使用POST的基于Amazon AWS S3浏览器的上传 -

时间:2015-12-18 04:40:32

标签: python post amazon-web-services amazon-s3 boto3

我正在构建一个包含文件上传功能的Web应用程序。我的目标是从用户直接上传到S3存储桶。策略是预先签署一个POST请求,该请求将作为表单提交。

包版广告出现SignatureDoesNotMatch错误 - 据我所知,我已经完全符合文档,并且已经探索了很多选项,但仍然无法解决。我能够生成预先签名的下载链接。

引用:

AWS POST documentation

Example

boto3 generate_presigned_post reference

生成签名请求:

def s3_upload_creds(name, user):
    s3 = boto3.client('s3')
    key = '${filename}'
    region = 'us-east-1'
    date_short = datetime.datetime.utcnow().strftime('%Y%m%d')
    date_long = datetime.datetime.utcnow().strftime('%Y%m%dT000000Z')
    fields = { 
        'acl': 'private',
        'date': date_short,
        'region': region,
        'x-amz-algorithm': 'AWS4-HMAC-SHA256',
        'x-amz-date': date_long
    }

    return s3.generate_presigned_post(
        Bucket = 'leasy',
        Fields = fields,
        Key = key,
        Conditions = [
            {'acl': 'private'},
            {'x-amz-algorithm': 'AWS4-HMAC-SHA256'},
            {'x-amz-credential': '/'.join(['AKI--snip--', date_short, region, 's3', 'aws4_request'])},
            {'x-amz-date': date_long}
        ]
    )

上传表单(上面填充了fields):

<html>
  <head>

    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

  </head>
  <body>
  {{ creds }}
  <form action="{{ creds.url }}" method="post" enctype="multipart/form-data">
    Key to upload: 
    <input type="input"  name="key" value="${filename}" /><br />
    <input type="input"  name="acl" value="{{ creds.fields.acl }}" />
    <input type="hidden" name="Policy" value="{{ creds.fields.policy }}" />
    <input type="text"   name="X-Amz-Algorithm" value="{{ creds.fields['x-amz-algorithm'] }}" />
    <input type="input"   name="X-Amz-Credential" value="{{ creds.fields.AWSAccessKeyId }}/{{ creds.fields.date }}/us-east-1/s3/aws4_request" />
    <input type="input"   name="X-Amz-Date" value="{{ creds.fields['x-amz-date'] }}" />
    <input type="input" name="X-Amz-Signature" value="{{ creds.fields.signature }}" />
    File: 
    <input type="file"   name="file" /> <br />
    <!-- The elements after this will be ignored -->
    <input type="submit" name="submit" value="Upload to Amazon S3" />
  </form>

</html>

回复的相关部分:

<Error>
<Code>SignatureDoesNotMatch</Code>
<Message>
The request signature we calculated does not match the signature you provided. Check your key and signing method.
</Message>
<AWSAccessKeyId>AKI--snip--</AWSAccessKeyId>
<StringToSign>
eyJjb25kaXRpb25zIjogW3siYWNsIjogInByaXZhdGUifSwgeyJ4LWFtei1hbGdvcml0aG0iOiAiQVdTNC1ITUFDLVNIQTI1NiJ9LCB7IngtYW16LWNyZWRlbnRpYWwiOiAiQUtJQUlDVjRNVlBUUlFHU1lLV1EvMjAxNTEyMTgvdXMtZWFzdC0xL3MzL2F3czRfcmVxdWVzdCJ9LCB7IngtYW16LWRhdGUiOiAiMjAxNTEyMThUMDAwMDAwWiJ9LCB7ImJ1Y2tldCI6ICJsZWFzeSJ9LCBbInN0YXJ0cy13aXRoIiwgIiRrZXkiLCAiIl1dLCAiZXhwaXJhdGlvbiI6ICIyMDE1LTEyLTE4VDA1OjEwOjU2WiJ9
</StringToSign>
<SignatureProvided>wDOjsBRc0iIW7JNtz/4GHgfvKaU=</SignatureProvided>

上述错误中StringToSign的Base64解码:

{u'conditions': [{u'acl': u'private'},
                 {u'x-amz-algorithm': u'AWS4-HMAC-SHA256'},
                 {u'x-amz-credential': u'AKI--snip--/20151218/us-east-1/s3/aws4_request'},
                 {u'x-amz-date': u'20151218T000000Z'},
                 {u'bucket': u'leasy'},
                 [u'starts-with', u'$key', u'']],
 u'expiration': u'2015-12-18T04:59:32Z'}

3 个答案:

答案 0 :(得分:5)

找到解决方案:必须明确配置s3客户端以使用亚马逊的新签名v4。发生错误,因为它默认为旧版本,导致不匹配。有点像facepalm - 当时这不是用boto3文档编写的,虽然亚马逊的人说它应该很快。

该方法已简化,因为它现在可以准确返回所需的字段:

def s3_upload_creds(name):
    BUCKET = 'mybucket'
    REGION = 'us-west-1'
    s3 = boto3.client('s3', region_name=REGION, config=Config(signature_version='s3v4'))
    key = '${filename}'
    return s3.generate_presigned_post(
        Bucket = BUCKET,
        Key = key
    )

这意味着可以轻松生成表单:

<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  </head>
  <body>
    {{ creds }}
      <form action="https://mybucket.s3.amazonaws.com" method="post" enctype="multipart/form-data">
        {% for key, value in creds.fields.items() %}
          <input type="hidden" name="{{ key }}" value="{{ value }}" />
        {% endfor %}
      File:
      <input type="file"   name="file" /> <br />
    <input type="submit" name="submit" value="Upload to Amazon S3" />
  </form>
</html>

干杯

答案 1 :(得分:1)

自上次回复以来已经过了几年,但是我在最后一两天都坚持了这一点,所以我将与我分享经验,这可能会有所帮助。

我一直得到错误:“ 403:您提供的AWS Access Key ID在我们的记录中不存在” ,尝试通过我的预签名网址上传到s3存储桶。

>

使用服务器端代码,我能够成功生成与上面类似的预签名网址:

signed_url_dict = self.s3_client.generate_presigned_post(
                self.bucket_name,
                object_name,
                ExpiresIn=300

这返回了一个具有以下结构的字典:

{
    url: "https://___",
    fields: {
        key: "___",
        AWSAccesKeyId: "___",
        x-amz-security-token: "___",
        policy: "___",
        signature: "___"
    }
}

这导致部分内容在2019年与浏览器端javascript有所不同,所需的表单输入似乎已更改。不必像OP那样设置表单,而是必须创建如下所示的表单:

<form action="https://pipeline-poc-ed.s3.amazonaws.com/" method="post" enctype="multipart/form-data" name="upload_form">
            <!-- Copy ALL of the 'fields' key:values returned by S3Client.generate_presigned_post() -->
            <input type="hidden" name="key" value="___" />
            <input type="hidden" name="AWSAccessKeyId" value="___" />
            <input type="hidden" name="policy" value="___"/>
            <input type="hidden" name="signature" value="___" />
            <input type="hidden" name="x-amz-security-token" value="___" />
        File:
            <input type="file"   name="file" /> <br />
            <input type="submit" name="submit" value="Upload to Amazon S3" />
        </form>

我的错误是,我遵循了boto3 1.9.138 docs中的一个示例,并在表单上省略了“ x-amz-security-token”,这非常有必要。可能会进行漫不经心的疏忽,但希望这会对其他人有所帮助。

编辑:我以上的结果基于N. Virginia Lambda函数。当我在俄亥俄州(装有水桶的区域)运行generate_presigned_post(...)时,得到的结果类似于OP:

{
  "url": "https://__",
  "fields": {
    "key": "___",
    "x-amz-algorithm": "___",
    "x-amz-credential": "___",
    "x-amz-date": "___",
    "x-amz-security-token": "___",
    "policy": "___",
    "x-amz-signature": "___"
  }
}

也许函数的结果是特定于区域的?

答案 2 :(得分:0)

就我而言,我正在生成一个使用Base64编码的表单。

该问题是由于Firefox固有地将Policy和Security令牌值编码为在其顶部的Base64编码。

因此存在双重编码,因此签名与要求不符。