使用 Amazon S3 预签名 URL - Amazon SDK for Java 2.x
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使用 Amazon S3 预签名 URL

预签名 URL 提供对私有 S3 对象的临时访问权限,无需用户拥有 Amazon 凭证或权限。

例如,假设 Alice 有权访问 S3 对象,并希望临时与 Bob 分享对该对象的访问权限。Alice 可以生成预签名的 GET 请求来与 Bob 分享,这样 Bob 就可以下载该对象而无需访问 Alice 的凭证。您可以为 HTTP GET 和 HTTP PUT 请求生成预签名 URL。

为对象生成预签名 URL,然后下载对象(GET 请求)

以下示例由两部分组成。

  • 第 1 部分:Alice 为对象生成预签名 URL。

  • 第 2 部分:Bob 使用预签名 URL 下载对象。

第 1 部分:生成 URL

Alice 在 S3 桶中已有一个对象。她使用以下代码生成一个 URL 字符串,Bob 可以在后续的 GET 请求中使用该字符串。

import com.example.s3.util.PresignUrlUtils; import org.slf4j.Logger; import software.amazon.awssdk.http.HttpExecuteRequest; import software.amazon.awssdk.http.HttpExecuteResponse; import software.amazon.awssdk.http.SdkHttpClient; import software.amazon.awssdk.http.SdkHttpMethod; import software.amazon.awssdk.http.SdkHttpRequest; import software.amazon.awssdk.http.apache.ApacheHttpClient; import software.amazon.awssdk.services.s3.S3Client; import software.amazon.awssdk.services.s3.model.GetObjectRequest; import software.amazon.awssdk.services.s3.model.S3Exception; import software.amazon.awssdk.services.s3.presigner.S3Presigner; import software.amazon.awssdk.services.s3.presigner.model.GetObjectPresignRequest; import software.amazon.awssdk.services.s3.presigner.model.PresignedGetObjectRequest; import software.amazon.awssdk.utils.IoUtils; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URISyntaxException; import java.net.URL; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; import java.nio.file.Paths; import java.time.Duration; import java.util.UUID;
/* Create a pre-signed URL to download an object in a subsequent GET request. */ public String createPresignedGetUrl(String bucketName, String keyName) { try (S3Presigner presigner = S3Presigner.create()) { GetObjectRequest objectRequest = GetObjectRequest.builder() .bucket(bucketName) .key(keyName) .build(); GetObjectPresignRequest presignRequest = GetObjectPresignRequest.builder() .signatureDuration(Duration.ofMinutes(10)) // The URL will expire in 10 minutes. .getObjectRequest(objectRequest) .build(); PresignedGetObjectRequest presignedRequest = presigner.presignGetObject(presignRequest); logger.info("Presigned URL: [{}]", presignedRequest.url().toString()); logger.info("HTTP method: [{}]", presignedRequest.httpRequest().method()); return presignedRequest.url().toExternalForm(); } }

第 2 部分:下载对象

Bob 使用以下三个代码选项之一来下载对象。或者,他可以使用浏览器来执行 GET 请求。

/* Use the JDK HttpURLConnection (since v1.1) class to do the download. */ public byte[] useHttpUrlConnectionToGet(String presignedUrlString) { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); // Capture the response body to a byte array. try { URL presignedUrl = new URL(presignedUrlString); HttpURLConnection connection = (HttpURLConnection) presignedUrl.openConnection(); connection.setRequestMethod("GET"); // Download the result of executing the request. try (InputStream content = connection.getInputStream()) { IoUtils.copy(content, byteArrayOutputStream); } logger.info("HTTP response code is " + connection.getResponseCode()); } catch (S3Exception | IOException e) { logger.error(e.getMessage(), e); } return byteArrayOutputStream.toByteArray(); }
/* Use the JDK HttpClient (since v11) class to do the download. */ public byte[] useHttpClientToGet(String presignedUrlString) { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); // Capture the response body to a byte array. HttpRequest.Builder requestBuilder = HttpRequest.newBuilder(); HttpClient httpClient = HttpClient.newHttpClient(); try { URL presignedUrl = new URL(presignedUrlString); HttpResponse<InputStream> response = httpClient.send(requestBuilder .uri(presignedUrl.toURI()) .GET() .build(), HttpResponse.BodyHandlers.ofInputStream()); IoUtils.copy(response.body(), byteArrayOutputStream); logger.info("HTTP response code is " + response.statusCode()); } catch (URISyntaxException | InterruptedException | IOException e) { logger.error(e.getMessage(), e); } return byteArrayOutputStream.toByteArray(); }
/* Use the AWS SDK for Java SdkHttpClient class to do the download. */ public byte[] useSdkHttpClientToPut(String presignedUrlString) { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); // Capture the response body to a byte array. try { URL presignedUrl = new URL(presignedUrlString); SdkHttpRequest request = SdkHttpRequest.builder() .method(SdkHttpMethod.GET) .uri(presignedUrl.toURI()) .build(); HttpExecuteRequest executeRequest = HttpExecuteRequest.builder() .request(request) .build(); try (SdkHttpClient sdkHttpClient = ApacheHttpClient.create()) { HttpExecuteResponse response = sdkHttpClient.prepareRequest(executeRequest).call(); response.responseBody().ifPresentOrElse( abortableInputStream -> { try { IoUtils.copy(abortableInputStream, byteArrayOutputStream); } catch (IOException e) { throw new RuntimeException(e); } }, () -> logger.error("No response body.")); logger.info("HTTP Response code is {}", response.httpResponse().statusCode()); } } catch (URISyntaxException | IOException e) { logger.error(e.getMessage(), e); } return byteArrayOutputStream.toByteArray(); }

请参阅 GitHub 上的完整示例测试

为上传生成预签名 URL,然后上传文件(PUT 请求)

以下示例由两部分组成。

  • 第 1 部分:Alice 生成用于上传对象的预签名 URL。

  • 第 2 部分:Bob 使用预签名 URL 上传文件。

第 1 部分:生成 URL

Alice 已有一个 S3 桶。她使用以下代码生成一个 URL 字符串,Bob 可以在后续的 PUT 请求中使用该字符串。

import com.example.s3.util.PresignUrlUtils; import org.slf4j.Logger; import software.amazon.awssdk.core.internal.sync.FileContentStreamProvider; import software.amazon.awssdk.http.HttpExecuteRequest; import software.amazon.awssdk.http.HttpExecuteResponse; import software.amazon.awssdk.http.SdkHttpClient; import software.amazon.awssdk.http.SdkHttpMethod; import software.amazon.awssdk.http.SdkHttpRequest; import software.amazon.awssdk.http.apache.ApacheHttpClient; import software.amazon.awssdk.services.s3.S3Client; import software.amazon.awssdk.services.s3.model.PutObjectRequest; import software.amazon.awssdk.services.s3.model.S3Exception; import software.amazon.awssdk.services.s3.presigner.S3Presigner; import software.amazon.awssdk.services.s3.presigner.model.PresignedPutObjectRequest; import software.amazon.awssdk.services.s3.presigner.model.PutObjectPresignRequest; import java.io.File; import java.io.IOException; import java.io.OutputStream; import java.io.RandomAccessFile; import java.net.HttpURLConnection; import java.net.URISyntaxException; import java.net.URL; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; import java.nio.ByteBuffer; import java.nio.channels.FileChannel; import java.nio.file.Path; import java.nio.file.Paths; import java.time.Duration; import java.util.Map; import java.util.UUID;
/* Create a presigned URL to use in a subsequent PUT request */ public String createPresignedUrl(String bucketName, String keyName, Map<String, String> metadata) { try (S3Presigner presigner = S3Presigner.create()) { PutObjectRequest objectRequest = PutObjectRequest.builder() .bucket(bucketName) .key(keyName) .metadata(metadata) .build(); PutObjectPresignRequest presignRequest = PutObjectPresignRequest.builder() .signatureDuration(Duration.ofMinutes(10)) // The URL expires in 10 minutes. .putObjectRequest(objectRequest) .build(); PresignedPutObjectRequest presignedRequest = presigner.presignPutObject(presignRequest); String myURL = presignedRequest.url().toString(); logger.info("Presigned URL to upload a file to: [{}]", myURL); logger.info("HTTP method: [{}]", presignedRequest.httpRequest().method()); return presignedRequest.url().toExternalForm(); } }

第 2 部分:上传文件对象

Bob 使用以下三个代码选项之一来上传文件。

/* Use the JDK HttpURLConnection (since v1.1) class to do the upload. */ public void useHttpUrlConnectionToPut(String presignedUrlString, File fileToPut, Map<String, String> metadata) { logger.info("Begin [{}] upload", fileToPut.toString()); try { URL presignedUrl = new URL(presignedUrlString); HttpURLConnection connection = (HttpURLConnection) presignedUrl.openConnection(); connection.setDoOutput(true); metadata.forEach((k, v) -> connection.setRequestProperty("x-amz-meta-" + k, v)); connection.setRequestMethod("PUT"); OutputStream out = connection.getOutputStream(); try (RandomAccessFile file = new RandomAccessFile(fileToPut, "r"); FileChannel inChannel = file.getChannel()) { ByteBuffer buffer = ByteBuffer.allocate(8192); //Buffer size is 8k while (inChannel.read(buffer) > 0) { buffer.flip(); for (int i = 0; i < buffer.limit(); i++) { out.write(buffer.get()); } buffer.clear(); } } catch (IOException e) { logger.error(e.getMessage(), e); } out.close(); connection.getResponseCode(); logger.info("HTTP response code is " + connection.getResponseCode()); } catch (S3Exception | IOException e) { logger.error(e.getMessage(), e); } }
/* Use the JDK HttpClient (since v11) class to do the upload. */ public void useHttpClientToPut(String presignedUrlString, File fileToPut, Map<String, String> metadata) { logger.info("Begin [{}] upload", fileToPut.toString()); HttpRequest.Builder requestBuilder = HttpRequest.newBuilder(); metadata.forEach((k, v) -> requestBuilder.header("x-amz-meta-" + k, v)); HttpClient httpClient = HttpClient.newHttpClient(); try { final HttpResponse<Void> response = httpClient.send(requestBuilder .uri(new URL(presignedUrlString).toURI()) .PUT(HttpRequest.BodyPublishers.ofFile(Path.of(fileToPut.toURI()))) .build(), HttpResponse.BodyHandlers.discarding()); logger.info("HTTP response code is " + response.statusCode()); } catch (URISyntaxException | InterruptedException | IOException e) { logger.error(e.getMessage(), e); } }
/* Use the AWS SDK for Java V2 SdkHttpClient class to do the upload. */ public void useSdkHttpClientToPut(String presignedUrlString, File fileToPut, Map<String, String> metadata) { logger.info("Begin [{}] upload", fileToPut.toString()); try { URL presignedUrl = new URL(presignedUrlString); SdkHttpRequest.Builder requestBuilder = SdkHttpRequest.builder() .method(SdkHttpMethod.PUT) .uri(presignedUrl.toURI()); // Add headers metadata.forEach((k, v) -> requestBuilder.putHeader("x-amz-meta-" + k, v)); // Finish building the request. SdkHttpRequest request = requestBuilder.build(); HttpExecuteRequest executeRequest = HttpExecuteRequest.builder() .request(request) .contentStreamProvider(new FileContentStreamProvider(fileToPut.toPath())) .build(); try (SdkHttpClient sdkHttpClient = ApacheHttpClient.create()) { HttpExecuteResponse response = sdkHttpClient.prepareRequest(executeRequest).call(); logger.info("Response code: {}", response.httpResponse().statusCode()); } } catch (URISyntaxException | IOException e) { logger.error(e.getMessage(), e); } }

请参阅 GitHub 上的完整示例测试