api: Enhance presignedGetObject API to support request params. (#488)

This is needed in cases when certain types of responses are
expected for a GET on presigned requests.

Supports response header overrides for

 [ response-expires,
   response-content-type,
   response-cache-control,
   response-content-disposition ]

Author: harshavardhana

api/src/main/java/io/minio/MinioClient.java

@@ -1355,15 +1355,17 @@ public void getObject(String bucketName, String objectName, String fileName)
 
 
   /**
-   * Returns an presigned URL to download the object in the bucket with given expiry time.
+   * Returns an presigned URL to download the object in the bucket with given expiry time with custom request params.
    *
    * </p><b>Example:</b><br>
-   * <pre>{@code String url = minioClient.presignedGetObject("my-bucketname", "my-objectname", 60 * 60 * 24);
+   * <pre>{@code String url = minioClient.presignedGetObject("my-bucketname", "my-objectname", 60 * 60 * 24, reqParams);
    * System.out.println(url); }</pre>
    *
    * @param bucketName  Bucket name.
    * @param objectName  Object name in the bucket.
    * @param expires     Expiration time in seconds of presigned URL.
+   * @param reqParams   Override values for set of response headers. Currently supported request parameters are
+   *                    [response-expires, response-content-type, response-cache-control, response-content-disposition]
    *
    * @return string contains URL to download the object.
    *
@@ -1373,7 +1375,8 @@ public void getObject(String bucketName, String objectName, String fileName)
    * @throws NoSuchAlgorithmException     upon requested algorithm was not found during signature calculation
    * @throws InvalidExpiresRangeException upon input expires is out of range
    */
-  public String presignedGetObject(String bucketName, String objectName, Integer expires)
+  public String presignedGetObject(String bucketName, String objectName, Integer expires,
+                                   Map<String, String> reqParams)
     throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidExpiresRangeException {
@@ -1386,11 +1389,37 @@ public String presignedGetObject(String bucketName, String objectName, Integer e
     String region = BucketRegionCache.INSTANCE.region(bucketName);
 
     Request request = createRequest(Method.GET, bucketName, objectName, region,
-                                    null, null, null, null, 0);
+                                    null, reqParams, null, null, 0);
     HttpUrl url = Signer.presignV4(request, region, accessKey, secretKey, expires);
     return url.toString();
   }
 
+  /**
+   * Returns an presigned URL to download the object in the bucket with given expiry time.
+   *
+   * </p><b>Example:</b><br>
+   * <pre>{@code String url = minioClient.presignedGetObject("my-bucketname", "my-objectname", 60 * 60 * 24);
+   * System.out.println(url); }</pre>
+   *
+   * @param bucketName  Bucket name.
+   * @param objectName  Object name in the bucket.
+   * @param expires     Expiration time in seconds of presigned URL.
+   *
+   * @return string contains URL to download the object.
+   *
+   * @throws InvalidBucketNameException   upon an invalid bucket name
+   * @throws InvalidKeyException          upon an invalid access key or secret key
+   * @throws IOException                  upon signature calculation failure
+   * @throws NoSuchAlgorithmException     upon requested algorithm was not found during signature calculation
+   * @throws InvalidExpiresRangeException upon input expires is out of range
+   */
+  public String presignedGetObject(String bucketName, String objectName, Integer expires)
+    throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
+           InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
+           InternalException, InvalidExpiresRangeException {
+    return presignedGetObject(bucketName, objectName, expires, null);
+  }
+
 
   /**
    * Returns an presigned URL to download the object in the bucket with default expiry time.
@@ -1413,7 +1442,7 @@ public String presignedGetObject(String bucketName, String objectName)
     throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidExpiresRangeException {
-    return presignedGetObject(bucketName, objectName, DEFAULT_EXPIRY_TIME);
+    return presignedGetObject(bucketName, objectName, DEFAULT_EXPIRY_TIME, null);
   }
 
 

functional/FunctionalTest.java

@@ -141,7 +141,7 @@ public static void removeBucket_test() throws Exception {
   }
 
   /**
-   * Tear down test setup. 
+   * Tear down test setup.
    */
   public static void setup() throws Exception {
     client.makeBucket(bucketName);
@@ -595,6 +595,70 @@ public static void presignedGetObject_test2() throws Exception {
     client.removeObject(bucketName, fileName);
   }
 
+  /**
+   * public String presignedGetObject(String bucketName, String objectName, Integer expires, Map reqParams).
+   */
+  public static void presignedGetObject_test3() throws Exception {
+    System.out.println("Test: presignedGetObject(String bucketName, String objectName, Integer expires, "
+                       + "Map<String, String> reqParams)");
+    String fileName = createFile(3 * MB);
+    client.putObject(bucketName, fileName, fileName);
+
+    Map<String, String> reqParams = new HashMap<>();
+    reqParams.put("response-content-type", "application/json");
+
+    String urlString = client.presignedGetObject(bucketName, fileName, 3600, reqParams);
+    Request.Builder requestBuilder = new Request.Builder();
+    Request request = requestBuilder
+        .url(HttpUrl.parse(urlString))
+        .method("GET", null)
+        .build();
+    OkHttpClient transport = new OkHttpClient();
+    Response response = transport.newCall(request).execute();
+
+    if (response != null) {
+      if (response.isSuccessful()) {
+        OutputStream os = Files.newOutputStream(Paths.get(fileName + ".downloaded"), StandardOpenOption.CREATE);
+        ByteStreams.copy(response.body().byteStream(), os);
+        if (!response.header("Content-Type").equals("application/json")) {
+          throw new Exception("[FAILED] Test: presignedGetObject(String bucketName, String objectName,"
+                              + " Integer expires, Map<String, String> reqParams)"
+                              + ", Response: " + response);
+        }
+        response.body().close();
+        os.close();
+      } else {
+        String errorXml = "";
+
+        // read entire body stream to string.
+        Scanner scanner = new java.util.Scanner(response.body().charStream()).useDelimiter("\\A");
+        if (scanner.hasNext()) {
+          errorXml = scanner.next();
+        }
+
+        throw new Exception("[FAILED] Test: presignedGetObject(String bucketName, String objectName,"
+                            + " Integer expires, Map<String, String> reqParams)"
+                            + ", Response: " + response
+                            + ", Error: " + errorXml);
+      }
+    } else {
+      throw new Exception("[FAILED] Test: presignedGetObject(String bucketName, String objectName,"
+                          + " Integer expires, Map<String, String> reqParams)"
+                          + ", Error: <No response from server>");
+    }
+
+    if (!Arrays.equals(Files.readAllBytes(Paths.get(fileName)),
+                       Files.readAllBytes(Paths.get(fileName + ".downloaded")))) {
+      throw new Exception("[FAILED] Test: presignedGetObject(String bucketName, String objectName,"
+                          + " Integer expires, Map<String, String> reqParams)"
+                          + ", Error: <Content differs>");
+    }
+
+    Files.delete(Paths.get(fileName));
+    Files.delete(Paths.get(fileName + ".downloaded"));
+    client.removeObject(bucketName, fileName);
+  }
+
   /**
    * public String presignedPutObject(String bucketName, String objectName).
    */
@@ -801,6 +865,7 @@ public static void main(String[] args) {
 
       presignedGetObject_test1();
       presignedGetObject_test2();
+      presignedGetObject_test3();
 
       presignedPutObject_test1();
       presignedPutObject_test2();