我想要的图像上传到Amazon S3这个红宝石code：

 要求净/ HTTP /后/多部分

    URL = URI.parse（'http://public.domain.com/）
    File.open方法（/ tmp目录/ uup_1114.jpg）做| JPG |
      REQ =网:: HTTP ::邮政:: Multipart.new url.path，
                      '键'=＆GT; s3_key，
                      ACL=＆GT; s3_acl，
                      CONTENT_TYPE'=＆GT; s3_content_type，
                      AWSAccessKeyId'=＆GT; s3_AWSAccessKeyId，
                      政策=＆GT; s3_policy，
                      签名=＆GT; s3_signature，
                      文件=＆GT; UploadIO.new（JPG，图像/ PNG，image.jpg文件）
      RES =净:: HTTP.start（url.host，url.port）办| HTTP |
        http.request（REQ）
      结束
    结束
 

和我从亚马逊获得错误：

InvalidArgument：斗POST必须包含一个名为键字段。如果它被指定，请检查字段的顺序。

看起来像'文件'场在前的查询，并导致上述错误。我想不出如何发布文件字段在查询结束。

我已经成功地使用了AWS-SDK的红宝石创建后的形式。但是，在我的情况下，我是让用户通过浏览器上传到AWS账户。不过，这可能帮助：

在AWS-SDK提供了一个呼叫一桶名为presigned_post（选件），创建一个pre签订后工作正常。

另请参阅 https://forums.aws.amazon.com/thread.jspa？邮件ID = 296867＆放大器;＃296867

I'm trying to upload image to Amazon S3 with this Ruby code:

    require 'net/http/post/multipart'

    url = URI.parse('http://public.domain.com/')
    File.open("/tmp/uup_1114.jpg") do |jpg|
      req = Net::HTTP::Post::Multipart.new url.path,
                      'key' => s3_key,
                      'acl' => s3_acl,
                      'content_type' => s3_content_type,
                      'AWSAccessKeyId' => s3_AWSAccessKeyId,
                      'policy' => s3_policy,
                      'signature' => s3_signature,
                      "file" => UploadIO.new(jpg, "image/png", "image.jpg")
      res = Net::HTTP.start(url.host, url.port) do |http|
        http.request(req)
      end
    end

And I'm getting error from Amazon:

InvalidArgument: Bucket POST must contain a field named 'key'. If it is specified, please check the order of the fields.

Looks like 'file' field goes first in query and that causes an error above. I can't figure out how to post file field at the end of query.

I have successfully used the AWS-SDK in ruby to create post forms. But in my case I was getting users to upload from a browser into an AWS account. Still this may help:

the aws-sdk has a call on a bucket called presigned_post(options) that creates a pre signed post that works fine.

See also https://forums.aws.amazon.com/thread.jspa?messageID=296867&#296867