var params = {
    Bucket: process.env.BUCKET,
    Fields: {
      key: body.key,
      acl: "public-read",
      ContentType:body.type,
      ContentMD5: body.type
    },
    Conditions: [
      ["content-length-range", 1, 10485000]
    ]
  };

form.append('key',result.sign.fields['key']);//
form.append('X-Amz-Algorithm',result.sign.fields['X-Amz-Algorithm']);
form.append('X-Amz-Credential', result.sign.fields['X-Amz-Credential']);
form.append('Policy', result.sign.fields['Policy']);
form.append('X-Amz-Signature', result.sign.fields['X-Amz-Signature']);
form.append('X-Amz-Date', result.sign.fields['X-Amz-Date']);
form.append('acl', 'public-read');
form.append('ContentMD5', image.type);
form.append('ContentType', image.type);
form.append('file', image);