Method: Aws::S3::Client#get_object

Defined in:

lib/aws-sdk-s3/client.rb

#get_object(params = {}) ⇒ Types::GetObjectOutput

Retrieves objects from Amazon S3. To use ‘GET`, you must have `READ` access to the object. If you grant `READ` access to the anonymous user, you can return the object without using an authorization header.

An Amazon S3 bucket has no directory hierarchy such as you would find in a typical computer file system. You can, however, create a logical hierarchy by using object key names that imply a folder structure. For example, instead of naming an object ‘sample.jpg`, you can name it `photos/2006/February/sample.jpg`.

To get an object from such a logical hierarchy, specify the full key name for the object in the ‘GET` operation. For a virtual hosted-style request example, if you have the object `photos/2006/February/sample.jpg`, specify the resource as `/photos/2006/February/sample.jpg`. For a path-style request example, if you have the object `photos/2006/February/sample.jpg` in the bucket named `examplebucket`, specify the resource as `/examplebucket/photos/2006/February/sample.jpg`. For more information about request types, see [HTTP Host Header Bucket Specification].

To distribute large files to many people, you can save bandwidth costs by using BitTorrent. For more information, see [Amazon S3 Torrent]. For more information about returning the ACL of an object, see GetObjectAcl.

If the object you are retrieving is stored in the GLACIER or DEEP_ARCHIVE storage classes, before you can retrieve the object you must first restore a copy using . Otherwise, this operation returns an ‘InvalidObjectStateError` error. For information about restoring archived objects, see [Restoring Archived Objects].

Encryption request headers, like ‘x-amz-server-side-encryption`, should not be sent for GET requests if your object uses server-side encryption with CMKs stored in AWS KMS (SSE-KMS) or server-side encryption with Amazon S3–managed encryption keys (SSE-S3). If your object does use these types of keys, you’ll get an HTTP 400 BadRequest error.

If you encrypt an object by using server-side encryption with customer-provided encryption keys (SSE-C) when you store the object in Amazon S3, then when you GET the object, you must use the following headers:

• x-amz-server-side​-encryption​-customer-algorithm

• x-amz-server-side​-encryption​-customer-key

• x-amz-server-side​-encryption​-customer-key-MD5

For more information about SSE-C, see [Server-Side Encryption (Using Customer-Provided Encryption Keys)].

Assuming you have permission to read object tags (permission for the ‘s3:GetObjectVersionTagging` action), the response also returns the `x-amz-tagging-count` header that provides the count of number of tags associated with the object. You can use GetObjectTagging to retrieve the tag set associated with an object.

Permissions

You need the ‘s3:GetObject` permission for this operation. For more information, see [Specifying Permissions in a Policy]. If the object you request does not exist, the error Amazon S3 returns depends on whether you also have the `s3:ListBucket` permission.

• If you have the ‘s3:ListBucket` permission on the bucket, Amazon S3 will return an HTTP status code 404 (“no such key”) error.

• If you don’t have the ‘s3:ListBucket` permission, Amazon S3 will return an HTTP status code 403 (“access denied”) error.

Versioning

By default, the GET operation returns the current version of an object. To return a different version, use the ‘versionId` subresource.

<note markdown=“1”> If the current version of the object is a delete marker, Amazon S3 behaves as if the object was deleted and includes ‘x-amz-delete-marker: true` in the response.

</note>

For more information about versioning, see PutBucketVersioning.

**Overriding Response Header Values**

There are times when you want to override certain response header values in a GET response. For example, you might override the Content-Disposition response header value in your GET request.

You can override values for a set of response headers using the following query parameters. These response header values are sent only on a successful request, that is, when status code 200 OK is returned. The set of headers you can override using these parameters is a subset of the headers that Amazon S3 accepts when you create an object. The response headers that you can override for the GET response are ‘Content-Type`, `Content-Language`, `Expires`, `Cache-Control`, `Content-Disposition`, and `Content-Encoding`. To override these header values in the GET response, you use the following request parameters.

<note markdown=“1”> You must sign the request, either using an Authorization header or a presigned URL, when using these parameters. They cannot be used with an unsigned (anonymous) request.

</note>

• ‘response-content-type`

• ‘response-content-language`

• ‘response-expires`

• ‘response-cache-control`

• ‘response-content-disposition`

• ‘response-content-encoding`

**Additional Considerations about Request Headers**

If both of the ‘If-Match` and `If-Unmodified-Since` headers are present in the request as follows: `If-Match` condition evaluates to `true`, and; `If-Unmodified-Since` condition evaluates to `false`; then, S3 returns 200 OK and the data requested.

If both of the ‘If-None-Match` and `If-Modified-Since` headers are present in the request as follows:` If-None-Match` condition evaluates to `false`, and; `If-Modified-Since` condition evaluates to `true`; then, S3 returns 304 Not Modified response code.

For more information about conditional requests, see [RFC 7232].

The following operations are related to ‘GetObject`:

• ListBuckets

• GetObjectAcl

[1]: docs.aws.amazon.com/AmazonS3/latest/dev/VirtualHosting.html#VirtualHostingSpecifyBucket [2]: docs.aws.amazon.com/AmazonS3/latest/dev/S3Torrent.html [3]: docs.aws.amazon.com/AmazonS3/latest/dev/restoring-objects.html [4]: docs.aws.amazon.com/AmazonS3/latest/dev/ServerSideEncryptionCustomerKeys.html [5]: docs.aws.amazon.com/AmazonS3/latest/dev/using-with-s3-actions.html [6]: tools.ietf.org/html/rfc7232

Examples:

Example: To retrieve a byte range of an object

# The following example retrieves an object for an S3 bucket. The request specifies the range header to retrieve a
# specific byte range.

resp = client.get_object({
  bucket: "examplebucket", 
  key: "SampleFile.txt", 
  range: "bytes=0-9", 
})

resp.to_h outputs the following:
{
  accept_ranges: "bytes", 
  content_length: 10, 
  content_range: "bytes 0-9/43", 
  content_type: "text/plain", 
  etag: "\"0d94420ffd0bc68cd3d152506b97a9cc\"", 
  last_modified: Time.parse("Thu, 09 Oct 2014 22:57:28 GMT"), 
  metadata: {
  }, 
  version_id: "null", 
}

Example: To retrieve an object

# The following example retrieves an object for an S3 bucket.

resp = client.get_object({
  bucket: "examplebucket", 
  key: "HappyFace.jpg", 
})

resp.to_h outputs the following:
{
  accept_ranges: "bytes", 
  content_length: 3191, 
  content_type: "image/jpeg", 
  etag: "\"6805f2cfc46c0f04559748bb039d69ae\"", 
  last_modified: Time.parse("Thu, 15 Dec 2016 01:19:41 GMT"), 
  metadata: {
  }, 
  tag_count: 2, 
  version_id: "null", 
}

Download an object to disk

# stream object directly to disk
resp = s3.get_object(
  response_target: '/path/to/file',
  bucket: 'bucket-name',
  key: 'object-key')

# you can still access other response data
resp.metadata #=> { ... }
resp.etag #=> "..."

Download object into memory

# omit :response_target to download to a StringIO in memory
resp = s3.get_object(bucket: 'bucket-name', key: 'object-key')

# call #read or #string on the response body
resp.body.read
#=> '...'

Streaming data to a block

# WARNING: yielding data to a block disables retries of networking errors
File.open('/path/to/file', 'wb') do |file|
  s3.get_object(bucket: 'bucket-name', key: 'object-key') do |chunk|
    file.write(chunk)
  end
end

Request syntax with placeholder values

resp = client.get_object({
  bucket: "BucketName", # required
  if_match: "IfMatch",
  if_modified_since: Time.now,
  if_none_match: "IfNoneMatch",
  if_unmodified_since: Time.now,
  key: "ObjectKey", # required
  range: "Range",
  response_cache_control: "ResponseCacheControl",
  response_content_disposition: "ResponseContentDisposition",
  response_content_encoding: "ResponseContentEncoding",
  response_content_language: "ResponseContentLanguage",
  response_content_type: "ResponseContentType",
  response_expires: Time.now,
  version_id: "ObjectVersionId",
  sse_customer_algorithm: "SSECustomerAlgorithm",
  sse_customer_key: "SSECustomerKey",
  sse_customer_key_md5: "SSECustomerKeyMD5",
  request_payer: "requester", # accepts requester
  part_number: 1,
})

Response structure

resp.body #=> IO
resp.delete_marker #=> Boolean
resp.accept_ranges #=> String
resp.expiration #=> String
resp.restore #=> String
resp.last_modified #=> Time
resp.content_length #=> Integer
resp.etag #=> String
resp.missing_meta #=> Integer
resp.version_id #=> String
resp.cache_control #=> String
resp.content_disposition #=> String
resp.content_encoding #=> String
resp.content_language #=> String
resp.content_range #=> String
resp.content_type #=> String
resp.expires #=> Time
resp.expires_string #=> String
resp.website_redirect_location #=> String
resp.server_side_encryption #=> String, one of "AES256", "aws:kms"
resp.metadata #=> Hash
resp.metadata["MetadataKey"] #=> String
resp.sse_customer_algorithm #=> String
resp.sse_customer_key_md5 #=> String
resp.ssekms_key_id #=> String
resp.storage_class #=> String, one of "STANDARD", "REDUCED_REDUNDANCY", "STANDARD_IA", "ONEZONE_IA", "INTELLIGENT_TIERING", "GLACIER", "DEEP_ARCHIVE"
resp.request_charged #=> String, one of "requester"
resp.replication_status #=> String, one of "COMPLETE", "PENDING", "FAILED", "REPLICA"
resp.parts_count #=> Integer
resp.tag_count #=> Integer
resp.object_lock_mode #=> String, one of "GOVERNANCE", "COMPLIANCE"
resp.object_lock_retain_until_date #=> Time
resp.object_lock_legal_hold_status #=> String, one of "ON", "OFF"

Parameters:

• params (Hash) (defaults to: {}) —

  ({})

Options Hash (params):

• :response_target (String, IO) —

  Where to write response data, file path, or IO object.

• :bucket (required, String) —

  The bucket name containing the object.

  When using this API with an access point, you must direct requests to the access point hostname. The access point hostname takes the form AccessPointName-AccountId.s3-accesspoint.Region.amazonaws.com. When using this operation using an access point through the AWS SDKs, you provide the access point ARN in place of the bucket name. For more information about access point ARNs, see [Using Access Points] in the *Amazon Simple Storage Service Developer Guide*.

  [1]: docs.aws.amazon.com/AmazonS3/latest/dev/using-access-points.html

• :if_match (String) —

  Return the object only if its entity tag (ETag) is the same as the one specified, otherwise return a 412 (precondition failed).

• :if_modified_since (Time, DateTime, Date, Integer, String) —

  Return the object only if it has been modified since the specified time, otherwise return a 304 (not modified).

• :if_none_match (String) —

  Return the object only if its entity tag (ETag) is different from the one specified, otherwise return a 304 (not modified).

• :if_unmodified_since (Time, DateTime, Date, Integer, String) —

  Return the object only if it has not been modified since the specified time, otherwise return a 412 (precondition failed).

• :key (required, String) —

  Key of the object to get.

• :range (String) —

  Downloads the specified range bytes of an object. For more information about the HTTP Range header, see [www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35]().

• :response_cache_control (String) —

  Sets the ‘Cache-Control` header of the response.

• :response_content_disposition (String) —

  Sets the ‘Content-Disposition` header of the response

• :response_content_encoding (String) —

  Sets the ‘Content-Encoding` header of the response.

• :response_content_language (String) —

  Sets the ‘Content-Language` header of the response.

• :response_content_type (String) —

  Sets the ‘Content-Type` header of the response.

• :response_expires (Time, DateTime, Date, Integer, String) —

  Sets the ‘Expires` header of the response.

• :version_id (String) —

  VersionId used to reference a specific version of the object.

• :sse_customer_algorithm (String) —

  Specifies the algorithm to use to when encrypting the object (for example, AES256).

• :sse_customer_key (String) —

  Specifies the customer-provided encryption key for Amazon S3 to use in encrypting data. This value is used to store the object and then it is discarded; Amazon S3 does not store the encryption key. The key must be appropriate for use with the algorithm specified in the ‘x-amz-server-side​-encryption​-customer-algorithm` header.

• :sse_customer_key_md5 (String) —

  Specifies the 128-bit MD5 digest of the encryption key according to RFC 1321. Amazon S3 uses this header for a message integrity check to ensure that the encryption key was transmitted without error.

• :request_payer (String) —

  Confirms that the requester knows that they will be charged for the request. Bucket owners need not specify this parameter in their requests. For information about downloading objects from requester pays buckets, see [Downloading Objects in Requestor Pays Buckets] in the *Amazon S3 Developer Guide*.

  [1]: docs.aws.amazon.com/AmazonS3/latest/dev/ObjectsinRequesterPaysBuckets.html

• :part_number (Integer) —

  Part number of the object being read. This is a positive integer between 1 and 10,000. Effectively performs a ‘ranged’ GET request for the part specified. Useful for downloading just a part of an object.

Returns:

• (Types::GetObjectOutput) —

  Returns a response object which responds to the following methods:

  • #body => IO

  • #delete_marker => Boolean

  • #accept_ranges => String

  • #expiration => String

  • #restore => String

  • #last_modified => Time

  • #content_length => Integer

  • #etag => String

  • #missing_meta => Integer

  • #version_id => String

  • #cache_control => String

  • #content_disposition => String

  • #content_encoding => String

  • #content_language => String

  • #content_range => String

  • #content_type => String

  • #expires => Time

  • #expires_string => String

  • #website_redirect_location => String

  • #server_side_encryption => String

  • #metadata => Hash&lt;String,String&gt;

  • #sse_customer_algorithm => String

  • #sse_customer_key_md5 => String

  • #ssekms_key_id => String

  • #storage_class => String

  • #request_charged => String

  • #replication_status => String

  • #parts_count => Integer

  • #tag_count => Integer

  • #object_lock_mode => String

  • #object_lock_retain_until_date => Time

  • #object_lock_legal_hold_status => String

See Also:

• AWS API Documentation

# File 'lib/aws-sdk-s3/client.rb', line 4698

def get_object(params = {}, options = {}, &block)
  req = build_request(:get_object, params)
  req.send_request(options, &block)
end