud Storage JavaScript Client Library Application</h1> 
</header> 
<label id="api-label">Try a sample API call!</label> 
<select id="api-selection-options"> 
    <option value="null"> 
     Please select an example API call from the dropdown menu 
    </option> 
    <option value="listBuckets"> 
     List Buckets 
    </option> 
    <option value="insertBucket"> 
     Insert Bucket 
    </option> 
    <option value="getBucket"> 
     Get Bucket 
    </option> 
    <option value="getBucketAccessControls"> 
     Get Bucket Access Controls 
    </option> 
    <option value="insertBucketAccessControls"> 
     Insert Bucket Access Controls 
    </option> 
    <option value="listBucketsAccessControls"> 
     List Buckets Access Control List 
    </option> 
    <option value="insertObject"> 
     Insert Object 
    </option> 
    <option value="listObjects"> 
     List Objects 
    </option> 
    <option value="getObjectAccessControls"> 
     Get Object Access Controls 
    </option> 
    <option value="insertObjectAccessControls"> 
     Insert Object Access Controls 
    </option> 
    <option value="listObjectsAccessControls"> 
     List Objects Access Control List 
    </option> 
    <option value="deleteObject"> 
     Delete Object 
    </option> 
    <option value="deleteBucket"> 
     Delete Bucket 
    </option> 
</select> 
<br/> 
<input type="file" id="filePicker" style="display: none" /> 
<div id="main-content"> 
</div> 
</body> 
</html>

下面是上傳文件，從上面的例子充分激發的功能。請注意，它使用JavaScript客戶端庫與Google API（gapi）進行交互，這意味着您可以通過Google帳戶（https://developers.google.com/api-client-library/javascript/start/start-js）通過身份驗證來保護上傳。

function uploadFile(fileData, bucket) { 
    var boundary = '-------314159265358979323846'; 
    var delimiter = "\r\n--" + boundary + "\r\n"; 
    var close_delim = "\r\n--" + boundary + "--"; 
    var reader = new FileReader(); 
    reader.readAsBinaryString(fileData); 

    reader.onload = function (e) { 
     var contentType = fileData.type || 'application/octet-stream'; 
     var metadata = { 
      'name': fileData.name, 
      'mimeType': contentType 
     }; 
     var base64Data = btoa(reader.result); 
     var multipartRequestBody = 
       delimiter + 
       'Content-Type: application/json\r\n\r\n' + 
       JSON.stringify(metadata) + 
       delimiter + 
       'Content-Type: ' + contentType + '\r\n' + 
       'Content-Transfer-Encoding: base64\r\n' + 
       '\r\n' + 
       base64Data + 
       close_delim; 

     var request = gapi.client.request({ 
      'path': '/upload/storage/v1/b/' + bucket + '/o', 
      'method': 'POST', 
      'params': {'uploadType': 'multipart'}, 
      'headers': { 
       'Content-Type': 'multipart/mixed; boundary="' + boundary + '"' 
      }, 
      'body': multipartRequestBody 
     }); 

     try { 
      request.execute(function (resp) { 
       if (resp.hasOwnProperty("error")) { 
        //Treat Error 
       } else { 
        //Treat Success 
       } 
      }); 
     } 
     catch (e) { 
      //Treat Error 
     } 

    }; 

}

最後，你可以使用雲存儲的對象更改通知調用在App Engine中的任務。您可以傳遞存儲桶和文件名，並通過App Engine處理剛剛上傳的文件。 https://cloud.google.com/storage/docs/object-change-notification

來源

2016-12-20 16:01:11

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我找回了網上的例子：https：//github.com/googlearchive/storage-getting-started-javascript –

+0

但服務器端（Java）呢？我只想將文件上傳到servlet並將文件從servlet上傳到GCS – user2354982

+0

您需要檢查文檔和代碼示例，因爲在許多地方可以找到與客戶端或服務器端進行雲存儲交互的示例。 – Nick

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