Amazon S3的POST的API，并签订NodeJS政策 [英] Amazon S3 POST api, and signing a policy with NodeJS

问题描述

我想获得建，允许用户直接上传文件到我的Amazon S3的桶，从NodeJS动力网站。这似乎是唯一的教程在那里，比 实际亚马逊的文档该 都非常过时了。

I'm trying to get an built that allows users to upload a file directly to my Amazon S3 bucket, from a NodeJS powered website. It seems the only tutorials out there, other than the actual amazon docs for this are all very out of date.

我一直在下面的 本教程 ，对于基本信息，但同样它的过时。它没有方法调用加密正确的，因为它试图原始JavaScript对象传递给更新方法，它抛出一个错误，因为它不是一个字符串或缓冲区。

I've been following this tutorial, for the basic info, but again it's out dated. It doesn't have the method calls to crypto correct, as it tries to pass a raw JavaScript object to the update method, which throws an error because it's not a string or buffer.

我也一直在寻找的源代码的 诺克斯NPM包 。它没有内置的POST支持 - 这我完全理解，因为它是做自检，一旦有合适的领域的浏览器。诺克斯确实出现了有正确的code签署一项政策，我已经尽力让我的code工作在此基础上... ...但同样无济于事。

I've also been looking at the source for the knox npm package. It doesn't have POST support built in - which I totally understand, because it's the browser doing the POST once it has the right fields. Knox does appear to have the right code to sign a policy, and I've tried to get my code working based on this... but again to no avail.

下面是我想出来的，为code。它产生一个base64连接codeD政策，它创建了一个签名...但它是错误的签名根据亚马逊，当我尝试做一个文件上传。

Here is what I've come up with, for code. It produces a base64 encoded policy, and it creates a signature... but it's the wrong signature according to Amazon, when I try to do a file upload.

var crypto = require("crypto");
var config = require("../../amazonConfig.json");

exports.createS3Policy = function(callback) {
  var date = new Date();

  var s3Policy = {
    "expiration": "2014-12-01T12:00:00.000Z",
    "conditions": [
      {"acl": "public-read"}, 
      ["content-length-range", 0, 2147483648],
      {"bucket": "signalleaf"}, 
      ["starts-with", "$Cache-Control", ""],
      ["starts-with", "$Content-Type", ""],
      ["starts-with", "$Content-Disposition", ""],
      ["starts-with", "$Content-Encoding", ""],
      ["starts-with", "$Expires", ""],
      ["starts-with", "$key", "/myfolder/"], 
      {"success_action_redirect": "http://example.com/uploadsuccess"},
    ]
  };

  var stringPolicy = JSON.stringify(s3Policy).toString("utf-8");
  var buffer = Buffer(stringPolicy, "utf-8");

  var encoded = buffer.toString("base64");
  var signature = crypto.createHmac("sha1", config.secretKey)
    .update(new Buffer(stringPolicy, "utf-8")).digest("base64");


  var s3Credentials = {
    s3PolicyBase64: encoded,
    s3Signature: signature
  };

  GLOBAL.s3creds = s3Credentials;

  callback(s3Credentials);
};

我明明做错了什么，在这里。但是，我不知道。任何人都可以帮忙鉴定一下我做错了吗？当我的问题是？ 有没有人有一个工作教程如何生成正确的Amazon S3的政策，有特色，从NodeJS v0.10.x，对于一个POST到S3 REST API？

推荐答案

好吧，我终于想通了。玩随机猜谜游戏了很长一段时间后，我心想

Ok, I finally figured it out. After playing the random guessing game for a VERY long time, I thought to myself

也许我需要签署的base64 EN codeD政策 - 我

"maybe i need to sign the base64 encoded policy" - me

和 BAM 仅此而已。

我也重新排序条件匹配形式如何被发布，虽然我不知道这有差别。

I also re-ordered the conditions to match how the form is posting, though I'm not sure this makes a difference.

var crypto = require("crypto");
var config = require("../../amazonConfig.json");

exports.createS3Policy = function(contentType, callback) {
  var date = new Date();

  var s3Policy = {
    "expiration": "2014-12-01T12:00:00.000Z", // hard coded for testing
    "conditions": [
      ["starts-with", "$key", "somefolder/"], 
      {"bucket": "my-bucket-name"}, 
      {"acl": "public-read"}, 
      ["starts-with", "$Content-Type", contentType],
      {"success_action_redirect": "http://example.com/uploadsuccess"},
    ]
  };

  // stringify and encode the policy
  var stringPolicy = JSON.stringify(s3Policy);
  var base64Policy = Buffer(stringPolicy, "utf-8").toString("base64");

  // sign the base64 encoded policy
  var signature = crypto.createHmac("sha1", config.secretKey)
    .update(new Buffer(base64Policy, "utf-8")).digest("base64");

  // build the results object
  var s3Credentials = {
    s3Policy: base64Policy,
    s3Signature: signature
  };

  // send it back
  callback(s3Credentials);
};

希望这会帮助别人运行到同样的问题。

Hopefully this will help others that run in to the same problem.

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