Object Storage Service:Fazer upload de um objeto usando uma URL pré-assinada (C# SDK V2)

1. O proprietário do objeto gera uma URL pré-assinada para uma requisição PUT com cabeçalhos de requisição e metadados personalizados.

   using System.Text;
   using OSS = AlibabaCloud.OSS.V2;  // Create an alias for the Alibaba Cloud OSS SDK to simplify subsequent use.
   using System.Globalization;
   using System.Net.Http.Headers;
   
   var region = "cn-hangzhou";  // Required. Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
   var endpoint = null as string;  // Optional. Specify the endpoint that is used to access OSS. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
   var bucket = "your bucket name";  // Required. The bucket name.
   var key = "your object key";  // Required. The name of the object after it is uploaded to OSS.
   
   // Load the default configurations of the OSS SDK. The configurations automatically read credential information (such as AccessKey) from environment variables.
   var cfg = OSS.Configuration.LoadDefault();
   // Explicitly configure the use of environment variables to obtain credentials for identity verification. Format: OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET.
   cfg.CredentialsProvider = new OSS.Credentials.EnvironmentVariableCredentialsProvider();
   // Set the region of the bucket in the configuration.
   cfg.Region = region;   
   // If an endpoint is specified, it overwrites the default endpoint. 
   if(endpoint != null) 
   { 
       cfg.Endpoint = endpoint;
   } 
   
   // Create an OSS client instance using the configuration information.
   using var client = new OSS.Client(cfg); 
   // Call the Presign method to obtain the presigned upload URL.
   var result = client.Presign(new OSS.Models.PutObjectRequest()
       {
           Bucket = bucket,
           Key = key,
           StorageClass = "Standard",         // Set the storage class to Standard.
           ContentType = "text/plain; charset=utf8",    // Set the content type.
           Metadata = new Dictionary<string, string>() {
               { "key1", "value1" },    // Add custom metadata.
               { "key2", "value2" }
           }
       }
   );
   
   // Create an HTTP client instance.
   using var hc = new HttpClient();
   
   // Prepare the content to be uploaded.
   var content1 = "hello oss";
   var requestMessage = new HttpRequestMessage(HttpMethod.Put, new Uri(result.Url));
   requestMessage.Content = new ByteArrayContent(Encoding.UTF8.GetBytes(content1));
   
   // Add the HTTP headers included in the presigned URL.
   foreach (var item in result.SignedHeaders!)
   {
       switch (item.Key.ToLower())
       {
           case "content-disposition":
               // Set the content disposition.
               requestMessage.Content.Headers.ContentDisposition = ContentDispositionHeaderValue.Parse(item.Value);
               break;
           case "content-encoding":
               // Set the content encoding.
               requestMessage.Content.Headers.ContentEncoding.Add(item.Value);
               break;
           case "content-language":
               // Set the content language.
               requestMessage.Content.Headers.ContentLanguage.Add(item.Value);
               break;
           case "content-type":
               // Set the content type.
               requestMessage.Content.Headers.ContentType = MediaTypeHeaderValue.Parse(item.Value);
               break;
           case "content-md5":
               // Set the MD5 hash of the content.
               requestMessage.Content.Headers.ContentMD5 = Convert.FromBase64String(item.Value);
               break;
           case "content-length":
               // Set the content length.
               requestMessage.Content.Headers.ContentLength = Convert.ToInt64(item.Value);
               break;
           case "expires":
               // Set the expiration time of the content.
               if (DateTime.TryParse(
                       item.Value,
                       CultureInfo.InvariantCulture,
                       DateTimeStyles.None,
                       out var expires
                   ))
                   requestMessage.Content.Headers.Expires = expires;
               break;
           default:
               // Add other general header information.
               requestMessage.Headers.Add(item.Key, item.Value);
               break;
       }
   }
   // Send an HTTP request and obtain the response.
   var httpResult = await hc.SendAsync(requestMessage);
   
   Console.WriteLine("PutObject done");  // Print a message indicating that the operation is complete.
   Console.WriteLine($"StatusCode: {httpResult.StatusCode}");  // The HTTP status code of the response.

2. Outros usuários usam a URL pré-assinada na requisição PUT para fazer o upload de um objeto.

   curl

   curl -X PUT \
        -H "Content-Type: text/plain;charset=utf8" \
        -H "x-oss-storage-class: Standard" \
        -H "x-oss-meta-key1: value1" \
        -H "x-oss-meta-key2: value2" \
        -T "C:\\Users\\demo.txt" \
        "https://exampleobject.oss-cn-hangzhou.aliyuncs.com/exampleobject.txt?x-oss-date=20241112T083238Z&x-oss-expires=3599&x-oss-signature-version=OSS4-HMAC-SHA256&x-oss-credential=LTAI****************%2F20241112%2Fcn-hangzhou%2Foss%2Faliyun_v4_request&x-oss-signature=ed5a******************************************************"

   Java

   package com.aliyun.sample;
   
   import com.aliyun.oss.internal.OSSHeaders;
   import com.aliyun.oss.model.StorageClass;
   import org.apache.http.HttpEntity;
   import org.apache.http.client.methods.CloseableHttpResponse;
   import org.apache.http.client.methods.HttpPut;
   import org.apache.http.entity.FileEntity;
   import org.apache.http.impl.client.CloseableHttpClient;
   import org.apache.http.impl.client.HttpClients;
   import java.io.*;
   import java.net.URL;
   import java.util.*;
   
   public class SignUrlUpload {
       public static void main(String[] args) throws Throwable {
           CloseableHttpClient httpClient = null;
           CloseableHttpResponse response = null;
   
           // Replace <signedUrl> with the authorized URL.
           URL signedUrl = new URL("<signedUrl>");
   
           // Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the project path of the sample program by default.
           String pathName = "C:\\Users\\demo.txt";
   
           // Set the request headers. The request header information must be the same as the information used when the URL was generated.
           Map<String, String> headers = new HashMap<String, String>();
           //Specify the storage class of the object.
           headers.put(OSSHeaders.STORAGE_CLASS, StorageClass.Standard.toString());
           //Specify the ContentType.
           headers.put(OSSHeaders.CONTENT_TYPE, "text/plain;charset=utf8");
   
           // Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
           Map<String, String> userMetadata = new HashMap<String, String>();
           userMetadata.put("key1","value1");
           userMetadata.put("key2","value2");
   
           try {
               HttpPut put = new HttpPut(signedUrl.toString());
               System.out.println(put);
               HttpEntity entity = new FileEntity(new File(pathName));
               put.setEntity(entity);
               // If you set header parameters, such as user metadata and storage class, when you generate the presigned URL, you must also send these parameters to the server when you use the presigned URL to upload the file. A signature error is reported if the parameters sent to the server are inconsistent with the signed parameters.
               for(Map.Entry<String, String> header: headers.entrySet()){
                   put.addHeader(header.getKey(), header.getValue());
               }
               for(Map.Entry<String, String> meta: userMetadata.entrySet()){
                   // If you use userMeta, the SDK internally adds the 'x-oss-meta-' prefix. When you use other methods to generate a presigned URL for an upload, you must also add the 'x-oss-meta-' prefix to the userMeta.
                   put.addHeader("x-oss-meta-"+meta.getKey(), meta.getValue());
               }
   
               httpClient = HttpClients.createDefault();
   
               response = httpClient.execute(put);
   
               System.out.println("Status code returned for the upload:"+response.getStatusLine().getStatusCode());
               if(response.getStatusLine().getStatusCode() == 200){
                   System.out.println("Upload successful using network library.");
               }
               System.out.println(response.toString());
           } catch (Exception e){
               e.printStackTrace();
           } finally {
               if (response != null) {
                   response.close();
               }
               if (httpClient != null) {
                   httpClient.close();
               }
           }
       }
   }

   Go

   package main
   
   import (
   	"bytes"
   	"fmt"
   	"io/ioutil"
   	"net/http"
   	"os"
   )
   
   func uploadFile(signedUrl string, filePath string, headers map[string]string, metadata map[string]string) error {
   	// Open the file.
   	file, err := os.Open(filePath)
   	if err != nil {
   		return err
   	}
   	defer file.Close()
   
   	// Read the file content.
   	fileBytes, err := ioutil.ReadAll(file)
   	if err != nil {
   		return err
   	}
   
   	// Create a request.
   	req, err := http.NewRequest("PUT", signedUrl, bytes.NewBuffer(fileBytes))
   	if err != nil {
   		return err
   	}
   
   	// Set the request headers.
   	for key, value := range headers {
   		req.Header.Set(key, value)
   	}
   
   	// Set the custom user metadata.
   	for key, value := range metadata {
   		req.Header.Set(fmt.Sprintf("x-oss-meta-%s", key), value)
   	}
   
   	// Send the request.
   	client := &http.Client{}
   	resp, err := client.Do(req)
   	if err != nil {
   		return err
   	}
   	defer resp.Body.Close()
   
   	// Process the response.
   	fmt.Printf("Status code returned for the upload: %d\n", resp.StatusCode)
   	if resp.StatusCode == 200 {
   		fmt.Println("Upload successful using network library.")
   	} else {
   		fmt.Println("Upload failed.")
   	}
   	body, _ := ioutil.ReadAll(resp.Body)
   	fmt.Println(string(body))
   
   	return nil
   }
   
   func main() {
   	// Replace <signedUrl> with the authorized URL.
   	signedUrl := "<signedUrl>"
   
   	// Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the project path of the sample program by default.
   	filePath := "C:\\Users\\demo.txt"
   
   	// Set the request headers. The request header information must be the same as the information used when the URL was generated.
   	headers := map[string]string{
   		"Content-Type": "text/plain;charset=utf8",
   		"x-oss-storage-class": "Standard",
   	}
   
   	// Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
   	metadata := map[string]string{
   		"key1": "value1",
   		"key2": "value2",
   	}
   
   	err := uploadFile(signedUrl, filePath, headers, metadata)
   	if err != nil {
   		fmt.Printf("An error occurred: %v\n", err)
   	}
   }
   

   Python

   import requests
   from requests.auth import HTTPBasicAuth
   import os
   
   def upload_file(signed_url, file_path, headers=None, metadata=None):
       """
       Use a presigned URL to upload a file to OSS.
   
       :param signed_url: The presigned URL.
       :param file_path: The full path of the file to upload.
       :param headers: Optional. Custom HTTP headers.
       :param metadata: Optional. Custom metadata.
       :return: None
       """
       if not headers:
           headers = {}
       if not metadata:
           metadata = {}
   
       # Update headers and add the metadata prefix.
       for key, value in metadata.items():
           headers[f'x-oss-meta-{key}'] = value
   
       try:
           with open(file_path, 'rb') as file:
               response = requests.put(signed_url, data=file, headers=headers)
               print(f"Status code returned for the upload: {response.status_code}")
               if response.status_code == 200:
                   print("Upload successful using network library.")
               else:
                   print("Upload failed.")
               print(response.text)
       except Exception as e:
           print(f"An error occurred: {e}")
   
   if __name__ == "__main__":
       # Replace <signedUrl> with the authorized URL.
       signed_url = "<signedUrl>"
      
       # Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the directory where the script is located by default.
       file_path = "C:\\Users\\demo.txt"
   
       # Set the request headers. The request header information must be the same as the information used when the URL was generated.
       headers = {
            "Content-Type": "text/plain;charset=utf8",
            "x-oss-storage-class": "Standard"
       }
   
       # Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
       metadata = {
            "key1": "value1",
            "key2": "value2"
       }
   
       upload_file(signed_url, file_path, headers, metadata)
   

   Node.js

   const fs = require('fs');
   const axios = require('axios');
   
   async function uploadFile(signedUrl, filePath, headers = {}, metadata = {}) {
       try {
           // Update headers and add the metadata prefix.
           for (const [key, value] of Object.entries(metadata)) {
               headers[`x-oss-meta-${key}`] = value;
           }
   
           // Read the file stream.
           const fileStream = fs.createReadStream(filePath);
   
           // Send a PUT request.
           const response = await axios.put(signedUrl, fileStream, {
               headers: headers
           });
   
           console.log(`Status code returned for the upload: ${response.status}`);
           if (response.status === 200) {
               console.log("Upload successful using network library.");
           } else {
               console.log("Upload failed.");
           }
           console.log(response.data);
       } catch (error) {
           console.error(`An error occurred: ${error.message}`);
       }
   }
   
   // Main function.
   (async () => {
       // Replace <signedUrl> with the authorized URL.
       const signedUrl = "<signedUrl>";
   
       // Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the directory where the script is located by default.
       const filePath = "C:\\Users\\demo.txt";
   
       // Set the request headers. The request header information must be the same as the information used when the URL was generated.
       const headers = {
            "Content-Type": "text/plain;charset=utf8",
            "x-oss-storage-class": "Standard"
       };
   
       // Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
       const metadata = {
            "key1": "value1",
            "key2": "value2"
       };
   
       await uploadFile(signedUrl, filePath, headers, metadata);
   })();
   

   Browser.js

   Importante

   Se você encontrar um erro 403 de incompatibilidade de assinatura ao usar o Browser.js para fazer o upload de um arquivo, isso geralmente ocorre porque o navegador adiciona automaticamente o cabeçalho de requisição Content-Type, e esse cabeçalho não foi incluído quando a URL pré-assinada foi gerada. Essa incompatibilidade causa uma falha na verificação de assinatura. Para resolver esse problema, especifique o cabeçalho de requisição Content-Type ao gerar a URL pré-assinada.

   <!DOCTYPE html>
   <html lang="en">
   <head>
       <meta charset="UTF-8">
       <meta name="viewport" content="width=device-width, initial-scale=1.0">
       <title>File Upload Example</title>
   </head>
   <body>
       <h1>File Upload Example (Java SDK)</h1>
   
       <input type="file" id="fileInput" />
       <button id="uploadButton">Upload File</button>
   
       <script>
           // Replace this with the actual presigned URL.
           const signedUrl = "<signedUrl>"; 
   
           document.getElementById('uploadButton').addEventListener('click', async () => {
               const fileInput = document.getElementById('fileInput');
               const file = fileInput.files[0];
   
               if (file) {
                   try {
                       await upload(file, signedUrl);
                   } catch (error) {
                       console.error('Error during upload:', error);
                       alert('Upload failed: ' + error.message);
                   }
               } else {
                   alert('Please select a file to upload.');
               }
           });
   
           const upload = async (file, presignedUrl) => {
               const headers = {
                   "Content-Type": "text/plain;charset=utf8",
                   'x-oss-storage-class': 'Standard',
                   'x-oss-meta-key1': 'value1',
                   'x-oss-meta-key2': 'value2'
               };
   
               const response = await fetch(presignedUrl, {
                   method: 'PUT',
                   headers: headers,
                   body: file
               });
   
               if (!response.ok) {
                   throw new Error(`Upload failed, status: ${response.status}`);
               }
   
               alert('File uploaded successfully');
               console.log('File uploaded successfully');
           };
       </script>
   </body>
   </html>

   C#

   using System.Net.Http.Headers;
   
   // Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the project path of the sample program by default.
   var filePath = "C:\\Users\\demo.txt";
   // Replace <signedUrl> with the authorized URL.
   var presignedUrl = "<signedUrl>";
   
   // Create an HTTP client and open the local file stream.
   using var httpClient = new HttpClient(); 
   using var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
   using var content = new StreamContent(fileStream);
               
   // Create a PUT request.
   var request = new HttpRequestMessage(HttpMethod.Put, presignedUrl);
   request.Content = content;
   
   // If you set header parameters, such as user metadata and storage class, when you generate the presigned URL, you must also send these parameters to the server when you use the presigned URL to upload the file. A signature error is reported if the parameters sent to the server are inconsistent with the signed parameters.
   // Set the request headers. The request header information must be the same as the information used when the URL was generated.
   request.Content.Headers.ContentType = new MediaTypeHeaderValue("text/plain") { CharSet = "utf8" };  // Specify the ContentType.       
   // Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
   request.Content.Headers.Add("x-oss-meta-key1", "value1");
   request.Content.Headers.Add("x-oss-meta-key2", "value2");
   // Specify the storage class of the object.
   request.Content.Headers.Add("x-oss-storage-class", "Standard");
   
   // Print the request headers.
   Console.WriteLine("Request headers:");
   foreach (var header in request.Content.Headers)
   {
       Console.WriteLine($"{header.Key}: {string.Join(", ", header.Value)}");
   }
   
   // Send the request.
   var response = await httpClient.SendAsync(request);
   
   // Process the response.
   if (response.IsSuccessStatusCode)
   {
       Console.WriteLine($"Upload successful! Status code: {response.StatusCode}");
       Console.WriteLine("Response headers:");
       foreach (var header in response.Headers)
       {
           Console.WriteLine($"{header.Key}: {string.Join(", ", header.Value)}");
       }
   }
   else
   {
       string responseContent = await response.Content.ReadAsStringAsync();
       Console.WriteLine($"Upload failed! Status code: {response.StatusCode}");
       Console.WriteLine("Response content: " + responseContent);
   }

   C++

   #include <iostream>
   #include <fstream>
   #include <curl/curl.h>
   #include <map>
   #include <string>
   
   // Callback function to handle the HTTP response.
   size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* output) {
       size_t totalSize = size * nmemb;
       output->append((char*)contents, totalSize);
       return totalSize;
   }
   
   void uploadFile(const std::string& signedUrl, const std::string& filePath, const std::map<std::string, std::string>& headers, const std::map<std::string, std::string>& metadata) {
       CURL* curl;
       CURLcode res;
       std::string readBuffer;
   
       curl_global_init(CURL_GLOBAL_DEFAULT);
       curl = curl_easy_init();
   
       if (curl) {
           // Set the URL.
           curl_easy_setopt(curl, CURLOPT_URL, signedUrl.c_str());
   
           // Set the request method to PUT.
           curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
   
           // Open the file.
           FILE* file = fopen(filePath.c_str(), "rb");
           if (!file) {
               std::cerr << "Unable to open file: " << filePath << std::endl;
               return;
           }
   
           // Set the file size.
           fseek(file, 0, SEEK_END);
           long fileSize = ftell(file);
           rewind(file);
   
           // Set the file read callback.
           curl_easy_setopt(curl, CURLOPT_READDATA, file);
           curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE, (curl_off_t)fileSize);
   
           // Set the request headers.
           struct curl_slist* chunk = nullptr;
           for (const auto& header : headers) {
               std::string headerStr = header.first + ": " + header.second;
               chunk = curl_slist_append(chunk, headerStr.c_str());
           }
           for (const auto& meta : metadata) {
               std::string metaStr = "x-oss-meta-" + meta.first + ": " + meta.second;
               chunk = curl_slist_append(chunk, metaStr.c_str());
           }
           curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
   
           // Set the response handling callback.
           curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
           curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer);
   
           // Execute the request.
           res = curl_easy_perform(curl);
   
           // Check the response.
           if (res != CURLE_OK) {
               std::cerr << "curl_easy_perform() failed: " << curl_easy_strerror(res) << std::endl;
           } else {
               long responseCode;
               curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &responseCode);
               std::cout << "Status code returned for the upload: " << responseCode << std::endl;
               if (responseCode == 200) {
                   std::cout << "Upload successful using network library." << std::endl;
               } else {
                   std::cout << "Upload failed." << std::endl;
               }
               std::cout << readBuffer << std::endl;
           }
   
           // Clean up.
           fclose(file);
           curl_slist_free_all(chunk);
           curl_easy_cleanup(curl);
       }
   
       curl_global_cleanup();
   }
   
   int main() {
       // Replace <signedUrl> with the authorized URL.
       std::string signedUrl = "<signedUrl>";
   
       // Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the project path of the sample program by default.
       std::string filePath = "C:\\Users\\demo.txt";
   
       // Set the request headers. The request header information must be the same as the information used when the URL was generated.
       std::map<std::string, std::string> headers = {
            {"Content-Type", "text/plain;charset=utf8"},
            {"x-oss-storage-class", "Standard"}
       };
   
       // Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
       std::map<std::string, std::string> metadata = {
            {"key1", "value1"},
            {"key2", "value2"}
       };
   
       uploadFile(signedUrl, filePath, headers, metadata);
   
       return 0;
   }
   

   Android

   import android.os.AsyncTask;
   import android.util.Log;
   
   import java.io.DataOutputStream;
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.IOException;
   import java.io.InputStream;
   import java.net.HttpURLConnection;
   import java.net.URL;
   import java.util.HashMap;
   import java.util.Map;
   import java.util.Map.Entry;
   
   public class SignUrlUploadActivity extends AppCompatActivity {
   
       private static final String TAG = "SignUrlUploadActivity";
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
   
           // Replace <signedUrl> with the authorized URL.
           String signedUrl = "<signedUrl>";
   
           // Specify the full path of the local file. If you do not specify a local path, the file is uploaded from the project path of the sample program by default.
           String pathName = "/storage/emulated/0/demo.txt";
   
           // Set the request headers. The request header information must be the same as the information used when the URL was generated.
           Map<String, String> headers = new HashMap<>();
           headers.put("Content-Type", "text/plain;charset=utf8");
           headers.put("x-oss-storage-class", "Standard");
   
           // Set the custom user metadata. The custom user metadata must be the same as the information used when the URL was generated.
           Map<String, String> userMetadata = new HashMap<>();
           userMetadata.put("key1", "value1");
           userMetadata.put("key2", "value2");
   
           new UploadTask().execute(signedUrl, pathName, headers, userMetadata);
       }
   
       private class UploadTask extends AsyncTask<Object, Void, Integer> {
           @Override
           protected Integer doInBackground(Object... params) {
               String signedUrl = (String) params[0];
               String pathName = (String) params[1];
               Map<String, String> headers = (Map<String, String>) params[2];
               Map<String, String> userMetadata = (Map<String, String>) params[3];
   
               try {
                   URL url = new URL(signedUrl);
                   HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                   connection.setRequestMethod("PUT");
                   connection.setDoOutput(true);
                   connection.setUseCaches(false);
   
                   // Set the request headers.
                   for (Entry<String, String> header : headers.entrySet()) {
                       connection.setRequestProperty(header.getKey(), header.getValue());
                   }
   
                   // Set the custom user metadata.
                   for (Entry<String, String> meta : userMetadata.entrySet()) {
                       connection.setRequestProperty("x-oss-meta-" + meta.getKey(), meta.getValue());
                   }
   
                   // Read the file.
                   File file = new File(pathName);
                   FileInputStream fileInputStream = new FileInputStream(file);
                   DataOutputStream dos = new DataOutputStream(connection.getOutputStream());
   
                   byte[] buffer = new byte[1024];
                   int count;
                   while ((count = fileInputStream.read(buffer)) != -1) {
                       dos.write(buffer, 0, count);
                   }
   
                   fileInputStream.close();
                   dos.flush();
                   dos.close();
   
                   // Get the response.
                   int responseCode = connection.getResponseCode();
                   Log.d(TAG, "Status code returned for the upload: " + responseCode);
                   if (responseCode == 200) {
                       Log.d(TAG, "Upload successful using network library.");
                   } else {
                       Log.d(TAG, "Upload failed.");
                   }
   
                   InputStream is = connection.getInputStream();
                   byte[] responseBuffer = new byte[1024];
                   StringBuilder responseStringBuilder = new StringBuilder();
                   while ((count = is.read(responseBuffer)) != -1) {
                       responseStringBuilder.append(new String(responseBuffer, 0, count));
                   }
                   Log.d(TAG, responseStringBuilder.toString());
   
                   return responseCode;
               } catch (IOException e) {
                   e.printStackTrace();
                   return -1;
               }
           }
   
           @Override
           protected void onPostExecute(Integer result) {
               super.onPostExecute(result);
               if (result == 200) {
                   Toast.makeText(SignUrlUploadActivity.this, "Upload successful.", Toast.LENGTH_SHORT).show();
               } else {
                   Toast.makeText(SignUrlUploadActivity.this, "Upload failed.", Toast.LENGTH_SHORT).show();
               }
           }
       }
   }
   

Para fazer o upload de um objeto usando uma URL pré-assinada e upload multipart, configure o tamanho da parte e gere uma URL pré-assinada para cada parte. O código de exemplo a seguir demonstra essa operação:

using OSS = AlibabaCloud.OSS.V2;  // Create an alias for the Alibaba Cloud OSS SDK to simplify subsequent use.

var region = "cn-hangzhou";  // Required. Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
var endpoint = null as string;  // Optional. Specify the endpoint that is used to access OSS. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
var bucket = "you bucket name";  // Required. The bucket name.
var key = "your object key";  // Required. The name of the object to be uploaded.
var partSize = 512*1024;  // Required. The size of each part for each upload. In this example, the part size is 512 KB.
var filePath = "filePath";  // Required. The path of the object to be uploaded.

// Load the default configurations of the OSS SDK. The configurations automatically read credential information (such as AccessKey) from environment variables.
var cfg = OSS.Configuration.LoadDefault();
// Explicitly configure the use of environment variables to obtain credentials for identity verification. Format: OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET.
cfg.CredentialsProvider = new OSS.Credentials.EnvironmentVariableCredentialsProvider();
// Set the region of the bucket in the configuration.
cfg.Region = region;   
// If an endpoint is specified, it overwrites the default endpoint. 
if(endpoint != null) 
{
    cfg.Endpoint = endpoint;
} 

// Create an OSS client instance using the configuration information.
using var client = new OSS.Client(cfg); 

// Initiate a multipart upload.
var initResult = await client.InitiateMultipartUploadAsync(new()
{
    Bucket = bucket,
    Key = key
});

// Open the file to be uploaded.
using var hc = new HttpClient();
using var file = File.OpenRead(filePath);
long fileSize = file.Length;
long partNumber = 1;

// Upload the file in parts.
for (long offset = 0; offset < fileSize; offset += partSize)
{
    // Calculate the size of the current part.
    var size = Math.Min(partSize, fileSize - offset);

    // Generate a presigned URL for direct upload from the client.
    var presignResult = client.Presign(new OSS.Models.UploadPartRequest
    {
        Bucket = bucket,
        Key = key,
        PartNumber = partNumber,
        UploadId = initResult.UploadId,
        Body = new OSS.IO.BoundedStream(file, offset, size)
    });

    // Use the presigned URL to send a PUT request to upload the part.
    var httpResult = await hc.PutAsync(
        presignResult.Url,
        new StreamContent(new OSS.IO.BoundedStream(file, offset, size))
    );

    // Check whether the upload is successful.
    if (!httpResult.IsSuccessStatusCode)
    {
        throw new Exception("upload part fail");
    }
    partNumber++;
}

// List all uploaded parts.
var uploadParts = new List<OSS.Models.UploadPart>();
var paginator = client.ListPartsPaginator(new ()
{
    Bucket = bucket,
    Key = key,
    UploadId = initResult.UploadId,
});

// Obtain all part information by page.
await foreach (var page in paginator.IterPageAsync())
{
    foreach (var part in page.Parts ?? [])
    {
        uploadParts.Add(new() { PartNumber = part.PartNumber, ETag = part.ETag });
    }
}

// Sort the parts by part number.
uploadParts.Sort((left, right) => { return (left.PartNumber > right.PartNumber) ? 1 : -1; });

// Complete the multipart upload.
var cmResult = await client.CompleteMultipartUploadAsync(new()
{
    Bucket = bucket,
    Key = key,
    UploadId = initResult.UploadId,
    CompleteMultipartUpload = new()
    {
        Parts = uploadParts
    }
});

// Print the upload result.
Console.WriteLine("MultipartUpload done");  // A message indicating that the operation is complete.
Console.WriteLine($"StatusCode: {cmResult.StatusCode}");  // The HTTP status code.
Console.WriteLine($"RequestId: {cmResult.RequestId}");  // The request ID, which is used by Alibaba Cloud for troubleshooting.
Console.WriteLine("Response Headers:");  // The response header information.
cmResult.Headers.ToList().ForEach(x => Console.WriteLine(x.Key + " : " + x.Value));  // Traverse and print all response headers.

O upload será concluído com êxito.

A verificação da assinatura ocorre quando a requisição de upload é iniciada. O upload poderá prosseguir se a URL for válida naquele momento. Ao usar um token temporário, o período de validade da URL pré-assinada corresponderá ao menor período entre a validade do token e o tempo de expiração especificado para a URL.

Não, não é necessário.

Os cabeçalhos de requisição e os metadados personalizados são parâmetros opcionais. Caso não defina esses elementos, remova o código relacionado do exemplo.