确定节点js中读取流的长度 [英] Determining the length of a read stream in node js

问题描述

我想知道是否有一种简单的方法来确定节点js中readStream的长度.我正在写一个工人将PDF上传到S3，但出现错误:无法确定[对象PDFDocument]的长度". pdf是可读的流(我可以将其通过管道传输到当前内存中的文件中，并查看生成的pdf).

I am wondering if there is an easy way to determine the length of a readStream in node js. I am writing a worker to upload PDFs to S3 and it is puking with the error: 'Cannot determine length of [object PDFDocument]'. The pdf is a readable stream (I can pipe it to a file in memory currently and view the generated pdf).

我正在考虑做的一些事情: 1.将整个pdf放入内存(例如缓冲区)，然后在该缓冲区上调用fstat以确定大小.

Some stuff I was thinking about doing: 1. Piping the entire pdf to memory (such as to a buffer) and then call fstat on that buffer to determine the size.

1. 创建一些在通过pdf将其通过管道动态找到尺寸时使用的方法.

还是有一种更简单的方法?开放所有建议，在此先感谢！

Or is there an easier way? Open to all suggestions, thanks in advance!

这是对S3的呼叫.可读的pdf流称为doc:

Here is the call to S3. The readable pdf stream is called doc:

return Q.ninvoke(s3, 'putObject', {Bucket: 'REDACTED', Key: obfuscatedFN, Body: doc, ContentType: 'application/pdf'})
     .then(function() {
           console.log("Successfully uploaded data to myBucket/myKey");
           return Q(true);
     })
     .fail(function(err) {
           console.log(err);
     })

推荐答案

S3还有另一种称为上载"的方法，您可以在不需要知道长度的地方使用它.

S3 has another method called 'upload' that you can use where you don't need to know the length.

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