Python 使用 Boto3 作为字符串打开 S3 对象
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Open S3 object as a string with Boto3
提问by Gahl Levy
I'm aware that with Boto 2 it's possible to open an S3 object as a string with: get_contents_as_string()
我知道使用 Boto 2 可以将 S3 对象作为字符串打开： get_contents_as_string()
Is there an equivalent function in boto3 ?
boto3 中是否有等效功能？
回答by Gahl Levy
This isn't in the boto3 documentation. This worked for me:
这不在 boto3 文档中。这对我有用：
object.get()["Body"].read()
object being an s3 object: http://boto3.readthedocs.org/en/latest/reference/services/s3.html#object
对象是 s3 对象：http: //boto3.readthedocs.org/en/latest/reference/services/s3.html#object
回答by Kamil Sindi
readwill return bytes. At least for Python 3, if you want to return a string, you have to decode using the right encoding:
read将返回字节。至少对于 Python 3，如果你想返回一个字符串，你必须使用正确的编码进行解码：
import boto3
s3 = boto3.resource('s3')
obj = s3.Object(bucket, key)
obj.get()['Body'].read().decode('utf-8')
回答by Pyglouthon
If body contains a io.StringIO, you have to do like below:
如果 body 包含 io.StringIO，则必须执行以下操作：
object.get()['Body'].getvalue()
回答by EvgenyKolyakov
I had a problem to read/parse the object from S3 because of .get()using Python 2.7 inside an AWS Lambda.
由于.get()在 AWS Lambda中使用 Python 2.7，我在从 S3 读取/解析对象时遇到问题。
I added json to the example to show it became parsable :)
我在示例中添加了 json 以显示它可以解析:)
import boto3
import json
s3 = boto3.client('s3')
obj = s3.get_object(Bucket=bucket, Key=key)
j = json.loads(obj['Body'].read())
NOTE (for python 2.7): My object is all ascii, so I don't need .decode('utf-8')
注意（对于 python 2.7）：我的对象都是 ascii，所以我不需要 .decode('utf-8')
NOTE (for python 3.6+): We moved to python 3.6 and discovered that read()now returns bytesso if you want to get a string out of it, you must use:
注意（对于 python 3.6+）：我们转移到 python 3.6 并发现read()现在返回，bytes所以如果你想从中获取一个字符串，你必须使用：
j = json.loads(obj['Body'].read().decode('utf-8'))
j = json.loads(obj['Body'].read().decode('utf-8'))
回答by Gatsby Lee
Python3 + Using boto3 API approach.
Python3 + 使用 boto3 API 方法。
By using S3.Client.download_fileobj APIand Python file-like object, S3 Object content can be retrieved to memory.
通过使用S3.Client.download_fileobj API和Python 类文件对象，可以将 S3 对象内容检索到内存中。
Since the retrieved content is bytes, in order to convert to str, it need to be decoded.
由于检索到的内容是字节，为了转换为str，需要对其进行解码。
import io
import boto3
client = boto3.client('s3')
bytes_buffer = io.BytesIO()
client.download_fileobj(Bucket=bucket_name, Key=object_key, Fileobj=bytes_buffer)
byte_value = bytes_buffer.getvalue()
str_value = byte_value.decode() #python3, default decoding is utf-8
